Wang Y H, Nomura J, Faye-Petersen O M, Cooper M D
Department of Medicine, University of Alabama, Birmingham 35924-3300, USA.
J Immunol. 1998 Aug 1;161(3):1132-9.
Expression of the surrogate light (psi L) chain genes encoding the VpreB and lambda 5/14.1 proteins is restricted to B-lineage cells. Pro-B and pre-B cells produce psi L chains, but whether both employ these as cell surface receptor components remains enigmatic. Recombinant human VpreB protein was used to generate a large panel of monoclonal anti-VpreB Abs to examine this issue. Native psi L chain proteins within pro-B cells as well as those serving as receptor components on pre-B cells were precipitated by 16 of the 26 anti-VpreB Abs. Surrogate light chains were easily detected on pre-B cell lines, whereas these anti-VpreB Abs reacted with pro-B cell lines only after plasma membrane permeabilization. The subpopulation of normal bone marrow cells bearing pre-B receptors included large and small pre-B cells exclusively, although pro-B cells also contained intracellular VpreB. VpreB proteins were not detected on or within B cells in bone marrow or the circulation, but a subpopulation of B cells in germinal centers was found to express the VpreB proteins intracellularly. Surrogate L chains are thus intermittently produced during human B-lineage differentiation, while their role as receptor components appears limited to the pre-B cell stage.
编码VpreB和λ5/14.1蛋白的替代轻链（ψL）基因的表达仅限于B淋巴细胞系细胞。前B细胞和前B细胞产生ψL链，但它们是否都将其用作细胞表面受体成分仍不清楚。重组人VpreB蛋白被用于制备大量单克隆抗VpreB抗体以研究这个问题。26种抗VpreB抗体中有16种沉淀了前B细胞内的天然ψL链蛋白以及那些作为前B细胞上受体成分的蛋白。替代轻链在前B细胞系上很容易被检测到，而这些抗VpreB抗体仅在细胞膜通透后才与前B细胞系发生反应。携带前B受体的正常骨髓细胞亚群仅包括大的和小的前B细胞，尽管前B细胞也含有细胞内VpreB。在骨髓或循环中的B细胞表面或细胞内未检测到VpreB蛋白，但发现生发中心的一个B细胞亚群在细胞内表达VpreB蛋白。因此，替代轻链在人类B淋巴细胞系分化过程中是间歇性产生的，而它们作为受体成分的作用似乎仅限于前B细胞阶段。
