致病性CD8 T细胞是浸润并杀伤胰岛，导致1型糖尿病发生的关键因素。近期研究证实该病不同患者胰岛损伤存在异质性，但其机制尚不明确。本课题组前期研究表明，该病新发及长病程患者外周血CD8 T细胞对HLA-A*0201限制性表位ZnT8 107-116的反应性差异显著，这提示致病性CD8 T细胞本身异质性可能导致患者胰岛损伤的异质性。因此本课题拟采用基于Tetramer标记的多色流式细胞术及分子生物学等技术，揭示胰岛功能快速丢失和仍有残存的两组1型糖尿病患者PBMC中，ZnT8 107-116等多种自身抗原阳性表位反应性CD8 T细胞活化分化并浸润杀伤胰岛能力的差异；阐明两组患者Treg活化分化及其与致病性CD8 T细胞比例平衡的差异；并明确该病易感基因位点对上述细胞免疫表型的影响与患者胰岛损伤异质性的关联。本课题将为1型糖尿病病程进展中免疫状态监测及其个体化免疫治疗提供新的生物学标志。

Pathogenic CD8 T cells have the ability to infiltrate and kill islet beta cells, and play a key role in type 1 diabetes (T1D) onset and progression. Recent studies have proved the heterogenicity of islet destruction in different T1D subjects, but it is poorly understood the mechanisms contributed to it. Our previous study indicated that CD8 T cells responses to ZnT8 107-116 (a novel HLA-A*0201 restricted CTL epitope) stimulation were significantly different between recent onset and longstanding T1D subjects, this suggested the heterogenicity of pathogenic CD8 T cells themselves might result in the heterogenicity of islet destruction in different T1D subjects. Consequently, this proposed work will utilize multi-color flow cytometry based on HLA-A*0201 restricted tetramer staining and molecular biological techniques etc, and compare HLA-A*0201 restricted recent onset T1D subjects with rapid loss of islet function to longstanding T1D subjects with residual C peptide, (1) to obtain a robust understanding of phenotype differences of various auto-antigen (including ZnT8 107-116) specific CD8 T cells, such as their activation, differentiation and cytokine secretion etc, (2) to further reveal their different capacity to infiltrate and kill islet beta cells, (3) to clarify differences of global Treg activation and differentiation and their ratio to the investigated islet-specific CD8 T cells, (4) to elucidate whether the effects of T1D risk alleles on Treg and islet-specific CD8 T cells immune phenotypes are correlated with heterogenicity of islet destruction. This project will help define potentially more precise composite biomarkers of disease progression along with providing insight into disease mechanisms and appropriate combination therapies required to prevent T1D.