Abstract:

Objective To clone, express and purify Chlamydia trachomatis polymorphic membrane protein （Pmp G）, and to identify its immunogenicity. Methods The Pmp G gene of C. trachomatis serotype E was amplified by PCR, cloned into prokaryotic expression vector PET30a（+）. The positive recombinant was transformed into the bacterium E. coli （BL-21）, identified by enzyme digestion, PCR amplification and gene sequencing. Then, it was induced to express followed by the identification of expression product with SDS-PAGE and Western blotting. The purified protein was used to immunize BALB/C mice to test its immunogenicity. Results PCR produced a 1092 bp-sized DNA fragment, which had a sequence consistent with that of PmpG gene of C. trachomatis E type in the GenBank database. The molecular weight of expression product was 55 kD, which was proved to be the expected size, and Western Blotting confirmed it to be the specific protein. Moreover, special antibodies to PmpG were induced to be generated by mice immunized with the purified protein. Conclusions The constructed prokaryotic expression vector for PmpG is expressed successfully in E. coli, and the expression product shows immunogenicity.

Key words: Chlamydia trachomatis, Polymorphic membrane protein , purifying, immunogenicity