CD8A and HIV infectious disease: In the acute phase of HIV infection, there is an increase in CD8+ T cell activity due to APCs and CD4 T cell stimulation, resulting in CD8+ T cells killing virus-infected cells by releasing granzymes, which can induce apoptosis in the target cell and a pore-forming protein called perforin, which perforates the cell membrane of the target cell, thereby killing the cell [214].