In vivo homing of α₄-R/A^GFFKR lymphocytes to the gut is suppressed. Competitive homing assay to compare α₄-R/A^GFFKR (KI) and wild-type (WT) splenic lymphocytes. Equal numbers (2 × 10⁷) of fluorescently labeled cells were mixed and injected into C57BL/6J-CD45.1⁺ congeneic mice in the absence (A) or presence (B) of DSS-induced colitis. Homing indices were determined 18 hours after injection. Data are expressed as the mean values plus or minus SEM of at least 5 independent experiments. *P < .05; **P < .01; and ***P < .001, versus SP. SP indicates spleen; PBL, peripheral blood lymphocyte; PLN, peripheral lymph node; MLN, mesenteric lymph node; PP, Peyer patch; SI, small intestine; LI, large intestine; BM, bone marrow; LIV, liver; and LUN, lung.