CD8A and infection: The majority of the LCMV-specific CD8 T cells in GITR+/+ and GITR-/- mice were PD-1+ Tim-3+ after LCMV cl 13 infection, but CD8 T cells from GITR-/- mice expressed significantly higher levels of PD-1 and Tim-3 per cell at days eight and 45 p.i. (Fig. 2, A and B).