Phenotypic characteristics of nasal mast cells in a mouse model of allergic rhinitis.

Abstract

BACKGROUND: Mast cells (MCs) in the nasal respiratory mucosa (NRM) play a triggering role in the pathogenesis of allergic rhinitis (AR). Recent research evidence in mouse models of AR suggests an underlying MC-related allergic response in mouse nasal olfactory mucosa (NOM). OBJECTIVE: We sought to investigate the phenotypic characteristics of nasal MCs in a mouse model of AR. METHODS: By MC-specific staining and immunohistochemistry, we analyzed the subset, protease and IgE-binding phenotypes of nasal MCs in ovalbumin (OVA)-sensitized unchallenged and challenged mice. RESULTS: In OVA-sensitized challenged mice, increased serum OVA-specific IgE levels (p < 0.001) and eosinophil infiltration confirmed AR induction. In addition to constitutive connective tissue MCs, mucosal MCs were induced in NRM and NOM of OVA-sensitized challenged mice. Connective tissue MCs and mucosal MCs in mouse NRM and NOM were positive for mouse MC protease-1, -4, -5, -6, -7 and carboxypeptidase-A3. In line with MCs in NRM, there were increased numbers (p = 0.019) and proportions (p = 0.027) of MCs with surface-bound IgE in NOM of OVA-sensitized challenged mice. CONCLUSION: In the setting of AR, MCs in mouse NOM exhibit the same subset, protease and IgE-binding phenotypes as MCs in mouse NRM.