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Thomson-Luque R, Stabler TC, Fürle K, Silva JC, Daubenberger C. Plasmodium falciparum merozoite surface protein 1 as asexual blood stage malaria vaccine candidate. Expert Rev Vaccines 2024; 23:160-173. [PMID: 38100310 DOI: 10.1080/14760584.2023.2295430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 12/12/2023] [Indexed: 12/17/2023]
Abstract
INTRODUCTION Malaria represents a public health challenge in tropical and subtropical regions, and currently deployed control strategies are likely insufficient to drive elimination of malaria. Development and improvement of malaria vaccines might be key to reduce disease burden. Vaccines targeting asexual blood stages of the parasite have shown limited efficacy when studied in human trials conducted over the past decades. AREAS COVERED Vaccine candidates based on the merozoite surface protein 1 (MSP1) were initially envisioned as one of the most promising approaches to provide immune protection against asexual blood-stage malaria. Successful immunization studies in monkey involved the use of the full-length MSP1 (MSP1FL) as vaccine construct. Vaccines using MSP1FL for immunization have the potential benefit of including numerous conserved B-cell and T-cell epitopes. This could result in improved parasite strain-transcending, protective immunity in the field. We review outcomes of clinical trials that utilized a variety of MSP1 constructs and formulations, including MSP1FL, either alone or in combination with other antigens, in both animal models and humans. EXPERT OPINION Novel approaches to analyze breadth and magnitude of effector functions of MSP1-targeting antibodies in volunteers undergoing experimental vaccination and controlled human malaria infection will help to define correlates of protective immunity.
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Affiliation(s)
- Richard Thomson-Luque
- Centre for Infectious Diseases-Parasitology, Heidelberg University Hospital, Heidelberg, Germany
- Sumaya-Biotech GmbH & Co. KG Heidelberg, Germany
| | - Thomas C Stabler
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
- University of Basel Basel, Switzerland
- Swiss Tropical and Public Health Institute Allschwil, Switzerland
| | - Kristin Fürle
- Centre for Infectious Diseases-Parasitology, Heidelberg University Hospital, Heidelberg, Germany
| | - Joana C Silva
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade NOVA de Lisboa (GHTM IHMT, UNL), Lisbon, Portugal
| | - Claudia Daubenberger
- University of Basel Basel, Switzerland
- Swiss Tropical and Public Health Institute Allschwil, Switzerland
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Production and Immunogenicity of a Tag-Free Recombinant Chimera Based on PfMSP-1 and PfMSP-3 Using Alhydrogel and Dipeptide-Based Hydrogels. Vaccines (Basel) 2021; 9:vaccines9070782. [PMID: 34358198 PMCID: PMC8310097 DOI: 10.3390/vaccines9070782] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 05/23/2021] [Accepted: 05/26/2021] [Indexed: 12/13/2022] Open
Abstract
A fusion chimeric vaccine comprising multiple protective domains of different blood-stage Plasmodium falciparum antigens is perhaps necessary for widening the protective immune responses and reducing the morbidity caused by the disease. Here we continue to build upon the prior work of developing a recombinant fusion chimera protein, His-tagged PfMSP-Fu24, by producing it as a tag-free recombinant protein. In this study, tag-free recombinant PfMSPFu24 (rFu24) was expressed in Escherichia coli, and the soluble protein was purified using a three-step purification involving ammonium sulphate precipitation followed by 2-step ion exchange chromatography procedures and shown that it was highly immunogenic with the human-compatible adjuvant Alhydrogel. We further investigated two dipeptides, phenylalanine-α, β-dehydrophenylalanine (FΔF) and Leucine-α, β-dehydrophenylalanine (LΔF) based hydrogels as effective delivery platforms for rFu24. These dipeptides self-assembled spontaneously to form a highly stable hydrogel under physiological conditions. rFu24 was efficiently entrapped in both the F∆F and L∆F hydrogels, and the three-dimensional (3D) mesh-like structures of the hydrogels remained intact after the entrapment of the antigen. The two hydrogels significantly stimulated rFu24-specific antibody titers, and the sera from the immunized mice showed an invasion inhibitory activity comparable to that of Alhydrogel. Easily synthesized dipeptide hydrogels can be used as an effective antigen delivery platform to induce immune responses.
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Goh XT, Lim YAL, Lee PC, Nissapatorn V, Chua KH. Diversity and natural selection of Merozoite surface Protein-1 in three species of human malaria parasites: Contribution from South-East Asian isolates. Mol Biochem Parasitol 2021; 244:111390. [PMID: 34087264 DOI: 10.1016/j.molbiopara.2021.111390] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 05/28/2021] [Accepted: 05/28/2021] [Indexed: 11/19/2022]
Abstract
The present study aimed to examine the genetic diversity of human malaria parasites (i.e., P. falciparum, P. vivax and P. knowlesi) in Malaysia and southern Thailand targeting the 19-kDa C-terminal region of Merozoite Surface Protein-1 (MSP-119). This region is essential for the recognition and invasion of erythrocytes and it is considered one of the leading candidates for asexual blood stage vaccines. However, the genetic data of MSP-119 among human malaria parasites in Malaysia is limited and there is also a need to update the current sequence diversity of this gene region among the Thailand isolates. In this study, genomic DNA was extracted from 384 microscopy-positive blood samples collected from patients who attended the hospitals or clinics in Malaysia and malaria clinics in Thailand from the year 2008 to 2016. The MSP-119 was amplified using PCR followed by bidirectional sequencing. DNA sequences identified in the present study were subjected to Median-joining network analysis with sequences of MSP-119 obtained from GenBank. DNA sequence analysis revealed that PfMSP-119 of Malaysian and Thailand isolates was not genetically conserved as high number of haplotypes were detected and positive selection was prevalent in PfMSP-119, hence questioning its suitability to be used as a vaccine candidate. A novel haplotype (Q/TNG/L) was also detected in Thailand P. falciparum isolate. In contrast, PvMSP-119 was highly conserved, however for the first time, a non-synonymous substitution (A1657S) was reported among Malaysian isolates. As for PkMSP-119, the presence of purifying selection and low nucleotide diversity indicated that it might be a potential vaccine target for P. knowlesi.
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Affiliation(s)
- Xiang Ting Goh
- Department of Biomedical Science, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Yvonne A L Lim
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
| | - Ping Chin Lee
- School of Science and Technology, University Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
| | - Veeranoot Nissapatorn
- Research Excellence Center for Innovation and Health Products (RECIHP) and School of Allied Health Sciences, Walailak University, Nakhon Si Thammarat, Thailand
| | - Kek Heng Chua
- Department of Biomedical Science, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
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A Chimeric Plasmodium vivax Merozoite Surface Protein Antibody Recognizes and Blocks Erythrocytic P. cynomolgi Berok Merozoites In Vitro. Infect Immun 2021; 89:IAI.00645-20. [PMID: 33199351 DOI: 10.1128/iai.00645-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 10/14/2020] [Indexed: 01/22/2023] Open
Abstract
Research on erythrocytic Plasmodium vivax merozoite antigens is critical for identifying potential vaccine candidates in reducing P. vivax disease. However, many P. vivax studies are constrained by its inability to undergo long-term culture in vitro Conserved across all Plasmodium spp., merozoite surface proteins are essential for invasion into erythrocytes and highly expressed on erythrocytic merozoites, thus making it an ideal vaccine candidate. In clinical trials, the P. vivax merozoite surface protein 1 (PvMSP1-19) vaccine candidate alone has shown to have limited immunogenicity in patients; hence, we incorporate the highly conserved and immunogenic C terminus of both P. vivax merozoite surface protein 8 (PvMSP8) and PvMSP1-19 to develop a multicomponent chimeric protein rPvMSP8+1 for immunization of mice. The resulted chimeric rPvMSP8+1 antibody was shown to recognize native protein MSP8 and MSP1-19 of mature P. vivax schizonts. In the immunized mice, an elevated antibody response was observed in the rPvMSP8+1-immunized group compared to that immunized with single-antigen components. In addition, we examined the growth inhibition of these antibodies against Plasmodium cynomolgi (Berok strain) parasites, which is phylogenetically close to P. vivax and sustains long-term culture in vitro Similarly, the chimeric anti-rPvMSP8+1 antibodies recognize P. cynomolgi MSP8 and MSP1-19 on mature schizonts and showed strong inhibition in vitro via growth inhibition assay. This study provides support for a new multiantigen-based paradigm rPvMSP8+1 to explore potential chimeric vaccine candidates against P. vivax malaria using sister species P. cynomolgi.
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Parzych EM, Miura K, Long CA, Burns JM. Maintaining immunogenicity of blood stage and sexual stage subunit malaria vaccines when formulated in combination. PLoS One 2020; 15:e0232355. [PMID: 32348377 PMCID: PMC7190115 DOI: 10.1371/journal.pone.0232355] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 04/13/2020] [Indexed: 11/18/2022] Open
Abstract
Background Eradication of Plasmodium falciparum malaria will likely require a multivalent vaccine, but the development of a highly efficacious subunit-based formulation has been challenging. We previously showed that production and immunogenicity of two leading vaccine targets, PfMSP119 (blood-stage) and Pfs25 (sexual stage), could be enhanced upon genetic fusion to merozoite surface protein 8 (PfMSP8). Here, we sought to optimize a Pfs25-based formulation for use in combination with rPfMSP1/8 with the goal of maintaining the immunogenicity of each subunit. Methods Comparative mouse studies were conducted to assess the effects of adjuvant selection (Alhydrogel vs. glucopyranosyl lipid adjuvant-stable emulsion (GLA-SE)) and antigen dose (2.5 vs. 0.5 μg) on the induction of anti-Pfs25 immune responses. The antibody response (magnitude, IgG subclass profile, and transmission-reducing activity (TRA)) and cellular responses (proliferation, cytokine production) generated in response to each formulation were assessed. Similarly, immunogenicity of a bivalent vaccine containing rPfMSP1/8 and rPfs25/8 was evaluated. Results Alum-based formulations elicited strong and comparable humoral and cellular responses regardless of antigen form (unfused rPfs25 or chimeric rPfs25/8) or dose. In contrast, GLA-SE based formulations elicited differential responses as a function of both parameters, with 2.5 μg of rPfs25/8 inducing the highest titers of functional anti-Pfs25 antibodies. Based on these data, chimeric rPfs25/8 was selected and tested in a bivalent formulation with rPfMSP1/8. Strong antibody titers against Pfs25 and PfMSP119 domains were induced with GLA-SE based formulations, with no indication of antigenic competition. Conclusions We were able to generate an immunogenic bivalent vaccine designed to target multiple parasite stages that could reduce both clinical disease and parasite transmission. The use of the same PfMSP8 carrier for two different vaccine components was effective in this bivalent formulation. As such, the incorporation of additional protective targets fused to the PfMSP8 carrier into the formulation should be feasible, further broadening the protective response.
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Affiliation(s)
- Elizabeth M. Parzych
- Department of Microbiology and Immunology, Center for Molecular Parasitology, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Kazutoyo Miura
- Malaria Immunology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Carole A. Long
- Department of Microbiology and Immunology, Center for Molecular Parasitology, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
- Malaria Immunology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - James M. Burns
- Department of Microbiology and Immunology, Center for Molecular Parasitology, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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Gupta R, Mishra A, Choudhary HH, Narwal SK, Nayak B, Srivastava PN, Mishra S. Secreted protein with altered thrombospondin repeat (SPATR) is essential for asexual blood stages but not required for hepatocyte invasion by the malaria parasite Plasmodium berghei. Mol Microbiol 2019; 113:478-491. [PMID: 31755154 DOI: 10.1111/mmi.14432] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 11/18/2019] [Accepted: 11/19/2019] [Indexed: 11/30/2022]
Abstract
Upon entering its mammalian host, the malaria parasite productively invades two distinct cell types, that is, hepatocytes and erythrocytes during which several adhesins/invasins are thought to be involved. Many surface-located proteins containing thrombospondin Type I repeat (TSR) which help establish host-parasite molecular crosstalk have been shown to be essential for mammalian infection. Previous reports indicated that antibodies produced against Plasmodium falciparum secreted protein with altered thrombospondin repeat (SPATR) block hepatocyte invasion by sporozoites but no genetic evidence of its contribution to invasion has been reported. After failing to generate Spatr knockout in Plasmodium berghei blood stages, a conditional mutagenesis system was employed. Here, we show that SPATR plays an essential role during parasite's blood stages. Mutant salivary gland sporozoites exhibit normal motility, hepatocyte invasion, liver stage development and rupture of the parasitophorous vacuole membrane resulting in merosome formation. But these mutant hepatic merozoites failed to establish a blood stage infection in vivo. We provide direct evidence that SPATR is not required for hepatocyte invasion but plays an essential role during the blood stages of P. berghei.
