[Development of genetically engineered 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 (VH), and a 318 bp light chain variable domains (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 IgG1 heavy chain CH1 and light chain kappa constant regions, respectively, to form a chimeric gene which was then inserted into an expression vector pHEN1-SZ39 Fab/Hu. In addition, the two cDNA fragments were connected directly with a universal linker and inserted to an expression vector pHEN1-SZ39 ScFv. The two expression vectors were separately introduced into E. coli HB2151 to secrete chimeric antibodies and single-clain antibodies, respectively. On ELISA and Western blot, the two genetically engineered antibodies bond to the same 180,000 cell surface membrane antigen on human brain glioma cell line SHG44 as did the parental mAb SZ39.