To determine whether the altered Th1 phenotype observed after infection in the lungs of CXCR6-deficient mice was due to an intrinsic defect in CXCR6KO CD4+ T-lymphocytes, CXCR6KO P25 TCR transgenic mice were generated on a CD45.1 background (C6GKO-P25). The gene discussed is CD4; the disease is infection.