1
|
Van Gompel E, Demirdal D, Fernandes-Cerqueira C, Horuluoglu B, Galindo-Feria A, Wigren E, Gräslund S, De Langhe E, Benveniste O, Notarnicola A, Chemin K, Lundberg IE. Autoantibodies against the melanoma differentiation-associated protein 5 in patients with dermatomyositis target the helicase domains. Rheumatology (Oxford) 2024; 63:1466-1473. [PMID: 37572295 PMCID: PMC11065437 DOI: 10.1093/rheumatology/kead400] [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: 04/13/2023] [Revised: 06/30/2023] [Accepted: 07/17/2023] [Indexed: 08/14/2023] Open
Abstract
OBJECTIVES Clinical observations in patients with dermatomyositis (DM) and autoantibodies against the melanoma differentiation-associated protein 5 (MDA5) suggest that the autoantibodies contribute to the pathogenesis of MDA5(+) DM. To gain insight into the role of the anti-MDA5 autoantibodies, we aimed to identify their binding sites on the different domains of the MDA5 protein. METHODS We developed an in-house ELISA to assess the reactivity against the MDA5 domains (conformational epitopes) in plasma (n = 8) and serum (n = 24) samples from MDA5(+) patients with varying clinical manifestations and disease outcomes. The reactivities were also assessed using western blot (linearized epitopes). An ELISA-based depletion assay was developed to assess cross-reactivity among the different MDA5 domains. RESULTS All eight plasma samples consistently showed reactivity towards conformational and linearized epitopes on the helicase domains of the MDA5 protein. The ELISA-based depletion assay suggests that anti-MDA5 autoantibodies specifically target each of the three helicase domains. Twenty-two of the 24 serum samples showed reactivity in the in-house ELISA and all 22 displayed reactivity towards the helicase domains of the MDA5 protein. CONCLUSIONS Our data revealed that the main immunogenic targets of anti-MDA5 autoantibodies from MDA5(+) patients are the helicase domains. Considering that the helicase domains are responsible for the enzymatic activity and subsequent triggering of an inflammatory response, our findings suggest that binding of anti-MDA5 autoantibodies could alter the canonical activity of the MDA5 protein and potentially affect the downstream induction of a pro-inflammatory cascade.
Collapse
Affiliation(s)
- Eveline Van Gompel
- Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
- Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
- Laboratory of Tissue Homeostasis and Disease, Skeletal Biology and Engineering Research Center, Department of Development and Regeneration, KU Leuven, Leuven, Belgium
| | - Deniz Demirdal
- Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
- Department of Gastro, Dermatology and Rheumatology, Karolinska University Hospital, Stockholm, Sweden
| | - Catia Fernandes-Cerqueira
- Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
- Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Begum Horuluoglu
- Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
- Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Angeles Galindo-Feria
- Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
- Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
- Department of Gastro, Dermatology and Rheumatology, Karolinska University Hospital, Stockholm, Sweden
| | - Edvard Wigren
- Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
- Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
- Structural Genomics Consortium, Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - Susanne Gräslund
- Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
- Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
- Structural Genomics Consortium, Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - Ellen De Langhe
- Laboratory of Tissue Homeostasis and Disease, Skeletal Biology and Engineering Research Center, Department of Development and Regeneration, KU Leuven, Leuven, Belgium
- Division of Rheumatology, University Hospitals Leuven, Leuven, Belgium
| | - Olivier Benveniste
- Centre de Recherche en Myologie, Unité Mixte de Recherche Scientifique 974, Sorbonne Université, INSERM, Paris, France
- Département de Médecine Interne et Immunologie Clinique, Centre de Référence Maladies Neuro-Musculaires, Assistance Publique-Hôpitaux de Paris, Groupe Hospitalier Pitié-Salpêtrière, Paris, France
| | - Antonella Notarnicola
- Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
- Department of Gastro, Dermatology and Rheumatology, Karolinska University Hospital, Stockholm, Sweden
| | - Karine Chemin
- Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
- Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Ingrid E Lundberg
- Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
- Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
- Department of Gastro, Dermatology and Rheumatology, Karolinska University Hospital, Stockholm, Sweden
| |
Collapse
|
2
|
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.
