ABSTRACT
Objective:To display human CD137 extra-cellular domain on phage using phage display technique and detect its antigenicity and bioactivity.Methods:CD137 extra-cellular gene was amplified from CIS plasmid using PCR and then clone it into pComb3HSS.The recombinant pComb3H-CD137 was transfected into competent bacteria XL1-Blue, then the transfected bacteria was co-infected with help phage VCSM13 and CD137 extra-cellular domain was displayed on the phage surface. The antigenicity and bioactivity of CD137 displayed on phage was detected by ELISA and inhibition assay of lymphocyte proliferation(MTT).Results:CD137 PCR products was 525 bp, the recombined plasmid was named pComb3H-CD137, CD137 was displayed on phage. ELISA detection showed that phage displayed CD137 possesses antigenicity of human CD137. MTT inhibition assay showed that lymphocytes proliferation stimulated by PHA and CD137 could be inhibited by phage displayed CD137, indicating that it has bioactivity of nature CD137.Conclusion:The studies demonstrate that phage display system can display human CD137 extra-cellular domain homodimer with antigenicity and bioactivity.