Likewise, even during acute toxoplasmosis, the co-expression of cell surface receptors KLRG1 and CXCR3 distinguishes CD8+ T cell subsets that have memory potential or are terminally differentiated, with continued presence of infection driving the KLRG1+CXCR3- terminally differentiated population [12,30]. Here, CXCR3 is linked to infection.