When we analyzed T-bet and Eomes expression longitudinally for perforin+ CD8+ T cells within the HIV-infected cohort we found the proportion of T-bet+Eomes+ cells decreased over the first 30 days of infection and T-bet-Eomes- cells increased over the first 60 days before gradually returning to pre-infection levels (Fig 5C and 5D). Here, PRF1 is linked to infection.