ABSTRACT
Objective To clone, express, purify and evaluate the immunoreactivity of the recombinant protein Tp0844 of Treponema pallidum (Tp), and to screen major Tp proteins with high host reactivity. Methods The Tp0844 gene sequence was obtained through bioinformatics analysis. A prokaryotic expression vector of the Tp0844 gene was constructed and transformed into E. coli BL21 followed by isopropyl-1-thio-β-D-galactopyranoside (IPTG)induction for the expression of the recombinant protein Tp0844. Nickel-NTA affinity chromatography columns were utilized to purify the recombinant protein, and Western blotting was performed to evaluate the reactivity of the recombinant protein with sera positive or negative for anti-Tp IgG antibodies. Results The recombinant prokaryotic expression vector PET-30a (+)-Tp0844 was successfully constructed. After IPTG induction, a soluble recombinant protein with a relative molecular mass of about 43 000 was highly expressed, and purified by affinity chromatography. Western blotting showed that the Tp0844 recombinant protein specifically reacted with anti-Tp IgG antibody-positive sera, but not with anti-Tp IgG antibody-negative sera. Conclusions The soluble recombinant protein Tp0844 has good immunoreactivity, and can serve as a candidate antigen for investigation into the pathogenesis of syphilis.