Avaliação da resposta sorológica ao antígeno MSP1 de Plasmodium vivax em uma comunidade da Amazônia brasileira

Abstract

Plasmodium vivax is geographically the most widely distributed, accounting for 80 to 300 million estimated cases, including severe cases and deaths. In endemic areas, frequent exposure to parasites leads to the emergence of individuals with asymptomatic malaria, which develops a natural immunity that protects against the clinical symptoms of the disease. This immune status is important to evaluate malaria vaccine candidates. One of the antigens that can generate specific immune response is the merozoite surface protein-1 (MSP-1), known for its role in host cell invasion. We analyzed the immune response against the N-and C-Terminal Merozoite surface protein 1 of Plasmodium vivax, PvMSP1, in 312 sera of a population from an agricultural settlement located adjacent to the Rio Pardo, Amazonas, whom they were followed by a clinical epidemiologic study. The results showed that 51.0% had total IgG against c-terminal portion and 29.5% had total IgG against N-terminal portion of the protein. As expected antibodies against the N-terminal portion were correlated with age, number of previous episodes, time of residence in the area. There was a predominance of IgG subclass 3 against the N-terminal portion. Our data suggested that IgG3 antibodies against the N-terminus of PvMSP1 to the local repertoire of variable domains of PvMSP-1 occur in asymptomatic patients indicating as sera-epidemiological markers of clinical protection.