Akin to our observations, CD44int memory CD8+ T cells were shown to be the predominate pro-inflammatory cytokine-secreting cell population upon influenza NP366-374 peptide re-stimulation of F5 TCR transgenic mice.43 Thus, we propose that GIFT7 treatment corrects age-associated immune deficiency during acute viral infection by (a) expanding the pool of thymic-derived de novo T cells available in responding to neo-antigens and (b) converting antigen-experienced effector T cells to a phenotype (IL2+tetramer+CD8+ and IL2Rα+CD4+) more amendable for longer in vivo persistence. Here, CD4 is linked to Immunodeficiency.