Increased efficacy of a trivalent nicotine vaccine compared to a dose-matched monovalent vaccine when formulated with alum

Abstract

Vaccination against nicotine is a potential treatment for tobacco smoking. Clinical trials show effect only in high antibody responders; therefore it is necessary to increase the effectiveness of nicotine vaccines. The use of a multivalent vaccine that activates several B cell populations is a possible approach to increase antibody response. The aim of this study was to investigate whether three different nicotine immunogens could be mixed to generate independent responses resulting in additive antibody titers, and whether this would alter nicotine distribution to a greater extent than antibodies generated by a monovalent vaccine. When immunogens were administered s.c. with alum adjuvant, the trivalent vaccine generated significantly higher titers and prevented the distribution of an i.v. nicotine dose to brain to a greater extent than an equivalent dose of a monovalent vaccine. The number of rats with antibody titers >1:10,000 was significantly increased in the trivalent group compared to the monovalent group. There were no correlations between the titers generated by the different nicotine immunogens in the trivalent vaccine, supporting the hypothesis that the immunogens generated independent responses from distinct populations of B cells. In contrast, when administered i.p. in Freund’s adjuvant, the trivalent nicotine vaccine was not more immunogenic than its component monovalent vaccine. Vaccine immunogenicity was suppressed if unconjugated protein was added to the monovalent vaccine formulated in Freund’s adjuvant, compared to monovalent vaccine alone. These data suggest a protein–protein interaction that affects titers negatively and is apparent when the vaccines are formulated with Freund’s adjuvant. In summary, a trivalent nicotine vaccine formulated with alum showed significantly higher efficacy than a dose-matched monovalent vaccine and may offer a strategy for increasing nicotine vaccine immunogenicity. This approach may be generalizable to other nicotine immunogens or vaccines for other addictive drugs.

New Directions in Nicotine Vaccine Design and Use

“…14.3A). The effects of bi- or trivalent nicotine vaccines on nicotine distribution in rats mirror the titers and are also additive (de Villiers, Cornish, Troska, Pravetoni, Pentel, 2013). An additional benefit seen in this study is that some animals with a low response to one immunogen had a high response to another, reducing the number of low or nonresponders.…”

“…(A) Trivalent nicotine vaccine (de Villiers et al, 2013). Rats were vaccinated with three structurally distinct nicotine immunogens (linkers attached at different positions, carrier proteins; rEPA, recombinant exoprotein A; KLH, keyhole limpet hemocyanin; malKLH, maleimide activated KLH) or a dose-matched monovalent immunogen s.c. with alum adjuvant.…”

Scientific overview: 2013 BBC plenary symposium on tobacco addiction

“…In rats, combining 3 nicotine immunogens based on haptens with linkers at the 1′ or 3′ position of the pyrrolidine ring, or 6 position of the pyridine ring, produced additive antibody titers and greater ability to prevent nicotine distribution to brain than a monovalent vaccine (de Villiers et al, 2013). In addition, some rats with poor responses to one immunogen had brisk responses to one of the others.…”

New Pharmacological Agents to Aid Smoking Cessation and Tobacco Harm Reduction: What Has Been Investigated, and What Is in the Pipeline?

“…To increase efficacy, support has been given to the use of multivalent vaccines, i.e. combination of multiple vaccine products and concurrent use with other smoking cessation pharmacotherapy [152]. Animal studies have shown a strong synergistic effect of a nicotine vaccine in combination with the nAChR antagonist mecamylamine [153].…”