Immunoprevalence and Immunodominance of HLA-Cw∗0801-Restricted T Cell Response Targeting the Hepatitis B Virus Envelope Transmembrane Region

HLA-C-restricted T cells have been shown to play an important role in HIV control, but their impact on protection or pathogenesis in other viral infections remains elusive. Here, we characterized the hierarchy of HLA class I-restricted hepatitis B virus (HBV) epitopes targeted by CD8 T cells in HBV-infected subjects. The frequency of CD8 T cells specific for a panel of 18 HBV epitopes (restricted by HLA-A∗0201/03/07 [hereinafter HLA-A0201/03/07], -A1101, -A2402/07, -B5801, -B4001, -B1301, and -Cw0801) was quantified in a total of 59 subjects who resolved HBV infection. We found that the HLA-Cw0801-restricted epitope comprised of Env residues 171 to 180 (Env171-180) is immunoprevalent in the Southeast Asian subjects (10/17 HLA-Cw0801-positive subjects) and immunodominant in the majority of HLA-Cw0801-positive subjects able to control HBV infection. HLA-Cw0801-restricted Env171-180-specific CD8 T cells recognized endogenously produced HBV surface antigen (HBsAg) and tolerated amino acid variations within the epitope detected in HBV genotypes B and C. In conclusion, we demonstrate that the HLA-Cw0801-restricted Env171-180 T cell response is an important component of the HBV-specific adaptive T cell immunity in Asians infected with HBV. Thus, HLA-C restricted T cells might play an important role in various viral infections.