[Construction of anti-CD28 single chain antibody genes and expression of the ScFv in BmN cells and the larvae of Bombyx mori].

The V(H) and V(L) gene fragments of anti-CD28 mAb were combined to form anti-CD28 ScFv gene by using TP-PCR method. Sequence analysis showed that 6 x His tag was added to it for the ease of purification and the V(H), and V(L) gene fragments were connected by a linker containing 15 amino acids which are biased by the baculovirus promoter, ph. Then ScFv gene fragment was inserted into baculovirus transfer vector pBacPAK8.

[Construction of a recombinant baculovirus transfer vector with two promoters expressing the anti-human CD28 chimeric antibody by using TP-PCR method].

CD28, a cell surface glycoprotein, predominantly expressed on T cells, belongs to the Ig superfamily and provides critical co-stimulatory signals. The data which have published indicate that the monoclonal antibody against CD28 can decrease curative effects when it was applied in vivo for a long time. In order to avoid the human-anti-mouse action, anti-CD28 mAb must be humanized before it can be used in clinical study.