De Paoli P, Cozzi M, Tedeschi R, Gloghini A, Cilia A M, van Kooten C, Gaidano G, Carbone A
Department of Microbiology, Centro di Riferimento Oncologico, Istituto Nazionale di Ricovero e Cura a Carattere Scientifico, Aviano, Italy.
Cytometry. 1997 Feb 15;30(1):33-8. doi: 10.1002/(sici)1097-0320(19970215)30:1<33::aid-cyto5>3.3.co;2-j.
CD40 is a membrane glycoprotein expressed on normal and neoplastic B lymphocytes. Stimulation through CD40 regulates important cellular functions, but the effects depend on its membrane density. While extensive studies have characterized CD40 in non-Hodgkin lymphomas of immunocompetent individuals, little is known on the characteristics of this molecule in lymphomas arising in immunocompromised hosts. The aim of this study was to characterize the pattern of CD40 expression in an in vitro model constituted by AIDS small non-cleaved lymphoma (SNCCL) cell lines. The analysis of CD45 isoforms, a group of molecules alternatively spliced during B cell differentiation, has been chosen to correlate this process to the number of CD40 molecules per cell in these cell lines. Since Apo 1/Fas expression is upregulated on B lymphocytes after CD40 ligation and this expression is functionally relevant, we wanted to know whether a different CD40 pattern in AIDS-SNCCL cell lines could influence CD95 expression. We have shown that 3 of these cell lines (PA 682, Es III, and HBL-2) have high membrane CD40 expression (> 100,000 molecules/cell); they release large amounts of soluble CD40 (sCD40) in culture supernatants (>500 pg/ml), are CD45RA/RO double labelled, and express the Apo 1/Fas (CD95) antigen. On the contrary, low CD40 membrane antigen cell lines (BRGIgA, HBL-2, NC 71, AS 283A, and LAM C3+, < 50,000 molecules/cell) release low amounts of sCD40 (<300 pg/ml), are CD45RA+ but CD45RO-, and do not express CD95. EBV has no role in CD40 and CD45 isoform behaviour, because EBV superinfection of the EBV negative, low membrane CD40 HBL-2 cell line does not modify CD40 membrane expression, sCD40 production, or CD45 isoform and CD95 expression. Our data suggest that membrane CD40 in AIDS-SNCCL cell lines might be a key element in the regulation of their pathophysiology by influencing the expression of CD45 isoforms and of CD95, and by the release of its soluble form.
CD40是一种在正常和肿瘤性B淋巴细胞上表达的膜糖蛋白。通过CD40的刺激可调节重要的细胞功能，但其效果取决于其膜密度。虽然广泛的研究已对免疫功能正常个体的非霍奇金淋巴瘤中的CD40进行了表征，但对于免疫功能低下宿主中发生的淋巴瘤中该分子的特征知之甚少。本研究的目的是在由艾滋病小无裂细胞淋巴瘤（SNCCL）细胞系构成的体外模型中表征CD40的表达模式。已选择分析CD45异构体（一组在B细胞分化过程中选择性剪接的分子），以将此过程与这些细胞系中每个细胞的CD40分子数量相关联。由于CD40连接后B淋巴细胞上Apo 1/Fas表达上调且该表达具有功能相关性，我们想知道艾滋病-SNCCL细胞系中不同的CD40模式是否会影响CD95表达。我们已表明，这些细胞系中的3个（PA 682、Es III和HBL-2）具有高膜CD40表达（>100,000个分子/细胞）；它们在培养上清液中释放大量可溶性CD40（sCD40）（>500 pg/ml），是CD45RA/RO双标记的，并表达Apo 1/Fas（CD95）抗原。相反，低CD40膜抗原细胞系（BRGIgA、HBL-2、NC 71、AS 283A和LAM C3+，<50,000个分子/细胞）释放少量sCD40（<300 pg/ml），是CD45RA+但CD45RO-，且不表达CD95。EBV在CD40和CD45异构体行为中不起作用，因为EBV阴性、低膜CD40的HBL-2细胞系的EBV超感染不会改变CD40膜表达、sCD40产生或CD45异构体和CD95表达。我们的数据表明，艾滋病-SNCCL细胞系中的膜CD40可能是通过影响CD45异构体和CD95的表达以及其可溶性形式的释放来调节其病理生理学的关键因素。
