The Effect of Intranasal Immunization with Streptococcus Pilus Protein on Nasopharyngeal pIgR and IgA Expression in Rats

Abstract

Introduction: Streptococcus pneumoniae (S. pneumoniae) causes pneumococcal disease, which has high mortality and morbidity in children under two years of age, the elderly and immunocompromised individuals. This disease can be prevented by immunization, but the current vaccine, pili protein vaccine (PPV), is less likely to protect children under the age of two and only protects against the serotypes contained in the vaccine. Hence, a new vaccine is needed to enable full protection. The use of bacterial pili proteins may offer an alternative new vaccine. Therefore, the determination of the ability of such proteins to stimulate mucosal immunity with indicator expression of pIgR and s-IgA is required. Materials and Methods: Pili were isolated using the pili bacterial cutter method, and used for nasal vaccination to the rats. TGF-β1, IL-17A, and s-IgA were measured by ELISA while pIgR was examined by immunohistochemistry. Results: This study demonstrated that intranasal immunization with antigen (54 kDa pili protein) and antigen plus adjuvant significantly increased (p<0.05) the expression of TGF-β1. However, the expression of IL-17A increased significantly (p<0.05) only in rats immunized with antigen plus adjuvant. Further analysis demonstrated that intranasal immunization with antigen and antigen plus adjuvant significantly increased (p<0.05) expression of pIgR. Expression of sIgA in nasal lavage significantly increased (p<0.05) in those rats which had been immunized with pili protein plus adjuvant. Conclusion: This study showed that the immünization with S. pneumoniae pili protein increased expression of pIgR and sIgA which are important mucosal immunity components. Therefore, this protein has potency to be developed as nasal vaccination to prevent S. pneumoniae infection.