TCR recognition of MHC class II peptide compexes in multiple sclerosis

T细胞受体序列分析表明，髓磷脂特异性T细胞在多发性硬化症（MS）患者中扩增，但与疾病过程相关的抗原特异性T细胞计数的适当技术不可用。我们推测，髓鞘衍生肽特异性T细胞的频率已大大低估了有限稀释技术。用敏感的技术分析抗原特异性CD 4 + T细胞将对理解MS的发病机制和开发适当的免疫监测工具具有重要意义。病毒感染中CD 8 + T细胞的分析已经通过产生MHC I类/肽复合物的四聚体形式而发生了革命性的变化。在急性和慢性病毒感染中均记录了抗原特异性CD 8 + T细胞的大量扩增。这项技术的引入使人们认识到，抗原特异性CD 8 + T细胞在病毒感染中的频率被大大低估了。人类MHC II类分子的四聚体形式的产生可能对人类自身免疫性疾病的研究产生重大影响。可溶性HLA-DR 2的表达系统先前被开发用于结晶HLA-DR 2与结合的肽形式的人髓鞘碱性蛋白。基于该表达系统，已经用荧光标记的链霉亲和素产生了HLA-DR 2/肽复合物的四聚体。这些分子将用于确定具有HLA-DR 2单倍型的MS患者的脑脊液和血液中抗原特异性T细胞的频率、活化状态和细胞因子谱。四聚体方法也将用于使用源自髓磷脂特异性T细胞克隆的cDNA产生多价TCR。MS斑块组织将用这些多价TCR染色，以检查靶器官中抗原呈递细胞对HLA-DR 2结合的髓鞘肽的表面表达。

T cell receptor sequence analysis indicates that myelin specific T cells are expanded in multiple sclerosis (MS) patients, but adequate techniques for the enumerization of antigen-specific T cells in relationship to the disease process are not available. We hypothesize that the frequency of T cells specific for myelin-derived peptides has been greatly underestimated by limiting dilution techniques. Analysis of antigen-specific CD4+ T cells with sensitive techniques will have important implications for understanding the pathogenesis of MS and for developing adequate tools for immune monitoring. The analysis of CD8+ T cells in viral infections has been revolutionized by the creation of tetrameric forms of MHC class I/peptide complexes. Massive expansion of antigen-specific CD8+ T cells has been documented in both acute and chronic viral infections. The introduction of this technology led to the realization that the frequency of antigen specific CD8+ T cells in viral infections had been greatly underestimated. The generation of tetrameric forms of human MHC class II molecules may have a major impact on the investigation of human autoimmune disease. An expression system for soluble HLA-DR2 was previously developed for crystallization of HLA-DR2 with a bound peptide form human myelin basic protein. Based on this expression system, tetramers of HLA-DR2/peptide complexes have been generated with fluorescently labeled streptavidin. These molecules will be used to determine the frequency, activation state and cytokine profile of antigen specific T cells in the cerebrospinal fluid and blood of MS patients with the HLA-DR2 haplotype. The tetramer approach will also be used to generate multivalent TCRs using cDNAs derived from myelin specific T cell clones. MS plaque tissue will be stained with these multivalent TCRs to examine surface expression of HLA-DR2-bound myelin peptides by antigen presenting cells in the target organ.