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Biabi MFAB, Fogang B, Essangui E, Maloba F, Donkeu C, Keumoe R, Cheteug G, Magoudjou N, Slam C, Kemleu S, Efange N, Perraut R, Nsango SE, Eboumbou Moukoko CE, Assam JPA, Etoa FX, Lamb T, Ayong L. High Prevalence of Polyclonal Plasmodium falciparum Infections and Association with Poor IgG Antibody Responses in a Hyper-Endemic Area in Cameroon. Trop Med Infect Dis 2023; 8:390. [PMID: 37624328 PMCID: PMC10459087 DOI: 10.3390/tropicalmed8080390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 06/29/2023] [Accepted: 06/30/2023] [Indexed: 08/26/2023] Open
Abstract
Malaria remains a major public health problem worldwide, with eradication efforts thwarted by drug and insecticide resistance and the lack of a broadly effective malaria vaccine. In continuously exposed communities, polyclonal infections are thought to reduce the risk of severe disease and promote the establishment of asymptomatic infections. We sought to investigate the relationship between the complexity of P. falciparum infection and underlying host adaptive immune responses in an area with a high prevalence of asymptomatic parasitaemia in Cameroon. A cross-sectional study of 353 individuals aged 2 to 86 years (median age = 16 years) was conducted in five villages in the Centre Region of Cameroon. Plasmodium falciparum infection was detected by multiplex nested PCR in 316 samples, of which 278 were successfully genotyped. Of these, 60.1% (167/278) were polyclonal infections, the majority (80.2%) of which were from asymptomatic carriers. Host-parasite factors associated with polyclonal infection in the study population included peripheral blood parasite density, participant age and village of residence. The number of parasite clones per infected sample increased significantly with parasite density (r = 0.3912, p < 0.0001) but decreased with participant age (r = -0.4860, p < 0.0001). Parasitaemia and the number of clones per sample correlated negatively with total plasma levels of IgG antibodies to three highly reactive P. falciparum antigens (MSP-1p19, MSP-3 and EBA175) and two soluble antigen extracts (merozoite and mixed stage antigens). Surprisingly, we observed no association between the frequency of polyclonal infection and susceptibility to clinical disease as assessed by the recent occurrence of malarial symptoms or duration since the previous fever episode. Overall, the data indicate that in areas with the high perennial transmission of P. falciparum, parasite polyclonality is dependent on underlying host antibody responses, with the majority of polyclonal infections occurring in persons with low levels of protective anti-plasmodial antibodies.
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Affiliation(s)
- Marie Florence A Bite Biabi
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaounde BP 1274, Cameroon; (M.F.A.B.B.); (B.F.); (E.E.); (F.M.); (C.D.); (R.K.); (G.C.); (N.M.); (S.K.); (N.E.); (S.E.N.); (C.E.E.M.)
- Department of Biochemistry, Faculty of Science, University of Douala, Douala BP 2701, Cameroon
| | - Balotin Fogang
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaounde BP 1274, Cameroon; (M.F.A.B.B.); (B.F.); (E.E.); (F.M.); (C.D.); (R.K.); (G.C.); (N.M.); (S.K.); (N.E.); (S.E.N.); (C.E.E.M.)
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaounde I, Yaounde BP 812, Cameroon
| | - Estelle Essangui
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaounde BP 1274, Cameroon; (M.F.A.B.B.); (B.F.); (E.E.); (F.M.); (C.D.); (R.K.); (G.C.); (N.M.); (S.K.); (N.E.); (S.E.N.); (C.E.E.M.)
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala BP 2701, Cameroon
| | - Franklin Maloba
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaounde BP 1274, Cameroon; (M.F.A.B.B.); (B.F.); (E.E.); (F.M.); (C.D.); (R.K.); (G.C.); (N.M.); (S.K.); (N.E.); (S.E.N.); (C.E.E.M.)
| | - Christiane Donkeu
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaounde BP 1274, Cameroon; (M.F.A.B.B.); (B.F.); (E.E.); (F.M.); (C.D.); (R.K.); (G.C.); (N.M.); (S.K.); (N.E.); (S.E.N.); (C.E.E.M.)
