Morgan A C, Woodhouse C, Bartholemew R, Schroff R
Mol Immunol. 1986 Feb;23(2):193-200. doi: 10.1016/0161-5890(86)90042-8.
The relationship of antigenic heterogeneity to the epitope recognized by an antibody was examined with monoclonal antibodies to human melanoma-associated antigens. Expression of the human melanoma-associated antigens, 250-Kd glycoprotein/proteoglycan and p97, was examined quantitatively by flow cytometry on fresh cell suspensions of human melanoma. Percent positive cells and mean fluorescence intensity were consistently higher with antibody 9.2.27 to the 250-Kd glycoprotein/proteoglycan than with antibody to p97. In addition, assessment of percent positive cells in multiple skin lesions biopsied from individual patients indicated that in 26 of 30 lesions, greater than 90% of the cells stained positively with 9.2.27. This relative lack of antigenic heterogeneity with antibody 9.2.27 contrasted with previous reports which showed considerable antigenic heterogeneity with other antibodies to the 250-Kd glycoprotein/proteoglycan. The explanation for this distinction was sought by quantitative flow cytometric and sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) techniques. Comparison by flow cytometry and immunoperoxidase of three antibodies, which recognized distinct epitopes of the 250-Kd glycoprotein/proteoglycan, indicated that 9.2.27 reacted more intensely with cultured cells and tissue sections than other antibodies to the same antigen. Examination by SDS-PAGE indicated that 9.2.27 could immunoprecipitate a larger proportion of 250-Kd glycoprotein molecules than other antibodies. In addition, immunodepletion experiments in gels indicated that the 9.2.27 determinant was present on a higher proportion of 250-Kd glycoprotein molecules than PG-2 antibody to a separate determinant. It is likely that 9.2.27 antibody displays less antigenic heterogeneity because its epitope is represented on a higher proportion of the antigen molecules. Thus, not only the nature of the antigen but also the epitope recognized by an antibody influences the degree of antigenic heterogeneity.
利用针对人黑色素瘤相关抗原的单克隆抗体，研究了抗原异质性与抗体识别的表位之间的关系。通过流式细胞术对人黑色素瘤新鲜细胞悬液中的人黑色素瘤相关抗原250-Kd糖蛋白/蛋白聚糖和p97的表达进行了定量检测。针对250-Kd糖蛋白/蛋白聚糖的抗体9.2.27所检测到的阳性细胞百分比和平均荧光强度始终高于针对p97的抗体。此外，对从个体患者身上活检的多个皮肤病变中的阳性细胞百分比进行评估表明，在30个病变中的26个中，超过90%的细胞被9.2.27抗体染成阳性。与之前显示针对250-Kd糖蛋白/蛋白聚糖的其他抗体存在相当大抗原异质性的报告相比，抗体9.2.27相对缺乏抗原异质性。通过定量流式细胞术和十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）技术寻找这种差异的解释。通过流式细胞术和免疫过氧化物酶对三种识别250-Kd糖蛋白/蛋白聚糖不同表位的抗体进行比较表明，与针对相同抗原的其他抗体相比，9.2.27与培养细胞和组织切片的反应更强烈。SDS-PAGE检测表明，9.2.27比其他抗体能免疫沉淀更大比例的250-Kd糖蛋白分子。此外，凝胶中的免疫耗竭实验表明，与针对另一个表位的PG-2抗体相比，9.2.27所识别的表位在更高比例的250-Kd糖蛋白分子上存在。9.2.27抗体可能表现出较少的抗原异质性，因为其表位在更高比例的抗原分子上存在。因此，不仅抗原的性质，而且抗体识别的表位也会影响抗原异质性的程度。
