Cloning and Expression of the Extracellular Domain of Human CD40 Antigen Gene

Objective To clone and express the 582 bp cDNA fragment of the extracellular domain of human CD40.Methods The cDNA of human CD40 antigen was amplified from total RNA of XG-2 cells by RT-PCR,and it was inserted into pMD18-T.The extracelluar domain of human CD40 was amplified from the recombinant vector pMD18-T/CD40,then it was subcloned into expression vector pGEX-5x-3,E.coli BL21(DE3) was transfected with the recombinant vector and the expression was induced with IPTG.Results DNA sequencing showed that the obtained 582 bp cDNA sequence was identical with the reported CD40 gene.The target fragment was expressed in bacterial cells.Conclusion The expressed product of 582 bp cDNA fragment of human CD40 obtained lays the foundation for studing the functions of human CD40 antigen.