RHEUMATOID FACTOR SPECIFICITY

描述（改编自申请人摘要）：研究者建议 提供关于人IgM特异性的更直接的信息 类风湿因子（RF），特别是那些具有异型性的 反应性 因此，研究人员将探索免疫化学基础， 对于GM（a）阴性RA患者的RF抗GM（a）特异性，以及 GM（a）阴性RA患者RF与GM（g）（+）IgG反应的原因。 由于大多数 人RF可能在相对小的4 - 8A0位点反应， C-γ 2-C-γ 3界面，构象或选择性改变 在这个区域的残基将进行研究，特别是关于 通过单体IgG从血清中分离的RF的个体Gm特异性 亲和柱或用EBV产生的高亲合力人单克隆RF 刺激CD5限制性B细胞。 GM的定量研究 在短期5至7天的美洲商陆过程中产生的IgG表型 正常人和RA患者的培养将使用新开发的 小鼠抗Gm（a）和Gm（f）决定簇的单克隆抗体。 这些研究将试图 检测Gm（a）阴性RA患者和正常人淋巴细胞 当在体外培养时，对照将产生少量的Gm（a）（+）IgG 用美洲商陆有丝分裂原 平行的Gm（a）寡核苷酸特异性探针 将与Gm（a）阴性受试者的DNA一起使用，以通过 聚合酶链反应扩增可能发生的 在培养的PBMC中存在的突变的Gm（a）编码核苷酸序列 正常人和类风湿性关节炎受试者。 因为三个组氨酸聚在一起 在C-γ 2-C-γ 3裂缝处的残基433、435和310中一起 当RF结合时，这些组氨酸的化学改变使用 焦碳酸二乙酯、铂发色团或自旋标记将被 试图研究对GM相关抗原以及RF的影响， 约束力 此外，将研究已知Gm表型的骨髓瘤蛋白 在化学组氨酸、酪氨酸或赖氨酸修饰后， 这些残基对构象或单个构象的相对贡献 负责Gm（a）、（B）、（g）或（f）同种异型特异性的残基。

DESCRIPTION (adapted from applicant's abstract): The investigators propose to provide more direct information on the specificity of human IgM rheumatoid factors (RFs) and particularly those with heteroclitic reactivity. Thus, the investigators will explore the immunochemical basis for RF anti-Gm(a) specificity in a GM(a) negative RA patient, as well as why GM(a) negative RA patients RF react with GM(g)(+) IgG. Since most human RFs probably react at a relatively small 4-8A0 site between the C-gamma 2 - C-gamma 3 interface, changes in either conformation or selected residues in this region will be studied with particular respect to the individual Gm specificities of RFs isolated from serum by monomeric IgG affinity columns or with high avidity human monoclonal RFs produced by EBV stimulation of CD5 restricted B-cells. Quantitative studies of Gm phenotypes of IgG produced during short-term five to seven day pokeweed cultures of normals and RA patients will be completed using newly developed mouse MAbs to Gm(a) and Gm(f) determinants. These studies will attempt to examine whether lymphocytes from Gm(a) negative RA patients and normal controls will produce small amounts of Gm(a)(+) IgG when cultured in vitro with pokeweed mitogen. In parallel Gm(a) oligonucleotide-specific probes will be used with DNA in Gm(a) negative subjects to determine through polymerase chain reaction amplification the possible occurrence of mutational Gm(a) coding nucleotide sequences occurring in cultured PBMC from normals and RA subjects. Since three histidines are clustered together in residues 433, 435, and 310 at the C-gamma 2 - C-gamma 3 cleft where RF binds, chemical alteration of these histidines using diethylpyrocarbonate, platinum chromophores or spin-labeling will be attempted to study the effects both on Gm-related antigens as well as RF binding. Moreover, myeloma proteins of known Gm phenotypes will be studied after chemical histidine, tyrosine or lysine modifications to determine relative contributions of these residues to conformations or single residues responsible for Gm(a), (b), (g), or (f) allotypic specificities.