MHC CLASS II ANTIGENS IN THE PATHOGENESIS OF INFLAMMATORY DISEASES

MHC II类抗原，人的HLA-DR和小鼠的Ia， 是膜结合糖蛋白，由以下基因编码： 主要组织相容性复合体 表达这些 抗原对于启动和 免疫反应的延续。 在一些 免疫病理条件HLA-DR抗原阴性细胞是 刺激表达II类抗原。 在这些情况下， II类抗原的免疫学作用已被假定 表情 在过去的一年里，我们已经确定了II类抗原是否 在某些疾病中表达，我们已经评估了它们的可能性， 在自身免疫性和炎症性疾病中的作用。 初步研究 确定了眼前节中的细胞和视网膜（RPE）中的细胞 细胞）表达II类抗原 疾病 单克隆抗Ia抗体治疗减少了 临床疾病和MHC II类抗原的表达。 这些研究已经扩展到评估干燥综合征。 我们发现干燥综合征患者的唾液腺 主要由T淋巴细胞浸润， 与腺上皮II类抗原表达相关 细胞 此外，我们评估了环孢菌素A对 干燥综合征的免疫病理学病变。 我们发现 环孢菌素治疗导致T细胞减少， 浸润和HLA-DR抗原表达减少。 这些研究表明，MHC Ⅱ类抗原表达的局部 自身免疫性疾病提供的证据表明， 这些抗原可能有助于免疫发病机制 这些疾病。

MHC class II antigens, HLA-DR in the human and Ia in the mouse, are membrane bound glycoproteins that are encoded by genes of the major histocompatibility complex. Expression of these antigens is of great functional importance for the initiation and perpetuation of immune responses. In a number of immunopathologic conditions HLA-DR antigen negative cells are stimulated to express class II antigens. In these cases an immunologic role has been postulated for the class II antigen expression. During the past year, we have determine if class II antigens are expressed in certain diseases and we have evaluated their possible role in autoimmune and inflammatory diseases. Initial studies identified cells in the anterior segment and cells in the retina (rpe cell) which express class II antigens during inflammatory eye disease. Treatment with monoclonal anti-Ia antibodies diminished the clinical disease and the expression of MHC class II antigens. These studies have been extended to evaluate Sjogren's syndrome. We found that the salivary gland in Sjogren's syndrome is infiltrated predominantly by T-lymphocytes and that this is associated with class II antigen expression on glandular epithelial cells. Moreover, we evaluated the effect of cyclosporin A on the immunopathological lesions in Sjogren's syndrome. We found that cyclosporin treatment resulted in decrease in both T cell infiltration and a decrease in HLA-DR antigen expression. These studies on MHC class II antigen expression in localized autoimmune diseases provide evidence that the activation of these antigens may contribute to the immunopathogenesis of these disease.