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Affiliation(s)
- Roshni Gupta
- Division of Molecular Parasitology and Immunology, CSIR-Central Drug Research Institute, Lucknow, India
| | - Akancha Mishra
- Division of Molecular Parasitology and Immunology, CSIR-Central Drug Research Institute, Lucknow, India.,Academy of Scientific and Innovative Research, Ghaziabad, India
| | - Hadi Hasan Choudhary
- Division of Molecular Parasitology and Immunology, CSIR-Central Drug Research Institute, Lucknow, India
| | - Sunil Kumar Narwal
- Division of Molecular Parasitology and Immunology, CSIR-Central Drug Research Institute, Lucknow, India
| | - Bandita Nayak
- Division of Molecular Parasitology and Immunology, CSIR-Central Drug Research Institute, Lucknow, India.,Academy of Scientific and Innovative Research, Ghaziabad, India
| | - Pratik Narain Srivastava
- Division of Molecular Parasitology and Immunology, CSIR-Central Drug Research Institute, Lucknow, India
| | - Satish Mishra
- Division of Molecular Parasitology and Immunology, CSIR-Central Drug Research Institute, Lucknow, India.,Academy of Scientific and Innovative Research, Ghaziabad, India
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Dewasurendra RL, Jeffreys A, Gunawardena SA, Chandrasekharan NV, Rockett K, Kwiatkowski D, Karunaweera ND. Host genetic polymorphisms and serological response against malaria in a selected population in Sri Lanka. Malar J 2018; 17:473. [PMID: 30558622 PMCID: PMC6296029 DOI: 10.1186/s12936-018-2622-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 12/11/2018] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Antibodies against the merozoite surface protein 1-19 (MSP1-19) and the apical membrane antigen 1 (AMA1) of the malaria parasite (Plasmodium vivax) are proven to be important in protection against clinical disease. Differences in the production/maintenance of antibodies may be due to many factors including host genetics. This paper discusses the association of 4 anti-malarial antibodies with selected host genetic markers. METHODS Blood was collected from individuals (n = 242) with a history of malaria within past 15 years for DNA and serum. ELISA was carried out for serum to determine the concentration of anti-malarial antibodies MSP1-19 and AMA1 for both vivax and falciparum malaria. 170 SNPs related to malaria were genotyped. Associations between seropositivity, antibody levels and genetic, non-genetic factors were determined. RESULTS Age ranged 13-74 years (mean age = 40.21 years). Majority were females. Over 90% individuals possessed either one or more type(s) of anti-malarial antibodies. Five SNPs were significantly associated with seropositivity. One SNP was associated with MSP1-19_Pv(rs739718); 4 SNPs with MSP1-19_Pf (rs6874639, rs2706379, rs2706381 and rs2075820) and1 with AMA1_Pv (rs2075820). Eleven and 7 genotypes (out of 15) were significantly associated with either presence or absence of antibodies. Three SNPs were found to be significantly associated with the antibody levels viz. rs17411697 with MSP1-19_Pv, rs2227491 with AMA1_Pv and rs229587 with AMA1_Pf. Linkage of the markers in the two groups was similar, but lower LOD scores were observed in seropositives compared to seronegatives. DISCUSSION AND CONCLUSIONS The study suggests that several SNPs in the human genome that exist in Sri Lankan populations are significantly associated with anti-malarial antibodies, either with generation and/or maintenance of antibodies for longer periods, which can be due to either individual polymorphisms or most probably a combined effect of the markers.
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Affiliation(s)
- Rajika L Dewasurendra
- Department of Parasitology, Faculty of Medicine, University of Colombo, Kynsey Road, Colombo 8, Sri Lanka
| | - Anna Jeffreys
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Sharmini A Gunawardena
- Department of Parasitology, Faculty of Medicine, University of Colombo, Kynsey Road, Colombo 8, Sri Lanka
| | | | - Kirk Rockett
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | | | - Nadira D Karunaweera
- Department of Parasitology, Faculty of Medicine, University of Colombo, Kynsey Road, Colombo 8, Sri Lanka.
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Parzych EM, Miura K, Ramanathan A, Long CA, Burns JM. Evaluation of a Plasmodium-Specific Carrier Protein To Enhance Production of Recombinant Pfs25, a Leading Transmission-Blocking Vaccine Candidate. Infect Immun 2018; 86:e00486-17. [PMID: 28993460 PMCID: PMC5736822 DOI: 10.1128/iai.00486-17] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 10/03/2017] [Indexed: 01/25/2023] Open
Abstract
Challenges with the production and suboptimal immunogenicity of malaria vaccine candidates have slowed the development of a Plasmodium falciparum multiantigen vaccine. Attempting to resolve these issues, we focused on the use of highly immunogenic merozoite surface protein 8 (MSP8) as a vaccine carrier protein. Previously, we showed that a genetic fusion of the C-terminal 19-kDa fragment of merozoite surface protein 1 (MSP119) to P. falciparum MSP8 (PfMSP8) facilitated antigen production and folding and the induction of neutralizing antibodies to conformational B cell epitopes of MSP119 Here, using the PfMSP1/8 construct, we further optimized the recombinant PfMSP8 (rPfMSP8) carrier by the introduction of two cysteine-to-serine substitutions (CΔS) to improve the yield of the monomeric product. We then sought to test the broad applicability of this approach using the transmission-blocking vaccine candidate Pfs25. The production of rPfs25-based vaccines has presented challenges. Antibodies directed against the four highly constrained epidermal growth factor (EGF)-like domains of Pfs25 block sexual-stage development in mosquitoes. The sequence encoding mature Pfs25 was codon harmonized for expression in Escherichia coli We produced a rPfs25-PfMSP8 fusion protein [rPfs25/8(CΔS)] as well as unfused, mature rPfs25. rPfs25 was purified with a modest yield but required the incorporation of refolding protocols to obtain a proper conformation. In comparison, chimeric rPfs25/8(CΔS) was expressed and easily purified, with the Pfs25 domain bearing the proper conformation without renaturation. Both antigens were immunogenic in rabbits, inducing IgG that bound native Pfs25 and exhibited potent transmission-reducing activity. These data further demonstrate the utility of PfMSP8 as a parasite-specific carrier protein to enhance the production of complex malaria vaccine targets.
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Affiliation(s)
- Elizabeth M Parzych
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Kazutoyo Miura
- Malaria Immunology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
| | - Aarti Ramanathan
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Carole A Long
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
- Malaria Immunology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
| | - James M Burns
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
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Plasmodium falciparum infection and age influence parasite growth inhibition mediated by IgG in Beninese infants. Acta Trop 2016; 159:111-9. [PMID: 27001144 DOI: 10.1016/j.actatropica.2016.03.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 02/10/2016] [Accepted: 03/17/2016] [Indexed: 11/22/2022]
Abstract
Antibodies that impede the invasion of Plasmodium falciparum (P. falciparum) merozoites into erythrocytes play a critical role in anti-malarial immunity. The Growth Inhibition Assay (GIA) is an in vitro measure of the functional capacity of such antibodies to limit erythrocyte invasion and/or parasite growth. Up to now, it is unclear whether growth-inhibitory activity correlates with protection from clinical disease and there are inconsistent results from studies performed with GIA. Studies that have focused on the relationship between IgGs and their in vitro parasite Growth Inhibition Activity (GIAc) in infants aged less than two years old are rare. Here, we used clinical and parasitological data to precisely define symptomatic or asymptomatic infection with P. falciparum in groups of infants followed-up actively for 18 months post-natally. We quantified the levels of IgG1 and IgG3 directed to a panel of candidate P. falciparum vaccine antigens (AMA-1, MSP1, 2, 3 and GLURP) using ELISA and the functional activity of IgG was quantified using GIA. Data were then correlated with individuals' infection status. At 18 months of age, infants harbouring infections at the time of blood sampling had an average 19% less GIAc than those not infected (p=0.004, multivariate linear regression). GIAc decreased from 12 to 18 months of age (p=0.003, Wilcoxon matched pairs test). Antibody levels quantified at 18 months in infants were strongly correlated with their exposure to malarial infection, however GIAc was not correlated with malaria infectious status (asymptomatic and symptomatic groups). In conclusion, both infection status at blood draw and age influence parasite growth inhibition mediated by IgG in the GIA. Both factors must be taken into account when correlations between GIAc and anti-malarial protection or vaccine efficacy have to be made.
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Rouhani M, Zakeri S, Mehrizi AA, Djadid ND. Comparative analysis of the profiles of IgG subclass-specific responses to Plasmodium falciparum apical membrane antigen-1 and merozoite surface protein-1 in naturally exposed individuals living in malaria hypoendemic settings, Iran. Malar J 2015; 14:58. [PMID: 25652589 PMCID: PMC4365771 DOI: 10.1186/s12936-015-0547-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 01/06/2015] [Indexed: 01/27/2023] Open
Abstract
Background Plasmodium falciparum apical membrane antigen-1 (PfAMA-1) and the 19-kDa C-terminal region of merozoite surface protein-1 (PfMSP-119) are candidate malaria vaccine antigens expressed on merozoites and sporozoites. This investigation was performed to evaluate simultaneously the naturally-acquired antibodies to PfAMA-1 and PfMSP-119 and to compare IgG subclass profiles to both antigens in naturally exposed individuals living in malaria hypoendemic areas in Iran to determine which antigen has better ability to detect sero-positive individuals infected with P. falciparum. Methods In this investigation, 101 individuals from the malaria-endemic areas in Iran were examined. PfAMA-1 and PfMSP-119 were expressed in Escherichia coli, and IgG isotype composition of naturally acquired antibodies to the antigens (as single or in combination) was measured by ELISA assay. Results The result showed that 87.1% and 84.2% of the studied individuals had positive anti-PfAMA-1 and -PfMSP-119 IgG antibody responses, respectively, and the prevalence of responders did not differ significantly (P > 0.05). Moreover, IgG1 and IgG3 were predominant over IgG2 and IgG4 antibodies and the prevalence of IgG and its subclasses to two tested antigens had no significant correlation with age and exposure (P > 0.05). The present data confirmed that when recombinant PfAMA-1 and recombinant PfMSP-119 antigens were combined in ELISA at equal ratios of 200 ng (100 ng each antigen/well) and 400 ng (200 ng each antigen/well), 86.1% and 87.1% of positives sera were detected among the examined samples, respectively. Conclusions The two tested recombinant antigens are immunogenic molecules, and individuals in low transmission areas in Iran could develop and maintain equal immune responses to PfAMA-1 and PfMSP-119. Therefore, these results could support the design of a universal PfAMA-1- and PfMSP-119-based vaccine. Also, both recombinant antigens could be used in combination as reliable serology markers to perform immuno-epidemiological studies in malaria-endemic areas of Iran during elimination strategy. The present information could be of use in control and elimination programmes in Iran and other similar malaria settings.
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Affiliation(s)
- Maryam Rouhani
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Pasteur Avenue, P.O. BOX 1316943551, Tehran, Iran.
| | - Sedigheh Zakeri
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Pasteur Avenue, P.O. BOX 1316943551, Tehran, Iran.
| | - Akram A Mehrizi
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Pasteur Avenue, P.O. BOX 1316943551, Tehran, Iran.
| | - Navid D Djadid
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Pasteur Avenue, P.O. BOX 1316943551, Tehran, Iran.
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Spiegel H, Boes A, Voepel N, Beiss V, Edgue G, Rademacher T, Sack M, Schillberg S, Reimann A, Fischer R. Application of a Scalable Plant Transient Gene Expression Platform for Malaria Vaccine Development. FRONTIERS IN PLANT SCIENCE 2015; 6:1169. [PMID: 26779197 PMCID: PMC4688378 DOI: 10.3389/fpls.2015.01169] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 12/07/2015] [Indexed: 05/23/2023]
Abstract
Despite decades of intensive research efforts there is currently no vaccine that provides sustained sterile immunity against malaria. In this context, a large number of targets from the different stages of the Plasmodium falciparum life cycle have been evaluated as vaccine candidates. None of these candidates has fulfilled expectations, and as long as we lack a single target that induces strain-transcending protective immune responses, combining key antigens from different life cycle stages seems to be the most promising route toward the development of efficacious malaria vaccines. After the identification of potential targets using approaches such as omics-based technology and reverse immunology, the rapid expression, purification, and characterization of these proteins, as well as the generation and analysis of fusion constructs combining different promising antigens or antigen domains before committing to expensive and time consuming clinical development, represents one of the bottlenecks in the vaccine development pipeline. The production of recombinant proteins by transient gene expression in plants is a robust and versatile alternative to cell-based microbial and eukaryotic production platforms. The transfection of plant tissues and/or whole plants using Agrobacterium tumefaciens offers a low technical entry barrier, low costs, and a high degree of flexibility embedded within a rapid and scalable workflow. Recombinant proteins can easily be targeted to different subcellular compartments according to their physicochemical requirements, including post-translational modifications, to ensure optimal yields of high quality product, and to support simple and economical downstream processing. Here, we demonstrate the use of a plant transient expression platform based on transfection with A. tumefaciens as essential component of a malaria vaccine development workflow involving screens for expression, solubility, and stability using fluorescent fusion proteins. Our results have been implemented for the evidence-based iterative design and expression of vaccine candidates combining suitable P. falciparum antigen domains. The antigens were also produced, purified, and characterized in further studies by taking advantage of the scalability of this platform.
