Induction of antigen-specific IgA-forming cells in the middle ear mucosa.

Antigen-specific IgA-forming cells were induced in the middle ear mucosa by the use of soluble and particulate forms of dinitrophenylated ovalbumin. Hartley guinea pigs were locally immunized in the duodenum (group A) and trachea (group B) with the particulate form of dinitrophenylated ovalbumin one week after systemic priming with the soluble form. Otitis media was then induced with the intratympanic inoculation of the antigen. The control animals (group C) received only intratympanic inoculation after systemic priming. The mean titers of salivary IgA antibody of groups A and B were significantly greater than that of group C, and the mean value of serum IgG antibody titers of group C was significantly greater than those of groups A and B. The occurrences of otitis media in groups A and B were significantly suppressed, and histologic changes of the middle ear mucosa of groups A and B were slighter than those of group C. Antigen-specific IgA-forming cells were detected in the inflamed middle ear mucosa from group A and B animals, while these cells could not be found in group C animals. These results demonstrate the immunization strategy whereby the mucosal IgA immunity of the middle ear cavity can be effectively induced and enhanced to prevent otitis media.