Potential Use of Bispecific Antibodies (BSABS) for Targeting Gliomas and Melanomas

Abstract

A major requirement for the success of BNCT is the selective delivery of boron to individual tumor cells ^1,2. Monoclonal antibodies (MoAbs) have been used as selective delivery agents for drugs, toxins and radionuclides to tumor cells for cancer therapy³. However, one major limitation of boron containing immunoconjugates is that their tumor localizing properties may be significantly reduced when compared to native, unmodified antibodies^4,5. Primarily for this reason we have been interested in the possibility of using bispecific antibodies (BsAbs) for tumor targeting. BsAbs have two distinct antigen combining sites, one of which can bind to a tumor associated antigen on the cell surface, and the other to a tumoricidal agent⁶. Since BsAbs have not been chemically modified, they presumably have both immunoreactivity and distribution profiles that are similar to native MoAbs. BsAbs can be produced by fusing two different hybridoma cell lines to produce a hybrid-hybridoma (quadroma). In the present report, we describe the production of quadro-mas secreting BsAbs reactive with polyhedral borane anions and a tumor associated cell surface proteoglycan expressed on glioblastomas and melanomas⁷.