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Strain-transcending immune response generated by chimeras of the malaria vaccine candidate merozoite surface protein 2. Sci Rep 2016; 6:20613. [PMID: 26865062 PMCID: PMC4749986 DOI: 10.1038/srep20613] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 01/08/2016] [Indexed: 12/16/2022] Open
Abstract
MSP2 is an intrinsically disordered protein that is abundant on the merozoite surface and essential to the parasite Plasmodium falciparum. Naturally-acquired antibody responses to MSP2 are biased towards dimorphic sequences within the central variable region of MSP2 and have been linked to naturally-acquired protection from malaria. In a phase IIb study, an MSP2-containing vaccine induced an immune response that reduced parasitemias in a strain-specific manner. A subsequent phase I study of a vaccine that contained both dimorphic forms of MSP2 induced antibodies that exhibited functional activity in vitro. We have assessed the contribution of the conserved and variable regions of MSP2 to the generation of a strain-transcending antibody response by generating MSP2 chimeras that included conserved and variable regions of the 3D7 and FC27 alleles. Robust anti-MSP2 antibody responses targeting both conserved and variable regions were generated in mice, although the fine specificity and the balance of responses to these regions differed amongst the constructs tested. We observed significant differences in antibody subclass distribution in the responses to these chimeras. Our results suggest that chimeric MSP2 antigens can elicit a broad immune response suitable for protection against different strains of P. falciparum.
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2
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Reddy SB, Anders RF, Cross N, Mueller I, Senn N, Stanisic DI, Siba PM, Wahlgren M, Kironde F, Beeson JG, Persson KEM. Differences in affinity of monoclonal and naturally acquired polyclonal antibodies against Plasmodium falciparum merozoite antigens. BMC Microbiol 2015; 15:133. [PMID: 26149471 PMCID: PMC4491891 DOI: 10.1186/s12866-015-0461-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 06/03/2015] [Indexed: 11/10/2022] Open
Abstract
Background Malaria is a major global cause of deaths and a vaccine is urgently needed. Results We have employed the P. falciparum merozoite antigens MSP2-3D7/FC27 and AMA1, used them in ELISA, and coupled them in different ways using surface plasmon resonance (SPR) and estimated affinity (measured as kd) of monoclonal as well as naturally-acquired polyclonal antibodies in human plasma. There were major differences in kd depending on how the antigens were immobilized and where the His-tag was placed. For AMA1 we could see correlations with invasion inhibition. Using different immobilizations of proteins in SPR, we could see only moderate correlations with levels of antibodies in ELISA, indicating that in ELISA the proteins were not uniformly bound and that antibodies with many specificities exist in natural immunisation. The correlations between ELISA and SPR were enhanced when only parasite positive samples were included, which may indicate that high affinity antibodies are difficult to maintain over long periods of time. We found higher kd values for MSP2 (indicating lower affinity) compared to AMA1, which might be partly explained by MSP2 being an intrinsically disordered protein, while AMA1 is globular. Conclusions For future vaccine studies and for understanding immunity, it is important to consider how to present proteins to the immune system to achieve highest antibody affinities. Electronic supplementary material The online version of this article (doi:10.1186/s12866-015-0461-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sreenivasulu B Reddy
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77, Stockholm, Sweden
| | - Robin F Anders
- Department of Biochemistry, La Trobe University, Vic, 3086, Australia
| | - Nadia Cross
- The Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
| | - Ivo Mueller
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Papua New Guinea Institute of Medical Research, Goroka, 441, Papua New Guinea
| | - Nicolas Senn
- Papua New Guinea Institute of Medical Research, Goroka, 441, Papua New Guinea.,Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Danielle I Stanisic
- Papua New Guinea Institute of Medical Research, Goroka, 441, Papua New Guinea.,Institute for Glycomics, Griffith University, Queensland, Australia
| | - Peter M Siba
- Papua New Guinea Institute of Medical Research, Goroka, 441, Papua New Guinea
| | - Mats Wahlgren
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77, Stockholm, Sweden
| | - Fred Kironde
- Department of Biochemistry, Makerere University, Kampala, Uganda.,Habib Medical School, IUIU, Kampala, Uganda
| | - James G Beeson
- The Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia.,The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Kristina E M Persson
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77, Stockholm, Sweden. .,Department of Laboratory Medicine, Lund University, 22185, Lund, Sweden.
