OBJECTIVETo evaluate the effect of the small intestinal mesenteric lymphoid tissues stimulating mixed lymphocyte reaction with dendritic cells (DC) and peripheral blood monocyte cells (PBMC), and observe the changes of the MHC molecular expression on DC.

METHODSDC, PBMC and mixed lymphocyte were separated to culture from SD rats. Lymphoid tissue suspension was adopted from small intestinal mesentery of Wistar rats. In the mixed lymphocyte reaction (MLR), the cellular proliferation of small intestinal mesenteric lymphoid tissue antigen act on DC and PBMC was detected with cell counting of CCK-8 assay, the same assay used in small intestinal mesenteric lymphoid tissue antigen and ovalbumin (OVA) acting on DC. FACS analysis was performed after lymphoid tissue suspension stimulating DC to observe the MHC molecular expression.

RESULTSIn the lymphoid tissue suspension, 91% of the cells was lymphocyte, others including granulocyte, plasmocyte, epithelium. The effect of stimulating mixed lymphocyte proliferation were higher in DC groups than in PBMC groups with the small intestinal mesenteric lymphoid tissue (P < 0.05). In the proportion of DC and mixed lymphocyte >or= 1:100 groups, the mixed lymphocyte proliferation were higher in the small intestinal mesenteric lymphoid tissues groups than in the OVA groups (P < 0.05). After stimulated by the small intestinal mesenteric lymphoid tissue, DC expressed higher MHC-I and -II molecules than control groups.

CONCLUSIONSThe small intestinal mesenteric lymphoid tissue has high antigenicity; the antigen presenting ability of DC was much stronger than granulocytes; DC expresses high MHC-I and MHC-II molecules after stimulated by mixed lymphoid tissue suspension.