Natali P G, Wilson B S, Imai K, Bigotti A, Ferrone S
Cancer Res. 1982 Feb;42(2):583-9.
The mouse immunoglobulin G2 monoclonal antibody (MoAb) 465.12S reacts with a cytoplasmic antigen present in human melanoma cells but not detectable in melanocytes. Indirect immunofluorescent staining of a large number of surgically removed normal adult and fetal tissues with the MoAb 465.12S detected the cytoplasmic antigen in epithelial cells from several organs. The intensity of staining was greater in adult tissues than in the corresponding fetal tissues. Furthermore, the MoAb 465.12S stained nearly all of the surgically removed tumors tested but did not stain many of the normal tissues from which they originated. In almost all cases, the intensity and frequency of staining wa greater for tumor cells than for corresponding normal tissues. From cultured carcinoma and melanoma cells, the MoAb 465.12S immunoprecipitated four glycopolypeptides with molecular weights of 94,000, 75,000, 70,000, and 25,000. Incorporation of 3H-labeled sugars into the various components of the cytoplasmic antigen revealed that the M.W. 75,000 component was unusual in that it contained only glucosamine and mannose. The antigenic determinant defined by the MoAb 465.12S appears to be protein rather than carbohydrate in nature since it is heat sensitive and is expressed on the antigens synthesized by cells in presence of tunicamycin. Analysis of the spent culture medium of carcinoma and melanoma cell lines revealed that the cytoplasmic antigen is readily shed by these cells and consists of a major M.W. 94,000 and a minor M.W. 72,000 component. Treatment of cultured melanoma cells with the antibiotic tunicamycin showed that glycosylation of the cytoplasmic antigen is required for its shedding and/or stability in the spent culture medium.
小鼠免疫球蛋白G2单克隆抗体（MoAb）465.12S可与人黑色素瘤细胞中存在的一种细胞质抗原发生反应，但在黑素细胞中无法检测到。用MoAb 465.12S对大量手术切除的正常成人和胎儿组织进行间接免疫荧光染色，在多个器官的上皮细胞中检测到了细胞质抗原。成人组织中的染色强度高于相应的胎儿组织。此外，MoAb 465.12S对几乎所有检测的手术切除肿瘤都有染色，但对其起源的许多正常组织没有染色。在几乎所有情况下，肿瘤细胞的染色强度和频率都高于相应的正常组织。从培养的癌细胞和黑色素瘤细胞中，MoAb 465.12S免疫沉淀出四种分子量分别为94,000、75,000、70,000和25,000的糖多肽。将3H标记的糖掺入细胞质抗原的各种成分中发现，分子量为75,000的成分不同寻常，因为它只含有氨基葡萄糖和甘露糖。MoAb 465.12S所定义的抗原决定簇似乎本质上是蛋白质而非碳水化合物，因为它对热敏感，并且在衣霉素存在的情况下由细胞合成的抗原上表达。对癌细胞和黑色素瘤细胞系的用过的培养基进行分析发现，细胞质抗原很容易被这些细胞释放出来，并且由一个主要的分子量为94,000的成分和一个次要的分子量为72,000的成分组成。用抗生素衣霉素处理培养的黑色素瘤细胞表明，细胞质抗原的糖基化是其在用过的培养基中释放和/或稳定所必需的。
