CD8A and hepatitis A virus infection: In hepatitis B vaccine immune non-response, the genes involved in the activity of naive and memory T cells, such as the MAPK signalling pathway and Nf-kb, are downregulated, as are the genes involved in many activities, such as cell activation, oxidative phosphorylation, interferon-γ, calcium ion reactions, and the IL-4 production of the three T-cell subsets, which are the CD4+ effector cells, CD8+ effector T cells, and CD8+ effector memory T cells.