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaounde I, Yaounde BP 812, Cameroon
| | - Rodrigue Keumoe
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaounde BP 1274, Cameroon; (M.F.A.B.B.); (B.F.); (E.E.); (F.M.); (C.D.); (R.K.); (G.C.); (N.M.); (S.K.); (N.E.); (S.E.N.); (C.E.E.M.)
- Department of Biochemistry, Faculty of Science, University of Yaounde I, Yaounde BP 812, Cameroon
| | - Glwadys Cheteug
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaounde BP 1274, Cameroon; (M.F.A.B.B.); (B.F.); (E.E.); (F.M.); (C.D.); (R.K.); (G.C.); (N.M.); (S.K.); (N.E.); (S.E.N.); (C.E.E.M.)
- Department of Medical Laboratory Sciences, Faculty of Science, University of Buea, Buea BP 63, Cameroon
| | - Nina Magoudjou
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaounde BP 1274, Cameroon; (M.F.A.B.B.); (B.F.); (E.E.); (F.M.); (C.D.); (R.K.); (G.C.); (N.M.); (S.K.); (N.E.); (S.E.N.); (C.E.E.M.)
- Department of Biochemistry, Faculty of Science, University of Yaounde I, Yaounde BP 812, Cameroon
| | - Celine Slam
- Department of Pathology, School of Medicine, University of Utah, 15 N Medical Drive, Salt Lake City, UT 84112, USA;
| | - Sylvie Kemleu
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaounde BP 1274, Cameroon; (M.F.A.B.B.); (B.F.); (E.E.); (F.M.); (C.D.); (R.K.); (G.C.); (N.M.); (S.K.); (N.E.); (S.E.N.); (C.E.E.M.)
| | - Noella Efange
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaounde BP 1274, Cameroon; (M.F.A.B.B.); (B.F.); (E.E.); (F.M.); (C.D.); (R.K.); (G.C.); (N.M.); (S.K.); (N.E.); (S.E.N.); (C.E.E.M.)
- Department of Biochemistry, Faculty of Science, University of Buea, Buea BP 63, Cameroon
| | - Ronald Perraut
- Centre Pasteur du Cameroun Annex, Garoua BP 921, Cameroon;
| | - Sandrine Eveline Nsango
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaounde BP 1274, Cameroon; (M.F.A.B.B.); (B.F.); (E.E.); (F.M.); (C.D.); (R.K.); (G.C.); (N.M.); (S.K.); (N.E.); (S.E.N.); (C.E.E.M.)
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala BP 2701, Cameroon
| | - Carole Else Eboumbou Moukoko
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaounde BP 1274, Cameroon; (M.F.A.B.B.); (B.F.); (E.E.); (F.M.); (C.D.); (R.K.); (G.C.); (N.M.); (S.K.); (N.E.); (S.E.N.); (C.E.E.M.)
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala BP 2701, Cameroon
| | - Jean Paul Assam Assam
- Department of Microbiology, Faculty of Science, University of Yaounde I, Yaounde BP 812, Cameroon; (J.P.A.A.); (F.-X.E.)
| | - François-Xavier Etoa
- Department of Microbiology, Faculty of Science, University of Yaounde I, Yaounde BP 812, Cameroon; (J.P.A.A.); (F.-X.E.)
| | - Tracey Lamb
- Department of Pathology, School of Medicine, University of Utah, 15 N Medical Drive, Salt Lake City, UT 84112, USA;
| | - Lawrence Ayong
- Malaria Research Unit, Centre Pasteur du Cameroun, Yaounde BP 1274, Cameroon; (M.F.A.B.B.); (B.F.); (E.E.); (F.M.); (C.D.); (R.K.); (G.C.); (N.M.); (S.K.); (N.E.); (S.E.N.); (C.E.E.M.)
