John E, Wilder S, Thakur M L
Department of Nuclear Medicine, Thomas Jefferson University, Philadelphia, PA 19107.
Nucl Med Commun. 1994 Jan;15(1):24-8. doi: 10.1097/00006231-199401000-00005.
Antibodies are labelled routinely with direct labelling techniques in which some of the native disulphide groups are reduced to sulphydryls. Using polyacrylamide gel electrophoresis (PAGE) as an analytical tool and human polyclonal IgG (HIgG) labelled with 99Tcm by the ascorbic acid (AA), stannous chloride (SnCl2) and 2-mercaptoethanol (2-ME) techniques, we have quantitatively determined any fragmentation of the protein and the radioactivity associated with fragments. HIgG labelled with 99Tcm by two bifunctional chelating agents provided the vital comparison. The results indicated that in the bifunctional chelating agent (BFCA) methods 65 and 61% of the activity was associated with protein with an apparent molecular weight of 150,000 D. The corresponding numbers for the AA, SnCl2 and 2-ME methods were 46.4, 21 and 3.9%. With 2-ME, 96% of the activity was associated with low molecular weight fragments. Although monoclonal antibody fragmentation may not affect immunoreactivity of the protein, it may influence biodistribution.
抗体通常用直接标记技术进行标记，其中一些天然二硫键会被还原为巯基。使用聚丙烯酰胺凝胶电泳（PAGE）作为分析工具，并以抗坏血酸（AA）、氯化亚锡（SnCl2）和2-巯基乙醇（2-ME）技术用99Tcm标记人多克隆IgG（HIgG），我们已经定量测定了蛋白质的任何片段化以及与片段相关的放射性。用两种双功能螯合剂用99Tcm标记的HIgG提供了重要的比较。结果表明，在双功能螯合剂（BFCA）方法中，65%和61%的活性与表观分子量为150,000 D的蛋白质相关。AA、SnCl2和2-ME方法的相应数字分别为46.4%、21%和3.9%。使用2-ME时，96%的活性与低分子量片段相关。虽然单克隆抗体片段化可能不会影响蛋白质的免疫反应性，但它可能会影响生物分布。
