Monoclonal anti-idiotype antibody bearing the internal image of nasopharyngeal carcinoma associated antigen

Objective To generate and characterize anti-idiotypic monoclonal antibody ( Ab2) that bears the internal image of nasopharyngeal carcinoma (NPC) associ ated antigen. Methods Using NPC monoclonal antibody (Abl) as immunogen, hybridoma cells w ere obtained by fusion of SP2/0 myeloma cells with immunized murine spleen cells. Positive clones were screened by Sandwich ELISA and a binding inhibi tion test. To determine whether Ab2 possess the internal image of the origi nal antigen or not, mice were immunized with Ab2. ELISA and the competitive inhibition assay tested anti-antiidiotypic antibodies (AW) in anti-sera. C ell-mediated immunity to tumors induced by Ab2 was investigated by a delaye d-type hypersensitivity response and the mouse T-cell proliferation assay. Results Anti-idiotypic monoclonal antibodies against the monoclonal anti-NP C antibodies FC2 and HNL5 were generated that recognize NPC associated anti gens. These Ab2, which were designated 2H4 and 5D3, could inhibit the bindi ng of FC2 or HNL5 to NPC cell lines. Anti-sera from the immunized mice, whi ch contained AW, could compete with FC2 or HNL5 for binding with NPC cell b y a competitive inhibition assay. Mice immunized with 2H4 or 5D3 coupled wi th keyhole limpet hemocyanin (KLH), showed a positive and specific delayed- type hypersensitivity (DTH) reaction after stimulation by NPC cells. The mo use T cell proliferative assay indicated that there was a significantly hig her proliferative response of the splenocytes in the experimental groups th an that in control groups. Conclusions Anti-idiotypic antibodies 2H4 and 5D3 are Ab2 beta bearing the internal image of the epitope of NPC associated antigen. Either 2H4 or 5D3 expressing three-dimensional shapes that resemble the structure of natural antigens could induce humoral and cellular immune response.