HLA polymorphism and T cell recognition of a conserved region of p190, a malaria vaccine candidate

We have examined T cell recognition of a recombinant polypeptide (190L), corresponding to a 175-amino-acid-long conserved region of the major surface antigen (p190) of Plasmodium falciparum merozoites. We show that 190L contains a variety of T cell epitopes, and can be recognized in association with many different MHC class II molecules, including HLA-DR, DP, and DQ antigens. Most of the epitope-containing peptides are able to bind to more than one DR, and a single DR molecule can bind to different peptides. These findings, together with the fact that humans are generally heterozygous at the DR, DQ, and DP beta chain loci, suggest that MHC restriction should not be a major constraint in the development of malaria subunit vaccines.