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Sahu PK, Mohanty S. Pathogenesis of Cerebral Malaria: New Trends and Insights for Developing Adjunctive Therapies. Pathogens 2023; 12:pathogens12040522. [PMID: 37111408 PMCID: PMC10142940 DOI: 10.3390/pathogens12040522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 03/20/2023] [Accepted: 03/21/2023] [Indexed: 03/29/2023] Open
Abstract
No specific or adjunctive therapies exist to treat cerebral malaria (CM) as of date. CM is a neuropathological manifestation of the malaria infection in humans, caused by the hemoparasitic pathogen Plasmodium falciparum. Driven through a multitude of virulence factors, varied immune responses, variations in brain swelling with regard to the age of patients, parasite biomass, and parasite-typing, the essential pathogenetic mechanisms underlying clinical CM have remained elusive. However, a recent series of studies based on molecular, immunologic, and advanced neuroradiologic and machine-learning approaches have unraveled new trends and insights to better understand and focus on the key determinants of CM in humans. This could possibly be the beginning of the design of new and effective adjunctive therapies that may not be common or applicable to the entire malarious world, but that could, rather, be specific to the variations in the determinants of CM.
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B-Cell Epitope Mapping of the Plasmodium falciparum Malaria Vaccine Candidate GMZ2.6c in a Naturally Exposed Population of the Brazilian Amazon. Vaccines (Basel) 2023; 11:vaccines11020446. [PMID: 36851323 PMCID: PMC9966924 DOI: 10.3390/vaccines11020446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 02/09/2023] [Accepted: 02/13/2023] [Indexed: 02/17/2023] Open
Abstract
The GMZ2.6c malaria vaccine candidate is a multi-stage P. falciparum chimeric protein that contains a fragment of the sexual-stage Pfs48/45-6C protein genetically fused to GMZ2, an asexual-stage vaccine construction consisting of the N-terminal region of the glutamate-rich protein (GLURP) and the C-terminal region of the merozoite surface protein-3 (MSP-3). Previous studies showed that GMZ2.6c is widely recognized by antibodies from Brazilian exposed individuals and that its components are immunogenic in natural infection by P. falciparum. In addition, anti-GMZ2.6c antibodies increase with exposure to infection and may contribute to parasite immunity. Therefore, identifying epitopes of proteins recognized by antibodies may be an important tool for understanding protective immunity. Herein, we identify and validate the B-cell epitopes of GMZ2.6c as immunogenic and immunodominant in individuals exposed to malaria living in endemic areas of the Brazilian Amazon. Specific IgG antibodies and subclasses against MSP-3, GLURP, and Pfs48/45 epitopes were detected by ELISA using synthetic peptides corresponding to B-cell epitopes previously described for MSP-3 and GLURP or identified by BepiPred for Pfs48/45. The results showed that the immunodominant epitopes were P11 from GLURP and MSP-3c and DG210 from MSP-3. The IgG1 and IgG3 subclasses were preferentially induced against these epitopes, supporting previous studies that these proteins are targets for cytophilic antibodies, important for the acquisition of protective immunity. Most individuals presented detectable IgG antibodies against Pfs48/45a and/or Pfs48/45b, validating the prediction of linear B-cell epitopes. The higher frequency and antibody levels against different epitopes from GLURP, MSP-3, and Pfs48/45 provide additional information that may suggest the relevance of GMZ2.6c as a multi-stage malaria vaccine candidate.
