Pretreatment with RA⁺T exosomes suppresses lymphocyte homing to the small intestine. (A) We investigated the effect of exosomal pretreatment of recipient mice on the homing of adoptively transferred T cells. Recipient mice were pretreated with an intravenous injection of either vehicle (mock), RA^– T exosomes, or RA⁺ T exosomes. Three hours after injection, recipient mice were intravenously administered an identical number of CFSE-labeled lymphocytes (2 × 10⁷). Sixteen hours after lymphocytes were administered, organs were harvested, mononuclear cells were isolated, and the percentages of donor cells were examined by flow cytometry. Representative flow cytometry dot plots of the small intestine lamina propria lymphocytes (LPLs), large intestine LPLs, and MLN cells are shown. CFSE-labeled donor cells are circled and the percentages are shown. (B) Bar graphs represent the percentages of homed donor cells in different tissues. Results are expressed as the mean ± SEM of 3 independent experiments. *P < .05 (vs mock).