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

摘要

Background It has been reported that CD8+ regulatory cells could be induced upon oral tolerance.The purpose of this study was to investigate the changes of CD8α+ 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 CD8α+ T ceils 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 CD8α+ 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 CD8α+ 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 CD8α+ T cells in spleen and large intestinal mucosa.