NOD小鼠自身免疫性糖尿病自然进程中耗竭性CD8+T淋巴细胞及其亚群的动态变化与功能特征OA

Objective To observe the dynamic changes of exhausted CD8⁺ T cells and their subsets,progenitor ex-hausted T cells(TPEX)and terminally exhausted T cells(TEX),during the natural progression of autoimmune diabetes in NOD mice,and to analyze their functional characteristics.Methods Twenty NOD mice were randomly divided into 4-week(4W),9-week(9W),18-week(18W),and hyperglycemic(Hi)groups,with 5 in each,representing the early dis-ease stage,immune activation stage,disease progression stage,and hyperglycemic stage,respectively.Random blood glu-cose and diabetes incidence were monitored weekly.Pancreatic insulitis was assessed by hematoxylin-eosin(HE)stain-ing.Isolated splenic and pancreatic lymphocytes were analyzed by flow cytometry to detect the proportions of exhausted CD8⁺ T cells and their subsets(TPEX and TEX).Further analysis of the functional characteristics of TPEX and TEX was conducted using intracellular interferon-γ(IFN-γ)staining and detection of activation and proliferation-related phenotypes CD69 and CD62L.Results Diabetes incidence and random blood glucose increased with disease progression,with blood glucose in Hi group significantly higher than that in 18W,9W,and 4W groups(all P<0.05).HE staining showed progressively aggravated islet inflammation,and insulitis scores increased significantly across groups(all P<0.05).The proportions of exhausted CD8⁺ T cells in the spleen and pancreas showed a trend of initial increase followed by decline,and were lower than that of non-exhausted CD8⁺ T cells(all P<0.05).TPEX and TEX exhibited distinct dynamic pat-terns.TPEX decreased in the 9W group,rebounded in the 18W group,and declined again in the Hi group,whereas TEX increased in the 9W group,decreased in the 18W group,and increased again in the Hi group.The IFN-γ secretion capaci-ty of TPEX was generally higher than that of TEX,and it progressively increased with disease progression,reaching its peak in the 18W group before declining in the Hi group.In contrast,the IFN-γ secretion capacity of TEX increased in the 9W group,and then decreased in the 18W group and in the Hi group.The expression of CD69 and CD62L in splenic TPEX was higher than that in TEX in the 9W group(both P<0.05).Conclusions During the natural course of autoim-mune diabetes in NOD mice,the proportion of exhausted CD8+T lymphocytes generally showed an initial increase followed by a decrease,while TPEX and TEX showed distinct dynamic changes.Compared with TEX,TPEX demonstrated stronger IFN-γ secretion capacity and higher CD69 and CD62L expression.