CD8A and infection: The HCV‐specific CD8 T cells in the subjects who successfully cleared repeated infections demonstrated greater poly‐functionality (i.e., producing more than one cytokine) and expansion of CD127lo HCV‐specific memory CD8 T cells after virus re‐challenge, suggesting a pre‐existing subset of memory T cells responded rapidly to the second virus with differentiation into CD127lo effector T cells [5].