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MacRaild CA, Zachrdla M, Andrew D, Krishnarjuna B, Nováček J, Žídek L, Sklenář V, Richards JS, Beeson JG, Anders RF, Norton RS. Conformational dynamics and antigenicity in the disordered malaria antigen merozoite surface protein 2. PLoS One 2015; 10:e0119899. [PMID: 25742002 PMCID: PMC4351039 DOI: 10.1371/journal.pone.0119899] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 01/16/2015] [Indexed: 12/14/2022] Open
Abstract
Merozoite surface protein 2 (MSP2) of Plasmodium falciparum is an abundant, intrinsically disordered protein that is GPI-anchored to the surface of the invasive blood stage of the malaria parasite. Recombinant MSP2 has been trialled as a component of a malaria vaccine, and is one of several disordered proteins that are candidates for inclusion in vaccines for malaria and other diseases. Nonetheless, little is known about the implications of protein disorder for the development of an effective antibody response. We have therefore undertaken a detailed analysis of the conformational dynamics of the two allelic forms of MSP2 (3D7 and FC27) using NMR spectroscopy. Chemical shifts and NMR relaxation data indicate that conformational and dynamic properties of the N- and C-terminal conserved regions in the two forms of MSP2 are essentially identical, but significant variation exists between and within the central variable regions. We observe a strong relationship between the conformational dynamics and the antigenicity of MSP2, as assessed with antisera to recombinant MSP2. Regions of increased conformational order in MSP2, including those in the conserved regions, are more strongly antigenic, while the most flexible regions are minimally antigenic. This suggests that modifications that increase conformational order may offer a means to tune the antigenicity of MSP2 and other disordered antigens, with implications for vaccine design.
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Affiliation(s)
- Christopher A. MacRaild
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, 3052, Australia
- * E-mail:
| | - Milan Zachrdla
- NCBR, Faculty of Science, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic
- CEITEC, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic
| | - Dean Andrew
- Centre for Biomedical Research, Burnet Institute, Melbourne, Victoria, 3004, Australia
| | - Bankala Krishnarjuna
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, 3052, Australia
| | - Jiří Nováček
- NCBR, Faculty of Science, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic
- CEITEC, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic
| | - Lukáš Žídek
- NCBR, Faculty of Science, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic
- CEITEC, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic
| | - Vladimír Sklenář
- NCBR, Faculty of Science, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic
- CEITEC, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic
| | - Jack S. Richards
- Centre for Biomedical Research, Burnet Institute, Melbourne, Victoria, 3004, Australia
| | - James G. Beeson
- Centre for Biomedical Research, Burnet Institute, Melbourne, Victoria, 3004, Australia
| | - Robin F. Anders
- Department of Biochemistry, La Trobe University, Victoria, 3086, Australia
| | - Raymond S. Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, 3052, Australia
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Rono J, Osier FHA, Olsson D, Montgomery S, Mhoja L, Rooth I, Marsh K, Färnert A. Breadth of anti-merozoite antibody responses is associated with the genetic diversity of asymptomatic Plasmodium falciparum infections and protection against clinical malaria. Clin Infect Dis 2013; 57:1409-16. [PMID: 23983244 DOI: 10.1093/cid/cit556] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Elucidating the mechanisms of naturally acquired immunity to Plasmodium falciparum infections would be highly valuable for malaria vaccine development. Asymptomatic multiclonal infections have been shown to predict protection from clinical malaria in a transmission-dependent manner, but the mechanisms underlying this are unclear. We assessed the breadth of antibody responses to several vaccine candidate merozoite antigens in relation to the infecting parasite population and clinical immunity. METHODS In a cohort study in Tanzania, 320 children aged 1-16 years who were asymptomatic at baseline were included. We genotyped P. falciparum infections by targeting the msp2 gene using polymerase chain reaction and capillary electrophoresis and measured antibodies to 7 merozoite antigens using a multiplex assay. We assessed the correlation between the number of clones and the breadth of the antibody response, and examined their effects on the risk of malaria during 40 weeks of follow-up using age-adjusted multivariate regression models. RESULTS The antibody breadth was positively correlated with the number of clones (RR [risk ratio], 1.63; 95% confidence interval [CI], 1.32-2.02). Multiclonal infections were associated with a nonsignificant reduction in the risk of malaria in the absence of antibodies (RR, 0.83; 95% CI, .29-2.34). The breadth of the antibody response was significantly associated with a reduced risk of malaria in the absence of infections (RR, 0.25; 95% CI, .09-.66). In combination, these factors were associated with a lower risk of malaria than they were individually (RR, 0.14; 95% CI, .04-.48). CONCLUSIONS These data suggest that malaria vaccines mimicking naturally acquired immunity should ideally induce antibody responses that can be boosted by natural infections.
