Pulido R, Cebrián M, Acevedo A, de Landázuri M O, Sánchez-Madrid F
Servicio de Inmunología, Universidad Autónoma, Madrid, Spain.
J Immunol. 1988 Jun 1;140(11):3851-7.
Studies on the antigenic structure of the human CD45 glycoproteins using mAb have revealed the existence of four reactivity patterns defined specifically by distinct biochemical, cellular, and histochemical distributions. In addition to the two well characterized Ag specificities, CD45 and CD45R, present on the four glycoproteins (220, 205, 190, and 180 kDa) and on the 220-kDa member, respectively, we have identified two novel specificities. These have been defined by two different mAb, UCHL1 and PD7/26/16, that recognize an epitope exclusively expressed on the 180-kDa lowest molecular sized polypeptide and an epitope shared by the three higher molecular sized polypeptides (220, 205, 190 kDa) of the complex, respectively. It has been demonstrated that they are also part of the CD45 complex by immunoprecipitation, immunoblotting, and binding assays with purified CD45 molecules. Comparative analysis by flow cytometry and immunoperoxidase techniques also showed a distinct pattern of cell distribution for each specificity. The 180-kDa specificity is present on a subset of T cells but absent on B lymphocytes, whereas the 220-kDa specificity is mainly expressed by B cells and a subpopulation of T lymphocytes. On the other hand, the cell distribution of the epitope common to the three higher members is slightly different to the conventional pan-leukocyte CD45 specificity. Thus, certain CD45+ cell types such as cutaneous Langerhans' cells, sinusoidal lymph node macrophages, and a small subset of T cells in both lymph node and tonsil did not express the 220/205/190-kDa specificity. These results further support that CD45 glycoproteins constitute a very heterogeneous molecular complex with epitopes that are selectively expressed by different cell types and by T cells at different stages of maturation.
利用单克隆抗体（mAb）对人CD45糖蛋白抗原结构进行的研究揭示了四种反应模式的存在，这些模式由不同的生化、细胞和组织化学分布特异性定义。除了四种糖蛋白（220、205、190和180 kDa）以及220 kDa成员上分别存在的两种特征明确的抗原特异性CD45和CD45R外，我们还鉴定出了两种新的特异性。它们由两种不同的单克隆抗体UCHL1和PD7/26/16定义，分别识别仅在180 kDa最低分子量多肽上表达的表位以及复合物中三种较高分子量多肽（220、205、190 kDa）共有的表位。通过免疫沉淀、免疫印迹以及与纯化的CD45分子进行结合试验，已证明它们也是CD45复合物的一部分。通过流式细胞术和免疫过氧化物酶技术进行的比较分析也显示了每种特异性的独特细胞分布模式。180 kDa特异性存在于一部分T细胞亚群上，而B淋巴细胞上不存在，而220 kDa特异性主要由B细胞和一部分T淋巴细胞亚群表达。另一方面，三种较高成员共有的表位的细胞分布与传统的全白细胞CD45特异性略有不同。因此，某些CD45+细胞类型，如皮肤朗格汉斯细胞、窦状淋巴结巨噬细胞以及淋巴结和扁桃体中的一小部分T细胞，不表达220/205/190 kDa特异性。这些结果进一步支持CD45糖蛋白构成了一个非常异质的分子复合物，其表位由不同细胞类型以及处于不同成熟阶段的T细胞选择性表达。