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Affiliation(s)
- Holger Spiegel
- Fraunhofer Institute for Molecular Biology and Applied Ecology IMEAachen, Germany
| | - Alexander Boes
- Fraunhofer Institute for Molecular Biology and Applied Ecology IMEAachen, Germany
- *Correspondence: Alexander Boes
| | - Nadja Voepel
- Fraunhofer Institute for Molecular Biology and Applied Ecology IMEAachen, Germany
| | - Veronique Beiss
- Fraunhofer Institute for Molecular Biology and Applied Ecology IMEAachen, Germany
| | - Gueven Edgue
- Fraunhofer Institute for Molecular Biology and Applied Ecology IMEAachen, Germany
| | - Thomas Rademacher
- Fraunhofer Institute for Molecular Biology and Applied Ecology IMEAachen, Germany
| | - Markus Sack
- Institute for Molecular Biotechnology, RWTH Aachen UniversityAachen, Germany
| | - Stefan Schillberg
- Fraunhofer Institute for Molecular Biology and Applied Ecology IMEAachen, Germany
| | - Andreas Reimann
- Fraunhofer Institute for Molecular Biology and Applied Ecology IMEAachen, Germany
| | - Rainer Fischer
- Fraunhofer Institute for Molecular Biology and Applied Ecology IMEAachen, Germany
- Institute for Molecular Biotechnology, RWTH Aachen UniversityAachen, Germany
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A conserved apicomplexan microneme protein contributes to Toxoplasma gondii invasion and virulence. Infect Immun 2014; 82:4358-68. [PMID: 25092910 DOI: 10.1128/iai.01877-14] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The obligate intracellular parasite Toxoplasma gondii critically relies on host cell invasion during infection. Proteins secreted from the apical micronemes are central components for host cell recognition, invasion, egress, and virulence. Although previous work established that the sporozoite protein with an altered thrombospondin repeat (SPATR) is a micronemal protein conserved in other apicomplexan parasites, including Plasmodium, Neospora, and Eimeria, no genetic evidence of its contribution to invasion has been reported. SPATR contains a predicted epidermal growth factor domain and two thrombospondin type 1 repeats, implying a role in host cell recognition. In this study, we assess the contribution of T. gondii SPATR (TgSPATR) to T. gondii invasion by genetically ablating it and restoring its expression by genetic complementation. Δspatr parasites were ~50% reduced in invasion compared to parental strains, a defect that was reversed in the complemented strain. In mouse virulence assays, Δspatr parasites were significantly attenuated, with ~20% of mice surviving infection. Given the conservation of this protein among the Apicomplexa, we assessed whether the Plasmodium falciparum SPATR ortholog (PfSPATR) could complement the absence of the TgSPATR. Although PfSPATR showed correct micronemal localization, it did not reverse the invasion deficiency of Δspatr parasites, because of an apparent failure in secretion. Overall, the results suggest that TgSPATR contributes to invasion and virulence, findings that have implications for the many genera and life stages of apicomplexans that express SPATR.
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Chandramohanadas R, Basappa, Russell B, Liew K, Yau YH, Chong A, Liu M, Gunalan K, Raman R, Renia L, Nosten F, Shochat SG, Dao M, Sasisekharan R, Suresh S, Preiser P. Small molecule targeting malaria merozoite surface protein-1 (MSP-1) prevents host invasion of divergent plasmodial species. J Infect Dis 2014; 210:1616-26. [PMID: 24864124 DOI: 10.1093/infdis/jiu296] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Malaria causes nearly 1 million deaths annually. Recent emergence of multidrug resistance highlights the need to develop novel therapeutic interventions against human malaria. Given the involvement of sugar binding plasmodial proteins in host invasion, we set out to identify such proteins as targets of small glycans. Combining multidisciplinary approaches, we report the discovery of a small molecule inhibitor, NIC, capable of inhibiting host invasion through interacting with a major invasion-related protein, merozoite surface protein-1 (MSP-1). This interaction was validated through computational, biochemical, and biophysical tools. Importantly, treatment with NIC prevented host invasion by Plasmodium falciparum and Plasmodium vivax--major causative organisms of human malaria. MSP-1, an indispensable antigen critical for invasion and suitably localized in abundance on the merozoite surface represents an ideal target for antimalarial development. The ability to target merozoite invasion proteins with specific small inhibitors opens up a new avenue to target this important pathogen.
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Affiliation(s)
- Rajesh Chandramohanadas
- Interdisciplinary Research Group of Infectious Diseases, Singapore MIT Alliance for Research and Technology Centre (SMART) Singapore University of Technology and Design, 20 Dover Drive
| | - Basappa
- Interdisciplinary Research Group of Infectious Diseases, Singapore MIT Alliance for Research and Technology Centre (SMART)
| | - Bruce Russell
- Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore and
| | - Kingsley Liew
- Interdisciplinary Research Group of Infectious Diseases, Singapore MIT Alliance for Research and Technology Centre (SMART)
| | - Yin Hoe Yau
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Alvin Chong
- Interdisciplinary Research Group of Infectious Diseases, Singapore MIT Alliance for Research and Technology Centre (SMART)
| | - Min Liu
- Interdisciplinary Research Group of Infectious Diseases, Singapore MIT Alliance for Research and Technology Centre (SMART)
| | | | - Rahul Raman
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Laurent Renia
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR)
| | - Francois Nosten
- Shoklo Malaria Research Unit, Mae Sot, Thailand Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford University, United Kingdom
| | | | - Ming Dao
- Interdisciplinary Research Group of Infectious Diseases, Singapore MIT Alliance for Research and Technology Centre (SMART) Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge
| | - Ram Sasisekharan
- Interdisciplinary Research Group of Infectious Diseases, Singapore MIT Alliance for Research and Technology Centre (SMART) Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Subra Suresh
- Department of Biomedical Engineering and Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh
| | - Peter Preiser
- Interdisciplinary Research Group of Infectious Diseases, Singapore MIT Alliance for Research and Technology Centre (SMART) School of Biological Sciences, Nanyang Technological University, Singapore
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Alaro JR, Partridge A, Miura K, Diouf A, Lopez AM, Angov E, Long CA, Burns JM. A chimeric Plasmodium falciparum merozoite surface protein vaccine induces high titers of parasite growth inhibitory antibodies. Infect Immun 2013; 81:3843-54. [PMID: 23897613 PMCID: PMC3811772 DOI: 10.1128/iai.00522-13] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Accepted: 07/23/2013] [Indexed: 01/20/2023] Open
Abstract
The C-terminal 19-kDa domain of Plasmodium falciparum merozoite surface protein 1 (PfMSP119) is an established target of protective antibodies. However, clinical trials of PfMSP142, a leading blood-stage vaccine candidate which contains the protective epitopes of PfMSP119, revealed suboptimal immunogenicity and efficacy. Based on proof-of-concept studies in the Plasmodium yoelii murine model, we produced a chimeric vaccine antigen containing recombinant PfMSP119 (rPfMSP119) fused to the N terminus of P. falciparum merozoite surface protein 8 that lacked its low-complexity Asn/Asp-rich domain, rPfMSP8 (ΔAsn/Asp). Immunization of mice with the chimeric rPfMSP1/8 vaccine elicited strong T cell responses to conserved epitopes associated with the rPfMSP8 (ΔAsn/Asp) fusion partner. While specific for PfMSP8, this T cell response was adequate to provide help for the production of high titers of antibodies to both PfMSP119 and rPfMSP8 (ΔAsn/Asp) components. This occurred with formulations adjuvanted with either Quil A or with Montanide ISA 720 plus CpG oligodeoxynucleotide (ODN) and was observed in both inbred and outbred strains of mice. PfMSP1/8-induced antibodies were highly reactive with two major alleles of PfMSP119 (FVO and 3D7). Of particular interest, immunization with PfMSP1/8 elicited higher titers of PfMSP119-specific antibodies than a combined formulation of rPfMSP142 and rPfMSP8 (ΔAsn/Asp). As a measure of functionality, PfMSP1/8-specific rabbit IgG was shown to potently inhibit the in vitro growth of blood-stage parasites of the FVO and 3D7 strains of P. falciparum. These data support the further testing and evaluation of this chimeric PfMSP1/8 antigen as a component of a multivalent vaccine for P. falciparum malaria.
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Affiliation(s)
- James R. Alaro
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
- Malaria Immunology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
| | - Andrea Partridge
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Kazutoyo Miura
- Malaria Immunology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
| | - Ababacar Diouf
- Malaria Immunology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
| | - Ana M. Lopez
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Evelina Angov
- U.S. Military Malaria Research Program, Malaria Vaccine Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
| | - Carole A. Long
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
- Malaria Immunology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
| | - James M. Burns
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
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Nasr A, Hamid O, Al-Ghamdi A, Allam G. Anti-malarial IgG subclasses pattern and FcγRIIa (CD32) polymorphism among pregnancy-associated malaria in semi-immune Saudi women. Malar J 2013; 12:110. [PMID: 23517907 PMCID: PMC3608938 DOI: 10.1186/1475-2875-12-110] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Accepted: 03/16/2013] [Indexed: 01/06/2023] Open
Abstract
Background Pregnant women remain are at an increased risk of malaria with primigravidae being at the highest risk. Genetic polymorphism of the Fc receptor IIa for immunologlobulin (Ig) G (FcγRIIa) determines IgG subclass binding. Protection against pregnancy-associated malaria (PAM) is associated with the production of IgG specific for apical membrane antigen-1 (AMA-1). The present study was undertaken to examine the relationship between specific IgG/IgG subclasses and malaria infection. The second aim of the study is to examine the association between FcγRIIa R/H131 polymorphism in correlation with specific anti-malarial IgG antibodies of AMA-1 distribution and asymptomatic malaria infection among Saudi women living in the southern part of Saudi Arabia. Methods One hundred and twenty pregnant women living in an area of meso-endemic Plasmodium falciparum malaria infection were consecutively enrolled onto the study. These pregnant women were asymptomatic and attending routine antenatal clinics. The levels of plasma antibodies (IgG and subclasses AMA-1) were measured using indirect enzyme-linked immunosorbent assays (ELISA). Genotyping of FcγRIIa-R/H131 dimorphism was performed using gene-specific polymerase chain reaction (PCR) amplification with allele-specific restriction enzyme digestion (BstU1) of the PCR product. Results A total of sixty-two (52%) pregnant women was diagnosed with asymptomatic malarial infection (ASM) compared with 58 (48%) malaria free controls (MFC). In the ASM group, there were high levels of anti-malarial IgG1 and IgG3, when compared to MFC (P value <0.001, respectively). The FcγRIIa-R/R131 genotype and R131 were found to be statistically significantly more prevalent in the ASM group when compared to the MFC group [55% for ASM versus 12% for MFC, odds ratio (OR) 5.62, 95% confidence interval (CI)= (2.03- 15.58), P value= 0.001]. However, the H/H131 genotype showed statistically significant association with MFC [14% for ASM versus 50% for MFC, OR(0.36), 95% CI= (0.14- 0.95), P value= 0.03]. Conclusions The study revealed that the ASM patients had higher anti-malarial IgG and IgG subclasses antibody levels when compared to the MFC. The FcγRIIa-R/R131 genotype and R131 allele were found to be statistically prevalent in the ASM when compared to the MFC group. The individuals carrying H/H131 were consistently associated with higher levels of anti-malarial IgG subclasses.
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Affiliation(s)
- Amre Nasr
- Department of Microbiology, College of Medicine, Taif University, PO Box 888, Taif, Saudi Arabia.
