Expression of a Gene for Single-chain Antibody to Carcinoembryonic Antigen in Bombyx mori cells and Its Larvae.
Recombinant Bm-BacScFv virus which contains a cDNA encoding anti-CEA single-chain antibody was generated by cotransfection into Bm N cells with the transfer plasmid pBacPAK-(His)(6)-ScFv and the modified Bombyx mori nuclear polyhedrosis virus Bm-BacPAK genomic DNA. Bombyx mori cells and larvae were infected by the recombinant virus, respectively. The anti-CEA single-chain antibody were expressed both in Bombyx mori cells and larvae, the former accounted for 6% of the total cell protein, the later 0.3 mg per larvae. The histidine-tagged ScFvs were respectively purified with nickel-iminodiacetic acid affinity chromatography. The purity of the former reached over 90% and that of the latter was lower. Purified protein products was able to bind to CEA with an affinity constant of 5.4x10(8)/mol.L(-1) and 2.3x10(8)/mol.L(-1), slightly lower than its parental monoclonal antibody E(7)B(10) which had 2.7x10(9)/mol.L(-1).
Shanghai Institute of Biochemistry, the Chinese Academia of Sciences, Shanghai 200031, China. xfwu@sunm.shcnc.ac.cn
Biao
B
Li
Cheng-Mo
CM
Zhu
Wei-Dong
WD
Yang
Xiang-Fu
XF
Wu