Specifically, T-bet and Eomes regulate dysfunctional CD8+ T cell responses upon viral infection (Intlekofer et al., 2007; Joshi et al., 2007; Intlekofer et al., 2008; Banerjee et al., 2010; Hersperger et al., 2011; Kao et al., 2011) and appear to be closely associated with the differentiation and self-renewal of memory CD8+ T cells (Intlekofer et al., 2007; Joshi et al., 2007; Banerjee et al., 2010). This evidence concerns the gene CD8A and viral infectious disease.