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16
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Kang JM, Ju HL, Kang YM, Lee DH, Moon SU, Sohn WM, Park JW, Kim TS, Na BK. Genetic polymorphism and natural selection in the C-terminal 42 kDa region of merozoite surface protein-1 among Plasmodium vivax Korean isolates. Malar J 2012; 11:206. [PMID: 22709605 PMCID: PMC3487983 DOI: 10.1186/1475-2875-11-206] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 06/05/2012] [Indexed: 11/30/2022] Open
Abstract
Background The carboxy-terminal 42 kDa region of Plasmodium vivax merozoite surface protein-1 (PvMSP-142) is a leading candidate antigen for blood stage vaccine development. However, this region has been observed to be highly polymorphic among filed isolates of P. vivax. Therefore it is important to analyse the existing diversity of this antigen in the field isolates of P. vivax. In this study, the genetic diversity and natural selection in PvMSP-142 among P. vivax Korean isolates were analysed. Methods A total of 149 P. vivax-infected blood samples collected from patients in Korea were used. The region flanking PvMSP-142 was amplified by PCR, cloned into Escherichia coli, and then sequenced. The polymorphic characteristic and natural selection of PvMSP-142 were analysed using the DNASTAR, MEGA4 and DnaSP programs. Results A total of 11 distinct haplotypes of PvMSP-142 with 40 amino acid changes, as compared to the reference Sal I sequence, were identified in the Korean P. vivax isolates. Most of the mutations were concentrated in the 33 kDa fragment (PvMSP-133), but a novel mutation was found in the 19 kDa fragment (PvMSP-119). PvMSP-142 of Korean isolates appeared to be under balancing selection. Recombination may also play a role in the resulting genetic diversity of PvMSP-142. Conclusions PvMSP-142 of Korean P. vivax isolates displayed allelic polymorphisms caused by mutation, recombination and balancing selection. These results will be useful for understanding the nature of the P. vivax population in Korea and for development of a PvMSP-142 based vaccine against P. vivax.
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17
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Evaluation of the immunogenicity and vaccine potential of recombinant Plasmodium falciparum merozoite surface protein 8. Infect Immun 2012; 80:2473-84. [PMID: 22585960 DOI: 10.1128/iai.00211-12] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The C-terminal 19-kDa domain of merozoite surface protein 1 (MSP1₁₉) is the target of protective antibodies but alone is poorly immunogenic. Previously, using the Plasmodium yoelii murine model, we fused P. yoelii MSP1₁₉ (PyMSP1₁₉) with full-length P. yoelii merozoite surface protein 8 (MSP8). Upon immunization, the MSP8-restricted T cell response provided help for the production of high and sustained levels of protective PyMSP1₁₉- and PyMSP8-specific antibodies. Here, we assessed the vaccine potential of MSP8 of the human malaria parasite, Plasmodium falciparum. Distinct from PyMSP8, P. falciparum MSP8 (PfMSP8) contains an N-terminal asparagine and aspartic acid (Asn/Asp)-rich domain whose function is unknown. Comparative analysis of recombinant full-length PfMSP8 and a truncated version devoid of the Asn/Asp-rich domain, PfMSP8(ΔAsn/Asp), showed that both proteins were immunogenic for T cells and B cells. All T cell epitopes utilized mapped within rPfMSP8(ΔAsn/Asp). The dominant B cell epitopes were conformational and common to both rPfMSP8 and rPfMSP8(ΔAsn/Asp). Analysis of native PfMSP8 expression revealed that PfMSP8 is present intracellularly in late schizonts and merozoites. Following invasion, PfMSP8 is found distributed on the surface of ring- and trophozoite-stage parasites. Consistent with a low and/or transient expression of PfMSP8 on the surface of merozoites, PfMSP8-specific rabbit IgG did not inhibit the in vitro growth of P. falciparum blood-stage parasites. These studies suggest that the further development of PfMSP8 as a malaria vaccine component should focus on the use of PfMSP8(ΔAsn/Asp) and its conserved, immunogenic T cell epitopes as a fusion partner for protective domains of poor immunogens, including PfMSP1₁₉.
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18
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Plasmodium falciparum line-dependent association of in vitro growth-inhibitory activity and risk of malaria. Infect Immun 2012; 80:1900-8. [PMID: 22392930 DOI: 10.1128/iai.06190-11] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Plasmodium falciparum's ability to invade erythrocytes is essential for its survival within the human host. Immune mechanisms that impair this ability are therefore expected to contribute to immunity against the parasite. Plasma of humans who are naturally exposed to malaria has been shown to have growth-inhibitory activity (GIA) in vitro. However, the importance of GIA in relation to protection from malaria has been unclear. In a case-control study nested within a longitudinally followed population in Tanzania, plasma samples collected at baseline from 171 individuals (55 cases and 116 age-matched controls) were assayed for GIA using three P. falciparum lines (3D7, K1, and W2mef) chosen based on their erythrocyte invasion phenotypes. Distribution of GIA differed between the lines, with most samples inhibiting the growth of 3D7 and K1 and enhancing the growth of W2mef. GIA to 3D7 was associated with a reduced risk of malaria within 40 weeks of follow-up (odds ratio, 0.45; 95% confidence interval [CI], 0.21 to 0.96; P = 0.04), whereas GIA to K1 and W2mef was not. These results show that GIA, as well as its association with protection from malaria, is dependent on the P. falciparum line and can be explained by differences in erythrocyte invasion phenotypes between parasite lines. Our study contributes knowledge on the biological importance of growth inhibition and the potential influence of P. falciparum erythrocyte invasion phenotypic differences on its relationship to protective immunity against malaria.
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Mehrizi AA, Zakeri S, Rafati S, Salmanian AH, Djadid ND. Immune responses elicited by co-immunization of Plasmodium vivax and P. falciparum MSP-1 using prime-boost immunization strategies. Parasite Immunol 2012; 33:594-608. [PMID: 21883290 DOI: 10.1111/j.1365-3024.2011.01331.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Carboxy-terminus of merozoite surface protein-1 (MSP-1(19) ) is the major protein on the surface of the plasmodial merozoite that acts as one of the most important blood-stage vaccine candidates. The present investigation was designed to evaluate the immune responses when either two recombinant antigens (rPvMSP-1(19) + rPfMSP-1(19)) or two plasmid constructs (pcDNA3.1 hygro-PvMSP-1(19) + pcDNA3.1 hygro-PfMSP-1(19)) were administered in combination at a single site in mice by using different immunization strategies (protein/protein, DNA/DNA and DNA/protein) at weeks 0, 5 and 8. All mice were monitored for the level of MSP-1(19) -specific antibody for up to 40 weeks. The inclusion of both recombinant antigens in a vaccine mixture could not inhibit induction of antibodies to the other antigen when the two recombinant antigens were combined in immunization formulation. Interestingly, antisera from immunized mice with either recombinant antigen failed to cross-react with heterologous antigen. Moreover, the results of this study showed that co-immunization with both antigens at a single site generated a substantial PvMSP-1(19) - and PfMSP-1(19) -specific antibody responses and also IFN-γ cytokine production (Th1 response) in DNA/protein prime-boost immunization strategies. The increased humoral response to PvMSP-1(19) and PfMSP-1(19) lasted nearly a year after immunization. Therefore, the results of this study are encouraging for the development of multi-species malaria vaccine based on MSP-1(19) antigen.
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Affiliation(s)
- A A Mehrizi
- Malaria and Vector Research Group, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
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Mehrizi AA, Asgharpour S, Salmanian AH, Djadid ND, Zakeri S. IgG subclass antibodies to three variants of Plasmodium falciparum merozoite surface protein-1 (PfMSP-1(19)) in an area with unstable malaria transmission in Iran. Acta Trop 2011; 119:84-90. [PMID: 21609709 DOI: 10.1016/j.actatropica.2011.04.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Revised: 04/20/2011] [Accepted: 04/26/2011] [Indexed: 11/28/2022]
Abstract
Plasmodium falciparum remains globally an important cause of mortality and morbidity and despite decades of research, no effective vaccine is available against this deadly parasite. The 19-kDa C-terminal fragment of P. falciparum merozoite surface protein 1 (PfMSP-1(19)) is a target for protective immunity against malaria and the major concern in development of vaccine based on this antigen is the presence of polymorphisms. This investigation was designed to evaluate naturally acquired antibodies and antigen-binding avidity of IgG antibodies to three variant forms of PfMSP-1(19) antigen (E/TSG/L, E/KNG/F and Q/KNG/L) in malaria individuals who are living in hypoendemic areas in Iran (n=92, 4-75 years old). The three variant forms of PfMSP-1(19) were expressed in Escherichia coli and IgG isotype composition and avidity of naturally acquired antibodies to the 19-kDa antigen were measured by ELISA assay. Results showed that almost 72% of the studied individuals had positive antibody responses to three PfMSP-1(19) variants and the prevalence of responders did not differ significantly (P>0.05). High-avidity IgG (62.7%, 65.7% and 47.76%) and IgG1 (64.2%, 50.75%, and 50.75%) were found in positive sera for E/TSG/L, E/KNG/F and Q/KNG/L variants, respectively. Moreover, the prevalence and titers of IgG1 antibody responses to the three variants increased with age (P<0.05). In summary, individuals in low transmission areas in Iran can develop and maintain equal immune responses with high avidity to the PfMSP-1(19) variants (E/TSG/L, E/KNG/F and Q/KNG/L); however, the precise role of the total IgG and its isotypes in protection requires further investigation. These results could support the design of a universal PfMSP-1(19)-based vaccine.
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Affiliation(s)
- Akram Abouie Mehrizi
- Malaria and Vector Research Group, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
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Abstract
The development of an effective malaria vaccine represents one of the most important approaches that would provide a cost-effective intervention for addition to currently available malaria control strategies. Here, Howard Engers and Tore Godal review recent advances. Over the past decade there has been considerable progress in the understanding of immune mechanisms involved in conferring protection to malaria and in the identification of vaccine candidate antigens and their genes. Several new vaccines have entered Phase I/II trials recently, new adjuvants have been developed for human use and new approaches, such as DNA vaccines and structural modification of antigens to circumvent some of the strategies the parasite uses to avoid the immune response, are being applied. Thus, from the TDR perspective, global malaria vaccine development is entering a crucial period with unprecedented opportunities.
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Storti-Melo LM, Souza-Neiras WC, Cassiano GC, Taveira LC, Cordeiro AJ, Couto VSCA, Póvoa MM, Cunha MG, Echeverry DM, Rossit ARB, Arévalo-Herrera M, Herrera S, Machado RLD. Evaluation of the naturally acquired antibody immune response to the Pv200L N-terminal fragment of Plasmodium vivax merozoite surface protein-1 in four areas of the Amazon Region of Brazil. Am J Trop Med Hyg 2011; 84:58-63. [PMID: 21292879 DOI: 10.4269/ajtmh.2011.10-0044] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Frequency and levels of IgG antibodies to an N-terminal fragment of the Plasmodium vivax MSP-1 (Pv200L) protein, in individuals naturally exposed to malaria in four endemic areas of Brazil, were evaluated by enzyme-linked immunosorbent assay. Plasma samples of 261 P. vivax-infected individuals from communities of Macapá, Novo Repartimento, Porto Velho, and Plácido de Castro in the Amazonian region with different malaria transmission intensities. A high mean number of studied individuals (89.3%) presented with antibodies to the Pv200L that correlated with the number of previous malaria infections; there were significant differences in the frequency of the responders (71.9-98.7) and in the antibody levels (1:200-1:51,200) among the four study areas. Results of this study provide evidence that Pv200L is a naturally immunogenic fragment of the PvMSP-1 and is associated with the degree of exposure to parasites. The fine specificity of antibodies to Pv200L is currently being assessed.
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Affiliation(s)
- Luciane M Storti-Melo
- University of São Paulo State Júlio Mesquita Filho, São José do Rio Preto, São Paulo State, Brazil.
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New candidate vaccines against blood-stage Plasmodium falciparum malaria: prime-boost immunization regimens incorporating human and simian adenoviral vectors and poxviral vectors expressing an optimized antigen based on merozoite surface protein 1. Infect Immun 2010; 78:4601-12. [PMID: 20713623 DOI: 10.1128/iai.00315-10] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Although merozoite surface protein 1 (MSP-1) is a leading candidate vaccine antigen for blood-stage malaria, its efficacy in clinical trials has been limited in part by antigenic polymorphism and potentially by the inability of protein-in-adjuvant vaccines to induce strong cellular immunity. Here we report the design of novel vectored Plasmodium falciparum vaccines capable of overcoming such limitations. We optimized an antigenic insert comprising the four conserved blocks of MSP-1 fused to tandemly arranged sequences that represent both allelic forms of the dimorphic 42-kDa C-terminal region. Inserts were expressed by adenoviral and poxviral vectors and employed in heterologous prime-boost regimens. Simian adenoviral vectors were used in an effort to circumvent preexisting immunity to human adenoviruses. In preclinical studies these vaccines induced potent cellular immune responses and high-titer antibodies directed against MSP-1. The antibodies induced were found to have growth-inhibitory activity against dimorphic allelic families of P. falciparum. These vectored vaccines should allow assessment in humans of the safety and efficacy of inducing strong cellular as well as cross-strain humoral immunity to P. falciparum MSP-1.
