Epitopes of the Plasmodium falciparum clustered‐asparagine‐rich protein (CARP) recognized by human T‐cells and antibodies

Abstract

Summary Linear B‐ and T‐cell epitopes have been identified in the Plasmodium falciparum clustered‐asparagine‐rich‐protein (CARP). Twenty‐six synthetic peptides. 15‐25 amino acids in length, were assayed for their ability to stimulate purified, human T‐cells primed to P. falciparum by natural infection to proliferate and/or secrete y‐interferon (IFNy). The plasma of malaria exposed individuals were tested for antibody reacthiu with peptides coupled to bovine scrum albumin in a semiquantitative ELISA. Two of the peptides (NNFMNRNMKNKNMN/NAKNVNDMYRDGEMS) induced T‐cells from many malaria exposed donors to proliferate and/or secrete ‐IFNy. Six peptides bound antibodies from a large number of the plasma samples, the amounts ranging from ten to more than 200/ug specific antibody/ml. T‐cell activation was most pronounced when the T‐cells were from highly immune donors. In contrast, high anti‐peptide specific antibody levels were usually detected in the plasma of less immune donors, recently exposed to infection. One short sequence (NAKNVNDMYRDGEMS) was found to contain both T‐ and B‐cell epitopes. Thus, CARP includes both T‐ and B‐cell reactive elements recognised by the human immune system following exposure lo the parasite by natural infection.