ESTABLISHMENT OF INTERNAL-IMAGE ANTIIDIOTYPE MONOCLONAL-ANTIBODIES TOA HUMAN-ANTIBODY TO LUNG-CANCER

Internal-image anti-idiotype antibodies are expected to enhance antica ncer effector mechanisms in vivo. The objective of this study was to e stablish hybridomas producing anti-idiotype monoclonal antibodies agai nst a human monoclonal antibody (hmAb) 4G12 that reacts strongly with lung squamous cell carcinomas. BALB/c female mice 6 weeks old were imm unized with 4G12. Splenocytes were hybridized with P3U1 cells and hybr id cells secreting anti-4G12 hmAb were cloned. Two clones reacted with 4G12 hmAb but not with 3H12 IgM hmAb, human IgM, human serum or fetal calf serum. These two Ab2 antibodies (IgG1 kappa) 2B12 and 2H1 demons trated 91.5% and 90.3% inhibition in their reactivity with radiolabell ed 4G12 on PC10 cells, indicating that 2B12 and 2H1 antibodies were of the Ab2 beta type. In criss-cross inhibition assays, the binding of 2 B12 or 2H1 to 4G12 was not inhibited by 2H1 or 2B12. Thus 2B12 and 2H1 were thought to recognize the different epitopes on the antigen-bindi ng sites. Antisera against 2B12 and 2H1 demonstrated specific reactivi ty to PC10 cells. The two Ab2 beta antibodies, 2B12 and 2H1, express i nternal images of lung squamous cell carcinoma recognized by the 4G12 antibody and may be useful for cancer immunotherapy.