Estudio de nuevas vacunas bacterianas en el modelo de infección en ratón (Mus musculus) por Streptococcus pneumoniae

Respiratory infections are a global health problem. Streptococcus pneumoniae (SPN) is one of the pathogens that causes more respiratory infections in children and elderly people, and its resistance to clinical antimicrobial agents has increased in the last few years. Several vaccines are currently available to prevent SPN infection, but their effectiveness is limited. In this work we have studied the efficacy of a new immunization protocol, using different instilled bacterial vaccines. The immunization procedure was developed in an experimental mouse model (Mus musculus) of respiratory infection caused by SPN instillation. The results show that two vaccines with different bacterial composition (MV130 y MV140) protect from lung infection caused by SPN by distinct immune responses. In the case of mice immunized with MV130, protection from weight loss and longer survival was observed compared with unimmunized infected animals. In addition, MV130-treated mice exhibited an efficient innate immune system (SII) response in the lung (massive recruitment of Nφ, proinflammatory monocyte-derived dendritic cells) along with an enhanced response of the adaptative immune system (SIA) response. Moreover, MV140-immunized mice had increased survival rates and protection from weight loss. MV140-immunized mice presented a predominant profile of anti-inflammatory monocytes. Finally, the effects of two other vaccine preparations, MV130X and Autovaccine, were evaluated without showing effective protection in this immunization model