Different Plasmodium falciparum recombinant MSP1(19) antigens differ in their capacities to stimulate in vitro peripheral blood T lymphocytes in individuals from various endemic areas

This study reports on T-cell proliferative responses to the 19-kDa C-termin al domain of the Plasmodium falciparum merozoite surface protein (MSP1(19)) . Three different recombinant proteins were used: an Escherichia coli produ ct expressing the first EGF-like domain and Saccharomyces cerevisiae and ba culovirus/insect-cell-produced proteins containing both EGF-like domains, t he latter protein being produced with or without N-glycosylation. Cell dono rs were P. falciparum-immune adults with no recent history of clinical mala ria and recruited from three Senegalese settings with different epidemiolog ical parasite transmission. Each mononuclear-blood-cell preparation was sti mulated with a range of concentrations of the three proteins. Most subjects ' mononuclear cells were reactive to at least one protein, but significant differences in lymphoproliferation were seen between the settings and withi n individual cultures depending on the protein source and concentration. Im portantly, lymphoproliferation indices correlated inversely with the intens ity of P, falciparum malaria transmission. When purified T lymphocytes were cultured in the presence of MSP1(19) plus autologous monocytes, B lymphocy tes or a proposed CD1(+) dendritic-cell population as costimulatory cells, significant differences were observed depending on the individual's previou s exposure to parasites. This study shows that the stimulation of lymphocyt e proliferation in vitro with MSP1(19) depends on several factors, includin g epidemiological conditions and protein preparations.