Mucosal vaccination and immune responses in the elderly

To develop a mucosal vaccine strategy for the elderly, we have compared mucosal and systemic immune responses between aged (12–14 months) and young adult (8–12 weeks) mice. Both aged and young mice were immunized weekly with three oral doses of 1 mg of ovalbumin (OVA) and 10 μg of cholera toxin as adjuvant. Although elevated levels of OVA-specific systemic IgG and mucosal IgA Ab responses were seen in young mice, aged mice showed impaired antigen-specific mucosal and systemic immune responses. These results suggest that mucosal immunity is down regulated in aged mice.