Comparison of antiallergic effects of pneumococcal conjugate vaccine and pneumococcal polysaccharide vaccine in a murine model of allergic rhinitis.

OBJECTIVES/HYPOTHESIS: Pneumococcal vaccines have been widely used, and Streptococcus pneumoniae has been suggested to be an effective therapeutic agent in allergic disease. OBJECTIVES: The present study was performed to evaluate the effects of pneumococcal polysaccharide vaccine (PV) and pneumococcal protein conjugate vaccine (PCV), and to examine differences between the vaccines in a murine model of allergic rhinitis. STUDY DESIGN: In vivo study using an animal model. SETTING: Catholic Research Institutes of Medical Science. METHODS: Allergic rhinitis was induced in 40 BALB/c mice by intraperitoneal sensitization and intranasal challenge with Dermatophagoides farinae (Derf). The animals were divided into four groups: control, Derf, PV, and PCV. Interferon-γ, interleukin-13, and interleukin-10 levels in nasal lavage fluid and Derf-specific immunoglobulin E levels in serum were measured. The levels of T-bet, GATA-3, and Foxp3 mRNA expression in splenic mononuclear cells were determined. The number of CD4(+) CD25(+) Foxp3(+) regulatory T cells in splenic mononuclear cells was compared between groups by flow cytometry. RESULTS: Allergic symptom scores, T-bet and GATA-3 mRNA levels, serum Derf-specific immunoglobulin E levels, and tissue eosinophil counts were lower in the PV and PCV groups than the Derf group (P < 0.05). The regulatory T (Treg) cell indicators, Foxp3 mRNA, and percentages of CD4(+) CD25(+) Foxp3(+) T cells were increased in the PV and PCV groups (P < 0.05). CONCLUSION AND CLINICAL RELEVANCE: Both PV and PCV suppressed the allergen-specific T helper 2 response and induced regulatory T cells in a murine model of allergic rhinitis. However, PV and PCV may activate Treg cells via different mechanisms. LEVEL OF EVIDENCE: N/A.