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Protective immune responses elicited by immunization with a chimeric blood-stage malaria vaccine persist but are not boosted by Plasmodium yoelii challenge infection. Vaccine 2010; 28:6876-84. [PMID: 20709001 DOI: 10.1016/j.vaccine.2010.08.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Revised: 07/17/2010] [Accepted: 08/02/2010] [Indexed: 11/20/2022]
Abstract
An efficacious malaria vaccine remains elusive despite concerted efforts. Using the Plasmodium yoelii murine model, we previously reported that immunization with the C-terminal 19 kDa domain of merozoite surface protein 1 (MSP1(19)) fused to full-length MSP8 protected against lethal P. yoelii 17XL, well beyond that achieved by single or combined immunizations with the component antigens. Here, we continue the evaluation of the chimeric PyMSP1/8 vaccine. We show that immunization with rPyMSP1/8 vaccine elicited an MSP8-restricted T cell response that was sufficient to provide help for both PyMSP1(19) and PyMSP8-specific B cells to produce high and sustained levels of protective antibodies. The enhanced efficacy of immunization with rPyMSP1/8, in comparison to a combined formulation of rPyMSP1(42) and rPyMSP8, was not due to improved conformation of protective B cell epitopes in the chimeric molecule. Unexpectedly, rPyMSP1/8 vaccine-induced antibody responses were not boosted by exposure to P. yoelii 17XL infected RBCs. However, rPyMSP1/8 immunized and infected mice mounted robust responses to a diverse set of blood-stage antigens. The data support the further development of an MSP1/8 chimeric vaccine but also suggest that vaccines that prime for responses to a diverse set of parasite proteins will be required to maximize vaccine efficacy.
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Peng H, Hu Y, Zhou A, Jin C, Pan W. Solution structure of a Plasmodium falciparum AMA-1/MSP 1 chimeric protein vaccine candidate (PfCP-2.9) for malaria. Malar J 2010; 9:76. [PMID: 20236549 PMCID: PMC2850360 DOI: 10.1186/1475-2875-9-76] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Accepted: 03/18/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The Plasmodium falciparum chimeric protein PfCP-2.9 is a promising asexual-stage malaria vaccine evaluated in clinical trials. This chimeric protein consists of two cysteine-rich domains: domain III of the apical membrane antigen 1 (AMA-1 [III]) and the C-terminal region of the merozoite surface protein 1 (MSP1-19). It has been reported that the fusion of these two antigens enhanced their immunogenicity and antibody-mediated inhibition of parasite growth in vitro. METHODS The 15N-labeled and 13C/15N-labeled PfCP-2.9 was produced in Pichia pastoris for nuclear magnetic resonance (NMR) structure analysis. The chemical shift assignments of PfCP-2.9 were compared with those previously reported for the individual domains (i.e., PfAMA-1(III) or PfMSP 1-19). The two-dimensional spectra and transverse relaxation rates (R2) of the PfMSP1-19 alone were compared with that of the PfCP-2.9. RESULTS Confident backbone assignments were obtained for 122 out of 241 residues of PfCP-2.9. The assigned residues in PfCP-2.9 were very similar to those previously reported for the individual domains. The conformation of the PfMSP1-19 in different constructs is essentially the same. Comparison of transverse relaxation rates (R2) strongly suggests no weak interaction between the domains. CONCLUSIONS These data indicate that the fusion of AMA-1(III) and MSP1-19 as chimeric protein did not change their structures, supporting the use of the chimeric protein as a potential malaria vaccine.
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Affiliation(s)
- Heng Peng
- Department of Pathogenic Biology, State Key Laboratory of Medical Immunology, Second Military Medical University, Shanghai 200433, China
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Child MA, Epp C, Bujard H, Blackman MJ. Regulated maturation of malaria merozoite surface protein-1 is essential for parasite growth. Mol Microbiol 2010; 78:187-202. [PMID: 20735778 PMCID: PMC2995310 DOI: 10.1111/j.1365-2958.2010.07324.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The malaria parasite Plasmodium falciparum invades erythrocytes where it replicates to produce invasive merozoites, which eventually egress to repeat the cycle. Merozoite surface protein-1 (MSP1), a prime malaria vaccine candidate and one of the most abundant components of the merozoite surface, is implicated in the ligand-receptor interactions leading to invasion. MSP1 is extensively proteolytically modified, first just before egress and then during invasion. These primary and secondary processing events are mediated respectively, by two parasite subtilisin-like proteases, PfSUB1 and PfSUB2, but the function and biological importance of the processing is unknown. Here, we examine the regulation and significance of MSP1 processing. We show that primary processing is ordered, with the primary processing site closest to the C-terminal end of MSP1 being cleaved last, irrespective of polymorphisms throughout the rest of the molecule. Replacement of the secondary processing site, normally refractory to PfSUB1, with a PfSUB1-sensitive site, is deleterious to parasite growth. Our findings show that correct spatiotemporal regulation of MSP1 maturation is crucial for the function of the protein and for maintenance of the parasite asexual blood-stage life cycle.
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Affiliation(s)
- Matthew A Child
- Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London NW7 1AA, UK
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Plasmodium falciparum merozoite surface protein 1 (MSP-1)-MSP-3 chimeric protein: immunogenicity determined with human-compatible adjuvants and induction of protective immune response. Infect Immun 2009; 78:872-83. [PMID: 19933832 DOI: 10.1128/iai.00427-09] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A chimeric gene, MSP-Fu(24), was constructed by genetically coupling immunodominant, conserved regions of the two leading malaria vaccine candidates, Plasmodium falciparum merozoite surface protein 1 (C-terminal 19-kDa region [PfMSP-1(19)]) and merozoite surface protein 3 (11-kDa conserved region [PfMSP-3(11)]). The recombinant MSP-Fu(24) protein was produced in Escherichia coli cells and purified to homogeneity by a two-step purification process with a yield of approximately 30 mg/liter. Analyses of conformational properties of MSP-Fu(24) using PfMSP-1(19)-specific monoclonal antibody showed that the conformational epitopes of PfMSP-1(19) that may be critical for the generation of the antiparasitic immune response remained intact in the fusion protein. Recombinant MSP-Fu(24) was highly immunogenic in mice and in rabbits when formulated with two different human-compatible adjuvants and induced an immune response against both PfMSP-1(19) and PfMSP-3(11). Purified anti-MSP-Fu(24) antibodies showed invasion inhibition of P. falciparum 3D7 and FCR parasites, and this effect was found to be dependent on antibodies specific for the PfMSP-1(19) component. The protective potential of MSP-Fu(24) was demonstrated by in vitro parasite growth inhibition using an antibody-dependent cell inhibition (ADCI) assay with anti-MSP-Fu(24) antibodies. Overall, the antiparasitic activity was mediated by a combination of growth-inhibitory antibodies generated by both the PfMSP-1(19) and PfMSP-3(11) components of the MSP-Fu(24) protein. The antiparasitic activities elicited by anti-MSP-Fu(24) antibodies were comparable to those elicited by antibodies generated with immunization with a physical mixture of two component antigens, PfMSP-1(19) and PfMSP-3(11). The fusion protein induces a protective immune response with human-compatible adjuvants and may form a part of a multicomponent malaria vaccine.
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IgG subclasses pattern and high-avidity antibody to the C-terminal region of merozoite surface protein 1 of Plasmodium vivax in an unstable hypoendemic region in Iran. Acta Trop 2009; 112:1-7. [PMID: 19481997 DOI: 10.1016/j.actatropica.2009.05.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2008] [Revised: 05/03/2009] [Accepted: 05/22/2009] [Indexed: 11/22/2022]
Abstract
The C-terminal region of Plasmodium vivax merozoite surface protein 1 (PvMSP-1(19)) is a leading vaccine candidate for inclusion in a polyvalent malaria vaccine. In the present study, the IgG subclasses profile and the avidity of IgG to PvMSP-1(19) were evaluated in individuals (n=94) naturally exposed to P. vivax parasite in malaria endemic areas in Chabahar districts, Iran. In individuals with patent P. vivax malaria, 86.1% was sero-positive to PvMSP-1(19) and IgG1 (81.9%) was the predominant subclass. In addition, to determine the persistence of specific IgG, IgG1 and IgG3 antibodies to PvMSP-1(19), the frequency of antibodies was determined in the infected subjects (n=74) after treatment with standard chloroquine and it was detected that the frequency of responders was significantly reduced to 51.3%, 51% and 16.2%, respectively. The antigen-binding avidity of IgG antibodies to PvMSP-1(19) was measured in sero-positive sera and the high-avidity of IgG, IgG1 and IgG3 was found in 66.6%, 61% and 47% of the infected subjects with P. vivax, respectively. The present result shows that individuals who exposed to vivax malaria in the endemic region in Iran develop antibodies with high-avidity to PvMSP-1(19). These results could help to understand the interactions between the host and P. vivax parasite in development of MSP-1(19)-based vaccine.
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Yeom JS, Kim ES, Lim KJ, Oh JH, Sohn MJ, Yoo SB, Kim E, Bae I, Jung YJ, Park JW. Naturally acquired IgM antibody response to the C-terminal region of the merozoite surface protein 1 of Plasmodium vivax in Korea: use for serodiagnosis of vivax malaria. J Parasitol 2009; 94:1410-4. [PMID: 18576813 DOI: 10.1645/ge-1484.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2007] [Accepted: 04/29/2008] [Indexed: 11/10/2022] Open
Abstract
The antibody levels against the C-terminal region of the merozoite surface protein 1 of Plasmodium vivax (PvMSP1c) were measured in 276 patients with P. vivax malaria (patient group), 320 malaria-naïve healthy individuals (control group 1), and 70 malaria-naïve individuals with various disorders (control group 2) using the immunoglobulin M (IgM) capture enzyme-linked immunosorbent assay (ELISA) and the direct sandwich ELISA. To evaluate the antibody response during relapse, 5 relapsed patients were tested using the IgM capture ELISA. The IgM antibodies were negative in 99.7% of control group 1 and in 100% of control group 2; they were positive in 90.6% of the patient group. The total antibody levels were positive in 88.4% of the patient group with the direct sandwich ELISA. The sera from the second malaria episode, i.e., relapsed patients, were 100% positive on the IgM capture ELISA. The results of this study suggest that the IgM capture ELISA may be a useful diagnostic method for P. vivax malaria for both primary infection and relapse.
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Affiliation(s)
- Joon-Sup Yeom
- Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Chongno-gu, Seoul 110-746, Republic of Korea.
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Prediction of merozoite surface protein 1 and apical membrane antigen 1 vaccine efficacies against Plasmodium chabaudi malaria based on prechallenge antibody responses. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2008; 16:293-302. [PMID: 19116303 DOI: 10.1128/cvi.00230-08] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
For the development of blood-stage malaria vaccines, there is a clear need to establish in vitro measures of the antibody-mediated and the cell-mediated immune responses that correlate with protection. In this study, we focused on establishing correlates of antibody-mediated immunity induced by immunization with apical membrane antigen 1 (AMA1) and merozoite surface protein 1(42) (MSP1(42)) subunit vaccines. To do so, we exploited the Plasmodium chabaudi rodent model, with which we can immunize animals with both protective and nonprotective vaccine formulations and allow the parasitemia in the challenged animals to peak. Vaccine formulations were varied with regard to the antigen dose, the antigen conformation, and the adjuvant used. Prechallenge antibody responses were evaluated by enzyme-linked immunosorbent assay and were tested for a correlation with protection against nonlethal P. chabaudi malaria, as measured by a reduction in the peak level of parasitemia. The analysis showed that neither the isotype profile nor the avidity of vaccine-induced antibodies correlated with protective efficacy. However, high titers of antibodies directed against conformation-independent epitopes were associated with poor vaccine performance and may limit the effectiveness of protective antibodies that recognize conformation-dependent epitopes. We were able to predict the efficacies of the P. chabaudi AMA1 (PcAMA1) and P. chabaudi MSP1(42) (PcMSP1(42)) vaccines only when the prechallenge antibody titers to both refolded and reduced/alkylated antigens were considered in combination. The relative importance of these two measures of vaccine-induced responses as predictors of protection differed somewhat for the PcAMA1 and the PcMSP1(42) vaccines, a finding confirmed in our final immunization and challenge study. A similar approach to the evaluation of vaccine-induced antibody responses may be useful during clinical trials of Plasmodium falciparum AMA1 and MSP1(42) vaccines.
