Berends D, Rhijnsburger E H, van Gaalen J L, van Houwelingen G, Zondervan P E, de Both N J
Department of Pathology, Medical Faculty, Erasmus University, Rotterdam, The Netherlands.
Int J Cancer. 1988 Jul 15;42(1):112-8. doi: 10.1002/ijc.2910420121.
Hybridomas producing syngeneic monoclonal antibodies (MAbs) were prepared by fusion of spleen cells of BALB/c mice, which were immunized with sublethal doses of RMB-I cells. This cell line originates from a Rauscher virus (R-MuLV)-induced myeloid leukemia and forms tumors when re-inoculated into mice. MAbs were characterized as regards their reactivity against virally and non-virally induced cell lines. Two selected MAbs, IC5F5 and 4D2B4, were analyzed further. Their binding to subcellular structures was determined, and so were the properties of the antigens to which they are directed. MAb IC5F5 is of the IgG2A and 4D2B4 of the IgG2b subclass. Both bind to R-MuLV-infected or -transformed cell lines and are not mutually competitive. The antibodies do not react with other murine and human myeloid leukemic cells. As shown by immuno-electron microscopy, these MAbs have affinity to the cell membrane of non-virus producing RMB-I cells. When lysates of purified virus were analyzed, the MAbs were found to be directed to the gag precursor protein Pr65, and one of them (IC5F5) also to be directed to the core protein p12. In RMB-I cells, binding occurs to a 50-kDa glycoprotein and 2 proteins of 26 and 29 kDa. Since RMB-I cells do not produce virus, but express aberrant viral proteins, these MAbs are tumor-specific and useful for immunotherapy.
通过将用亚致死剂量的 RMB-I 细胞免疫的 BALB/c 小鼠的脾细胞进行融合，制备出产生同基因单克隆抗体（MAb）的杂交瘤。该细胞系源自劳氏肉瘤病毒（R-MuLV）诱导的髓性白血病，重新接种到小鼠体内时会形成肿瘤。对单克隆抗体针对病毒诱导和非病毒诱导细胞系的反应性进行了表征。对两种选定的单克隆抗体 IC5F5 和 4D2B4 进行了进一步分析。确定了它们与亚细胞结构的结合情况，以及它们所针对的抗原的特性。单克隆抗体 IC5F5 属于 IgG2A 亚类，4D2B4 属于 IgG2b 亚类。两者都与 R-MuLV 感染或转化的细胞系结合，且不相互竞争。这些抗体不与其他小鼠和人类髓性白血病细胞发生反应。免疫电子显微镜显示，这些单克隆抗体对不产生病毒的 RMB-I 细胞的细胞膜具有亲和力。当分析纯化病毒的裂解物时，发现这些单克隆抗体针对 gag前体蛋白 Pr65，其中一种（IC5F5）还针对核心蛋白 p12。在 RMB-I细胞中，它们与一种 50 kDa 的糖蛋白以及两种 26 kDa 和 29 kDa 的蛋白质结合。由于 RMB-I 细胞不产生病毒，但表达异常病毒蛋白，这些单克隆抗体具有肿瘤特异性，可用于免疫治疗。
