Cloning, expression and biological activity identification of a cDNA encoding the extracellular region of human b7-2 / 中国实验血液学杂志

ABSTRACT

As one important member of B7/CD28/CTLA-4 costimulatory signal pathway, B7-2 molecule plays a critical role in regulating T-cell response. In order to further explore its effects on regulation of T cell activation, proliferation and associated signal pathways, the cDNA encoding extracellular region of human B7-2 was amplified via PCR and subcloned into some prokaryotic expression vectors to express target protein in host strains. The expressed protein was identified with Western blot and MTT. Results showed that after screening, the expression level of the protein of interest attained the yield of over 20% total bacterial protein by using pGEX-4T-2 vector and E. coli BL21 (DE3)-CodonPlus-RIL host cells. The recombinant protein could specially react with B7-2 McAb and could stimulate T-cell proliferation combined with anti-CD3 antibody. In conclusion, the recombinant protein was bioactive, therefore the study will make it possible for the research of relationship between B7-2 structure and its function.