Collapse
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.
| |
Collapse
|
3
|
Bowman NM, Juliano JJ, Snider CJ, Kharabora O, Meshnick SR, Vulule J, John CC, Moormann AM. Longevity of Genotype-Specific Immune Responses to Plasmodium falciparum Merozoite Surface Protein 1 in Kenyan Children from Regions of Different Malaria Transmission Intensity. Am J Trop Med Hyg 2016; 95:580-7. [PMID: 27481054 DOI: 10.4269/ajtmh.15-0710] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 06/02/2016] [Indexed: 01/06/2023] Open
Abstract
Naturally acquired immunity to Plasmodium falciparum presents a changing landscape as malaria control programs and vaccine initiatives are implemented. Determining which immunologic indicators remain surrogates of past infection, as opposed to mediators of protection, led us to compare stability of immune responses across regions with divergent malaria transmission intensities. A repeat cross-sectional study of Kenyan children from a malaria-holoendemic area and an epidemic-prone area was used to examine longitudinal antibody and interferon-gamma (IFN-γ) responses to the 3D7 and FVO variants of merozoite surface protein 1 (MSP1). Antibodies to MSP1 were common in both study populations and did not significantly wane over a 21-month time period. IFN-γ responses were less frequent and rapidly disappeared in children after a prolonged period of no malaria transmission. Antibody and IFN-γ responses rarely correlated with each other; however, MSP1-specific IFN-γ response correlated with lack of concurrent P. falciparum parasitemia of the same genotype, though only statistically significantly in the malaria-holoendemic region (odds ratio = 0.31, 95% confidence interval = 0.12-0.84). This study affirms that antimalarial antibodies are informative for evaluation of history of malaria exposure within individuals, whereas cell-mediated immunity, though short lived under natural exposure conditions, might provide an assessment of recent infection and protection from parasitemia.
Collapse
Affiliation(s)
- Natalie M Bowman
- Division of Infectious Diseases, University of North Carolina, School of Medicine, Chapel Hill, North Carolina
| | - Jonathan J Juliano
- Division of Infectious Diseases, University of North Carolina, School of Medicine, Chapel Hill, North Carolina. Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina. Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, North Carolina.
| | - Cynthia J Snider
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Oksana Kharabora
- Division of Infectious Diseases, University of North Carolina, School of Medicine, Chapel Hill, North Carolina
| | - Steven R Meshnick
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - John Vulule
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Chandy C John
- Ryan White Center for Pediatric Infectious Disease and Global Health, Indiana University, Indianapolis, Indiana
| | - Ann M Moormann
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts
| |
Collapse
|
4
|
Spring MD, Pichyangkul S, Lon C, Gosi P, Yongvanichit K, Srichairatanakul U, Limsalakpeth A, Chaisatit C, Chann S, Sriwichai S, Auayapon M, Chaorattanakawee S, Dutta S, Prom S, Meng Chour C, Walsh DS, Angov E, Saunders DL. Antibody profiles to plasmodium merozoite surface protein-1 in Cambodian adults during an active surveillance cohort with nested treatment study. Malar J 2016; 15:17. [PMID: 26747132 PMCID: PMC4706704 DOI: 10.1186/s12936-015-1058-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2015] [Accepted: 12/17/2015] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND In addition to evidence for a protective role of antibodies to the malaria blood stage antigen merozoite surface protein 1 (MSP1), MSP1 antibodies are also considered as a marker of past malaria exposure in sero-epidemiological studies. METHODS In order to better assess the potential use of MSP1 serology in malaria chemoprophylaxis trials in endemic areas, an analysis for the prevalence of antibodies to both Plasmodium falciparum and Plasmodium vivax MSP142 in healthy Cambodian adults was conducted at two sites as part of an active, observational cohort evaluating the efficacy of dihydroartemisinin-piperaquine (DP) for uncomplicated malaria (ClinicalTrials.gov identifier NCT01280162). RESULTS Rates of baseline sero-positivity were high (59 and 73% for PfMSP142 and PvMSP142, respectively), and titers higher in those who lived in a higher transmission area, although there was little correlation in titers between the two species. Those volunteers who subsequently went on to develop malaria had higher baseline MSP142 titers than those who did not for both species. Titers to both antigens remained largely stable over the course of the 4-6 month study, except in those infected with P. falciparum who had multiple recurrences. CONCLUSION These findings illuminate the difficulties in using MSP142 serology as either a screening criterion and/or biomarker of exposure in chemoprophylaxis studies. Further work remains to identify useful markers of malarial infection and/or immunity.
