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) associated antigen. Methods Using NPC monoclonal antibody (Abl) as immunogen, hybridoma cells were obtained by fusion of SP2/0 myeloma cells with immunized murine spleen cells. Positive clones were screened by Sandwich ELISA and a binding inhibition test. To determine whether Ab2 possess the internal image of the original antigen or not, mice were immunized with Ab2. ELISA and the competitive inhibition assay tested anti-antiidiotypic antibodies (AW) in anti-sera. Cell-mediated immunity to tumors induced by Ab2 was investigated by a delayed-type hypersensitivity response and the mouse T-cell proliferation assay. Results Anti-idiotypic monoclonal antibodies against the monoclonal anti-NPC antibodies FC2 and HNL5 were generated that recognize NPC associated antigens. These Ab2, which were designated 2H4 and 5D3, could inhibit the binding of FC2 or HNL5 to NPC cell lines. Anti-sera from the immunized mice, which contained AW, could compete with FC2 or HNL5 for binding with NPC cell by a competitive inhibition assay. Mice immunized with 2H4 or 5D3 coupled with keyhole limpet hemocyanin (KLH), showed a positive and specific delayed-type hypersensitivity (DTH) reaction after stimulation by NPC cells. The mouse T cell proliferative assay indicated that there was a significantly higher proliferative response of the splenocytes in the experimental groups than 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.