Clone expression of the caf1 gene of Yersinia pestis and immunological evaluation on recombinant F1 antigen

Objective To get recombinant F1 antigen （rF1） and to construct the detection dipstick of plague antibody. Methods The call gene removing the signal peptide coding sequence was cloned into plasmid pET32a （ ＋ ） by double-digested sites of BamHI and Not I. Recombinant plasmid caf1-pET32a （＋） was transformed into BL21 （DE3） and the rF 1 was expressed. Expression products were purified by affinity chromatography. Dual detection dipstick of plague antibody was constructed with purified rF1 and natural F1, and evaluated with 528 human serum samples of Zhejiang province. Results The fusion protein rF1 of 35.5 KD was expressed by BL21 strains containing cafl-pET32a （＋）. The sensitivity of rF 1 showed equivalent to or higher than the natural F1 antigen in detecting plague antibody. It seemed that there was a better consistency of 97.9% （κ = 0.466） when 528 human sera was detected by rF1 and natural F1. Conclusion We successfully extracted the rF 1 with good immunological activity that might be used to detecting Yersinia pestis. Key words: Yersinia pestis;  Recombinant F1 antigen;  cafl gene;  Clone expression;  Immunological activity