CD8A and viral infectious disease: Since TCF1 supports the CD8 T cell response against chronic viral infection in a cell-autonomous manner, in both the early phase (8 days post infection) and advanced phase (20 days post infection or later), by maintaining a virus-specific CD8 T cell pool as well as its effector function, we further investigated whether the upregulation of TCF1 could enhance the CD8 T cell response during LCMV chronic infection.