CD8A and infection: Finally, and consistent with these results, Selplg-/-Pdcd1-/- P14 CD8+ T cells had reduced frequencies of SLAMF6+CX3CR1- TEXprog cells and increased frequencies of SLAMF6-CX3CR1- TEXterm cells both at early and late stages of infection, suggesting that PSGL-1 and PD-1 deletion favor a more terminally exhausted T-cell fate.