Identifying polymorphic regions of the p190 protein from different Plasmodium falciparum strains by using specific T cells.

Abstract

The p190 protein (also called MSA1 or MSP1) of the asexual blood stage forms of Plasmodium falciparum, a human malaria vaccine candidate, shows polymorphism between different isolates. Mice were immunized with p190-3, a recombinant protein which contains mostly conserved sequences derived from the p190 protein of the K1 parasite isolate. Proliferative T-cell responses of lymph node cells from immunized mice were assessed by stimulation in vitro with p190-3 or preparations of parasitized red blood cells (PRBC) containing the native protein. The p190-3-specific T cells from C57BL/6 mice consistently responded to some P. falciparum isolates, representing either the K1 or MAD20 serotype of p190, but not to other P. falciparum strains or to rodent malaria parasite-infected red blood cells. p190-3-specific T-cell responses from other mouse strains (BALB/c, C3H/He) did not distinguish between P. falciparum isolates. The polymorphic epitopes which were preferentially recognized by T cells from C57BL/6 mice were identified.