Intranasal immunization of humans with Streptococcus mutans antigens

To evaluate the effectiveness of a low dose of soluble or liposomal (L) glucosyltransferase-enriched preparation (E-GTF) in inducing mucosal immune responses after intranasal immunization, 12 adults were immunized on days 0 and 7 by the IN route with 62.5 mug of soluble E-GTF or L-E-GTF. An increase in the mean salivary IgA anti-E-GTF response (P < 0.03) was seen in the L-E-GTF but not the soluble E-GTF group. A significant increase (P < 0.05) in the mean specific IgA antibody activity was also seen in nasal wash from both groups. Although the nasal wash responses were higher in the L-E-GTF than in the soluble E-GTF group, they were not significantly different. The soluble E-GTF immunized group showed a higher serum IgG response than the L-E-GTF immunized group on day 90 (P < 0.05). These results indicate that as little as 62.5 μg of E-GTF, when given by the intranasal route, induced an IgA response in secretions.