DEVELOPMENT OF GENETICALLY ENGINEERED MOUSE/ HUMAN CHIMERIC AND SINGLE CHAIN ANTIBODIES AGAINST HUMAN BRAIN GLIOMA: A PRELIMINARY REPORT

In order to improve the clinical usefulness of mAb of mouse origin in targeting diagnosis and therapy for human brain glioma, it is necessary to humanize it and reduce its molecular size. By means of RT-PCR technique, a 348 bp heavy chain variable domain (VII), and a 318 bp light chain variable domain (VL) cDNA fragments were cloned from mouse hybridoma cell line SZ₃₉ secreting mAb against human brain glioma. By recombinant DNA technique, the two cDNA fragments were linked to human IgGl heavy chain CH1 and light chain κ constant regions, respectively, to form a mouse/human chimeric gene which was then inserted into an expression vector pHEN1-SZ₃₉ Fab/Hu. In addition, the two cDNA fragments were linked directly with a universal linker and inserted into an expression vector pHEN1-SZ₃₉ScFv. The two expression vectors were separately introduced into non-suppressor E.coli HB2151 to secrete chimeric antibodies and single-chain antibodies, respectively. On ELISA and Western blot assays, the two genetically engineered antibodies were bound specifically to the same 180 kD cell surface membrane antigen on human brain glioma cell line SHG₄₄ as did the parental mAb SZ₃₉.