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Abad P, Marín-García P, Heras M, Fobil JN, Hutchful AG, Diez A, Puyet A, Reyes-Palomares A, Azcárate IG, Bautista JM. Microscopic and submicroscopic infection by Plasmodium falciparum: Immunoglobulin M and A profiles as markers of intensity and exposure. Front Cell Infect Microbiol 2022; 12:934321. [PMID: 36118030 PMCID: PMC9478039 DOI: 10.3389/fcimb.2022.934321] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 08/04/2022] [Indexed: 11/15/2022] Open
Abstract
Assessment of serological Plasmodium falciparum–specific antibodies in highly endemic areas provides valuable information about malaria status and parasite exposure in the population. Although serological evidence of Plasmodium exposure is commonly determined by Plasmodium-specific immunoglobulin G (IgG) levels; IgM and IgA are likely markers of malaria status that remain relatively unexplored. Previous studies on IgM and IgA responses have been based on their affinity for single antigens with shortage of immune responses analysis against the whole Plasmodium proteome. Here, we provide evidence of how P. falciparum infection triggers the production of specific IgM and IgA in plasma and its relationship with parasite density and changes in hematological parameters. A total of 201 individuals attending a hospital in Breman Asikuma, Ghana, were recruited into this study. Total and P. falciparum–specific IgM, IgA, and IgG were assessed by ELISA and examined in relation to age (0–5, 14–49, and ≥50 age ranges); infection (submicroscopic vs. microscopic malaria); pregnancy and hematological parameters. Well-known IgG response was used as baseline control. P. falciparum–specific IgM and IgA levels increased in the population with the age, similarly to IgG. These data confirm that acquired humoral immunity develops by repeated infections through the years endorsing IgM and IgA as exposure markers in endemic malaria regions. High levels of specific IgA and IgM in children were associated with microscopic malaria and worse prognosis, because most of them showed severe anemia. This new finding shows that IgM and IgA may be used as diagnostic markers in this age group. We also found an extremely high prevalence of submicroscopic malaria (46.27% on average) accompanied by IgM and IgA levels indistinguishable from those of uninfected individuals. These data, together with the observed lack of sensitivity of rapid diagnostic tests (RDTs) compared to PCR, invoke the urgent need to implement diagnostic markers for submicroscopic malaria. Overall, this study opens the potential use of P. falciparum–specific IgM and IgA as new serological markers to predict malaria status in children and parasite exposure in endemic populations. The difficulties in finding markers of submicroscopic malaria are highlighted, emphasizing the need to explore this field in depth.
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Affiliation(s)
- Paloma Abad
- Department of Biochemistry and Molecular Biology and Research Institute Hospital 12 de Octubre (Imas12), Universidad Complutense de Madrid, Madrid, Spain
| | | | - Marcos Heras
- Department of Biochemistry and Molecular Biology and Research Institute Hospital 12 de Octubre (Imas12), Universidad Complutense de Madrid, Madrid, Spain
| | - Julius N. Fobil
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Alfred G. Hutchful
- Laboratory of Hematology and Infectious Diseases, Our Lady of Grace Hospital, Breman-Asikuma, Ghana
| | - Amalia Diez
- Department of Biochemistry and Molecular Biology and Research Institute Hospital 12 de Octubre (Imas12), Universidad Complutense de Madrid, Madrid, Spain
| | - Antonio Puyet
- Department of Biochemistry and Molecular Biology and Research Institute Hospital 12 de Octubre (Imas12), Universidad Complutense de Madrid, Madrid, Spain
| | - Armando Reyes-Palomares
- Department of Biochemistry and Molecular Biology and Research Institute Hospital 12 de Octubre (Imas12), Universidad Complutense de Madrid, Madrid, Spain
| | - Isabel G. Azcárate
- Faculty of Health Sciences, Rey Juan Carlos University, Alcorcón, Spain
- *Correspondence: Isabel G. Azcárate, ; José M. Bautista,
| | - José M. Bautista
- Department of Biochemistry and Molecular Biology and Research Institute Hospital 12 de Octubre (Imas12), Universidad Complutense de Madrid, Madrid, Spain
- *Correspondence: Isabel G. Azcárate, ; José M. Bautista,
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Abstract
Apicomplexans are important pathogens that cause severe infections in humans and animals. The biology and pathogeneses of these parasites have shown that proteins are intrinsically modulated during developmental transitions, physiological processes and disease progression. Also, proteins are integral components of parasite structural elements and organelles. Among apicomplexan parasites, Eimeria species are an important disease aetiology for economically important animals wherein identification and characterisation of proteins have been long-winded. Nonetheless, this review seeks to give a comprehensive overview of constitutively expressed Eimeria proteins. These molecules are discussed across developmental stages, organelles and sub-cellular components vis-à-vis their biological functions. In addition, hindsight and suggestions are offered with intention to summarise the existing trend of eimerian protein characterisation and to provide a baseline for future studies.
