Optimized expression of listeriolysin O(LLO) gene in Escherichia coli and development of an ELISA for detection of anti-LLO antibody

Based on the cloning and expression of Listeria monocytogenes(LMO) hlyA gene,the concentration of IPTG,inducing time and temperature,all influence the target protein expression level,were optimized respectively.According to the optimal conditions,the target protein was highly expressed.With the purified recombinant listeriolysin O(LLO) protein as target antigen in an indirect ELISA,the animals infected with LMO could be identified by detecting the serum's specific antibody.The results showed that the purified-expressed LLO provided foundation for developing serological technology for diagnosis of animal listeriosis.