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McCallum FJ, Persson KEM, Mugyenyi CK, Fowkes FJI, Simpson JA, Richards JS, Williams TN, Marsh K, Beeson JG. Acquisition of growth-inhibitory antibodies against blood-stage Plasmodium falciparum. PLoS One 2008; 3:e3571. [PMID: 18958278 PMCID: PMC2570221 DOI: 10.1371/journal.pone.0003571] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Accepted: 10/07/2008] [Indexed: 11/18/2022] Open
Abstract
Background Antibodies that inhibit the growth of blood-stage Plasmodium falciparum may play an important role in acquired and vaccine-induced immunity in humans. However, the acquisition and activity of these antibodies is not well understood. Methods We tested dialysed serum and purified immunoglobulins from Kenyan children and adults for inhibition of P. falciparum blood-stage growth in vitro using different parasite lines. Serum antibodies were measured by ELISA to blood-stage parasite antigens, extracted from P. falciparum schizonts, and to recombinant merozoite surface protein 1 (42 kDa C-terminal fragment, MSP1-42). Results Antibodies to blood-stage antigens present in schizont protein extract and to recombinant MSP1-42 significantly increased with age and were highly correlated. In contrast, growth-inhibitory activity was not strongly associated with age and tended to decline marginally with increasing age and exposure, with young children demonstrating the highest inhibitory activity. Comparison of growth-inhibitory activity among samples collected from the same population at different time points suggested that malaria transmission intensity influenced the level of growth-inhibitory antibodies. Antibodies to recombinant MSP1-42 were not associated with growth inhibition and high immunoglobulin G levels were poorly predictive of inhibitory activity. The level of inhibitory activity against different isolates varied. Conclusions Children can acquire growth-inhibitory antibodies at a young age, but once they are acquired they do not appear to be boosted by on-going exposure. Inhibitory antibodies may play a role in protection from early childhood malaria.
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Affiliation(s)
- Fiona J. McCallum
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | | | - Cleopatra K. Mugyenyi
- Kenya Medical Research Institute, CGMRC/Wellcome Trust Collaborative Program, Kilifi, Kenya
| | - Freya J. I. Fowkes
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Julie A. Simpson
- Centre for Molecular, Environmental, Genetic and Analytic Epidemiology, University of Melbourne, Carlton, Victoria, Australia
| | - Jack S. Richards
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Thomas N. Williams
- Kenya Medical Research Institute, CGMRC/Wellcome Trust Collaborative Program, Kilifi, Kenya
| | - Kevin Marsh
- Kenya Medical Research Institute, CGMRC/Wellcome Trust Collaborative Program, Kilifi, Kenya
| | - James G. Beeson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- * E-mail:
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Protection induced by Plasmodium falciparum MSP1(42) is strain-specific, antigen and adjuvant dependent, and correlates with antibody responses. PLoS One 2008; 3:e2830. [PMID: 18665258 PMCID: PMC2474699 DOI: 10.1371/journal.pone.0002830] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Accepted: 06/23/2008] [Indexed: 11/25/2022] Open
Abstract
Vaccination with Plasmodium falciparum MSP142/complete Freund's adjuvant (FA) followed by MSP142/incomplete FA is the only known regimen that protects Aotus nancymaae monkeys against infection by erythrocytic stage malaria parasites. The role of adjuvant is not defined; however complete FA cannot be used in humans. In rodent models, immunity is strain-specific. We vaccinated Aotus monkeys with the FVO or 3D7 alleles of MSP142 expressed in Escherichia coli or with the FVO allele expressed in baculovirus (bv) combined with complete and incomplete FA, Montanide ISA-720 (ISA-720) or AS02A. Challenge with FVO strain P. falciparum showed that suppression of cumulative day 11 parasitemia was strain-specific and could be induced by E. coli expressed MSP142 in combination with FA or ISA-720 but not with AS02A. The coli42-FVO antigen induced a stronger protective effect than the bv42-FVO antigen, and FA induced a stronger protective effect than ISA-720. ELISA antibody (Ab) responses at day of challenge (DOC) were strain-specific and correlated inversely with c-day 11 parasitemia (r = −0.843). ELISA Ab levels at DOC meeting a titer of at least 115,000 ELISA Ab units identified the vaccinees not requiring treatment (noTx) with a true positive rate of 83.3% and false positive rate of 14.3 %. Correlation between functional growth inhibitory Ab levels (GIA) and cumulative day 11 parasitemia was weaker (r = −0.511), and was not as predictive for a response of noTx. The lowest false positive rate for GIA was 30% when requiring a true positive rate of 83.3%. These inhibition results along with those showing that antigen/FA combinations induced a stronger protective immunity than antigen/ISA-720 or antigen/AS02 combinations are consistent with protection as ascribed to MSP1-specific cytophilic antibodies. Development of an effective MSP142 vaccine against erythrocytic stage P. falciparum infection will depend not only on antigen quality, but also upon the selection of an optimal adjuvant component.
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Tao YL, Cheng XJ, Fu YF, Tsukamoto H, Yoshihara E, Tachibana H. Modification of a human monoclonal antibody Fab fragment specific for Plasmodium falciparum 19-kDa C-terminal merozoite surface protein 1 by site-directed mutagenesis. Parasitol Res 2008; 103:429-33. [PMID: 18446371 DOI: 10.1007/s00436-008-0994-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2008] [Accepted: 04/07/2008] [Indexed: 10/22/2022]
Abstract
We recently produced human monoclonal antibody Fab fragments specific for the 19-kDa C-terminal merozoite surface protein 1 of Plasmodium falciparum in a bacterial expression system. The effect of single amino acid modifications in the third complementarity-determining regions of the heavy and light chains on affinity was examined in one of the Fab fragments, Pf25. Recombination polymerase chain reaction was used to modify Tyr(92) or Ile(97) in the light chain and Val(101) or Trp(107) in the heavy chain. No effective replacements for Tyr(92) and Val(101) were found, but possible substitutions of Ile(97) with Gly, Leu, Glu, Ala and Ser, and of Trp(107) with Arg and Ser were demonstrated. Of these modified Fab fragments, the affinities of Fabs with Ile(97)-Leu and Trp(107)-Ser mutations were slightly higher than that of the original Fab. The effects of these modifications on the antigen-antibody interaction are discussed.
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Affiliation(s)
- Yan-Lin Tao
- Department of Medical Microbiology and Parasitology, Fudan University School of Medicine, Shanghai, 200032, China
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Huaman MC, Martin LB, Malkin E, Narum DL, Miller LH, Mahanty S, Long CA. Ex vivo cytokine and memory T cell responses to the 42-kDa fragment of Plasmodium falciparum merozoite surface protein-1 in vaccinated volunteers. THE JOURNAL OF IMMUNOLOGY 2008; 180:1451-61. [PMID: 18209040 DOI: 10.4049/jimmunol.180.3.1451] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A number of blood-stage malaria Ags are under development as vaccine candidates, but knowledge of the cellular responses to these vaccines in humans is limited. We evaluated the nature and specificity of cellular responses in healthy American volunteers vaccinated with a portion of the major merozoite surface protein-1 (MSP1) of Plasmodium falciparum, MSP1(42), formulated on Alhydrogel. Volunteers were vaccinated three times with 80 microg of either MSP1(42)-FVO/Alhydrogel or MSP1(42)-3D7/Alhydrogel. Cells collected 2 wk after the third vaccination produced Th1 cytokines, including IFN-gamma and IL-2 following Ag stimulation, and greater levels of the Th2 cytokines IL-5 and IL-13; the anti-inflammatory cytokine IL-10 and the molecule CD25 (IL-2Ralpha) were also detected. The volunteers were evaluated for the MSP1(42)-FVO or MSP1(42)-3D7 specificity of their T cell responses. Comparison of their responses to homologous and heterologous Ags showed ex vivo IFN-gamma and IL-5 levels that were significantly higher to homologous rather than to heterologous Ags. The epitopes involved in this stimulation were shown to be present in the dimorphic MSP1(33) portion of the larger MSP1(42)-3D7 polypeptide, and indirect experiment suggests the same for the MSP1(42)-FVO polypeptide. This contrasts with B cell responses, which were primarily directed to the conserved MSP1(19) portion. Furthermore, we explored the maturation of memory T cells and found that 46% of vaccinees showed specific memory T cells defined as CD4(+)CD45RO(+)CD40L(+) after long-term in vitro culture. The identification of human-specific CD4(+) memory T cells provides the foundation for future studies of these cells both after vaccination and in field studies.
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Affiliation(s)
- Maria Cecilia Huaman
- Malaria Vaccine Development Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 12735 Twinbrook Parkway, Rockville, MD 20852, USA
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Petritus PM, Burns JM. Suppression of lethal Plasmodium yoelii malaria following protective immunization requires antibody-, IL-4-, and IFN-gamma-dependent responses induced by vaccination and/or challenge infection. THE JOURNAL OF IMMUNOLOGY 2008; 180:444-53. [PMID: 18097046 DOI: 10.4049/jimmunol.180.1.444] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Immunization with Plasmodium yoelii merozoite surface protein (PyMSP)-8 protects mice from lethal malaria but does not prevent infection. Using this merozoite surface protein-based vaccine model, we investigated vaccine- and infection-induced immune responses that contribute to protection. Analysis of prechallenge sera from rPyMSP-8-immunized C57BL/6 and BALB/c mice revealed high and comparable levels of Ag-specific IgG, but differences in isotype profile and specificity for conformational epitopes were noted. As both strains of mice were similarly protected against P. yoelii, we could not correlate vaccine-induced responses with protection. However, passive immunization studies suggested that protection resulted from differing immune responses. Studies with cytokine-deficient mice showed that protection was induced by immunization of C57BL/6 mice only when IL-4 and IFN-gamma were both present. In BALB/c mice, the absence of either IL-4 or IFN-gamma led to predictable shifts in the IgG isotype profile but did not reduce the magnitude of the Ab response induced by rPyMSP-8 immunization. Immunized IL-4-/- BALB/c mice were solidly protected against P. yoelii. To our surprise, immunized IFN-gamma-/- BALB/c mice initially controlled parasite growth but eventually succumbed to infection. Analysis of cytokine production revealed that P. yoelii infection induced two distinct peaks of IFN-gamma that correlated with periods of controlled parasite growth in intact, rPyMSP-8-immunized BALB/c mice. Maximal parasite growth occurred during a period of sustained TGF-beta production. Combined, the data indicate that induction of protective responses by merozoite surface protein-based vaccines depends on IL-4 and IFN-gamma-dependent pathways and that vaccine efficacy is significantly influenced by host responses elicited upon infection.
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Affiliation(s)
- Patricia M Petritus
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA 19129, USA
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Mehrizi AA, Zakeri S, Salmanian AH, Sanati MH, Djadid ND. Plasmodium falciparum: Sequence analysis of the gene encoding the C-terminus region of the merozoite surface protein-1, a potential malaria vaccine antigen, in Iranian clinical isolates. Exp Parasitol 2008; 118:378-85. [DOI: 10.1016/j.exppara.2007.10.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2007] [Revised: 09/18/2007] [Accepted: 10/02/2007] [Indexed: 10/22/2022]
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The profile of IgG-antibody response against merozoite surface proteins 1 and 2 in severe Plasmodium falciparum malaria in Eastern Sudan. Parasitol Res 2007; 102:401-9. [PMID: 18038151 DOI: 10.1007/s00436-007-0777-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2007] [Accepted: 10/23/2007] [Indexed: 10/22/2022]
Abstract
In this study, antibodies (Ab) directed against three MSP antigens; MSP1(19), MSP2(A), and MSP2(B) were analyzed in blood samples obtained from 223 Sudanese patients who presented with either severe malaria (SM) or uncomplicated malaria (UM) and from 117 malaria-free donors (MF). The results showed that the prevalence of MSP Abs was associated with the clinical outcome of malaria infection, and the Ab prevalence was age-dependent (P<0.0005). More importantly, the prevalence of MSP Abs against the test antigens was lower in SM compared to UM (P=0.001 to 0.020), suggesting a protective role for these Abs against SM. Furthermore, the Ab responses between individual complications of SM were significantly different.
