Production of novel peptide-targeting antibodies for anti-Müllerian hormone receptor 2 and induction of cytotoxicity in ovarian cancer cells.

Ovarian cancer is generally diagnosed at late stages. Monoclonal antibodies (MAbs) targeting antigens in ovarian cancer are used in the clinic. Anti-Müllerian hormone receptor type 2 (AMHR2) is a receptor highly expressed in ovarian cancer and it is a potential target antigen for immunotherapy. Extracellular domain of AMHR2 was analysed in terms of 3D structure and physicochemical properties, and 3 peptide sequences (Peptides 1, 7 and 11) were determined as targets. MAb production protocol was performed, and 6 MAb clones showing high affinity for peptides were obtained. P3B1, P10A10, P10B6 and P2A6 clones were for peptide 11 (P11), P2C9 was for P7, and P6C5 was for P1. Antibody isotype of P2A6 was IgG2a and the others were of IgG1 isotype. MAb binding to the native recombinant protein (AMHR2-Fc) was analysed by enzyme-linked immunosorbent assay (ELISA) and MAb binding to AMHR2 expressed by SKOV-3 ovarian cancer cells was analysed by western blot and immunofluorescent staining. P3B1 showed strong, P10A10, P10B6 and P2C9 showed medium affinity for the native protein (AMHR2-Fc). P3B1 and P2C9 showed strong binding in western blot analysis. Clones showed moderate binding in immunoflorescent staining. A complement dependent cytotoxicity (CDC) experiment was conducted using MAbs and transfected SKOV-3 cells. P3B1 induced a significant CDC. Variable regions of P3B1 MAb were sequenced. In conclusion, MAbs for three different regions of AMHR2 were produced. One clone was shown to induce cytotoxicity in ovarian cancer cells and its sequence was determined for future use as a humanised therapeutic MAb.