CD4 and infection: Studying these surface markers on MPT70-specific CD4 T cells revealed a substantially higher proportion of CX3CR1+KLRG1+ T cells after H37Rv::mpt70high infection (20.6%) compared to H37Rv infection (11.8%), indicating increased differentiation and decreased lung homing capacity for H37Rv::mpt70high-primed MPT70 CD4 T cells (Fig. 4f).