Study on the diagnosis application using recombinant protein of immunodominant region gene of chlamydial protease-like activity factor from Chlamydophila psittaci / 中华微生物学和免疫学杂志

ABSTRACT

Objective To clone and express the immunodominant domain of the chlamydial proteaselike activity factor(CPAF) from Chlamydophila psittaci(Cps) and evaluated the diagnosing value of the recombinant protein in Cps infection.Methods The immunodominant region epitope of CPAF (CPAFm,A196-A450)from Cps was chosen according to bioinformatics analysis and references.The specific primer was designed and the gene was amplified by PCR and then ligated into a pGEX6p-2 vector.Recombinant protein was induced to express by IPTG and analyzed by SDS-PAGE and Western blot.Indirect EL1SA method of serological diagnosis was established with the reorganization protein as coating antigen.One hundred and eighty sera samples from ducks with respiratory tract infection symptoms were detected with the established indirect ELISA and a commercial ELISA-kit to assess the value of the recombinant protein in serodiagnosis.The results were further identified with Western blot.Results Prokaryotic expression vector pGEX6p-2/CPAFm was constructed and a 54x103 fusion protein was attained.The indirect ELISA method was established with reorganization protein for envelope antigen.Using the indirect ELISA to detect Cps lgG positive and negative reference sera,the sensitivity and specificity were both 100％ (20/20).And the recombinant protein has no cross reaction with either Chlamydophila pneumoniae or Chlamydophila trachomatis.The concordance rate between the indirect ELISA and Western blot to 180 ducks sera samples was 100％,while the concordance rate of the commercial ELISA kit was 77.5％-95.0％.Conclusion The prepared recombinant protein of the CPAF immunodominant region epitope gene from Gps can highly benefit on developing new indirect ELISA as methods to detect specific anti-Cps antibodies.