Nasal exposure to Staphylococcal enterotoxin enhances the development of allergic rhinitis in mice

Background: Staphylococcal enterotoxins (SEs) appear to play a role in the pathogenesis of allergic disease. However, little is known whether the nasal exposure to SE affects the development of allergic rhinitis (AR). Objective: We sought to determine the in vivo effect of nasal exposure to SE on the development of AR using mouse model. Methods: BALB/c mice were intranasally sensitized with Schistosoma mansoni egg antigen (SmEA) in the presence or absence of staphylococcal enterotoxin B (SEB). Control mice were intranasally sensitized with either SEB or SmEA alone. The production of antigen-specific antibodies including IgE, nasal eosinoplilia and cytokines by nasal mononuclear cells was compared among mice that had or had not received SEB treatment. Results: Nasal exposure to SEB enhanced the development of AR in SmEA-sensitized mice, as manifested by SmEA-specific IgE production, nasal eosinophilia, and IL-4 and IL-5 production by nasal mononuclear cells after Ag challenge. This treatment also elicited IFN-γ production by SmEA-primed cells. In addition, these mice produced SEB-specific IgE whereas mice treated with SEB without SmEA sensitization did not produce SEB-specific IgE or demonstrate nasal eosinophilia. Conclusion: These results suggest that the nasal exposure to SEB enhances susceptibility to AR although the exposure to SE solely does not induce AR.