Collapse
Affiliation(s)
- Michele D Spring
- Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand.
| | - Sathit Pichyangkul
- Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand.
| | - Chanthap Lon
- Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand.
| | - Panita Gosi
- Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand.
| | - Kosol Yongvanichit
- Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand.
| | | | - Amporn Limsalakpeth
- Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand.
| | - Chaiyaporn Chaisatit
- Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand.
| | - Soklyda Chann
- Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand.
| | - Sabaithip Sriwichai
- Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand.
| | - Montida Auayapon
- Center of Excellence for Biomedical and Public Health Informatics (BIOPHICS), Bangkok, Thailand.
| | | | - Sheetij Dutta
- Walter Reed Army Institute of Research, Silver Spring, MD, USA.
| | | | - Char Meng Chour
- National Center for Parasitology, Entomology and Malaria Control (CNM), Phnom Penh, Cambodia.
| | | | - Evelina Angov
- Walter Reed Army Institute of Research, Silver Spring, MD, USA.
| | - David L Saunders
- Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand.
| |
Collapse
|
5
|
Valizadeh V, Zakeri S, Mehrizi AA, Djadid ND. Non-allele specific antibody responses to genetically distinct variant forms of Plasmodium vivax Duffy binding protein (PvDBP-II) in Iranians exposed to seasonal malaria transmission. Acta Trop 2014; 136:89-100. [PMID: 24704284 DOI: 10.1016/j.actatropica.2014.03.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2013] [Revised: 03/17/2014] [Accepted: 03/24/2014] [Indexed: 10/25/2022]
Abstract
Duffy binding protein (DBP) is a leading vaccine candidate of Plasmodium vivax. The binding domain of DBP (DBP-II) is polymorphic, that may be a major challenge for development of a broadly effective vaccine against vivax malaria. The present investigation was undertaken to explore whether the sequence diversity of DBP-II causes variation in naturally acquired anti-DBP-II antibodies. In this study, the five genetically distinct variants were expressed, and anti-DBP-II responses were measured in P. vivax-infected individuals (n=202). Finally, by performing immune-depletion ELISA experiments, antibody responses to the conserved sites of all allelic forms were evaluated using the corresponding and non-corresponding patients' sera (n=20). In this study, natural P. vivax infection produces IgG against all five examined variant forms of PvDBP-II with no statistically difference. Sequence analysis in the 20 selected samples (for antibody depletion experiment) showed eight distinct haplotypes, DBPI (n=1), DBPIII (n=3), DBPIV (n=1), DBPV (n=1), DBPVI (n=5), DBPIX (n=6), DBPX (n=1), and DBP XI (n=2). The results showed the presence of the cross-reactive antibody responses to heterologous variants of PvDBP-II in Iranian individuals who were infected with distinct allelic forms of the PvDBP-II. Therefore, it is proposed that the majority of antibodies recognized sharing B-cell epitopes and this could overcome the PvDBP-II variation as a one of the biggest challenges of PvDBP-II-based vaccine development.
Collapse
|
6
|
Villasis E, Lopez-Perez M, Torres K, Gamboa D, Neyra V, Bendezu J, Tricoche N, Lobo C, Vinetz JM, Lustigman S. Anti-Plasmodium falciparum invasion ligand antibodies in a low malaria transmission region, Loreto, Peru. Malar J 2012; 11:361. [PMID: 23110555 PMCID: PMC3544580 DOI: 10.1186/1475-2875-11-361] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Accepted: 10/25/2012] [Indexed: 02/03/2023] Open
Abstract
Background Erythrocyte invasion by Plasmodium falciparum is a complex process that involves two families; Erythrocyte Binding-Like (EBL) and the Reticulocyte Binding-Like (PfRh) proteins. Antibodies that inhibit merozoite attachment and invasion are believed to be important in mediating naturally acquired immunity and immunity generated by parasite blood stage vaccine candidates. The hypotheses tested in this study were 1) that antibody responses against specific P. falciparum invasion ligands (EBL and PfRh) differ between symptomatic and asymptomatic individuals living in the low-transmission region of the Peruvian Amazon and 2), such antibody responses might have an association, either direct or indirect, with clinical immunity observed in asymptomatically parasitaemic individuals. Methods ELISA was used to assess antibody responses (IgG, IgG1 and IgG3) against recombinant P. falciparum invasion ligands of the EBL (EBA-175, EBA-181, EBA-140) and PfRh families (PfRh1, PfRh2a, PfRh2b, PfRh4 and PfRh5) in 45 individuals infected with P. falciparum from Peruvian Amazon. Individuals were classified as having symptomatic malaria (N=37) or asymptomatic infection (N=8). Results Antibody responses against both EBL and PfRh family proteins were significantly higher in asymptomatic compared to symptomatic individuals, demonstrating an association with clinical immunity. Significant differences in the total IgG responses were observed with EBA-175, EBA-181, PfRh2b, and MSP119 (as a control). IgG1 responses against EBA-181, PfRh2a and PfRh2b were significantly higher in the asymptomatic individuals. Total IgG antibody responses against PfRh1, PfRh2a, PfRh2b, PfRh5, EBA-175, EBA-181 and MSP119 proteins were negatively correlated with level of parasitaemia. IgG1 responses against EBA-181, PfRh2a and PfRh2b and IgG3 response for PfRh2a were also negatively correlated with parasitaemia. Conclusions These data suggest that falciparum malaria patients who develop clinical immunity (asymptomatic parasitaemia) in a low transmission setting such as the Peruvian Amazon have antibody responses to defined P. falciparum invasion ligand proteins higher than those found in symptomatic (non-immune) patients. While these findings will have to be confirmed by larger studies, these results are consistent with a potential role for one or more of these invasion ligands as a component of an anti-P. falciparum vaccine in low-transmission malaria-endemic regions.
