Immunization with the lipoprotein FtsB stimulates protective immunity against Streptococcus pyogenes infection in mice

Abstract

Streptococcus pyogenesis one of the main pathogenic bacteria that causes disease in humans. It is reported that over 18 million cases ofS. pyogenesdisease occurred in the world, and more than 500,000 deaths occur annually worldwide. An effective vaccine is widely regarded as the most reliable way to control and prevent streptococcal infections. However, there is currently no approved vaccine forS. pyogenes. In this study, we evaluated the potential of lipoprotein FtsB as a new vaccine candidate to preventS. pyogenesinfection. Mice vaccinated with purified FtsB protein elicited high titers of IgG, IgG1 and IgG2a antibodies in mouse serum. Vaccinated with FtsB can reduce bacterial systemic dissemination in the blood, heart, and spleen and reduce organ damage in the mouse bacteremia model. In addition, active immunization with FtsB protected against streptococcal abscess formation. Furthermore, immunization with FtsB was efficient in inducing a mixed cellular immune response and promoting the maturation of dendritic cells in mice. The lipoprotein HtsA was served as a positive control because it has been reported to protect mice fromS. pyogenesinfection in both active and passive immunization. These findings demonstrated that lipoprotein FtsB may serve as a candidate vaccine for the prevention ofS. pyogenesinfection.