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Affiliation(s)
- Josea Rono
- Infectious Diseases Unit, Department of Medicine, Solna, Karolinska Institutet, Stockholm, Sweden
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Dechavanne C, Pierrat C, Renard E, Costes B, Martin N, Ladekpo R, Ahouangninou C, Alvarez VM, Huynh BT, Garcia A, Migot-Nabias F. Genetic characterization of Plasmodium falciparum allelic variants infecting mothers at delivery and their children during their first plasmodial infections. INFECTION GENETICS AND EVOLUTION 2013; 20:16-25. [PMID: 23932959 DOI: 10.1016/j.meegid.2013.07.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 07/23/2013] [Accepted: 07/24/2013] [Indexed: 01/11/2023]
Abstract
INTRODUCTION Infants born to mothers with placental malaria at delivery develop Plasmodium falciparum parasitemia earlier than those born to mothers without placental infection. This phenomenon may be explained by the development of immune tolerance due to exposure to P. falciparum antigens in utero. The hypothesis of this study is that this increased susceptibility might be related to infections by parasites expressing the same blood stage allele's antigens as those to which the infants were exposed in utero. METHODS The comparison of P.falciparum msp2 (3D7 and FC27) and glurp gene polymorphisms of infected mothers at delivery to those of their offspring's infections during infancy was realized and the possible associations of the different polymorphisms with clinical outcomes were assessed. A second approach consisted in the use of a Geographic Information System to determine whether the antigen alleles were homogeneously distributed in the area of study. This was necessary to analyze whether the biological observations were due to high exposure to a particular antigen allelic form in the environment or to high infant permissiveness to the same allelic antigen polymorphism as the placental one. RESULTS Infants born to mothers with placental malaria at delivery were more susceptible to infections by parasites carrying the same glurp allele as encountered in utero compared to distinct alleles, independently of their geographic distribution. CONCLUSION The increased permissiveness of infants to plasmodial infections with shared placental-infant glurp alleles sheds light on the role that P. falciparum blood stage antigen polymorphisms may play in the first plasmodial infections in infancy.
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Affiliation(s)
- Célia Dechavanne
- Institut de Recherche Pour le Développement, UMR 216 Mère et Enfant Face Aux Infections Tropicales, Paris, France; PRES Sorbonne Paris Cité, Université Paris Descartes, Faculté de Pharmacie, Paris, France.