Collapse
Affiliation(s)
- Elizabeth Villasis
- Malaria Laboratory, Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru
| | | | | | | | | | | | | | | | | | | |
Collapse
|
7
|
Quantification of Plasmodium falciparum malaria from complex infections in the Peruvian Amazon using quantitative PCR of the merozoite surface protein 1, block 2 (PfMSP1-B2): in vitro dynamics reveal density-dependent interactions. Parasitology 2012; 139:701-8. [PMID: 22339946 DOI: 10.1017/s0031182011002393] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The majority of Plasmodium falciparum field isolates are defined as complex infections because they contain multiple genetically distinct clones. Studying interactions between clones in complex infections in vivo and in vitro could elucidate important phenomena in malaria infection, transmission and treatment. Using quantitative PCR (qPCR) of the P. falciparum merozoite surface protein 1, block 2 (PfMSP1-B2), we provide a sensitive and efficient genotyping method. This is important for epidemiological studies because it makes it possible to study genotype-specific growth dynamics. We compared 3 PfMSP1-B2 genotyping methods by analysing 79 field isolates from the Peruvian Amazon. In vivo observations from other studies using these techniques led to the hypothesis that clones within complex infections interact. By co-culturing clones with different PfMSP1-B2 genotypes, and measuring parasitaemia using qPCR, we found that suppression of clonal expansion was a factor of the collective density of all clones present in a culture. PfMSP1-B2 qPCR enabled us to find in vitro evidence for parasite-parasite interactions and could facilitate future investigations of growth trends in naturally occurring complex infections.
Collapse
|
8
|
Plasmodium falciparum malaria in the Peruvian Amazon, a region of low transmission, is associated with immunologic memory. Infect Immun 2012; 80:1583-92. [PMID: 22252876 DOI: 10.1128/iai.05961-11] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The development of clinical immunity to Plasmodium falciparum malaria is thought to require years of parasite exposure, a delay often attributed to difficulties in developing protective antibody levels. In this study, we evaluated several P. falciparum vaccine candidate antigens, including apical membrane antigen 1 (AMA-1), circumsporozoite protein (CSP), erythrocyte binding antigen 175 (EBA-175), and the 19-kDa region of merozoite surface protein 1 (MSP1(19)). After observing a more robust antibody response to MSP1(19), we evaluated the magnitude and longevity of IgG responses specific to this antigen in Peruvian adults and children before, during, and after P. falciparum infection. In this low-transmission region, even one reported prior infection was sufficient to produce a positive anti-MSP1(19) IgG response for >5 months in the absence of reinfection. We also observed an expansion of the total plasmablast (CD19(+) CD27(+) CD38(high)) population in the majority of individuals shortly after infection and detected MSP1-specific memory B cells in a subset of individuals at various postinfection time points. This evidence supports our hypothesis that effective antimalaria humoral immunity can develop in low-transmission regions.
