Study title

S. pneumoniae is one of the single most important global causes of infective morbidity and mortality. Although current vaccines have reduced the occurrence of diseases, there are important limitations such as high cost and limited serotype coverage, compounded by serotype replacement. In this project we tested the hypothesis that Streptococcus mitis may offer protection against S. pneumoniae infection. We demonstrated cross-reactive responses in animals and in humans. Further, using a mouse model of S. pneumoniae infection, we showed that S. mitis can indeed induce immune responses that confer serotype-independent protective effects against S. pneumoniae. In addition, we found that S. mitis can be engineered to enhance protection by expressing the S. pneumoniae capsule on their surface. This last approach opens for a vaccine that would have a low cost and provide serotype independent protection, while retaining the well-documented protective effect conferred by the capsules of S. pneumoniae. In a time that antimicrobial resistance is one of the largest threats to humanity, and given the importance of S. pneumoniae, it is imperative that different alternatives to fight infections by this pathogen are explored. For further information about ”Protective Immunity to Streptococcus pneumoniae”, please contact the principal investigator.