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6
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Antigenic characterization of an intrinsically unstructured protein, Plasmodium falciparum merozoite surface protein 2. Infect Immun 2012; 80:4177-85. [PMID: 22966050 DOI: 10.1128/iai.00665-12] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Merozoite surface protein 2 (MSP2) is an abundant glycosylphosphatidylinositol (GPI)-anchored protein of Plasmodium falciparum, which is a potential component of a malaria vaccine. As all forms of MSP2 can be categorized into two allelic families, a vaccine containing two representative forms of MSP2 may overcome the problem of diversity in this highly polymorphic protein. Monomeric recombinant MSP2 is an intrinsically unstructured protein, but its conformational properties on the merozoite surface are unknown. This question is addressed here by analyzing the 3D7 and FC27 forms of recombinant and parasite MSP2 using a panel of monoclonal antibodies raised against recombinant MSP2. The epitopes of all antibodies, mapped using both a peptide array and by nuclear magnetic resonance (NMR) spectroscopy on full-length recombinant MSP2, were shown to be linear. The antibodies revealed antigenic differences, which indicate that the conserved N- and C-terminal regions, but not the central variable region, are less accessible in the parasite antigen. This appears to be an intrinsic property of parasite MSP2 and is not dependent on interactions with other merozoite surface proteins as the loss of some conserved-region epitopes seen using the immunofluorescence assay (IFA) on parasite smears was also seen on Western blot analyses of parasite lysates. Further studies of the structural basis of these antigenic differences are required in order to optimize recombinant MSP2 constructs being evaluated as potential vaccine components.
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Khosravi A, Hommel M, Sayemiri K. Age-dependent antibody response to Plasmodium falciparum merozoite surface protein 2 (MSP-2). Parasite Immunol 2011; 33:145-57. [PMID: 21306398 DOI: 10.1111/j.1365-3024.2010.01260.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Merozoite surface protein 2 (MSP-2), a very immunogenic malaria antigen, is a highly polymorphic 45-53 kDa merozoite surface protein, which is regarded as a promising vaccine candidate. The highly polymorphic nature of MSP-2 suggests that the molecule can be involved in protective immunity against malaria. The antibody responses to MSP-2 antigen are mostly directed against polymorphic and dimorphic regions of the protein. The current study aimed at testing the reactivity of human sera from a malaria-endemic area of Gambia against MSP-2 regions 2, 3 and 4 compared to crude schizont extract in a period of 20 years. The age-dependent immunity was analysed in a manner of cross-sectional study (the data of the first visit) and also a longitudinal study design (analysing the data at four different time points from 1960 to 1980) testing the sera of 178 individuals randomly selected from the Keneba Serum Collection by using MSP-2 recombinant protein. The total IgG responses were measured by ELISA. Kolmogorov-Smirnov was used to check the normal distribution of OD, Hb and parasitaemia, and then Spearman correlation was applied to analyse the data. Most sera recognized, predominantly, the variable regions of the MSP-2, particularly the domain 3. The IgG response against all the antigens increased with age. The IgG responses against domain 3 of MSP-2 were associated with an increase in haemoglobin levels but a decrease in parasitaemia, suggesting that this immune response may be one of the most useful means for further studies on protective immunity against malaria.
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Affiliation(s)
- A Khosravi
- Immunology Department, Ilam University of Medical Sciences, Ilam, Iran.
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Lekana-Douki JB, Dinzouna Boutamba SD, Zatra R, Zang Edou SE, Ekomy H, Bisvigou U, Toure-Ndouo FS. Increased prevalence of the Plasmodium falciparum Pfmdr1 86N genotype among field isolates from Franceville, Gabon after replacement of chloroquine by artemether-lumefantrine and artesunate-mefloquine. INFECTION GENETICS AND EVOLUTION 2011; 11:512-7. [PMID: 21251998 DOI: 10.1016/j.meegid.2011.01.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Revised: 01/01/2011] [Accepted: 01/04/2011] [Indexed: 10/18/2022]