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Chua CLL, Ng IMJ, Yap BJM, Teo A. Factors influencing phagocytosis of malaria parasites: the story so far. Malar J 2021; 20:319. [PMID: 34271941 PMCID: PMC8284020 DOI: 10.1186/s12936-021-03849-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 07/07/2021] [Indexed: 12/16/2022] Open
Abstract
There are seven known species of Plasmodium spp. that can infect humans. The human host can mount a complex network of immunological responses to fight infection and one of these immune functions is phagocytosis. Effective and timely phagocytosis of parasites, accompanied by the activation of a regulated inflammatory response, is beneficial for parasite clearance. Functional studies have identified specific opsonins, particularly antibodies and distinct phagocyte sub-populations that are associated with clinical protection against malaria. In addition, cellular and molecular studies have enhanced the understanding of the immunological pathways and outcomes following phagocytosis of malaria parasites. In this review, an integrated view of the factors that can affect phagocytosis of infected erythrocytes and parasite components, the immunological consequences and their association with clinical protection against Plasmodium spp. infection is provided. Several red blood cell disorders and co-infections, and drugs that can influence phagocytic capability during malaria are also discussed. It is hoped that an enhanced understanding of this immunological process can benefit the design of new therapeutics and vaccines to combat this infectious disease.
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Affiliation(s)
| | - Ida May Jen Ng
- School of Biosciences, Taylor's University, Subang Jaya, Selangor, Malaysia
| | - Bryan Ju Min Yap
- School of Biosciences, Taylor's University, Subang Jaya, Selangor, Malaysia
| | - Andrew Teo
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore. .,Department of Medicine, The Doherty Institute, University of Melbourne, Victoria, Australia.
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Thouvenel CD, Fontana MF, Netland J, Krishnamurty AT, Takehara KK, Chen Y, Singh S, Miura K, Keitany GJ, Lynch EM, Portugal S, Miranda MC, King NP, Kollman JM, Crompton PD, Long CA, Pancera M, Rawlings DJ, Pepper M. Multimeric antibodies from antigen-specific human IgM+ memory B cells restrict Plasmodium parasites. J Exp Med 2021; 218:211852. [PMID: 33661302 PMCID: PMC7938364 DOI: 10.1084/jem.20200942] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 12/18/2020] [Accepted: 01/21/2021] [Indexed: 12/23/2022] Open
Abstract
Multimeric immunoglobulin-like molecules arose early in vertebrate evolution, yet the unique contributions of multimeric IgM antibodies to infection control are not well understood. This is partially due to the difficulty of distinguishing low-affinity IgM, secreted rapidly by plasmablasts, from high-affinity antibodies derived from later-arising memory cells. We developed a pipeline to express B cell receptors (BCRs) from Plasmodium falciparum–specific IgM+ and IgG+ human memory B cells (MBCs) as both IgM and IgG molecules. BCRs from both subsets were somatically hypermutated and exhibited comparable monomeric affinity. Crystallization of one IgM+ MBC-derived antibody complexed with antigen defined a linear epitope within a conserved Plasmodium protein. In its physiological multimeric state, this antibody displayed exponentially higher antigen binding than a clonally identical IgG monomer, and more effectively inhibited P. falciparum invasion. Forced multimerization of this IgG significantly improved both antigen binding and parasite restriction, underscoring how avidity can alter antibody function. This work demonstrates the potential of high-avidity IgM in both therapeutics and vaccines.