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Devi YS, Mukherjee P, Yazdani SS, Shakri AR, Mazumdar S, Pandey S, Chitnis CE, Chauhan VS. Immunogenicity of Plasmodium vivax combination subunit vaccine formulated with human compatible adjuvants in mice. Vaccine 2007; 25:5166-74. [PMID: 17544179 DOI: 10.1016/j.vaccine.2007.04.080] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2006] [Revised: 04/27/2007] [Accepted: 04/29/2007] [Indexed: 11/15/2022]
Abstract
An effective malaria vaccine will probably require the delivery of multiple antigens that induce several layers of immunity. Malaria antigens expressed on the surface and in apical organelles of blood-stage merozoites are potential vaccine candidates given their importance in the invasion of erythrocytes. The present study examined the kinetics of humoral response in BALB/c mice following immunization with combination of two blood-stage Plasmodium vivax invasion related molecules, the N-terminal, cysteine-rich region II of P. vivax Duffy binding protein (PvRII) and the 19kDa C-terminal region of merozoite surface protein 1 (PvMSP1(19)) formulated with Montanide ISA 720 and alhydrogel. Immunization with combination of recombinant PvRII and PvMSP1(19) formulated with the Montanide ISA 720 elicited higher antibody titer compared to the alhydrogel formulation. In case of both the adjuvants tested, combination of PvRII and PvMSP1(19) did not result in suppression of antibody response against either antigen when compared to immunization with individual antigens alone. Analysis of IgG subclasses showed that combination of both the recombinant proteins induced a mixed Th1/Th2-type response with almost all IgG subtypes being expressed in equivalent amount. Antibodies elicited against PvRII showed significant inhibitory effect on the binding of PvRII to recombinant Duffy antigen receptor for chemokines (DARC) in an in vitro binding assay. The results of the present study provide a rationale for a combination vaccine against P. vivax malaria based on PvMSP1(19) and PvRII.
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MESH Headings
- Adjuvants, Immunologic/administration & dosage
- Animals
- Antibodies, Protozoan/blood
- Antibody Formation/immunology
- Antigens, Protozoan/genetics
- Antigens, Protozoan/immunology
- Blotting, Western
- Chromatography, High Pressure Liquid
- Enzyme-Linked Immunosorbent Assay
- Immunization/methods
- Immunoglobulin G/blood
- Malaria Vaccines/administration & dosage
- Malaria Vaccines/immunology
- Malaria, Vivax/immunology
- Malaria, Vivax/prevention & control
- Male
- Merozoite Surface Protein 1/genetics
- Merozoite Surface Protein 1/immunology
- Mice
- Mice, Inbred BALB C
- Plasmodium vivax/genetics
- Plasmodium vivax/immunology
- Protozoan Proteins/genetics
- Protozoan Proteins/immunology
- Receptors, Cell Surface/genetics
- Receptors, Cell Surface/immunology
- Recombinant Proteins/immunology
- Time Factors
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Affiliation(s)
- Yengkhom Sangeeta Devi
- Malaria Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), P.O. Box 10504, Aruna Asaf Ali Marg, New Delhi 110067, India
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39
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Cheng XJ, Hayasaka H, Watanabe K, Tao YL, Liu JY, Tsukamoto H, Horii T, Tanabe K, Tachibana H. Production of high-affinity human monoclonal antibody fab fragments to the 19-kilodalton C-terminal merozoite surface protein 1 of Plasmodium falciparum. Infect Immun 2007; 75:3614-20. [PMID: 17452466 PMCID: PMC1932930 DOI: 10.1128/iai.00062-07] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A combinatorial immunoglobulin gene library was constructed from peripheral blood lymphocytes of eight patients infected with Plasmodium falciparum and was screened for the production of human monoclonal antibody Fab fragments to the C-terminal 19-kDa fragment of P. falciparum merozoite surface protein 1 (MSP-1(19)). Three Fab clones recognized recombinant MSP-1(19) under nonreducing conditions. Indirect immunofluorescence microscopy demonstrated that three Fab clones stained the surfaces of late trophozoites/schizonts and merozoites of the FCR3 and 3D7 strains, suggesting the Fabs' reactivities to a conserved epitope. Sequence analysis of the heavy-chain genes revealed that the closest germ line V segments were VH1-8 and VH7-81, with 91% to 98% homology. The closest germ line D segment was D3-10, and the closest germ line J segment was JH4 or JH5, with 90% to 97% homology. In the light-chain genes, the closest germ line V segment was A27 for the Jkappa2, Jkappa4, and Jkappa5 segments. The dissociation constants of these Fab fragments for recombinant MSP-1(19) ranged from 1.09 x 10(-9) to 2.66 x 10(-9) M. The binding of the three Fab fragments to MSP-1(19) was competitively inhibited by the anti-MSP-1(19) mouse monoclonal antibody 12.8, which inhibits erythrocyte invasion by merozoites. However, the human Fab fragment with the highest affinity did not inhibit in vitro growth of P. falciparum. This is the first report of gene analysis and bacterial expression of human monoclonal antibodies to P. falciparum MSP-1(19). The combinatorial immunoglobulin gene library derived from malaria patients provides a potential tool for producing high-affinity human antibodies specific for P. falciparum.
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Affiliation(s)
- Xun-Jia Cheng
- Department of Infectious Diseases, Tokai University School of Medicine, Isehara, Kanagawa 259-1193, Japan
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40
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Autore F, Melchiorre S, Kleinjung J, Morgan WD, Fraternali F. Interaction of malaria parasite-inhibitory antibodies with the merozoite surface protein MSP1(19) by computational docking. Proteins 2007; 66:513-27. [PMID: 17173281 DOI: 10.1002/prot.21212] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Merozoite surface protein 1 (MSP1) of the malaria parasite Plasmodium falciparum is an important vaccine candidate antigen. Antibodies specific for the C-terminal maturation product, MSP1(19), have been shown to inhibit erythrocyte invasion and parasite growth. Specific monoclonal antibodies react with conformational epitopes contained within the two EGF-like domains that constitute the antigen MSP1(19). To gain greater insight into the inhibitory process, the authors selected two strongly inhibitory antibodies (designated 12.8 and 12.10) and modeled their structures by homology. Computational docking was used to generate antigen-antibody complexes and a selection filter based on NMR data was applied to obtain plausible models. Molecular Dynamics simulations of the selected complexes were performed to evaluate the role of specific side chains in the binding. Favorable complexes were obtained that complement the NMR data in defining specific binding sites. These models can provide valuable guidelines for future experimental work that is devoted to the understanding of the action mechanism of invasion-inhibitory antibodies.
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Affiliation(s)
- Flavia Autore
- Dipartimento di Chimica Organica e Biochimica, Università di Napoli Federico II, Complesso Universitario Monte Sant'Angelo, via Cinthia, 80126, Naples, Italy
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41
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Shi Q, Lynch MM, Romero M, Burns JM. Enhanced protection against malaria by a chimeric merozoite surface protein vaccine. Infect Immun 2006; 75:1349-58. [PMID: 17158895 PMCID: PMC1828565 DOI: 10.1128/iai.01467-06] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The 42-kDa processed fragment of Plasmodium falciparum merozoite surface protein 1 (MSP-1(42)) is a prime candidate for a blood-stage malaria vaccine. Merozoite surface protein 8 contains two C-terminal epidermal growth factor (EGF)-like domains that may function similarly to those of MSP-1(42). Immunization with either MSP-1 or MSP-8 induces protection that is mediated primarily by antibodies against conformation-dependent epitopes. In a series of comparative immunogenicity and efficacy studies using the Plasmodium yoelii rodent model, we tested the ability of recombinant P. yoelii MSP-8 (rPyMSP-8) to complement rPyMSP-1-based vaccines. Unlike MSP-1, PyMSP-8-dependent protection required immunization with the full-length protein and was not induced with recombinant antigens that contained only the C-terminal EGF-like domains. Unlike PyMSP-8, the immunogenicity of the PyMSP-1 EGF-like domains was low when present as part of the rPyMSP-1(42) antigen. Immunization with a mixture of rPyMSP-1(42) and rPyMSP-8 further inhibited the antibody response to protective epitopes of rPyMSP-1(42) and did not improve vaccine efficacy. To improve PyMSP-1 immunogenicity, we produced a chimeric antigen containing the EGF-like domains of PyMSP-1 fused to the N terminus of PyMSP-8. Immunization with the chimeric rPyMSP-1/8 antigen induced high and comparable antibody responses against the EGF-like domains of both PyMSP-1 and PyMSP-8. This enhanced MSP-1-specific antibody response and the concurrent targeting of MSP-1 and MSP-8 resulted in improved, nearly complete protection against lethal P. yoelii 17XL malaria. Unexpectedly, immunization with rPyMSP-1/8 failed to protect against challenge infection with reticulocyte-restricted P. yoelii 17X parasites. Overall, these data establish an effective strategy to improve the efficacy of P. falciparum MSP-based vaccines.
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Affiliation(s)
- Qifang Shi
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, Pennsylvania 19129
| | - Michelle M. Lynch
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, Pennsylvania 19129
| | - Margarita Romero
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, Pennsylvania 19129
| | - James M. Burns
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, Pennsylvania 19129
- Corresponding author. Mailing address: Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA 19129. Phone: (215) 991-8490. Fax: (215) 848-2271. E-mail:
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42
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Serrano ML, Pérez HA, Medina JD. Structure of C-terminal fragment of merozoite surface protein-1 from Plasmodium vivax determined by homology modeling and molecular dynamics refinement. Bioorg Med Chem 2006; 14:8359-65. [PMID: 17035028 DOI: 10.1016/j.bmc.2006.09.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2006] [Revised: 09/07/2006] [Accepted: 09/07/2006] [Indexed: 10/24/2022]
Abstract
One current vaccine candidate against Plasmodium vivax targeting asexual blood stage is the major merozoite surface protein-1 of P. vivax (PvMSP-1). Vaccine trials with PvMSP-1(19) and PvMSP-1(33) have succeeded in protecting monkeys and a large proportion of individuals, naturally exposed to P. vivax transmission, develop specific antibodies to PvMSP-1(19). This study presents a model for the three-dimensional structure of the C-terminal 19kDa fragment of P. vivax MSP-1 determined by means of homology modeling and molecular dynamics refinement. The structure proved to be consistent with MSP-1(19) of known crystal or solution structures. The presence of a main binding pocket, well suited for protein-protein interactions, was determined by CASTp. Corrections reported to the sequence of PvMSP-1(19) Belem strain were also inspected. Our model is currently used as a basis to understand antibody interactions with PvMSP-1(19).
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Affiliation(s)
- María Luisa Serrano
- Laboratorio de Modelado Molecular, Unidad de Química Medicinal, Facultad de Farmacia, Universidad Central de Venezuela, Caracas 1041-A, Venezuela.
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43
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Nagata M, Wong T, Clements D, Hui G. Plasmodium falciparum: immunization with MSP1-42 induced non-inhibitory antibodies that have no blocking activities but enhanced the potency of inhibitory anti-MSP1-42 antibodies. Exp Parasitol 2006; 115:403-8. [PMID: 17118357 PMCID: PMC1857355 DOI: 10.1016/j.exppara.2006.10.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2006] [Revised: 10/10/2006] [Accepted: 10/12/2006] [Indexed: 11/22/2022]
Abstract
Hyperimmunization with Plasmodium falciparum MSP1-42 could induce antibodies that have little or no parasite growth inhibitory activities. These antisera had no blocking activities as determined by their ability to interfere with the in vitro activities of growth inhibitory anti-MSP1-42 sera. Equally important, they enhanced the potency of growth inhibitory anti-MSP1-42 sera.
