Construction of reshaped human antibodies with HIV-neutralizing activity

Abstract

Mouse monoclonal antibody (mAb) 0.5β binds to the envelope protein gp120 of human immunodeficiency virus (HIV) and neutralizes infection by HIV in vitro. Mouse mAb 0.5β, therefore, has potential as a therapeutic agent for the prevention and treatment of acquired immunodeficiency syndrome (AIDS). Since mouse mAbs are highly immunogenic in humans, efforts are being made to humanize mouse mAbs that are being considered for use in humans. This report describes the design, construction, and expression of reshaped human 0.5β antibodies. In these antibodies, the entire constant (C) regions were derived from human sequences. The variable (V) regions were derived from human framework regions (FRs) and mouse 0.5β complementarity determining regions (CDRs). One version of reshaped human 0.5β light (L) chain and six versions of reshaped human 0.5β heavy (H) chain were made and tested. Following transient expression in cos  cells, all of the constructions were capable of producing humanlike antibody. Three of the H chain constructions (RHc, RHe, and RHf), when co-expressed with the L chain construction (RL), produced reshaped human antibody capable of binding to the epitope on gp120 recognized by mouse 0.5β mAb. The best version (RL + RHe) of reshaped human 0.5 β antibody had both binding affinity and neutralizing activity that were within twofold that of the mouse or chimeric 0.5β antibody. © 1991 Butterworth–Heinemann.