Abstract
Despite global antimalarial measures, Plasmodium falciparum malaria remains a major public health problem. WHO has recommended the use of arteminisin-based combination therapy to limit the emergence of antimalarial drug resistance. However, ACT treatment failures have been linked to the selection of the wild types 86N genotype of P. falciparum multidrug resistance 1 (Pfmdr1) and the 76K genotype of P. falciparum chloroquine resistance (Pfcrt) genes. The aim of this study was to investigate the molecular impact of widespread implementation of artemether-lumefantrine and artesunate-mefloquine on local parasite population in Franceville, Gabon. We analyzed 230 pediatric field isolates (96 from 2004 and 134 from 2009). Routine hematological parameters were collected. Pfmdr1 codons 86 and 1246 and Pfcrt codon 76 were genotyped using PCR-RFLP and the prevalence of the genotypes was compared. The children's mean age did not differ between 2004 and 2009 (respectively 31.8 (6-84) months vs 38.6 (6-84) months, p=0.32), and neither did mean parasitemia [16,750 (1000-96,234) and 14,587 (1093-83,941) parasites/μL, respectively (p=0.21)]. The mean hemoglobin level was higher in 2009 than in 2004 (11.0 ± 2.4 vs 7.8 ± 2.0 g/dL, respectively; p=0.04). More interesting, the prevalence of Pfmdr1 wild type 86N increased from 15.6% (n=15/96) in 2004 to 31.3% (n=42/134) in 2009 (p=0.007). A significant increase combining pure and mixed genotypes (86N+86N/Y) was also found between 2004 and 2009 (p=0.02), while the prevalence of genotypes Pfmdr1 1246D, Pfcrt wild type 76T and all mixed genotypes (Pfmdr1 86N/Y and 1246D/Y, and 76K/T) remained stable. The complexity of isolates was high (around 2.9 and 2.4) and the FC27 allele of Pfmsp2 was more prevalent. These findings show a substantial benefice of artemether-lumefantrine and artesunate-mefloquine and of new control measures. The selection, in the general population, of wild type Pfmdr1 86N, which is associated with antiplasmodial resistance against some drugs, has been induced underlining the need for molecular surveillance of the impact of ACT on antimalarial resistance.
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Affiliation(s)
- Jean Bernard Lekana-Douki
- Unité de Parasitologie Médicale (UPARAM), Centre International de Recherches Médicales de Franceville (CIRMF), B.P. 769 Franceville, Gabon.
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Osier FHA, Murungi LM, Fegan G, Tuju J, Tetteh KK, Bull PC, Conway DJ, Marsh K. Allele-specific antibodies to Plasmodium falciparum merozoite surface protein-2 and protection against clinical malaria. Parasite Immunol 2010; 32:193-201. [PMID: 20398182 PMCID: PMC2847195 DOI: 10.1111/j.1365-3024.2009.01178.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
IgG and IgG3 antibodies to merozoite surface protein-2 (MSP-2) of Plasmodium falciparum have been associated with protection from clinical malaria in independent studies. We determined whether this protection was allele-specific by testing whether children who developed clinical malaria lacked IgG/IgG3 antibodies specific to the dominant msp2 parasite genotypes detected during clinical episodes. We analysed pre-existing IgG and IgG1/IgG3 antibodies to antigens representing the major dimorphic types of MSP-2 by ELISA. We used quantitative real-time PCR to determine the dominant msp2 alleles in parasites detected in clinical episodes. Over half (55%, 80/146) of infections contained both allelic types. Single or dominant IC1- and FC27-like alleles were detected in 46% and 42% of infections respectively, and both types were equally dominant in 12%. High levels of IgG/IgG3 antibodies to the FC27-like antigen were not significantly associated with a lower likelihood of clinical episodes caused by parasites bearing FC27-like compared to IC1-like alleles, and vice versa for IgG/IgG3 antibodies to the IC1-like antigen. These findings were supported by competition ELISAs which demonstrated the presence of IgG antibodies to allele-specific epitopes within both antigens. Thus, even for this well-studied antigen, the importance of an allele-specific component of naturally acquired protective immunity to malaria remains to be confirmed.
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Affiliation(s)
- F H A Osier
- KEMRI-Centre for Geographic Medicine Research, Coast, Kilifi, Kenya.