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Affiliation(s)
- Mark Nagata
- Department of Tropical Medicine and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa
| | | | | | - George Hui
- Department of Tropical Medicine and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa
- * Corresponding Author: George Hui, Department of Tropical Medicine and Pharmacology, John A Burns School of Medicine, BioSciences Building, Rm 320K, 651 Ilalo Street, Honolulu, HI 96813, Phone: (808)-692-1609, Fax: (808)-692-1979, E-mail:
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44
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Shimp RL, Martin LB, Zhang Y, Henderson BS, Duggan P, MacDonald NJ, Lebowitz J, Saul A, Narum DL. Production and characterization of clinical grade Escherichia coli derived Plasmodium falciparum 42kDa merozoite surface protein 1 (MSP142) in the absence of an affinity tag. Protein Expr Purif 2006; 50:58-67. [PMID: 16884920 DOI: 10.1016/j.pep.2006.06.018] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2006] [Revised: 06/06/2006] [Accepted: 06/20/2006] [Indexed: 11/24/2022]
Abstract
The 42 kDa cleavage product from the carboxyl end of the Plasmodium falciparum merozoite surface protein 1 (MSP1(42)) is an important blood-stage malaria vaccine target. Several recombinant protein expression systems have been used for production of MSP1(42) including yeast (Saccharomyces cerevisiae and Pichia pastoris), Escherichia coli, baculovirus and transgenic animals. To date, all of the reported recombinant proteins include a 6 x His affinity tag to facilitate purification, including three MSP1(42) clinical grade proteins currently in human trials. Under some circumstances, the presence of the 6 x His tag may not be desirable. Therefore, we were interested to produce clinical grade MSP1(42) without a 6 x His affinity tag from E. coli inclusion bodies. We produced a recombinant MSP1(42) with a P. falciparum FUP (Uganda-Palo Alto) phenotype which accounts for a substantial proportion of the MSP1(42) protein observed in African isolates. EcMSP1(42)-FUP was produced in E. coli inclusion bodies by high cell mass induction with IPTG using 5 L and 60 L bioreactors. Isolated inclusion bodies were solubilized in 8M guanidine-HCl and the EcMSP1(42)-FUP protein refolded by rapid dilution. Refolded EcMSP1(42)-FUP was purified using hydrophobic interaction chromatography, anion exchange chromatography, and size exclusion chromatography, and subject to biochemical characterization for integrity, identity, and purity. Endotoxin and host cell protein levels were within acceptable limits for human use. The process was successfully transferred to pilot-scale production in a cGMP environment. A final recovery of 87.8 mg of clinical-grade material per liter of fermentation broth was achieved. The EcMSP1(42)-FUP clinical antigen is available for preclinical evaluation and human studies.
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Affiliation(s)
- Richard L Shimp
- Malaria Vaccine Development Branch (MVDB), NIAID/NIH/DHHS, Rockville, MD, USA
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45
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James S, Moehle K, Renard A, Mueller MS, Vogel D, Zurbriggen R, Pluschke G, Robinson JA. Synthesis, Solution Structure and Immune Recognition of an Epidermal Growth Factor-Like Domain from Plasmodium falciparum Merozoite Surface Protein-1. Chembiochem 2006; 7:1943-50. [PMID: 17068840 DOI: 10.1002/cbic.200600357] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The Plasmodium falciparum merozoite surface protein-1 19 kDa fragment (MSP-1(19)) comprises two closely packed EGF-like domains (EGF=epidermal growth factor), each stabilized by three disulfide bonds. The native conformation of this protein is important for eliciting P. falciparum growth inhibitory antibodies. Here we show that the N-terminal EGF domain alone can be chemically synthesized and efficiently refolded to a native-like state, as shown by its solution structure as determined by NMR spectroscopy. In order to study its immunogenicity, the domain was coupled through its N terminus to a phospholipid and incorporated into reconstituted influenza virus-like particles (virosomes). When used to immunize mice, the peptide-loaded virosomes elicited potent humoral immune responses that were shown by Western blots and immunofluorescence assays to cross-react with native MSP-1 on the surfaces of P. falciparum blood stage parasites. This opens the way for a medicinal chemistry-oriented approach to the study and optimization of the antigenicity of the protein as a potential malaria vaccine candidate, whilst exploiting the immunopotentiating properties of influenza virosomes as a delivery vehicle.
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Affiliation(s)
- Sonya James
- Department of Chemistry, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
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46
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Hui G, Hashimoto C. Plasmodium falciparum anti-MSP1-19 antibodies induced by MSP1-42 and MSP1-19 based vaccines differed in specificity and parasite growth inhibition in terms of recognition of conserved versus variant epitopes. Vaccine 2006; 25:948-56. [PMID: 17023096 DOI: 10.1016/j.vaccine.2006.08.041] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2006] [Revised: 08/18/2006] [Accepted: 08/28/2006] [Indexed: 11/30/2022]
Abstract
The C-terminal 42 kDa fragment (MSP1-42) and its smaller 19 kDa subfragment (MSP1-19) of the Plasmodium falciparum merozoite surface protein, MSP1, are leading candidate malaria vaccines. Since the targets of protective immunity lie within the MSP1-19, we compared the anti-MSP1-19 antibodies induced by vaccination with recombinant MSP1-42 and MSP1-19. The specificities of the antibody responses were analyzed using five recombinant MSP1-19s expressing different naturally occurring variant amino acid residues. We observed dramatic differences in the specificities of the anti-MSP1-19 antibodies induced by the two vaccines. MSP1-42 consistently induced crossreactive antibodies; whereas the antibodies induced by recombinant MSP1-19 were highly variable among animals in terms of recognition of conserved versus variant epitopes. Of the variant residues examined, only a subset significantly contributed as part of immunogenic B epitopes. MSP1-42 consistently induced potent growth inhibitory antibodies that recognized conserved epitopes, leading to efficient inhibition of heterologous parasites. In contrast, MSP1-19 induced strong inhibitory antibody responses in only a subset of animals studied. In some of the MSP1-19 immunized animals, inhibition of homologous parasites may be due to recognition of inhibitory epitopes associated with the homologous variant residues, and the induction of antibodies to conserved inhibitory epitopes may not be efficiently achieved. These data suggest an advantage of using MSP1-42 over MSP1-19 based vaccines.
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Affiliation(s)
- George Hui
- Department of Tropical Medicine and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, United States.
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47
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Persson KEM, Lee CT, Marsh K, Beeson JG. Development and optimization of high-throughput methods to measure Plasmodium falciparum-specific growth inhibitory antibodies. J Clin Microbiol 2006; 44:1665-73. [PMID: 16672391 PMCID: PMC1479166 DOI: 10.1128/jcm.44.5.1665-1673.2006] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Antibodies that inhibit replication of Plasmodium falciparum in erythrocytes are thought to be important both in acquired immunity to malaria and as mediators of immunity generated by candidate blood-stage vaccines. However, several constraints have limited the study of these functional antibodies in population studies and vaccine trials. We report the development and optimization of high-throughput growth inhibition assays with improved sensitivity that use minimal volumes of test serum. The major inhibitory activity of serum from exposed donors was antibody mediated, but nonspecific inhibitory factors were found in untreated serum. Culture volumes could be effectively reduced to 25 microl to limit amounts of test serum or inhibitors used in assays. Performing inhibition assays over two cycles of parasite replication gave greater sensitivity than single-cycle assays, and a simple two-cycle inhibition assay was developed that yielded highly reproducible results. Determination of parasite growth by flow cytometry was most suitable for high-throughput assays using small culture volumes and was more sensitive than parasite lactate dehydrogenase assays and less prone to error and variation than microscopy. We evaluated and optimized methods to remove antimalarials and nonspecific inhibitory factors from serum that are suitable for use with small volumes of samples that are typically obtained from clinical studies. Both microdialysis and immunoglobulin purification by ammonium sulfate precipitation were effective and practical. These methods should facilitate evaluation of vaccine trials and clinical studies of immunity and are also suitable for testing drugs and other compounds for antimalarial activity.
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Affiliation(s)
- Kristina E M Persson
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3050, Australia
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48
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Shi Q, Cernetich-Ott A, Lynch MM, Burns JM. Expression, localization, and erythrocyte binding activity of Plasmodium yoelii merozoite surface protein-8. Mol Biochem Parasitol 2006; 149:231-41. [PMID: 16846654 DOI: 10.1016/j.molbiopara.2006.06.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2006] [Revised: 06/06/2006] [Accepted: 06/07/2006] [Indexed: 11/28/2022]
Abstract
PyMSP-8 is a member of a family of merozoite surface proteins that have been described in Plasmodium that are characterized by the presence of a glycolipid membrane anchor and 1-2 epidermal growth factor-like domains. Immunization with recombinant PyMSP-8 has also been shown to protect mice against lethal Plasmodium yoelii malaria. In this report, we demonstrate that PyMSP-8 expression is detectable throughout the entire erythrocytic life cycle of P. yoelii 17XL, reaching peak level during trophozoite development. As determined by immunofluorescence, PyMSP-8 co-localizes with PyMSP-1 on the surface of merozoites in segmented schizonts and on the surface of ring stages in newly invaded erythrocytes. PyMSP-8 binds to the surface of uninfected mouse RBCs in a species-dependent manner, suggesting a potential role in merozoite attachment to and/or invasion of erythrocytes. The receptor for PyMSP-8 on RBCs is sensitive to trypsin digestion but is resistant to treatment with chymotrypsin or neuraminidase and is putatively identified as a approximately 105kDa membrane protein. Since PyMSP-8 binds to both mature RBCs as well as reticulocytes, it appears unlikely that the function of PyMSP-8 is restricted to the invasion of normocytes. While proper folding and conformation of PyMSP-8 are important, linear determinants of PyMSP-8 also contribute to erythrocyte binding. Unexpectedly, however, PyMSP-8 specific antibodies that are protective in vivo, do not disrupt the binding of rPyMSP-8 to its receptor on erythrocytes. The data indicate that protective anti-PyMSP-8 antibodies mediate their effect in vivo by an alternate mechanism(s).
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Affiliation(s)
- Qifang Shi
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA 19129, United States
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49
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Abstract
That humans in endemic areas become immune to malaria offers encouragement to the idea of developing protective vaccines. However natural immunity is relatively inefficient, being bought at the cost of substantial childhood mortality, and current vaccines are only partially protective. Understanding potential targets and mechanisms of protective immunity is important in the development and evaluation of future vaccines. Some of the problems in identifying such targets and mechanisms in humans naturally exposed to malaria may stem from conceptual and methodological issues related to defining who in a population is susceptible, problems in defining immune responsiveness at single time points and issues related to antigenic polymorphism, as well as the failure of many current approaches to examine functional aspects of the immune response. Protective immune responses may be directed to the pre erythrocytic parasite, to the free merozoite of the blood stage parasite or to new antigens induced on the infected red cell surface. Tackling the methodological issues of defining protection and immune response, together with studies that combine functional assays with new approaches such as allelic exchange and gene knock out offer opportunities for better defining key targets and mechanisms.
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Affiliation(s)
- K Marsh
- KEMRI Centre for Geographic Medicine Research Coast (CGMRC), PO Box 230, Kilifi, Kenya.
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50
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Valderrama-Aguirre A, Quintero G, Gómez A, Castellanos A, Pérez Y, Méndez F, Arévalo-Herrera M, Herrera S. ANTIGENICITY, IMMUNOGENICITY, AND PROTECTIVE EFFICACY OF PLASMODIUM VIVAX MSP1 PV200L: A POTENTIAL MALARIA VACCINE SUBUNIT. Am J Trop Med Hyg 2005; 73:16-24. [PMID: 16291762 DOI: 10.4269/ajtmh.2005.73.16] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The merozoite surface protein 1 (MSP-1) is expressed in all Plasmodium species and is considered a major malaria vaccine candidate. We found that MSP-1 from Plasmodium vivax (PvMSP-1) contains a region of significant sequence homology with the 190L subunit vaccine derived from the P. falciparum MSP-1. The fragment, termed Pv200L, was expressed as a recombinant protein in Escherichia coli (rPv200L) and used to asses its immunologic relevance as a vaccine target. A cross-sectional, seroepidemiologic study conducted in Buenaventura, Colombia showed that 52.2% (95% confidence interval [CI] = 39.8-64.3) of individuals previously exposed to P. vivax and 72.8% (95% CI = 61.8-82.1) of P. vivax-infected patients had IgG antibodies to rPv200L. Immunization of BALB/c mice and Aotus monkeys induced IgG antibodies (titer > 10(6)) that cross-reacted with P. vivax parasites. Immunized monkeys displayed partial protection against a challenge with P. vivax blood stages. Our results suggest that Pv200L is a new malaria vaccine subunit and deserves further testing.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antibodies, Protozoan/blood
- Antigens, Protozoan/chemistry
- Antigens, Protozoan/genetics
- Antigens, Protozoan/immunology
- Antigens, Protozoan/metabolism
- Antigens, Surface/chemistry
- Antigens, Surface/genetics
- Antigens, Surface/immunology
- Antigens, Surface/metabolism
- Cebidae
- Colombia/epidemiology
- Cross-Sectional Studies
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Humans
- Immunization
- Immunoglobulin G/blood
- Malaria Vaccines/administration & dosage
- Malaria Vaccines/genetics
- Malaria Vaccines/immunology
- Malaria, Vivax/epidemiology
- Malaria, Vivax/immunology
- Malaria, Vivax/prevention & control
- Merozoite Surface Protein 1/chemistry
- Mice
- Mice, Inbred BALB C
- Molecular Sequence Data
- Plasmodium vivax/immunology
- Plasmodium vivax/pathogenicity
- Recombinant Proteins/genetics
- Recombinant Proteins/immunology
- Recombinant Proteins/metabolism
- Seroepidemiologic Studies
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