Antigen-binding sites of antibody molecules specific for cancer antigens

Abstract

Novel compositions are provided that are derived from antigen-binding sites of immunoglobulins having affinity for cancer antigens. The compositions exhibit immunological binding properties of antibody molecules capable of binding specifically to a human tumor cell expressing an antigen selected from the group consisting of high molecular weight mucins bound by 2G3 and 369F10, c-erbB-2 tumor antigen, an approximately 42 kD glycoprotein, an approximately 55 kD glycoprotein, and the approximately 40, 60, 100 and 200 kD antigens bound by 113F1. A number of synthetic molecules are provided that include CDR and FR regions derived from same or different immunoglobulin moieties. Also provided are single chain polypeptides wherein V.sub.H and V.sub.L domains are attached by a single polypeptide linker. The sFv molecules can include ancillary polypeptide moieties which can be bioactive, or which provide a site of attachment for other useful moieties. The compositions are useful in specific binding assays, affinity purification schemes, drug or toxin targeting, imaging, and genetic or immunological therapeutics for various cancers. The invention thus provides novel polypeptides, the DNAs encoding those polypeptides, expression cassettes comprising those DNAs, and methods of inducing the production of the polypeptides.