MECHANISMS OF AUTOANITBODY FORMATION IN HUMAN AGING

描述（改编自申请人的摘要）： 在许多研究中记录的老年人中的循环自身抗体， B细胞和T细胞功能的几种变化之一，可能是免疫信号 衰老 这种衰老反过来又可能是易感性增加的基础 传染病和恶性肿瘤的风险。 拟议研究 旨在测试可能导致自身抗体的可能机制， 在老化过程中形成，区分：i）持续或增加 产生由V区基因片段编码的天然自身抗体， ii）产生具有突变的V 区域区段，抗原选择性抗体的特征和/或 随机突变的累积。 将筛选健康志愿者，以确定三组受试者： i）老年人（65岁以上），具有针对一组以下疾病中的至少一种的自身抗体： 自身抗原; ii）没有自身抗体的老年人;和iii）年轻人 没有自身抗体 计划是测试同种型交叉反应 和阳性血清中自身抗体的相对亲和力， 复发性独特型的表达。 比较这三组受试者， 调查人员将： i）分析EBV转化的B细胞以确定EBV转化的B细胞的分数; 产生自身抗体、其同种型和cDNA的转化细胞 来自自身反应性的IG的H和L链V区的序列， 非自身反应性克隆。 ii）探测来自外周血B细胞的V区cDNA文库， 确定使用频率：VH家族、VK家族或个体 V基因片段，在天然自身抗体和正常 年轻人的剧目。 他们会随机排列 选择的克隆和具有重复VH和VK区段的克隆以确定 FR和CDR突变的频率、分布和编码效应 序列的 iii）分析重排H链和K链V区DNA文库 从外周血B细胞中以与cDNA文库相同的方式， 第二次测试的剧目和频率，地点和性质的突变， 包括那些非生产性的重组。

DESCRIPTION (Adapted from the Applicant's Abstract): An increase in circulating autoantibodies in aging humans, documented in many studies, is one of several changes in B cell and T cell function that may signal immune senescence. This senescence, in turn, may underlie increased susceptibility to infectious disease and malignancy in the aged. The proposed research aims to test possible mechanisms that may contribute to autoantibody formation in aging, distinguishing between: i) continued or increased production of natural autoantibodies encoded by V region gene segments with few or no mutations and ii) production of autoantibodies with mutated V region segments, characteristic of antigen-selected antibodies and/or accumulation of random mutations. Healthy volunteers will be screened to identify three groups of subjects: i) elderly (over 65 years) with autoantibodies to at least one of a panel of autoantigens; ii) elderly without the autoantibodies; and iii) young adults without the autoantibodies. Plans are to test isotypes, cross-reactivity, and relative affinities of autoantibodies in the positive sera and expression of a recurrent idiotype. Comparing the three subject groups, the investigators will: i) analyze EBV-transformed B cells to determine the fraction of transformed cells producing autoantibodies, their isotypes, and cDNA sequences for H and L chain V regions of Ig from autoreactive and non-autoreactive clones. ii) probe V region cDNA libraries from peripheral blood B cells to determine the frequency of use of: VH families, VK families, or individual V gene segments that are prominent in the natural autoantibody and normal repertoire of young persons. They will sequence the V regions of randomly chosen clones and clones with recurrent VH and VK segments to determine the frequency, distribution and coding effects of mutations in FR and CDR sequences. iii) analyze libraries of rearranged H chain and K chain V region DNA from peripheral blood B cells in the same way as the cDNA libraries as a second test of repertoire and the frequency, site and nature of mutations, including those in nonproductive rearrangements.