Changes of CD8⁺ T cells in dextran sulfate sodium-induced colitis mice pretreated with oral immune regulation.

Background 11 has been reported that CD8(+) regulatory cells could be induced upon oral tolerance. The purpose of this study was to investigate the changes of CD8 alpha(+) T cells in dextran sulfate sodium (DSS)-induced colitis mice pretreated by oral immune regulation. Methods The effects of five low oral doses of colitis-extracted proteins (CEP) on colitis were evaluated by clinical manifestation and histological lesions. The percentages of CD8 alpha(+) T cells gating on CD3(+) T cells were evaluated in the gut-associated lymphoid tissues (GALT) and the spleens by flow cytometry. Differences between the two groups were compared by Student's t test or Mann-Whitney U test. Results Compared to bovine serum albumin (BSA)-fed control mice, administration of CEP resulted in marked alleviation of colitis. The proportion of CD8 alpha(+) T cells, not only in intraepithelial lymphocytes (IELs) and lamina propria lymphocytes (LPLs) of the large intestine (LI) but also in spleen from CEP-fed colitis mice, was significantly higher than that from BSA-fed colitis mice (LI-IELs: (71.5 +/- 5.4)% vs. (60.1 +/- 4.3)%, P<0.01; LI-LPLs: (60.7 +/- 5.2)% vs. (51.9 +/- 4.7)%, P <0.01; spleen: (24.1 +/- 3.6)% vs. (20.3 +/- 4.1)%, P <0.05; n=8). Mucosal repair in repair-period mice five days after termination of DSS treatment was also accompanied by an increase of CD8 alpha(+) T cells in large intestinal mucosal lymphocytes (LI-IELs: (72.1 3.7)% vs. (61.5 4.5)%, P<0.01; LI-LPLs: (62.1 +/- 5.7)% vs. (52.7 +/- 3.6)%, P<0.01; n=8). The proportion of CD3(+) T cells increased in Peyer's patches (PPs) and decreased in mesenteric lymph nodes (MLNs) from colitis mice compared to untreated mice, whereas the change pattern of CD3(+) T cells in PPs and MLNs from CEP-fed colitis mice was just on the contrary. Conclusion Improvement of DSS-induced colitis resulted from oral immune regulation is associated with an increase in CD8 alpha(+) T cells in spleen and large intestinal mucosa. Chin Med J 2012;125(12):2173-2179