Cytolytic and cytostatic properties of an anti-human Fc gammaRI (CD64) x epidermal growth factor bispecific fusion protein.

摘要: A bispecific fusion protein (H22-EGF) that binds simultaneously to the epidermal growth factor receptor (EGF-R) and high affinity for Fc portion of human IgG, gammaRI (CD64), has been successfully constructed expressed. For this construction, genomic DNA encoding Fd fragment humanized anti-Fc mAb, H22, which at an epitope is distinct from binding site, was fused cDNA (EGF), a natural ligand EGF-R. The resulting H22Fd-EGF-expressing vector transfected into myeloma cell line previously with containing H22 kappa-light chain. SDS-PAGE analysis purified H22-EGF demonstrated secreted predominantly as H22Fab'-EGF monomer (approximately 55 kDa), even though free Cys residue exists in hinge region Fab' component. Using novel flow cytometry-binding assay, we protein, H22-EGF, able bind soluble EGF-R-expressing cells. inhibited EGF-R-overexpressing tumor cells mediated dose-dependent cytotoxicity these presence gammaRI-bearing cytotoxic effector These results suggest may have therapeutic utility malignancies.