A human immunoglobulin G1 antibody originating from an in vitro-selected Fab phage antibody binds avidly to tumor-associated MUC1 and is efficiently internalized.

We describe the engineering and characterization of a whole human antibody directed toward the tumor-associated protein core of human MUC1. The antibody PH1 originated from the in vitro selection on MUC1 of a nonimmune human Fab phage library. The PH1 variable genes were reformatted for expression as a fully human IgG1.