To investigate the potential influence of antigen (Ag) presentation on the immune response to MSP1 19, the 19 kDa C-terminal domain of the #Plasmodium falciparum MSP1 Ag, 3 recombinant MSP 19 Ags expressed in baculovirus, #E. coli and #Saccharomyces cerevisiae were used to stimulate in vitro peripheral blood mononuclear cells (PBMCS) from #P. falciparum immune adults with no recent history of clinical malaria. Donors were recruited in 2 senegalese villages (Dielmo and Ndiop), where malaria transmission is perennial and seasonal, respectively. Each PBMC preparation was stimulated with a range of concentrations of the 3 recombinant Ags (cleaved from carrier molecules when appropriate). Most subjects responded to at least 1 recombinant Ag (SI > 3 in 8/10 at Dielmo and 14/15 at Ndiop). The dose-dependent response to #Saccharomyces cerevisiae MSP1 19 was similar in both villages. In contrast, there was a 10-fold difference in the optimal concentration of the #E. coli product between the two villages. Both the optimal dose and the concentration-dependence of the simulation by the baculovirus recombinant protein differed in each setting. These studies show that the 3 recombinant antigens differ in their capacity to stimulate lymphocyte proliferation, suggesting that protein structure (folding and/or glycosylation) affecting Ag processing, is critical. Futhermore, these data suggest that the malaria transmission pattern influences the immune response to the various MSP1 19 recombinants. (Résumé d'auteur