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Affiliation(s)
| | - Mary F Fontana
- Department of Immunology, University of Washington School of Medicine, Seattle, WA
| | - Jason Netland
- Department of Immunology, University of Washington School of Medicine, Seattle, WA
| | | | - Kennidy K Takehara
- Department of Immunology, University of Washington School of Medicine, Seattle, WA
| | - Yu Chen
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, WA
| | - Suruchi Singh
- Vaccine and Infectious Diseases Division, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD
| | - Gladys J Keitany
- Department of Immunology, University of Washington School of Medicine, Seattle, WA
| | - Eric M Lynch
- Department of Biochemistry, University of Washington School of Medicine, Seattle, WA
| | - Silvia Portugal
- Malaria Infection Biology and Immunity Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD
| | - Marcos C Miranda
- Department of Biochemistry, University of Washington School of Medicine, Seattle, WA.,Institute for Protein Design, University of Washington, Seattle, WA
| | - Neil P King
- Department of Biochemistry, University of Washington School of Medicine, Seattle, WA.,Institute for Protein Design, University of Washington, Seattle, WA
| | - Justin M Kollman
- Department of Biochemistry, University of Washington School of Medicine, Seattle, WA
| | - Peter D Crompton
- Malaria Infection Biology and Immunity Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD
| | - Carole A Long
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD
| | - Marie Pancera
- Vaccine and Infectious Diseases Division, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - David J Rawlings
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, WA.,Department of Immunology, University of Washington School of Medicine, Seattle, WA.,Department of Pediatrics, University of Washington School of Medicine, Seattle, WA
| | - Marion Pepper
- Department of Immunology, University of Washington School of Medicine, Seattle, WA
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Ssewanyana I, Rek J, Rodriguez I, Wu L, Arinaitwe E, Nankabirwa JI, Beeson JG, Mayanja-Kizza H, Rosenthal PJ, Dorsey G, Kamya MR, Drakeley C, Greenhouse B, Tetteh KKA. Impact of a Rapid Decline in Malaria Transmission on Antimalarial IgG Subclasses and Avidity. Front Immunol 2021; 11:576663. [PMID: 33584643 PMCID: PMC7873448 DOI: 10.3389/fimmu.2020.576663] [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: 07/13/2020] [Accepted: 11/17/2020] [Indexed: 11/19/2022] Open
Abstract
Understanding how immunity to malaria is affected by declining transmission is important to aid vaccine design and understand disease resurgence. Both IgG subclasses and avidity of antigen-specific responses are important components of an effective immune response. Using a multiplex bead array assay, we measured the total IgG, IgG subclasses, and avidity profiles of responses to 18 P. falciparum blood stage antigens in samples from 160 Ugandans collected at two time points during high malaria transmission and two time points following a dramatic reduction in transmission. Results demonstrated that, for the antigens tested, (i) the rate of decay of total IgG following infection declined with age and was driven consistently by the decrease in IgG3 and occasionally the decrease in IgG1; (ii) the proportion of IgG3 relative to IgG1 in the absence of infection increased with age; (iii) the increase in avidity index (the strength of association between the antibody and antigen) following infection was largely due to a rapid loss of non-avid compared to avid total IgG; and (iv) both avid and non-avid total IgG in the absence of infection increased with age. Further studies are required to understand the functional differences between IgG1 and IgG3 in order to determine their contribution to the longevity of protective immunity to malaria. Measuring changes in antibody avidity may be a better approach of detecting affinity maturation compared to avidity index due to the differential expansion and contraction of high and low avidity total IgG.
