The IgM-associated protein mb-1 as a marker of normal and neoplastic B cells.
The IgM-associated protein mb-1 as a marker of normal and neoplastic B cells.
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IgM 相关蛋白 mb-1 作为正常和肿瘤 B 细胞的标记。
作者：
D. Mason;J. Cordell;Agd Tse;J. Van Dongen;C. van Noesel;K. Micklem;K. Pulford;F. Valensi;W. Comans;J. Borst;K. Gatter
最近的证据表明，鼠和人B淋巴细胞上IgM的跨膜形式与至少两种蛋白质物理相关，形成二硫键连接的二聚体，其可以控制IgM的细胞表面表达，并且还在Ag结合后的信号转导中起作用（通过与T淋巴细胞中TCR相关的CD 3组分类比）。我们已经使用针对这些多肽之一（先前在鼠B细胞中鉴定为B细胞特异性mb-1基因的产物）的胞质内表位的mAb和多克隆抗体来研究IgM相关二聚体在人细胞中的分布。通过免疫细胞化学染色的正常和肿瘤B细胞，我们表明，人MB-1蛋白出现在B细胞分化的早期，可能在表达细胞质的μ链，并持续到浆细胞阶段，在那里它被视为胞浆内成分。根据反应性淋巴组织和淋巴瘤样本的免疫组织学分析，MB-1蛋白完全是B细胞特异性的。抗-mb-1还标记来自七种不同哺乳动物物种的组织中的B细胞区域。最后，免疫球蛋白相关的二聚体可以从人毛细胞白血病细胞中分离出高纯度和产量的亲和层析使用抗mb-1抗体。用该材料免疫的小鼠产生了强烈的多克隆应答，因此现在应该可以制备一组与mb-1及其相关多肽上的不同表位反应的新mAb。
Recent evidence indicates that the transmembrane form of IgM on murine and human B lymphocytes is physically associated with at least two proteins, forming a disulfide-linked dimer, which may control cell surface expression of IgM and also play a role in signal transduction after Ag binding (by analogy with the TCR-associated CD3 components in T lymphocytes). We have used mAb and polyclonal antibodies against an intracytoplasmic epitope on one of these polypeptides (previously identified in murine B cells as the product of the B cell specific mb-1 gene) to study the distribution of the IgM-associated dimer in human cells. By immunocytochemical staining of normal and neoplastic B cells, we show that the human mb-1 protein appears early in B cell differentiation, probably before expression of cytoplasmic mu-chain, and persists until the plasma cell stage, where it is seen as an intracytoplasmic component. According to immunohistologic analysis of reactive lymphoid tissue and lymphoma samples, mb-1 protein is completely B cell specific. Anti-mb-1 also labels B cell areas in tissues from seven different mammalian species. Finally, the Ig-associated dimer could be isolated from human hairy-cell leukemia cells in high purity and yield by affinity chromatography using anti-mb-1 antibody. Mice immunized with this material have produced a strong polyclonal response, so that it should now be possible to prepare a panel of new mAb reactive with different epitopes on both mb-1 and on its associated polypeptide(s).