A New Model of Trispecific Antibody Resulting the Cytotoxicity Directed against Tumor Cells

SONG Li-Ping, CHENG Ju-Long, WANG Xiang-Bin, ZHANG Zhong, FANG Min, ZHOU Zhi-Yong, HUANG Hua-Liang*

( Institute of Genetics and Developmental Biology, the Chinese Academy of Sciences, Beijing 100101, China )

Abstract Bispecific antibodies (BsAb) with specificity to both tumor cells and CD3 molecule were believed to be promising immunological tools for the therapy with minimal residual diseases by activating cytotoxic T cells. However, without costimulatory molecule CD28, the activated T cells tended to apoptosis. In order to kill tumor cells more efficiently, a recombinant multifunctional single-chain trispecific antibody (scTsAb), which contains anti-ovarian carcinoma (OC) scFv, anti-CD3 scFv and VH domain of anti-CD28 antibody, was constructed and expressed in E. coli BL21 Star strain. The scTsAb showed strong binding avidities to membrane antigen of SK-OV-3 cell, CD3 molecule on Jurkat cell, and recombinant CD28 antigen. It was further demonstrated that this scTsAb could activate peripheral blood T cells to elicit strong cytotoxicity against SK-OV-3 cells. This new type of recombinant scFv antibody set up a new technological platform for T cells based immunotherapy against cancer, especially with the failure on MHC antigen presentation or absence of costimulating signal.

Key words trispecific antibody (TsAb); scFv; ovarian carcinoma (OC); CD3; CD28

*Corresponding author: Tel, 86-10-64857285; Fax, 86-10-64857285; e-mail, [email protected]