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

Pneumococcal Δpep27 Immunization Attenuates TLRs and NLRP3 Expression and Relieves Murine Ovalbumin-Induced Allergic Rhinitis

Allergic rhinitis (AR), one of the most common inflammatory diseases, is caused by immunoglobulin E (IgE)-mediated reactions against inhaled allergens. AR involves mucosal inflammation driven by type 2 helper T (Th2) cells. Previously, it was shown that the Streptococcus pneumoniae pep27 mutant (Δpep27) could prevent and treat allergic asthma by reducing Th2 responses. However, the underlying mechanism of Δpep27 immunization in AR remains undetermined. Here, we investigated the role of Δpep27 immunization in the development and progression of AR and elucidated potential mechanisms. In an ovalbumin (OVA)-induced AR mice model, Δpep27 alleviated allergic symptoms (frequency of sneezing and rubbing) and reduced TLR2 and TLR4 expression, Th2 cytokines, and eosinophil infiltration in the nasal mucosa. Mechanistically, Δpep27 reduced the activation of the NLRP3 inflammasome in the nasal mucosa by down-regulating the Toll-like receptor signaling pathway. In conclusion, Δpep27 seems to alleviate TLR signaling and NLRP3 inflammasome activation to subsequently prevent AR.

Inhibitory Effect of Pycnogenol® on Airway Inflammation in Ovalbumin-Induced Allergic Rhinitis

BACKGROUND

The supplement Pycnogenol® (PYC) has been used for the treatment of several chronic diseases including allergic rhinitis (AR). However, the in vivo effects on allergic inflammation have not been identified to date.

AIMS

To investigate the treatment results of PYC on allergic inflammation in a rat model of allergic rhinitis.

STUDY DESIGN

Animal experimentation.

METHODS

Allergic rhinitis was stimulated in 42 rats by intraperitoneal sensitization and intranasal challenge with Ovalbumin. The animals were divided into six subgroups: healthy controls, AR group, AR group treated with corticosteroid (dexamethasone 1 mg/kg; CS+AR), healthy rats group that were given only PYC of 10 mg/kg (PYC10), AR group treated with PYC of 3mg/kg (PYC3+AR), and AR group treated with PYC of 10 mg/kg (PYC10+AR). Interferon-γ (IFN-γ), interleukin-4 (IL-4), interleukin-10 (IL-10), and OVA-specific immunoglobulin E (Ig-E) levels of serum were measured. Histopathological changes in nasal mucosa and expression of tumor necrosis factor-α (TNF-α) and IL-1β were evaluated.

RESULTS

The levels of the IL-4 were significantly decreased in the PYC3+AR, PYC10+AR and CS+AR groups compared with the AR group (p=0.002, p<0.001, p=0.006). The production of the IFN-γ was significantly decreased in the PYC3+AR and PYC10+AR groups compared with the AR group (p=0.013, p=0.001). The administration of PYC to allergic rats suppressed the elevated IL-10 production, especially in the PYC3+AR group (p=0.006). Mucosal edema was significantly decreased respectively after treatment at dose 3 mg/kg and 10 mg/kg PYC (both, p<0.001). The mucosal expression of TNF-α has significantly decreased in the PYC3+AR and PYC10+AR groups (p=0.005, p<0.001), while the IL-1β expression significantly decreased in the CS+AR, PYC3+AR, and PYC10+AR groups (p<0.001, p=0.003, p=0.001).

CONCLUSION

PYC has multiple suppressive effects on allergic response. Thus, PYC may be used as a supplementary agent in allergic response.

Effect of Retinoic Acid in a Mouse Model of Allergic Rhinitis

PURPOSE

All-trans retinoic acid (ATRA) modulates immune responses by affecting T cells. Several studies have revealed that allergic inflammation of the lower airways is negatively associated with the vitamin A concentration. However, the role of ATRA in allergic inflammation of the upper airways is unclear. We investigated the effects of ATRA in an allergic rhinitis mouse model.

METHODS

BALB/c mice except control groups (CON group) were sensitized with and challenged intra-nasally with Dermatophagoides farina (AR group). The ATRA groups were administered ATRA intraperitoneally. The steroid groups were administered steroid intranasally (ST group). Allergic symptoms and the average eosinophil number were counted. Cytokines and transcription factors were measured by Real-Time PCR and Western blotting. Der f-specific immunoglobulin E (IgE) was measured. Flow cytometry results of CD4⁺CD25⁺Foxp3⁺ T cells were analyzed.

RESULTS

The symptom scores were lower in the ATRA group than in the AR group and higher than in the CON group. The levels of IgE were lower in the ATRA group than in the AR group and higher than in the CON and ST groups. The levels of Foxp3, TGF-β, and IL-10 mRNA, as well as the percentage of CD4⁺CD25⁺Foxp3⁺ T cells, were higher in the ATRA group than in theAR group. In the ATRA group the levels of IFN-γ mRNA were higher, and the levels of GATA-3 and IL-4 mRNA, and ROR-γt were lower. In Western blotting analyses, the expression patterns of all factors, except Foxp3, showed similar to those of mRNA expression.

CONCLUSIONS

ATRA has anti-allergic effects in an allergic rhinitis model, and its underlying mechanisms mainly include the induction of regulatory T cells and the inhibition of Th2 responses.