Expression of chimeric anti-CD3 IgG antibody in mammalian cells and analysis of its biological activity / 生物工程学报

ABSTRACT

The anti-CD3 antibody can improve success rate of organs transplant. HIT3a, a mouse anti-CD3 antibody, was chimerized by using gene engineering methods to decrease its immunogenity. The anti-CD3 genes, heavy chain and light chain, were cloned using PCR from the vector pCANTAB 5E containing anti-CD3 scFv gene fragment, and two PCR fragments were recombined into the expression vector pKN100 with human antibody light constant domain and pG1D105 with human antibody heavy constant domain, respectively. The two vectors were co-transfected into CHO cells using liposome. The anti-CD3 antibody was detected by ELISA and Western blot assay in supernatant of transfected CHO cells culture. The primary results of competitive assays by FACS showed that anti-CD3 antibody could partially block the sites through which parent antibody (HIT3a) bind to CD3+ Jurkat cells. The result of 3H-TdR incorporation showed that the chimeric anti-CD3 antibody could stimulated proliferation of peripheral blood mononuclear cells (PBMC) as the parent antibody. In this thesis, the results of some experiments indicated that the chimeric anti-CD3 antibody expressed in CHO cells was an antibody with native biological activity, and it is possible to apply to in clinic in the future.