Since the hierarchy of epitope immunogenicity determines the timing for activation during HIV infection and the immunogenicity varied among different HIV epitopes/antigens, HIV-specific CD8+ T cells against different epitopes/antigens could be developed at different time, and immunogenic epitopes, usually designated as dominant epitopes, could raise CD8+T-cell responses earlier than that less immunogenic epitopes (subdominant epitopes) [17], [27], [28], [31]. The gene discussed is CD8A; the disease is HIV infectious disease.