A partial human LCK defect causes a T cell immunodeficiency with intestinal inflammation

Partial T cell primary immunodeficiency disorders (PIDD) are a group of genetic disorders that have partial reduction of T cell number/function, and are commonly associated with autoimmune and inflammatory complications. T cell receptor (TCR) signaling is initiated by Lymphocyte cell-specific protein-tyrosine kinase (LCK). A novel homozygous mutation in LCK (p.Pro440Ser, LCK P440S) was identified in two siblings who were born to consanguineous parents, presenting with T lymphopenia, recurrent viral and fungal infections, and gastrointestinal inflammatory complications. We hypothesize the P440S mutation impairs LCK expression/function such that T cell-mediated intestinal immunity is dysfunctional, leading to inflammatory bowel disease (IBD). We generated a cell line and a mouse model that harbor the mutant kinase, and then performed downstream immunophenotypic and functional assessments. The P440S mutation results in shorter protein half-life, decreased protein expression, and defective TCR signaling responses. The P440S mouse demonstrates impaired thymocyte development with T cell lymphopenia, skewed memory phenotype of peripheral T cells, and colitis. The Lck knock out mouse replicates the T cell aberrations in the P440S mouse, but do not develop colitis, suggesting that the partial loss of Lck function drives colitis development. Our findings explain the aberrant immunological presentation of the human P440S patients, advance our understanding of IBD in the context of T cell PIDD, and establish a model system with which to develop therapies against IBD. Within this repository are .fcs files from flow cytometry and mass cytometry experiments that were collected for the publication of this project. They include data collected for the phenotyping of a novel P440S Lck mouse model, functional assessment of P440S T cells, and determination of the effects of CD4 depletion and Treg infusion into these mice.部分性T细胞原发性免疫缺陷病（Partial T cell primary immunodeficiency disorders, PIDD）是一类以T细胞数量与功能部分降低为特征的遗传性疾病，常伴随自身免疫与炎症并发症。T细胞受体（T cell receptor, TCR）信号通路由淋巴细胞特异性蛋白酪氨酸激酶（Lymphocyte cell-specific protein-tyrosine kinase, LCK）启动。本研究在一对近亲婚配父母所生的同胞兄妹中，鉴定出LCK的一种新型纯合突变（p.Pro440Ser，即LCK P440S），该患者群体表现为T淋巴细胞减少症、复发性病毒及真菌感染，以及胃肠道炎症并发症。我们推测该P440S突变会损害LCK的表达与功能，致使T细胞介导的肠道免疫功能失调，进而引发炎症性肠病（inflammatory bowel disease, IBD）。我们构建了携带该突变激酶的细胞系与小鼠模型，并开展了后续的免疫表型与功能学检测。结果显示，P440S突变可缩短蛋白半衰期、降低蛋白表达水平，并损害TCR信号通路的应答能力。P440S突变小鼠表现出胸腺细胞发育受损、T淋巴细胞减少、外周T细胞记忆表型偏倚，以及结肠炎症状。Lck敲除小鼠能够复制P440S小鼠的T细胞异常，但不会发生结肠炎，这提示LCK功能的部分缺失是结肠炎发生的驱动因素。本研究结果阐明了人类P440S患者异常免疫表型的分子机制，加深了我们对T细胞原发性免疫缺陷病背景下炎症性肠病的认识，并建立了可用于开发炎症性肠病治疗手段的模型体系。本数据集仓库包含本项目发表论文中所用的流式细胞术与质谱流式细胞术实验所得的.fcs文件，涵盖新型P440S Lck小鼠模型的表型分析、P440S T细胞的功能检测，以及CD4耗竭与调节性T细胞（Treg）输注对该类小鼠影响的相关实验数据。