T Cell Activation in Lupus Proteomic Characterization

描述(由申请人提供)： 系统性红斑狼疮(SLE)的特征是对普遍存在的细胞内成分产生免疫球蛋白抗体。几个近交系小鼠也会患上自发性狼疮，具有相同的自身抗体谱。其中某些特异性是致病的，包括那些针对染色质的特异性，导致免疫复合体肾小球肾炎。狼疮中的这种自身抗体似乎是自身抗原特异性的CD4+T细胞帮助的结果。虽然T细胞对无处不在的自体多肽的耐受逃逸机制尚不清楚，但在自发性狼疮中，中枢(胸腺)T细胞耐受似乎是完整的；因此，外周缺陷(S)可能导致了这种疾病中自身反应性T细胞的激活。本研究提出的假设是，与非自身免疫性T细胞相比，来自狼疮易感小鼠的初始CD_4~+T细胞存在固有的(遗传)缺陷，使它们在T细胞受体(T细胞受体)-CD_3复合体与自体多肽接触后具有高反应性，这种缺陷(S)导致次级淋巴器官中自身反应性T细胞的扩张，从而导致耐受性丧失。这一假说是基于发表的工作，即来自Fas(CD95)完整的、易患狼疮的MRL(MRL/+Fas/LPR)小鼠的初始T细胞在体外经TCR刺激后高度增殖，与来自非自身免疫小鼠的T细胞相比，并且这种T细胞避免了体内外周耐受诱导。这一数据表明，这些差异是狼疮表型所不可或缺的，而不是反映菌株之间的差异，这一信念在一定程度上是因为发现来自SLE患者的T细胞在体外参与TCR后具有类似的高增殖表型。在这项建议中，将使用最先进的蛋白质组学分析来解决导致狼疮患者CD4+T细胞过度增殖表型的生化机制，以确定所观察到的CD4+T细胞激活的表型差异是否与与对照细胞相比的蛋白质表达的变化有关。

DESCRIPTION (provided by applicant): Systemic lupus erythematosus (SLE) is characterized by IgG autoantibodies to ubiquitous intracellular components. Several inbred mouse strains also develop spontaneous lupus, with the same spectrum of autoantibodies. Certain of these specificities are pathogenic, including those directed against chromatin that induces immune-complex glomerulonephritis. Such autoantibodies in lupus appear to arise as a consequence of autoantigen-specific CD4 + T cell help. While the mechanisms of tolerance escape for T cells responsive to ubiquitous self peptides are unknown, central (thymic) T cell tolerance appears intact in spontaneous lupus; thus, a peripheral defect(s) presumably leads to activation of autoreactive T cells in this disorder. The hypothesis to be addressed in this proposal is that naive CD4 + T cells from lupus-prone MRL mice have intrinsic (genetic) defects that, compared to non-autoimmune T cells, render them hyperresponsive after T cell receptor (TCR)-CD3 complex contact with self-peptides, a defect(s) that contributes to tolerance loss with expansion of autoreactive T cells in secondary lymphoid organs. This hypothesis is based upon published work that naive T cells from Fas (CD95)-intact, lupus-prone MRL (MRL/+ FaS/lpr) mice are hyper-proliferative after TCR stimulation in vitro, compared to T cells from nonautoimmune mice, and that such T cells avoid peripheral tolerance induction in vivo. This data suggests that these differences are integral to the lupus phenotype, rather than reflective of differences in strains, a belief bolstered in part by the finding that T cells from humans with SLE have a similar hyper- proliferative phenotype after TCR engagement in vitro. In this proposal, the biochemical mechanisms responsible for the hyper-proliferative phenotype of CD4 + T cells in lupus will be addressed using state of- the art proteomic analysis to determine if the observed phenotypic differences in CD4 + T cell activation are associated with alterations in protein expression compared to control cells.