Collapse
|
9
|
Lourembam SD, Baruah S. Antibody response to allelic variants of 19kDa fragment of MSP-1: Recognition of a variant and protection associated with ethnicity in Assam, India. Vaccine 2012; 30:767-73. [DOI: 10.1016/j.vaccine.2011.11.069] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2011] [Revised: 11/06/2011] [Accepted: 11/16/2011] [Indexed: 11/29/2022]
|
10
|
Sexual recombination is a signature of a persisting malaria epidemic in Peru. Malar J 2011; 10:329. [PMID: 22039962 PMCID: PMC3231964 DOI: 10.1186/1475-2875-10-329] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Accepted: 10/31/2011] [Indexed: 11/22/2022] Open
Abstract
Background The aim of this study was to consider the impact that multi-clone, complex infections have on a parasite population structure in a low transmission setting. In general, complexity of infection (minimum number of clones within an infection) and the overall population level diversity is expected to be minimal in low transmission settings. Additionally, the parasite population structure is predicted to be clonal, rather than sexual due to infrequent parasite inoculation and lack of recombination between genetically distinct clones. However, in this low transmission of the Peruvian Amazon, complex infections are becoming more frequent, in spite of decreasing infection prevalence. In this study, it was hypothesized that sexual recombination between distinct clonal lineages of Plasmodium falciparum parasites were altering the subpopulation structure and effectively maintaining the population-level diversity. Methods Fourteen microsatellite markers were chosen to describe the genetic diversity in 313 naturally occurring P. falciparum infections from Peruvian Amazon. The population and subpopulation structure was characterized by measuring: clusteredness, expected heterozygosity (He), allelic richness, private allelic richness, and linkage disequilibrium. Next, microsatellite haplotypes and alleles were correlated with P. falciparum merozoite surface protein 1 Block 2 (Pfmsp1-B2) to examine the presence of recombinant microsatellite haplotypes. Results The parasite population structure consists of six genetically diverse subpopulations of clones, called "clusters". Clusters 1, 3, 4, and 6 have unique haplotypes that exceed 70% of the total number of clones within each cluster, while Clusters 2 and 5 have a lower proportion of unique haplotypes, but still exceed 46%. By measuring the He, allelic richness, and private allelic richness within each of the six subpopulations, relatively low levels of genetic diversity within each subpopulation (except Cluster 4) are observed. This indicated that the number of alleles, and not the combination of alleles, are limited. Next, the standard index of association (IAS) was measured, which revealed a significant decay in linkage disequilibrium (LD) associated with Cluster 6, which is indicative of independent assortment of alleles. This decay in LD is a signature of this subpopulation approaching linkage equilibrium by undergoing sexual recombination. To trace possible recombination events, the two most frequent microsatellite haplotypes observed over time (defined by either a K1 or Mad20) were selected as the progenitors and then potential recombinants were identified in within the natural population. Conclusions Contrary to conventional low transmission models, this study provides evidence of a parasite population structure that is superficially defined by a clonal backbone. Sexual recombination does occur and even arguably is responsible for maintaining the substructure of this population.
Collapse
|
11
|
Malaria immunoepidemiology in low transmission: correlation of infecting genotype and immune response to domains of Plasmodium falciparum merozoite surface protein 3. Infect Immun 2011; 79:2070-8. [PMID: 21383051 DOI: 10.1128/iai.01332-10] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Malaria caused by Plasmodium falciparum is a major cause of global infant mortality, and no effective vaccine currently exists. Multiple potential vaccine targets have been identified, and immunoepidemiology studies have played a major part in assessing those candidates. When such studies are carried out in high-transmission settings, individuals are often superinfected with complex mixtures of genetically distinct P. falciparum types, making it impossible to directly correlate the genotype of the infecting antigen with the antibody response. In contrast, in regions of low transmission P. falciparum infections are often genetically simple, and direct comparison of infecting genotype and antigen-specific immune responses is possible. As a test of the utility of this approach, responses against several domains and allelic variants of the vaccine candidate P. falciparum merozoite surface protein 3 (PfMSP3) were tested in serum samples collected near Iquitos, Peru. Antibodies recognizing both the conserved C-terminal and the more variable N-terminal domain were identified, but anti-N-terminal responses were more prevalent, of higher titers, and primarily of cytophilic subclasses. Comparing antibody responses to different PfMSP3 variants with the PfMSP3 genotype present at the time of infection showed that anti-N-terminal responses were largely allele class specific, but there was some evidence for responses that cross-reacted across allele classes. Evidence for cross-reactive responses was much stronger when variants within one allele class were tested, which has implications for the rational development of genotype-transcending PfMSP3-based vaccines.
