CD4 and infection: We found reduced frequencies of both CXCR3 + and CX3CR1 + CD4 T cells from lungs of Vhl cKO mice 8 weeks after infection with M. tuberculosis when compared to those of WT controls (Fig. 3p–r), while the fractions of CXCR3 + and CX3CR1 + CD8 T cells in lungs from Vhl cKO and WT M. tuberculosis infected mice were similar (Fig. 3q, r).