Lack of Correlation between HLA Class II Alleles and Immune Responses to Pf155/Ring-Infected Erythrocyte Surface Antigen (RESA) from Plasmodium Falciparum in Madagascar

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  • Institut National de la Sante et de la Recherche Medicale (INSERM) Unite 13, Institut de Medecine et d'Epidemiologie Africaines, et INSERM Unite 120, Hopital de Lille, Institut Pasteur, Paris, France
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To investigate the relationships between predominant HLA class II alleles and immune responses to the Plasmodium falciparum ring-infected erythrocyte surface antigen (Pf155/RESA), 50 individuals from the highlands of Madagascar were followed-up from 1988 to 1991. The T cell reactivity and antibody responses to synthetic peptides (EENV)4, (EENVEHDA)4, and (DDEHVEEPTVA)3, representing major T and B epitopes of Pf155/RESA antigen, were assessed with an average of five determinations per individual over the four-year follow-up period. The T cell reactivity was investigated by lymphocyte proliferation and assays for interferon-γ and interleukin-2 release. Anti-peptide antibodies were measured using the Falcon™ assay screening test-enzyme-linked immunosorbent assay. The cumulative prevalence rates of cellular (range for the three peptides = 64–68%) and antibody responders (range = 70–74%) were similar for each peptide. The HLA class II typing was performed using polymerase chain reaction-restriction fragment length polymorphisms. The prevalent alleles or groups of alleles (frequency > 20%) were similar in responders and nonresponders, both for cellular and antibody responses to each peptide. These were HLA-DR 5 group and HLA-DQA1 *0601, *0101-0102-0104, HLA-DQB1 *0301, and HLA-DPB1 *0101-2601 alleles. Allelic distribution was similar in individuals presenting with (74%) or without (26%) a malaria attack during a 20-week follow-up conducted when malaria was hyperendemic (P > 0.05, by Fisher's exact test). Despite repeated immunologic measures that better identify the responders, no relationship was found between HLA class II alleles and the cellular or antibody responses to Pf155/RESA epitopes. If immune responses to Pf155/RESA epitopes or susceptibility to malaria attacks are genetically regulated, our data suggest the HLA class II region is not involved.

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