MAJOR POPULATION DIFFERENCES IN T-CELL RESPONSE TO A MALARIA SPOROZOITE VACCINE CANDIDATE

Using a complete series of overlapping peptides, we have identified the T cell epitopes of a malaria vaccine candidate, the circumsporozoite (CS) protein, that are recognized by sporozoiteexposed residents of a non-endemic country. Thls protein and subunb from tt are belng considered as malarla sporozoite vaccine candidates, as CS-specific antibodies and cytotoxic T lymphocytes have been shown to have a role in protection. The rationale for deveioplng an antibody-based vaccine is that in Plasmodium falclpmmthe lmmunodominant B cell epttope of the protein, (Asn-AieAsn-Ala-Asn-Pro)n, [(NANP)n], is invariant. However, the Ideal vaccine must contain CS protein-derived T cell antigenlc epttopes to allow natural boosting of the antibody response following sporozoite exposure. Here, we show that major differences occur between the CS spectific T cell responses of non-endemic Caucasians and an endemic African population. HLA differencaa between the populations are, in part, responsible. Subunit malaria vacclnes for one population may be ineffective In a different population. © Oxford University Press.