Development of Nanogel-based Nasal Vaccine against Pneumonia

Abstract

Abstract Streptococcus pneumoniae (S. pneumoniae) cause pneumococcal disease in children and adults all over the world. Although there are vaccines comprising several pneumococcal polysaccharides in clinical use, they cannot cover the broad protections. Recently we established the cationic nanogel-based nasal vaccine against Pneumonia using a recombinant protein of pneumococcal surface protein A (PspA). We have designed three PspA chimeric antigens for trivalent vaccine and combined them with a cationic nanogel, a novel drug delivery system which adhere to the epithelial layer of the nasal cavity after nasal immunization and elicit the effective immunity by sustained antigen release. Indeed, the PspA nanogel vaccine induced not only the antigen-specific IgG in the body but also the antigen-specific secretory IgA (SIgA) at the mucosal surfaces such as nasal cavity where the entrance of pathogens. Both induced antigen-specific IgG and SIgA could bind to various serotypes of S. pneumoniae, indicating that these antibodies have neutralizing activity against broad types of S. pneumoniae. Moreover, the vaccinated mice were protected from infections by a several types of S. pneumoniae, and the nasal vaccine exhibited protective efficacy in some strains which cannot be covered by the current vaccines. Thus, our findings demonstrated the nasally administered PspA nanogel vaccine effectively elicit a protective immunity and provide a broad protection against S. pneumoniae infections.