Identification and characterization of 2 HIV-1 Gag immunodominant epitopes restricted by Asian HLA allele HLA-B*4801

HLA-B*4801 is frequently found in Asian populations but rarely in Caucasian or African populations. Although HLA-B*4801–restricted human immunodeficiency virus–1 (HIV-1) epitopes would be useful for acquired immune deficiency syndrome (AIDS) vaccine development in Asia, they have not been reported so far. In the present study, we sought to identify HLA-B*4801–restricted HIV-1 epitopes by using 17-mer overlapping peptides derived from HIV-1 Gag, Pol, and Nef as well as 8- to11-mer truncated peptides, and thereby identified two HLA-B*4801–restricted Gag epitopes. These epitope-specific CD8+ T cells strongly responded to HIV-1–infected cells expressing HLA-B*4801, confirming that these Gag epitopes were endogenously presented by HLA-B*4801. These epitope-specific CD8+ T cells were elicited in five of the seven tested chronically HIV-1–infected individuals with HLA-B*4801, suggesting them to be immunodominant epitopes. These epitopes will be useful for the studies of AIDS immunopathogenesis and the development of an HIV-1 vaccine in Asia.