Yeast-expressed p55 precursor core protein of human immunodeficiency virus type 1 does not elicit protective immunity in chimpanzees.

Yeast-expressed p55 precursor core protein of human immunodeficiency virus type 1 (HIV-1) was used to immunize chimpanzees. The animals developed high titers of antibodies to p55 as well as to the p24 and p17 mature cleavage products of the core precursor. Virus-neutralizing antibodies were not elicited. The induced immune responses did not prevent establishment of HIV-1 infection following challenge of one immunized chimpanzee with live virus.