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Nantulya FN, Kengeya-Kayondo JF, Ogundahunsi OAT. Research Themes and Advances in Malaria Research Capacity Made by the Multilateral Initiative on Malaria. Am J Trop Med Hyg 2007. [DOI: 10.4269/ajtmh.77.6.suppl.303] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Affiliation(s)
- Florence N. Nantulya
- Special Program for Research and Training in Tropical Diseases, World Health Organization, Geneva, Switzerland; Chemin du Joran, Nyon, Switzerland
| | - Jane F. Kengeya-Kayondo
- Special Program for Research and Training in Tropical Diseases, World Health Organization, Geneva, Switzerland; Chemin du Joran, Nyon, Switzerland
| | - Olumide A. T. Ogundahunsi
- Special Program for Research and Training in Tropical Diseases, World Health Organization, Geneva, Switzerland; Chemin du Joran, Nyon, Switzerland
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Sallenave-Sales S, Faria CP, Zalis MG, Daniel-Ribeiro CT, Ferreira-da-Cruz MDF. Merozoite surface protein 2 allelic variation influences the specific antibody response during acute malaria in individuals from a Brazilian endemic area. Mem Inst Oswaldo Cruz 2007; 102:421-4. [PMID: 17568950 DOI: 10.1590/s0074-02762007005000048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2007] [Accepted: 05/02/2007] [Indexed: 11/22/2022] Open
Abstract
The antibody response to Plasmodium falciparum parasites of naturally infected population is critical to elucidate the role of polymorphic alleles in malaria. Thus, we evaluated the impact of antigenic diversity of repetitive and family dimorphic domains of the merozoite surface protein 2 (MSP-2) on immune response of 96 individuals living in Peixoto de Azevedo (MT-Brazil), by ELISA using recombinant MSP-2 proteins. The majority of these individuals were carrying FC27-type infections. IgG antibody responses were predominantly directed to FC27 parasites and were correlated to the extension of polymorphism presented by each MSP-2 region. This finding demonstrated the impact of the genetic polymorphism on antibody response and therefore, its importance on malaria vaccine efficacy.
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12
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Ferreira MU, da Silva Nunes M, Wunderlich G. Antigenic diversity and immune evasion by malaria parasites. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 2005; 11:987-95. [PMID: 15539495 PMCID: PMC524792 DOI: 10.1128/cdli.11.6.987-995.2004] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Marcelo U Ferreira
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes 1374, 05508-900 São Paulo (SP), Brazil.
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Tonon AP, Hoffmann EHE, Silveira LAD, Ribeiro AG, Gonçalves CRDS, Ribolla PEM, Wunderlich G, Ferreira MU. Plasmodium falciparum: sequence diversity and antibody recognition of the Merozoite surface protein-2 (MSP-2) in Brazilian Amazonia. Exp Parasitol 2004; 108:114-25. [PMID: 15582508 DOI: 10.1016/j.exppara.2004.08.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2004] [Revised: 08/03/2004] [Accepted: 08/03/2004] [Indexed: 11/30/2022]
Abstract
The merozoite surface protein-2 (MSP-2) of Plasmodium falciparum comprises repeats flanked by dimorphic domains defining the allelic families FC27 and IC1. Here, we examined sequence diversity at the msp-2 locus in Brazil and its impact on MSP-2 antibody recognition by local patients. Only 25 unique partial sequences of msp-2 were found in 61 isolates examined. The finding of identical msp-2 sequences in unrelated parasites, collected 6-13 years apart, suggests that no major directional selection is exerted by variant-specific immunity in this malaria-endemic area. To examine antibody cross-reactivity, recombinant polypeptides derived from locally prevalent and foreign MSP-2 variants were used in ELISA. Foreign IC1-type variants, such as 3D7 (currently tested for human vaccination), were less frequently recognized than FC27-type and local IC1-type variants. Antibodies discriminated between local and foreign IC1-type variants, but cross-recognized structurally different local IC1-type variants. The use of evolutionary models of MSP-2 is suggested to design vaccines that minimize differences between local parasites and vaccine antigens.
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Affiliation(s)
- Angela Pedroso Tonon
- Departamento de Parasitologia, Instituto de Ciências Biomédicas da Universidade de São Paulo, Av. Prof. Lineu Prestes 1374, Cidade Universitária, 05508-900 São Paulo, Brazil
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