Effect of early allergen immunization on the development of allergic rhinitis in mouse

Abstract

To investigate the effect of early allergen exposure on later development of allergic rhinitis in mouse. Twenty-four BALB/c neonates were randomly divided into 4 groups (low-dose group, high-dose group, negative control group and positive control group), each group had 6 mice. The mice were administered ovalbumin (OVA) by subcutaneous injection on day 1, 5, 12 after birth (10 μg OVA in 0.05 ml saline for low-dose group, 1000 μg OVA in 0.05 ml saline for high-dose group, only saline for negative and positive control group). Then the mice were sensitized and intranasally challenged with OVA (saline without OVA was used in negative control group) after 6 weeks. Symptoms, histopathological changes of nasal mucosa were observed, OVA-IgE in serum was examined, cytokines IL-4, IL-5 and IFN-gamma were detected in the supernatant of cultured splenic mononuclear cells. Compared to the positive control group, symptoms and nasal mucosa histological changes of high-dose group was indistinctive. The level of OVA-IgE and cytokines IL-4, IL-5 (x(-) +/- s) in high-dose group [(265.11 +/- 26.29), (446.39 +/- 72.83) and (171.24 +/- 15.66) pg/ml, respectively] were significantly lower than those in positive control group [(665.85 +/- 43.15), (1113.45 +/- 30.47), (255.36 +/- 30.96) pg/ml, respectively, t value were 0.000, 0.000 and 0.009, respectively, all P < 0.05]. The level of IFN-γ in high-dose group [(319.74 +/- 56.30) pg/ml] was significantly higher than those in positive control group [(170.02 +/- 14.50) pg/ml, t = 0.000, P < 0.05]. There was no significant difference of the results between the low-dose group and positive control group. Neonatal immunization with high-dose OVA inhibited the future allergic rhinitis symptoms, nasal histological changes, serum OVA-IgE levels and Th1/Th2 cytokine imbalance, resulting in the protective effect.