C4B and ovarian cancer: To mitigate the HAMA responses, the murine CL (κ) and CH (γ1) regions were replaced with their human equivalents (γ1, κ) to generate the chimeric MOv18 antibody, which exerted ADCC activity against tumor cells.59 Radiolabeled chimeric MOv18 IgG1 was evaluated in several early phase trials, where it was found to localize effectively to ovarian cancer tissue.