Novel intranasal immunization techniques for antibody induction and protection of mice against gastric Helicobacter felis infection

Intranasal (i.n.) delivery of antigen can be highly effective for generating circulating and secretory antibody responses. Mice were immunized i.n. with two antigens, human IgA, and Helicobacter pylori urease in the presence or absence of mucosal adjuvant. To restrict antigen delivery to the upper airways, protein solutions were administered in a small volume without anesthesia. Repeated daily i.n. administration of antigen without adjuvant elicited high levels of specific IgG in serum and IgA in serum, saliva, and feces. Once weekly i.n. immunization with co-administration of cholera toxin or Escherichia coli heat-labile toxin as adjuvant elicited somewhat lower levels of antibody to urease. When challenged with Helicobacter felis, only mice immunized with urease in the presence of adjuvant were protected against gastric infection.