T Cell Activation in Lupus Proteomic Characterization

描述（由申请人提供）： 系统性红斑狼疮（SLE）的特征是针对普遍存在的细胞内成分的IgG自身抗体。几个近交系小鼠品系也发展为自发性狼疮，具有相同的自身抗体谱。这些特异性中的某些是致病性的，包括那些针对诱导免疫复合物肾小球肾炎的染色质。狼疮中的这种自身抗体似乎是自身抗原特异性CD 4 + T细胞帮助的结果。虽然对普遍存在的自身肽应答的T细胞的耐受逃逸的机制是未知的，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，外周缺陷可能导致这种疾病中自身反应性T细胞的活化。本提案中要解决的假设是，来自狼疮易感MRL小鼠的幼稚CD 4 + T细胞具有内在（遗传）缺陷，与非自身免疫T细胞相比，这些缺陷使它们在T细胞受体（TCR）-CD 3复合物与自身肽接触后具有高反应性，这种缺陷导致耐受性丧失，伴随次级淋巴器官中自身反应性T细胞的扩增。该假设基于已发表的工作，即与来自非自身免疫小鼠的T细胞相比，来自Fas（CD 95）-完整、狼疮倾向MRL（MRL/+ FaS/lpr）小鼠的初始T细胞在体外TCR刺激后过度增殖，并且此类T细胞避免了体内外周耐受诱导。该数据表明，这些差异是狼疮表型的组成部分，而不是反映菌株的差异，这一观点部分得到以下发现的支持：来自患有SLE的人的T细胞在体外TCR接合后具有类似的过度增殖表型。在该提案中，将使用最先进的蛋白质组学分析来解决负责狼疮中的CD 4 + T细胞的过度增殖表型的生化机制，以确定与对照细胞相比，观察到的CD 4 + T细胞活化的表型差异是否与蛋白质表达的改变相关。

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.