Objective      To investigate the purification methods of the exosomes derived form lymphoid tissues of rats and determine their effect on T cell proliferation.       Methods      The peripheral lymph nodes and mesenteric lymph nodes from BN (RT1n) rats were separated

and their impurity were removed by centrifugation. Then

the exosomes were purified from the acellular supernatants by means of differential ultracentrifugation or ultrafiltration and sucrose gradient centrifugation

and confirmed by transmission electron microscopy. The protein expression of the exosomes was analyzed by SDS-PAGE electrophoresis. Western blot analysis was used to test the expression of IL-10. Finally

mixed lymphocyte culture was used to evaluate the immune function of the exosomes from peripheral lymph nodes and mesenteric lymph nodes.       Results      The protein concentration of the exosomes purified from mesenteric lymph nodes were higher than that from peripheral lymph nodes (1.92±0.10 vs 1.57±0.06 μg/μL

P0.05). SDS-PAGE displayed the differences in protein contents and types between the exosomes from 2 kinds of lymph nodes. Western blotting indicated that the expression of IL-10 was stronger in the exosomes from mesenteric lymph nodes than those from peripheral lymph nodes. The two kinds of exosomes both promoted lymphocyte proliferation (P0.05)

while the exosomes from peripheral lymph nodes exosomes stronger than from mesenteric lymph nodes (P0.05).       Conclusion      There are exosomes in both peripheral and mesenteric lymph nodes

but with significant differences in protein contents and types. The exosomes from 2 kinds of lymph nodes promote lymphocyte proliferation

though with significant differences.