Production of murine V-human Cr1 chimeric anti-TAG72 antibody using V region cDNA amplified by PCR.

A mouse/human chimeric B72.3-1-3 antibody was produced by construction of a novel expression vector mpSV2neo-EP1-V-Cr1. This vector contains the neo gene as a selection marker, the murine immunoglobulin heavy chain promoter and enhancer, the murine V region cDNA containing mRNA splicing joint sequences, amplified and cloned by the PCR technique directly from the B72.3 hybridoma RNA, and the human genomic Cr1 region. The expression vector containing the murine/human chimeric immunoglobulin heavy chain gene was transfected into heavy chain loss mutant cell line, B72.3Ml. Chimeric B72.3-1-3 antibody was produced at 2 micrograms/ml and retained full binding reactivity to TAG72 compared to the murine B72.3 parental antibody. Using this method, chimeric immunoglobulin molecules can be produced rapidly in comparison with the cDNA and genomic cloning techniques.