Abstract: To investigate the enhanced effect of CD40 antibody binding to CD40 on B-cell response to small molecule haptens,in this study, the total RNA of BALB/c mouse spleen was extracted by TRIzol method and reverse transcribed into cDNA; Primers were designed based on the CDS region of the extracellular domain of CD40, and the target gene was amplified by PCR to construct the pGEX4T-1-CD40 expression vector for prokaryotic expression;The polyclonal antibody was prepared. The results showed that the 522 bp target gene was successfully amplified, CD40 recombinant protein of 45 ku was expressed and purified. The antibody obtained by Western-blot detection not only binds to recombinant protein, but also can specifically bind to mouse spleen natural CD40 protein. Those indicated that the expression of CD40 recombinant protein is successful, and the prepared antibody was expected to mimic CD40L to provide the second signal for B cell activation.

Key words: CD40, prokaryotic expression, polyclonal antibody, hapten, immune enhancement