Agostini H T, Gerstenecker B, Haessler C, Braun D G, Brandner G, Hess R D
Department of Virology, University of Freiburg, Germany.
Scand J Immunol. 1995 Mar;41(3):256-62. doi: 10.1111/j.1365-3083.1995.tb03561.x.
The murine monoclonal antibody PAb1605 defines an epitope, peptide Lys(698)-Thr(708) (KT), on the carboxyterminus of the tumour(T)antigen of SV40-transformed cells. In vivo and in vitro experiments had shown that this sequence represents an epitope for both humoral and cellular immune responses. When injected into rabbits PAb1605 induces anti-idiotypic antibodies (Ab-2). Ab-2 beta (internal image type) was purified by adsorption chromatography and characterized by the ability of KT to compete with the binding of ab-2 with ab-1. Murine anti-anti-idiotypic antibodies (ab-3) were obtained by immunization of mice with ab-2 beta. Both ab-1 and ab-3 JgG showed affinities to immunoprecipitated SV40 T antigen by immunoblot analysis and to nuclear SV40 T antigen by the immunofluorescence assay. The binding of ab-3 to SV40 T antigen was completely inhibited by competition with KT. We conclude that the polyclonal ab-3 is of the ab-3 subtype and specific for only one epitope which is represented by KT and defined by ab-1. The results demonstrate that the specificity for a defined peptide epitope of an antibody was conserved even after two consecutive steps of anti-idiotypic-antibody formation in two host species. Since this postulate of network theory could be verified for a sequence of a tumour-associated antigen which represents a B- and T cell epitope, this model is of great interest for further tumour immunological studies.
鼠单克隆抗体PAb1605可识别SV40转化细胞肿瘤（T）抗原羧基末端的一个表位，即肽段Lys(698)-Thr(708)（KT）。体内和体外实验表明，该序列代表体液免疫和细胞免疫应答的一个表位。将PAb1605注射到兔子体内可诱导产生抗独特型抗体（Ab-2）。Ab-2β（内影像型）通过吸附色谱法纯化，并通过KT与Ab-2和Ab-1结合的竞争性来表征。用Ab-2β免疫小鼠获得鼠抗抗独特型抗体（Ab-3）。通过免疫印迹分析，Ab-1和Ab-3 IgG均显示出与免疫沉淀的SV40 T抗原以及通过免疫荧光测定与核SV40 T抗原的亲和力。Ab-3与SV40 T抗原的结合可被KT竞争性完全抑制。我们得出结论，多克隆Ab-3属于Ab-3亚型，且仅对由KT代表并由Ab-1界定的一个表位具有特异性。结果表明，即使在两个宿主物种中连续进行两步抗独特型抗体形成后，抗体对特定肽表位的特异性仍得以保留。由于网络理论的这一假设可针对代表B细胞和T细胞表位的肿瘤相关抗原序列得到验证，该模型对进一步的肿瘤免疫学研究具有重要意义。
