兔B细胞抗原受体与独特的异源蛋白复合物非共价结合：对膜IgM/IgD共表达悖论的可能见解。

The rabbit B cell antigen receptor is non-covalently associated with unique heteromeric protein complexes: possible insights into the membrane IgM/IgD coexpression paradox.

作者信息

Fitts M G, Metzger D W, Hendershot L M, Mage R G

机构信息

Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.

出版信息

Mol Immunol. 1995 Jul;32(10):753-9. doi: 10.1016/0161-5890(95)00028-d.

DOI:10.1016/0161-5890(95)00028-d

PMID:7659100

Abstract

We describe several proteins that are components of the rabbit B cell receptor complex. Two proteins (37 kDa and 42 kDa) were found in non-covalent association with IgM expressed on B cells from peripheral blood. These proteins were also immunoprecipitated by anti-B29 (Ig-beta) and anti-mb1 (Ig-alpha) monoclonal antibodies. As in the mouse and human, the IgM associated molecules were found as heteromeric structures with non-reduced apparent molecular weights of approximately 70-75 kDa. On rabbit B cells we also found these proteins in a 100-135 kDa complex which may represent trimeric or tetrameric structures. By Western blot, the 37 kDa protein was identified as rabbit Ig-beta (B29), suggesting that the 42 kDa protein is rabbit Ig-alpha. These data suggest that rabbit IgM is associated with both Ig-alpha/beta and Ig-(alpha beta)2 or alpha beta gamma complexes. When similar immunoprecipitation studies were performed on lysates made from B cells isolated from appendix follicles, we found two additional IgM associated protein complexes containing 34 kDa and 36 kDa proteins.

摘要

我们描述了几种作为兔B细胞受体复合物组成成分的蛋白质。在与外周血B细胞上表达的IgM非共价结合中发现了两种蛋白质（37 kDa和42 kDa）。这些蛋白质也被抗B29（Ig-β）和抗mb1（Ig-α）单克隆抗体免疫沉淀。与小鼠和人类一样，IgM相关分子以异源三聚体结构形式存在，非还原状态下的表观分子量约为70 - 75 kDa。在兔B细胞上，我们还在一个100 - 135 kDa的复合物中发现了这些蛋白质，该复合物可能代表三聚体或四聚体结构。通过蛋白质免疫印迹法，37 kDa的蛋白质被鉴定为兔Ig-β（B29），这表明42 kDa的蛋白质是兔Ig-α。这些数据表明兔IgM与Ig-α/β以及Ig-(αβ)2或αβγ复合物相关。当对从阑尾滤泡分离的B细胞制备的裂解物进行类似的免疫沉淀研究时，我们发现了另外两种含有34 kDa和36 kDa蛋白质的IgM相关蛋白复合物。