MONOCLONAL ANTI-IGM REGULATION OF HUMAN B CELL FUNCTION

拟议的研究将调查配体相互作用的性质。 B淋巴细胞刺激所需的膜免疫球蛋白。这将是 通过使用一组抗人IgM单抗来实现 亲和力和/或表位特异性不同的抗体(MoAbbs)。 使用这些定义的抗Ig配体，解释了 过去观察到的抗Ig配体的调节作用 都会被追捕。这些研究可能会阐明决定因素 自身抗Ig恒定区抗体(类风湿 因子)可以调节它们所结合的B细胞的功能。 不同的鼠抗人IgM单抗的能力将进行比较 A)诱导静息B细胞增殖，b)影响增殖 和其他有丝分裂原刺激的B细胞分化，以及c) 刺激S期细胞前B细胞的早期变化 周而复始。一旦设置刺激性和非刺激性(或许是抑制性) 已经确定了MoAbbs，解释了 这些配体将被寻找。这将涉及比较刺激性和 非刺激性抗体及其F(ab‘)2片段的a)亲和力和 与IgM结合的化学计量学和b)表位特异性。表位 将通过竞争抑制来研究MoAbs的特异性 通过研究和分析每个摩押与化学物质结合的能力 已被修饰的IgM、IgM片段和合成肽 通过亲水性和构象分析预测可能 构成人免疫球蛋白M分子的免疫原性表位。 此外，膜分子交联性的本质是 有必要刺激B细胞的增殖将被研究。这将是 包括比较二价抗IgM单抗和 由一条针对IgM的F(ab‘)臂和一条 F(ab‘)臂指向人类主要组织相容性(MHC)抗原。

The proposed study will investigate the nature of the ligand interaction with membrane IgM which is needed for B lymphocyte stimulation. This will be accomplished through the use of a panel of anti-human IgM monoclonal antibodies (MoAbs) which differ in affinity and/or epitope specificity. Using these defined anti-Ig ligands, an explanation for the diverse regulatory effects of anti-Ig ligands which have been observed in the past will be sought. These studies may elucidate the factors that determine whether or not autologous anti-Ig constant region antibodies (rheumatoid factors) can regulate the function of B cells to which they bind. The different mouse anti-human IgM MoAbs will be compared in their ability to a) induce resting B cells to proliferate, b) affect the proliferation and differentiation of B cells stimulated with other mitogens, and c) stimulate early changes in B cells which precede the S phase of the cell cycle. Once sets of stimulatory and non-stimulatory (perhaps inhibitory) MoAbs have been identified, explanations for the functional differences in these ligands will be sought. This will involve comparing stimulatory and non-stimulatory MoAbs and their F(ab')2 fragments for a) affinity and stoichiometry of binding to IgM and b) epitope specificity. The epitope specificity of the MoAbs will be investigated by competitive inhibition studies and by analysis of the ability of each MoAb to bind to chemically modified IgM, IgM fragments, and synthesized peptides which have been predicted by hydrophilicity and conformational analysis as likely to constitute immunogenic epitopes on the human IgM molecule. In addition, the nature of membrane molecule crosslinkage which is necessary to stimulate B cell proliferation will be studied. This will involve comparing the mitogenic capacity of a divalent anti-IgM MoAb to a hybrid antibody which consists of one F(ab') arm directed to IgM and one F(ab') arm directed to a human major histocompatibility (MHC) antigen.