Anti-capsular immunity to Streptococcus pneumoniae serotype 22F prevents bacterial transmission in murine colonization and influenza virus co-infection models

We evaluated the effectiveness of anti-22F serotype immunity in the prevention of Streptococcus pneumoniae (Spn) bacterial transmission during colonization and influenza virus co-infection. Mice were immunized with 22F formulation and later colonized with Spn or co-infected with Spn and influenza virus. The 22F antisera exhibited strong reactivity to 22F bacteria and promoted the opsonic uptake of Spn by the neutrophils. The 22F vaccination led to a significant reduction of bacterial densities in the nasopharynx and prevented bacterial transmission during colonization and co-infection. The transfer of 22F antisera to infant mice resulted in reduced bacterial transmission in colonization and co-infection models.