Human immune responses to the highly repetitive Plasmodium falciparum antigen Pf332

The B and T cell responses to EB200, a repetitive part of the Plasmodium fa lciparum antigen Pf332, were examined in malaria-exposed Senegalese adults. Most donors had high levels of antibodies to recombinant EB200 and 17 over lapping peptides spanning EB200. Taking proliferation and/or cytokine (inte rferon-gamma and interleukin-4) production as a measure of T cell activatio n, eight of the EB200-derived peptides induced responses in > 40% of the do nors tested. There was no general association between the different types o f T cell responses measured, emphasizing the importance of including multip le parameters when analyzing T cell responses and suggesting that EB200 ind uces functionally distinct T cell responses. The most efficient peptide for induction of proliferative responses was one previously shown to induce T cell responses in five different H-2 congenic mouse strains primed with EB2 00, suggesting that this is a universal T cell epitope. The presence of mul tiple B and T cell epitopes in EB200, widely recognized by humans, is impor tant since EB200 has been shown to elicit protective antibody responses in monkeys and may be considered for inclusion in malaria subunit vaccines.