CD8A and viral infectious disease: Type I IFNs have pleiotropic anti-viral functions: they increase the resistance of non-infected cells to viral infection, inhibit viral gene transcription, induce apoptosis of infected cells, induce B cell differentiation into antibody-secreting plasma cells, promote the cytotoxic activity of NK and CD8+ T cells, promote survival and proliferation of CD8+ T cells, as well as differentiation and maturation of DCs [18], [43]–[46].