ABSTRACT
Objective To get recombinant F1 antigen (rF1) and to construct the detection dipstick of plague antibody. Methods The cafl 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 rFl 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 caf1-pET32a( + ). The sensitivity of rF1 showed equivalent to or higher than the natural Fl antigen in detecting plague antibody. It seemed that there was a better consistency of 97.9% (k= 0.466) when 528 human sera was detected by rF1 and natural F1. Conclusion We successfully extracted the rF1 with good immunological activity that might be used to detecting Yersinia pestis.