The costimulatory effect of mouse B7-H3 gene in the activation of T cells

The biological function of mouse B7-H3 was still not identified yet.This paper was aimed to generate an engineered CHO cell line harboring mouse B7-H3 and to investigate its biological function and effects on T lymphocyte activation.The genes coding mouse B7-H3 were obtained from mouse liver cDNA by RT-PCR and then the target gene fragment was inserted into eukaryotic vector pIRES2-EGFP after being digested with EcoR Ⅰ and Bgl Ⅱ to construct the recombinant vector pIRES2-EGFP/B7-H3.This recombinant vector was transfected into CHO cells with LipfectAMINETM 2000 and followed by G418 selection.RT-PCR,Western blotting and flow cytometry(FCM) were used to detect the expression of B7-H3.Effects of the transfected cells on T cells proliferation and cytokine production in vitro was studied by methods of CCK8 and ELISA.In these ways,a stable cell line constitutively expressing the mouse B7-H3 was established successfully,and the mouse B7-H3 could obviously promote the proliferation of T cells in and secretion of IL-2 and IFN-γ in vitro.This effect could be partly blocked by mAb.It is evident that the engineered mouse B7-H3/CHO cell line provides a gain of function cell model for the further understanding of the biological role of B7-H3.