The interplay between innate and adaptive immunity during viral infection constitutes a vital role and viral antigen uptake by APCs leads to cross-presentation of processed antigens, through major histocompatibility class I (MHC-I) molecules, to induce infected cell-specific CD8+ T cells, antibody and memory T cells for clearing infected cells and developing long-lasting protective immunity [14]. This evidence concerns the gene CD8A and viral infectious disease.