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Affiliation(s)
- Isaac Ssewanyana
- Infectious Diseases Research Collaboration, Kampala, Uganda.,Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - John Rek
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Isabel Rodriguez
- Department of Medicine, University of California San Francisco, San Francisco, CA, United States
| | - Lindsey Wu
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Emmanuel Arinaitwe
- Infectious Diseases Research Collaboration, Kampala, Uganda.,Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Joaniter I Nankabirwa
- Infectious Diseases Research Collaboration, Kampala, Uganda.,School of Medicine, Makerere University, Kampala, Uganda
| | - James G Beeson
- Burnet Institute, Melbourne, VIC, Australia.,Central Clinical School, Monash University, Melbourne, VIC, Australia.,Department of Medicine, University of Melbourne, Melbourne, VIC, Australia
| | | | - Philip J Rosenthal
- Department of Medicine, University of California San Francisco, San Francisco, CA, United States
| | - Grant Dorsey
- Department of Medicine, University of California San Francisco, San Francisco, CA, United States
| | - Moses R Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda.,School of Medicine, Makerere University, Kampala, Uganda
| | - Chris Drakeley
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Bryan Greenhouse
- Department of Medicine, University of California San Francisco, San Francisco, CA, United States.,Chan Zuckerberg Biohub, San Francisco, CA, United States
| | - Kevin K A Tetteh
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
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9
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Li C, Zhao Q, Zhu S, Wang Q, Wang H, Yu S, Yu Y, Liang S, Zhao H, Huang B, Dong H, Han H. Eimeria tenella Eimeria-specific protein that interacts with apical membrane antigen 1 (EtAMA1) is involved in host cell invasion. Parasit Vectors 2020; 13:373. [PMID: 32711572 PMCID: PMC7382093 DOI: 10.1186/s13071-020-04229-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 07/15/2020] [Indexed: 11/10/2022] Open
Abstract
Background Avian coccidiosis is a widespread, economically significant disease of poultry, caused by several Eimeria species. These parasites have complex and diverse life-cycles that require invasion of their host cells. This is mediated by various proteins secreted from apical secretory organelles. Apical membrane antigen 1 (AMA1), which is released from micronemes and is conserved across all apicomplexans, plays a central role in the host cell invasion. In a previous study, some putative EtAMA1-interacting proteins of E. tenella were screened. In this study, we characterized one putative EtAMA1-interacting protein, E. tenella Eimeria -specific protein (EtEsp). Methods Bimolecular fluorescence complementation (BiFC) and glutathione S-transferase (GST) fusion protein pull-down (GST pull-down) were used to confirm the interaction between EtAMA1 and EtEsp in vivo and in vitro. The expression of EtEsp was analyzed in different developmental stages of E. tenella with quantitative PCR and western blotting. The secretion of EtEsp protein was tested with staurosporine when sporozoites were incubated in complete medium at 41 °C. The localization of EtEsp was analyzed with an immunofluorescence assay (IFA). An in vitro invasion inhibition assay was conducted to assess the ability of antibodies against EtEsp to inhibit cell invasion by E. tenella sporozoites. Results The interaction between EtAMA1 and EtEsp was confirmed with BiFC and by GST pull-down. Our results show that EtEsp is differentially expressed during distinct phases of the parasite life-cycle. IFA showed that the EtEsp protein is mainly distributed on the parasite surface, and that the expression of this protein increases during the development of the parasite in the host cells. Using staurosporine, we showed that EtEsp is a secreted protein, but not from micronemes. In inhibition tests, a polyclonal anti-rEtEsp antibody attenuated the capacity of E. tenella to invade host cells. Conclusion In this study, we show that EtEsp interacts with EtAMA1 and that the protein is secreted protein, but not from micronemes. The protein participates in sporozoite invasion of host cells and is maybe involved in the growth of the parasite. These data have implications for the use of EtAMA1 or EtAMA1-interacting proteins as targets in intervention strategies against avian coccidiosis.![]()
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Affiliation(s)
- Cong Li
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Minhang, Shanghai, 200241, PR China
| | - Qiping Zhao
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Minhang, Shanghai, 200241, PR China
| | - Shunhai Zhu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Minhang, Shanghai, 200241, PR China
| | - Qingjie Wang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Minhang, Shanghai, 200241, PR China
| | - Haixia Wang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Minhang, Shanghai, 200241, PR China
| | - Shuilan Yu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Minhang, Shanghai, 200241, PR China
| | - Yu Yu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Minhang, Shanghai, 200241, PR China.,College of Life and Environment Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Shashan Liang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Minhang, Shanghai, 200241, PR China.,College of Life and Environment Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Huanzhi Zhao
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Minhang, Shanghai, 200241, PR China
| | - Bing Huang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Minhang, Shanghai, 200241, PR China
| | - Hui Dong
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Minhang, Shanghai, 200241, PR China.
