Prenatal TCDD and postnatal autoimmune disease

描述(由申请人提供)：SNF1小鼠在发育过程中暴露于TCDD会诱发和加重出生后自身免疫性狼疮性肾炎。可能单独或共同导致这种环境化学影响免疫发展的机制将被研究，包括：胸腺中自身反应性T细胞克隆的受损删除；控制对自身抗原的不适当反应的调节性T细胞减少；强迫T细胞分化到胸腺外的隔室，在否定选择无效的地方；出生后T细胞谱系向T辅助细胞和抗体产生的转变；以及不适当的B细胞活动，包括自身抗体的产生。在SNF1小鼠(自身免疫易感性但对TCDD不敏感)中，胸腺外和胸腺隔室中表达自身反应性CD4+Vbeta17a+和CD3+Vbeta3+TCR的T细胞和CD4+25+调节性T细胞的数量将在出生后一段时间内被跟踪，并与疾病进展相关。C57BL/6小鼠(非自身免疫但对TCDD敏感)将同时用于对TCDD敏感且遗传上易患自身免疫性疾病的个体的风险评估。在SNF1和C57BL/6小鼠中：ConA刺激的脾淋巴细胞将在出生后一段时间内进行评估，以确定可能沉淀或加剧出生后自身抗体反应的细胞因子产生的化学印迹变化。将测定针对单链DNA、双链DNA和心磷脂的抗体水平，以与细胞因子谱和辅助性T细胞活性进行比较。由适当的反应基因组成的聚焦的自身免疫基因阵列将被用来确定基本信号通路、蛋白质和介导免疫反应的信号转导通路的下游靶点的出生后完整性。基于逆转录聚合酶链式反应的差异显示将用于检测SNF1和C57BL/6小鼠胸腺MHC I和II类基因的表达，作为一种可能损害T细胞教育和增加外周自身反应细胞的机制。集体实验旨在检测TCDD引起的胎儿免疫发育的变化，TCDD是这种化学物质引起的恶化的出生后(青春期后)自身免疫性疾病的基础。

DESCRIPTION (provided by applicant): Developmental exposure of SNF1 mice to TCDD induces and exacerbates postnatal autoimmune lupus-like nephritis. Mechanisms that may singly or collectively underlie this environmental chemical effect on immune development will be examined, including: impaired deletion of autoreactive T cell clones in the thymus; diminished regulatory T cells that control inappropriate responses to self antigen; the forcing of T cell differentiation into extra-thymic compartments where negative selection is inefficient; a shift in the postnatal T cell repertoire toward a T helper profile and antibody production; and inappropriate B cell activity including autoantibody production. Numbers of T cells expressing autoreactive CD4+ Vbeta 17a+ and CD3+ Vbeta 3+ TcR, and numbers of CD4+25+ regulatory T cells, in extrathymic and thymic compartments, will be followed over postnatal time in SNF1 mice (autoimmune-predisposed but TCDD insensitive) and correlated to disease progression. C57Bl/6 mice (non-autoimmune but TCDD sensitive) will be used in parallel for risk assessment considerations in individuals who may be both sensitive to TCDD and genetically predisposed to autoimmune disease. In both SNF1 and C57Bl/6 mice: Con A stimulated splenic lymphocytes will be evaluated over postnatal time to identify chemical-imprinted shifts in cytokine production that may precipitate or exacerbate the postnatal autoantibody response. Antibody level to ssDNA, dsDNA and cardiolipin will be determined for comparison to cytokine profile and T helper cell activity. A focused autoimmunity gene array consisting of appropriate response genes will be used to determine the postnatal integrity of fundamental signaling pathways, proteins and downstream targets of signal transduction pathways that mediate the immune response. A reverse transcription PCR-based differential display will be used to examine thymic MHC class I and II gene expression in SNF1 and C57Bl/6 mice, with or without TCDD exposure during gestation, as a mechanism that may impair T cell education and increase peripheral autoreactive cells. The collective experiments are designed to detect alterations in fetal immune development caused by TCDD that underlie the worsened postnatal (postpubertal) autoimmune disease caused by this chemical.