Effectiveness of intragastric immunization with protein and oligodeoxynucleotides containing a CpG motif for inducing a gastrointestinal mucosal immune response in mice.

Abstract

PURPOSE: To investigate a new modality of mucosal vaccines, we evaluated the effectiveness of intragastric immunization for inducing a mucosal immune response in the gastrointestinal tract. METHODS: Mice were immunized with beta-galactosidase (beta-gal) and synthesized oligodeoxynucleotides containing a CpG motif (CpG-DNA) by intragastric injection, and the immune response was compared with those induced by 3 other immunization forms: intranasal, oral, and intradermal. RESULTS: Intragastric immunization with beta-gal and CpG-DNA induced significant anti-beta-gal fecal IgA production at 2 weeks; however, at 4 weeks the response was lacking. In contrast, intranasal immunization with beta-gal and CpG-DNA induced the highest anti-beta-gal fecal IgA production at 4 weeks. CONCLUSION: Although intragastric immunization with protein and CpG-DNA induces a mucosal immune response in the gastrointestinal tract, intranasal immunization is the most effective to induce both mucosal and systemic immune responses. This finding may increase the possibility for developing vaccines against mucosal pathogens, especially Helicobacter pylori.