Streptococcus equi ssp. zooepidemicus (SEZ) is an important pathogen of swine streptococcal diseases and can infect a wide range of animals as well as human beings. The absence of effective vaccine confounds the control of SEZ infection. Sec_205, a novel protein identified in the previous study, was inducibly over-expressed in Escherichia coli in the present study. The purified recombinant protein could elicit a significant humoral antibody response and provide efficient protection against lethal challenge of SEZ C55138 in mouse model. The protection against SEZ infection was mediated by specific antibodies to Sec_205 to some extent and was identified by the passive protection assay. The Sec_205 was an in vivo-induced antigen confirmed by the real-time PCR and could adhere to the Hep-2 cells by the inhibition assay. These suggest that Sec_205 may play a vital role in pathogenicity and serve as a new vaccine candidate against SEZ infection.
Keywords: Protective antigen; Streptococcus equi ssp. zooepidemicus; Subunit protein; Vaccine candidate.
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