Induction of Antigen-specific Antibody-secreting Cells in the Nasal Mucosa by Intranasal Immunization of BALB/c Mice

Recent studies have demonstrated that antigen-specific IgA immune responses in nasal cavity are induced by intranasal immunization with several antigens. However, the precise mechanisms regulating such immune responses are unclear. In the present study, mice were immunized intranasally with horseradish peroxidase (HRP) plus cholera toxin into the right nostril, and HRP-specific IgA immune responses were investigated. After the immunization, an enzyme-linked immunospot assay showed an increased number of anti-HRP IgA cells in the nasal mucosa. Histochemical staining demonstrated the presence of anti-HRP antibody-secreting cells, mainly in the nasal subepithelial layer. Interestingly, these cells were induced predominantly on the right nostril, where intranasal immunization was performed. These findings suggest that antigen-specific IgA antibodies in the nasal secretions were produced locally from antibody-secreting cells in the nasal mucosa and that IgA immune responses in the nose were compartmentalized. Furthermore, lectin histochemistry showed an accumulation of peanut agglutinin-positive cells in the nasal-associated lymphoreticular tissue, suggesting the development of germinal centers in the immunized animals.