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[Prokaryotic expression and application of SpiC protein of Salmonella pullorum].

OBJECTIVE
To express the SpiC protein of Salmonella pullorum and establish an indirect ELISA method with SpiC protein as antigen.


METHODS
The 384 bp spiC gene of Salmonella pullorum was amplified by PCR from the genomic DNA and cloned into pET30a vector. The recombinant plasmid pET30a-spiC was transformed into competent E.coli BL21(DE3) cells and induced by IPTG. The expressed product was analyzed by SDS-PAGE and Western blotting. Indirect ELISA based on purified SpiC protein was applied to detect 144 clinical serum samples.


RESULTS
SDS-PAGE and Western blotting confirmed that a soluble recombinant His-SpiC protein of 19.2 ku was expressed in BL21(DE3) cells. SPF chicken antibodies against GST-SpiC could recognize His-SpiC, indicating that His-SpiC had a good immunogenicity. The indirect ELISA that we established using His-SpiC protein as coating antigen for detecting antibodies against SpiC could differentiate infected from vaccinated animals (DIVA).


CONCLUSION
The recombinant His-SpiC was successfully expressed and the indirect ELISA with it as coating antigen could be used as DIVA method for the related vaccine of pullorum disease.