In TB infected mice, T-cells that cross the lung vasculature into the parenchyma express CXCR3 and are negative for Killer Cell Lectin Like Receptor G1 (KLRG1), while intravascular CD4+ T-cells express CX3CR1 and expressed a more terminally differentiated, KLRG1hi /T-bethi, phenotype (19). The gene discussed is CD4; the disease is tuberculosis.