Abstract：Objective To construct a prokaryotic recombinant plasmid containing the gene encoding microphage infectivity potentiator (Mip) of Chlamydia psittaci (C. psittaci), and lay a basis for further study on the function of the recombinant protein. Methods The C. psittaci 6BC Mip gene was amplified by PCR and cloned into plasmid pET-30(+), then transformed into E.coli BL21. After being identified by PCR, restriction enzymes cleavage and nucleotide sequencing, the positive strains were inducted by IPTG. Then the recombinant protein Mip was analyzed by SDS-PAGE and purified with Ni-NTA-His affinity chromatography. The purified recombinant Mip was used to immunize BALB/c mice, and the antibodies to Mip in mice sera were titrated with ELISA. Results A 768bp fragment of C. psittaci Mip gene was obtained by PCR. The target gene was proved to be successfully inserted into pET30(+) by PCR, restriction enzymes cleavage and nucleotide sequencing. The similarity was 100% between the inserted gene and Mip gene reported in Genbank by BLAST analysis. After the induction and purification, a recombinant protein about 34KD was obtained. Specific humoral response was elicited in BALB/c mouse after immunization with the purified recombinant protein and the antibody titer in mice’ sera was higher than 1:128,000. Conclusions Prokaryotic expression plasmid pET-30(+)-Cps Mip is successfully constructed, a molecular weight about 34 KDa protein is obtained and specific antibody is successfully prepared.
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2017, Vol. 24 
