Okumura A, Kishi H, Tagoh H, Minowada J, Muraguchi A
Department of Immunology, Toyama Medical and Pharmaceutical University, Japan.
Microbiol Immunol. 1995;39(11):879-90. doi: 10.1111/j.1348-0421.1995.tb03285.x.
The nature of lymphoid progenitors and factor(s) determining commitment to either the T- or B-lymphocyte pathway are poorly understood in the human system. In this study, we generated a monoclonal antibody (MoAb), 18.6, that recognizes a cell surface antigen on a human lymphoid progenitor cell line (FL4.4). MoAb 18.6 reacted with lymphoid progenitor lines, B lymphoid cell lines, and myelomonocytic cell lines. It did not react with any T cell or erythroid leukemic cell lines. Two color FACS analyses of normal lymphoid tissues showed that MoAb 18.6 reacted with a majority of CD20+ mature B cells and a minority of CD64+ monocytes. Molecules of 3 different sizes with MW of 34, 45, and 68 Kd were precipitated with MoAb 18.6 from the lymphoid progenitor cell line. The 18.6 antigen was not expressed on a fetal liver-derived lymphoid progenitor-like cell line, FL1.4, which has the capacity to differentiate into microglia-shaped cells upon PMA-stimulation. Stimulation of FL1.4 cells with PMA induced expression of the 18.6 antigen within 24 hr and the microglia-shaped cells stained positively with MoAb 18.6. Finally, cloning of a cDNA that encoded the 18.6 antigen revealed that the 18.6 antigen is identical to the CD23 antigen. Taken together, these data suggest that the 18.6/CD23 antigen is expressed on lymphoid precursors at a very early stage of differentiation.
在人类系统中，淋巴祖细胞的性质以及决定其向T淋巴细胞或B淋巴细胞途径定向分化的因子仍知之甚少。在本研究中，我们制备了一种单克隆抗体（MoAb）18.6，它可识别一种人类淋巴祖细胞系（FL4.4）上的细胞表面抗原。MoAb 18.6与淋巴祖细胞系、B淋巴细胞系和骨髓单核细胞系发生反应。它不与任何T细胞系或红白血病细胞系发生反应。对正常淋巴组织进行的双色荧光激活细胞分选分析表明，MoAb 18.6与大多数CD20 +成熟B细胞以及少数CD64 +单核细胞发生反应。用MoAb 18.6从淋巴祖细胞系中沉淀出了分子量分别为34、45和68 Kd的3种不同大小的分子。18.6抗原在一种源自胎肝的类淋巴祖细胞系FL1.4上不表达，该细胞系在佛波酯（PMA）刺激下有分化为小胶质细胞样细胞的能力。用PMA刺激FL1.4细胞可在24小时内诱导18.6抗原的表达，且小胶质细胞样细胞被MoAb 18.6阳性染色。最后，对编码18.6抗原的cDNA进行克隆显示，18.6抗原与CD23抗原相同。综上所述，这些数据表明18.6/CD23抗原在分化的非常早期阶段就在淋巴前体细胞上表达。
