Longitudinal study of naturally acquired humoral immune responses against the merozoite surface protein 1 of Plasmodium vivax in patients from Rondonia, Brazil.
A longitudinal study on the naturally acquired humoral immune responses against the merozoite surface protein 1 of Plasmodium vivax (PvMSP-1) was performed in malaria patients from the Brazilian Amazon region of Rondonia. We have previously cloned and expressed a recombinant protein, ICB2-5, that encodes 508 amino acids from the N-terminal portion of the PvMSP-1 protein. This affinity-purified polypeptide was tested by an enzyme-linked immunosorbent assay in a one-year longitudinal study using sera from 34 patients who had at least one malaria infection during the study period. The results demonstrated that more than 90% of the sera from patients having experienced more than three previous malaria infections contained antibodies to ICB2-5 at the time of a new clinical episode. Unexpectedly, more than half of these multiple-infected patients had an antibody response to ICB2-5 in which the predominant isotype was IgM. In contrast, more than 83% of the sera from these same patients contained predominantly IgG antibodies against total blood-stage antigen preparations. To determine if these results were due to the lack of boosting against this portion of the PvMSP-1 molecule, the presence of IgG antibodies to ICB2-5 in the sera from 11 patients who had consecutive malarial episodes during the study year was investigated. Five of these eleven patients failed to produce IgG antibodies to ICB2-5 even after 1-3 infections. Thus, these results suggest that no boosting against this region of the PvMSP-1 molecule was achieved by natural infections among these patients.
Departamento de Parasitologia (ICB II), Universidade de Sao Paulo, Brazil.
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Mertens
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Levitus
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Camargo
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Ferreira
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Dutra
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Del Portillo
D000293:Adolescent; D000328:Adult; D000818:Animals; D000913:Antibodies, Protozoan / Q000096:biosynthesis*; D000953:Antigens, Protozoan / Q000276:immunology*; D000954:Antigens, Surface / Q000276:immunology; D001938:Brazil; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000096:biosynthesis; D007075:Immunoglobulin M / Q000096:biosynthesis; D008137:Longitudinal Studies; D016780:Malaria, Vivax / Q000276:immunology*; D008297:Male; D020066:Merozoite Surface Protein 1; D008875:Middle Aged; D010963:Plasmodium falciparum / Q000276:immunology; D010966:Plasmodium vivax / Q000276:immunology*; D011498:Protein Precursors / Q000276:immunology*; D015800:Protozoan Proteins / Q000276:immunology*; D011994:Recombinant Proteins / Q000276:immunology; D012008:Recurrence
D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D000954:Antigens, Surface; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D020066:Merozoite Surface Protein 1; D011498:Protein Precursors; D015800:Protozoan Proteins; D011994:Recombinant Proteins