For example, human populations expressing HLA-A*02:01 can elicit strong, cross-protective CD8+ T cell responses following presentation of the internally conserved M158–66 epitope (157–160); this epitope is one of the most immunogenic influenza peptides observed in humans with HLA-A*02:01 being the most common HLA alleles expressed worldwide (157). This evidence concerns the gene CD8A and influenza.