A comparative study of natural immune responses against Plasmodium vivax C-terminal merozoite surface protein-1 (PvMSP-1) and apical membrane antigen-1 (PvAMA-1) in two endemic settings

摘要

The mechanisms of cellular and humoral immune responses against P. vivax parasite remain poorly understood.Several malaria immunological studies have been conducted in endemic regions where both P. falciparum and P.vivax parasites co-exist. In this study, a comparative analysis of immunity to Plasmodium vivax antigens in differentgeography and incidence of Plasmodium spp. infection was performed. We characterised antibodiesagainst two P. vivax antigens, PvMSP-1 and PvAMA-1, and the cross-reactivity between these antigens usingplasma from acute malaria infected patients living in the central region of China and in the western border ofThailand. P. vivax endemicity is found in central China whereas both P. vivax and P. falciparum are endemic inThailand. There was an increased level of anti-PvMSP-1/anti-PvAMA-1 in both populations. An elevated levelof antibodies to total P. vivax proteins and low level of antibodies to total P. falciparum proteins was found inacute P. vivax infected Chinese, suggesting antibody cross-reactivity between the two species. P. vivax infectedThai patients had both anti-P. vivax and anti-P. falciparum antibodies as expected since both species are presentin Thailand. More information on humoral and cell mediated immunity during acute P. vivax-infection in the areawhere only single P. vivax species existed is of great interest in the relation of building up anti-disease severitycaused by P. falciparum. This knowledge will support vaccine development in the future.