Nicotine-specific antibody titers and concentrations in monovalent vaccine groups and their individual dose-matched contributions when administered as a component of the bivalent vaccine (mean ± SD).

<p>Vaccines were administered i.p. in Freund’s adjuvant. Vertical axis indicates the hapten toward which the antibodies are directed. Note that the scales of vertical axes differ. When administered in this manner, combining immunogens impaired their immunogenicity compared to when they were administered alone. There were main effects of vaccine group on 3′-AmNic-rEPA specific titers (A) and concentrations (B), and on 6-CMUNic-KLH specific titers (A; p < 0.01 for each). Symbols show comparisons of monovalent v. bivalent vaccines at individual doses. * p < 0.05, ** p < 0.01, *** p < 0.001.