Chimerization of Mu-9: a colon-specific antigen-p antibody reactive with gastrointestinal carcinomas.

Abstract

Mu-9 is a murine monoclonal antibody that is directed against affinity-purified colon-specific antigen-p (CSAp). CSAp is a tumor-associated antigen that is present in 60% of colorectal carcinomas. Preclinical and clinical studies have shown Mu-9 to have excellent targeting abilities. However, as administration of the murine immunoglobulin G (IgG) provoked a human anti-mouse antibody response, chimerization of Mu-9 is warranted for decreasing immunogenicity. Polymerase chain reaction and cDNA library screening methods were used for the cloning of Mu-9 heavy and light chain variable regions for the construction of chimeric Mu-9. The functional chimeric Mu-9 antibody binds to the CSAp antigen in the GW-39 extracts. It has immunochemical properties similar to that of murine Mu-9. The V-region sequence information will be used for design of humanized Mu-9, which will be evaluated for targeting gastrointestinal carcinomas.