Collapse
|
12
|
Branch OH, Sutton PL, Barnes C, Castro JC, Hussin J, Awadalla P, Hijar G. Plasmodium falciparum genetic diversity maintained and amplified over 5 years of a low transmission endemic in the Peruvian Amazon. Mol Biol Evol 2010; 28:1973-86. [PMID: 21109587 PMCID: PMC3112368 DOI: 10.1093/molbev/msq311] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Plasmodium falciparum entered into the Peruvian Amazon in 1994, sparking an epidemic between 1995 and 1998. Since 2000, there has been sustained low P. falciparum transmission. The Malaria Immunology and Genetics in the Amazon project has longitudinally followed members of the community of Zungarococha (N = 1,945, 4 villages) with active household and health center-based visits each year since 2003. We examined parasite population structure and traced the parasite genetic diversity temporally and spatially. We genotyped infections over 5 years (2003–2007) using 14 microsatellite (MS) markers scattered across ten different chromosomes. Despite low transmission, there was considerable genetic diversity, which we compared with other geographic regions. We detected 182 different haplotypes from 302 parasites in 217 infections. Structure v2.2 identified five clusters (subpopulations) of phylogenetically related clones. To consider genetic diversity on a more detailed level, we defined haplotype families (hapfams) by grouping haplotypes with three or less loci differences. We identified 34 different hapfams identified. The Fst statistic and heterozygosity analysis showed the five clusters were maintained in each village throughout this time. A minimum spanning network (MSN), stratified by the year of detection, showed that haplotypes within hapfams had allele differences and haplotypes within a cluster definition were more separated in the later years (2006–2007). We modeled hapfam detection and loss, accounting for sample size and stochastic fluctuations in frequencies overtime. Principle component analysis of genetic variation revealed patterns of genetic structure with time rather than village. The population structure, genetic diversity, appearance/disappearance of the different haplotypes from 2003 to 2007 provides a genome-wide “real-time” perspective of P. falciparum parasites in a low transmission region.
Collapse
Affiliation(s)
- Oralee H Branch
- Department of Medical Parasitology, New York University, USA.
| | | | | | | | | | | | | |
Collapse
|
13
|
Non-variant specific antibody responses to the C-terminal region of merozoite surface protein-1 of Plasmodium falciparum (PfMSP-119) in Iranians exposed to unstable malaria transmission. Malar J 2010; 9:257. [PMID: 20846388 PMCID: PMC2945361 DOI: 10.1186/1475-2875-9-257] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Accepted: 09/16/2010] [Indexed: 11/12/2022] Open
Abstract
Background The C-terminal region of Plasmodium falciparum merozoite surface protein-1 (PfMSP-119) is a leading malaria vaccine candidate antigen. However, the existence of different variants of this antigen can limit efficacy of the vaccine development based on this protein. Therefore, in this study, the main objective was to define the frequency of PfMSP-119 haplotypes in malaria hypoendemic region of Iran and also to analyse cross-reactive and/or variant-specific antibody responses to four PfMSP-119 variant forms. Methods The PfMSP-119 was genotyped in 50 infected subjects with P. falciparum collected during 2006-2008. Four GST-PfMSP-119 variants (E/TSR/L, E/TSG/L, E/KNG/F and Q/KNG/L) were produced in Escherichia coli and naturally occurring IgG antibody to these proteins was evaluated in malaria patients' sera (n = 50) using ELISA. To determine the cross-reactivity of antibodies against each PfMSP-119 variant in P. falciparum-infected human sera, an antibody depletion assay was performed in eleven corresponding patients' sera. Results Sequence data of the PfMSP-119 revealed five variant forms in which the haplotypes Q/KNG/L and Q/KNG/F were predominant types and the second most frequent haplotype was E/KNG/F. In addition, the prevalence of IgG antibodies to all four PfMSP-119 variant forms was equal and high (84%) among the studied patients' sera. Immunodepletion results showed that in Iranian malaria patients, Q/KNG/L variant could induce not only cross-reactive antibody responses to other PfMSP-119 variants, but also could induce some specific antibodies that are not able to recognize the E/TSG/L or E/TSR/L variant forms. Conclusion The present findings demonstrated the presence of non-variant specific antibodies to PfMSP-119 in Iranian falciparum malaria patients. This data suggests that polymorphism in PfMSP-119 is less important and one variant of this antigen, particularly Q/KNG/L, may be sufficient to be included in PfMSP-119-based vaccine.
Collapse
|