ANALYSIS OF HIV-INDUCED AUTO-ANTIBODIES TO CRYPTIC EPITOPES OF HUMAN CD4

我们继续定义归纳的机制，并 鉴定人类抗CD4自身抗体。这项研究描述了一个 病毒诱导的自身免疫模型，它支持这样的假设， 由于HIV感染，CD4的异常处理 受体就会出现。这一过程揭示了神秘的表位 CD4上的膜锚定区域，然后被认为是外来的 导致自身免疫抗体产生的抗原。使用CD4抗原 作为一个模型，我们正在研究如何以及在细胞中或细胞上的位置 表面、HIV和推测的包膜蛋白复合体与 在膜的外部诱导CD4分子的裂解 蛋白质连接。这些研究是使用活的艾滋病毒进行的 与CD4阳性细胞相互作用，此外，还使用蛋白质 表达高水平mCD4的痘苗病毒载体表达系统 以及表达包膜蛋白的载体。降级 使用放射性同位素标记对CD4进行了动力学跟踪 免疫沉淀和免疫印迹。以确定卵裂是否 作为病毒结合的结果出现在膜表面， 表达高水平CD4的细胞已经与游离病毒孵育 或纯化包膜，然后监测CD4的降解情况。我们也是 计划确定这种自身免疫过程是否会延伸到 通过测试患者的细胞反应来进行细胞免疫隔间 SCD4。如果这些都是肯定的，那么我们将尝试映射这些 使用产生的多肽试剂分析自身抗体的反应性。 这个项目导致了一种假设，即异常的抗原处理 可以产生自身免疫反应性，并提出了一种理论范式 这可能为深入了解其他基因的分子机制提供依据 自身免疫性疾病。

We have continued to define the mechanism of induction and to characterize human anti-CD4 auto-antibodies. This study describes a model for virus induced autoimmunity which supports the hypothesis that, as a consequence of HIV infection, abnormal processing of the CD4 receptor occurs. This process uncovers cryptic epitopes near the membrane anchoring region on CD4, which are then recognized as foreign antigen leading to autoimmune antibody production. Using the CD4 antigen as a model, we are studying how and where in the cell or on the cell surface, HIV and presumably the envelope protein complex interacts with CD4 to induce cleavage of the CD4 molecule at the membrane-external protein junction. These studies are per-formed using live HIV interacting with CD4 positive cells and, in addition, using protein expression systems with vaccinia vectors expressing high levels of mCD4 together with vectors expressing the envelope proteins. Degradation of CD4 has been followed kinetically using radioisotope labelling and immunoprecipitation and western blotting. To determine whether cleavage of CD4 occurs on the membrane surface as a consequence of virus binding, cells expressing high levels of CD4 have been incubated with free virus or purified envelope and then degradation of CD4 monitored. We are also planning to determine whether this autoimmune process extends into the cellular immune compartment by testing patients for cellular response to sCD4. If these are positive we will then attempt to map these reactivities using peptide reagents generated to analyze autoantibodies. This project has led to the hypothesis that abnormal antigen processing can generate autoimmune reactivities and presents a theoretical paradigm which may provide insight into molecular mechanisms involved in other autoimmune disorders.