| | - Hongyu Han
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Minhang, Shanghai, 200241, PR China.
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Aniweh Y, Nyarko PB, Charles-Chess E, Ansah F, Osier FHA, Quansah E, Thiam LG, Kamuyu G, Marsh K, Conway DJ, Tetteh KKA, Awandare GA. Plasmodium falciparum Merozoite Associated Armadillo Protein (PfMAAP) Is Apically Localized in Free Merozoites and Antibodies Are Associated With Reduced Risk of Malaria. Front Immunol 2020; 11:505. [PMID: 32318061 PMCID: PMC7155890 DOI: 10.3389/fimmu.2020.00505] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 03/05/2020] [Indexed: 11/19/2022] Open
Abstract
Understanding the functional role of proteins expressed by Plasmodium falciparum is an important step toward unlocking potential targets for the development of therapeutic or diagnostic interventions. The armadillo (ARM) repeat protein superfamily is associated with varied functions across the eukaryotes. Therefore, it is important to understand the role of members of this protein family in Plasmodium biology. The Plasmodium falciparum armadillo repeats only (PfARO; Pf3D7_0414900) and P. falciparum merozoite organizing proteins (PfMOP; Pf3D7_0917000) are armadillo-repeat containing proteins previously characterized in P. falciparum. Here, we describe the characterization of another ARM repeat-containing protein in P. falciparum, which we have named the P. falciparum Merozoites-Associated Armadillo repeats protein (PfMAAP). Antibodies raised to three different synthetic peptides of PfMAAP show apical staining of free merozoites and those within the mature infected schizont. We also demonstrate that the antibodies raised to the PfMAAP peptides inhibited invasion of erythrocytes by merozoites from different parasite isolates. In addition, naturally acquired human antibodies to the N- and C- termini of PfMAAP are associated with a reduced risk of malaria in a prospective cohort analysis.
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Affiliation(s)
- Yaw Aniweh
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, Ghana
| | - Prince B. Nyarko
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
| | - Essel Charles-Chess
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
| | - Felix Ansah
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
| | - Faith H. A. Osier
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
- Centre for Infectious Diseases, Parasitology, Heidelberg University Hospital, Heidelberg, Germany
- Department of Biochemistry, Pwani University, Kilifi, Kenya
- Nuffield Department of Clinical Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
| | - Evelyn Quansah
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
| | - Laty Gaye Thiam
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
| | - Gathoni Kamuyu
- Division of Medicine, Department of Respiratory Medicine, UCL, London, United Kingdom
| | - Kevin Marsh
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
- Nuffield Department of Clinical Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - David J. Conway
- Department of Infection Biology, London School of Tropical Medicine and Hygiene, London, United Kingdom
| | - Kevin K. A. Tetteh
- Department of Infection Biology, London School of Tropical Medicine and Hygiene, London, United Kingdom
| | - Gordon A. Awandare
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
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