T-CELL SPECIFICITY IN IMMUNITY AND AUTOIMMUNITY TO DNA

针对多种细胞抗原的抗体，主要来源于核抗原， 在患有系统性红斑狼疮的小鼠和人类的血清中检测到 红斑狼疮。有令人信服的证据表明，这些自身抗体， 尤其是对DNA的自身抗体，至少在一定程度上导致了 狼疮的病理表现。黄斑狼疮的免疫学基础 在小鼠和人类中产生抗dna自身抗体一直很困难。 来澄清一下。以前用同样的方法刺激抗体的尝试 狼疮与DNA结合作为抗DNA抗体的特异性已被证实 不成功。这一事实再加上普遍存在的 狼疮小鼠模型中淋巴细胞发育异常导致 关于狼疮自身抗体是由非抗原引起的， 多克隆B细胞活化。然而，来自我们分子的最新结果 自身免疫性抗DNA抗体的结构和个体发育分析 已经表明对DNA的自身免疫既是启动的也是持续的 针对DNA或DNA复合体的克隆选择的、特定的免疫反应。这个 自身免疫性抗DNA抗体的二次免疫特性 提示抗原特异性辅助性T细胞参与了 这种自身抗体的产生，以及实验数据支持这一点 假设。然而，人们对其特异性和功能知之甚少。 这样的T细胞。我们最近建立了一种实验性免疫 非遗传性小鼠DNA抗体诱导模型的建立 易患自身免疫性疾病。在这个实验中使用的免疫原 系统是DNA与DNA结合肽的复合体。诱导出的反- DNA抗体具有相同的结构和特异性特征 狼疮自身免疫性抗DNA抗体的检测。此外，老鼠生产的 这种抗体出现早期狼疮性肾炎的症状。 本申请中提出的研究将开发新的 用于产生T细胞克隆和杂交的实验免疫系统 专用于DNA结合肽。T细胞克隆和杂交将是 由正常、非自身免疫倾向和自身免疫倾向的小鼠产生 DNA-多肽复合体免疫。然后这些克隆人和混血儿就会 用于确定辅助性T细胞的特异性和功能 可在体外诱导抗DNA抗体的产生 特异性DNA多肽。特别是，这些实验将确定 这类T细胞的MHC限制性T细胞表位是否由 单独的多肽或DNA和多肽的组合。这些实验 也将决定特定氨基酸序列的变化 多肽会影响特定T细胞对它们的识别。T细胞受体 T细胞针对不同多肽的可变区结构 DNA-多肽复合体将与T细胞受体变量- 自身免疫T细胞在体外激发抗DNA抗体的区域结构 抗体的产生。

Antibodies to a variety of cellular antigens, mostly nuclear in origin, have been detected in sera from mice and humans with systemic lupus erythematosus. There is compelling evidence that these autoantibodies, particularly autoantibody to DNA, are responsible at least in part for the pathological manifestations of lupus. The immunological basis for the generation of anti-DNA autoantibody in mice and humans has been difficult to elucidate. Previous attempts to stimulate antibody with the same specificity for binding to DNA as anti-DNA antibody in lupus have been unsuccessful. This fact coupled with the presence of a generalized abnormality in lymphoid cell development in mouse models for lupus has led to the proposal that lupus autoantibodies arise by antigen independent, polyclonal B cell activation. However, recent results from our molecular analyses of the structure and ontogeny of autoimmune anti-DNA antibodies have indicated that autoimmunity to DNA is both initiated and sustained as a clonally selected, specific immune response to DNA or DNA complexes. The secondary-immune characteristics of autoimmune anti-DNA antibody implicates the participation of antigen-specific helper T cells in the generation of this autoantibody, and experimental data support this hypothesis. However, little is known about the specificity and function of such T cells. We have recently established an experimental immunization model for the induction of antibody to DNA in mice not genetically predisposed to autoimmune disease. The immunogen used in this experimental system is DNA in a complex with a DNA-binding peptide. The induced anti- DNA antibody has structural and specificity characteristics identical to those of autoimmune anti-DNA antibody in lupus. Moreover, mice producing this antibody develop symptoms of early stage lupus-nephritis. The research proposed in this application will exploit the new experimental immunization system to generate T cell clones and hybrids specific for DNA-binding peptides. T cell clones and hybrids will be generated from normal, nonautoimmune-prone and autoimmune-prone mice immunized with DNA-peptide complexes. These clones and hybrids will then be used to determine the specificity and function of helper T cells that can induce in vitro anti-DNA antibody production when stimulated with specific DNA-peptide. In particular these experiments will determine whether the MHC-restricted T cell epitope for such T cells is formed by the peptide alone or a combination of DNA and peptide. The experiments will also determine how changes in the amino acid sequence of specific peptides affect their recognition by specific T cells. T-cell receptor variable-region structures from T cells specific for different peptide- or DNA-peptide complexes will be compared with T-cell receptor variable- region structures from autoimmune T cells that stimulate in vitro anti-DNA antibody production.