Characterization of SeseC_01411 as a surface protective antigen of Streptococcus equi ssp. zooepidemicus.

Streptococcus equi ssp. zooepidemicus (Streptococcus zooepidemicus, SEZ) is a commensal bacterium related to opportunistic infections of many species, including humans, dogs, cats, and pigs. SeseC_01411 has been proven to be immunogenic. However, its protective efficacy remained to be evaluated. In the present study, the purified recombinant SeseC_01411 could elicit a strong humoral antibody response and protect against lethal challenge with virulent SEZ in mice. Our finding confirmed that SeseC_01411 distributes on the surface of SEZ. In addition, the hyperimmune sera against SeseC_01411 could efficiently kill the bacteria in the phagocytosis test. The present study identified the immunogenic protein, SeseC_01411, as a novel surface protective antigen of SEZ.