Evaluating the immunogenicity of an intranasal vaccine against nicotine in mice using the Adjuvant Finlay Proteoliposome (AFPL1)

Abstract

Tobacco smoking is recognized as a global pandemic resulting in 6 million deaths per year. Despite a variety of anti-smoking products available to aid with tobacco cessation, the majority of people who attempt to quit smoking relapse within 6 months due to the addictive nature of nicotine. An immunotherapy approach could offer a promising treatment option by inducing a potent selective antibody response against nicotine in order to block its distribution to the brain and its addictive effects in the central nervous system. Our nicotine vaccine candidate was administered intranasally using the Neisseria meningitidis serogroup B Adjuvant Finlay Proteoliposome 1 (AFPL1) as a part of the delivery system. This system was designed to generate a robust immune response by stimulating IL-1β production through Toll-like receptor 4 (TLR4), a potent mechanism for mucosal immunity. The vaccine induced high antibody titers in mice sera in addition to inducing mucosal antibodies. The efficacy of our vaccine was demonstrated using in vivo challenge experiments with radioactive [3H]-nicotine, followed by an analysis of nicotine distribution in the lung, liver, blood and brain. Our results were encouraging as the nicotine concentration in the brain tissue of mice vaccinated with our candidate vaccine was four times lower than in non-vaccinated controls; suggesting that the anti-nicotine antibodies were able to block nicotine from crossing the blood brain barrier. In summary, we have developed a novel nicotine vaccine for the treatment of tobacco addiction by intranasal administration and also demonstrated that the AFPL1 can be used as a potential adjuvant for this vaccine design.

Repeat-Dose Toxicity Study Using the AFPL1-Conjugate Nicotine Vaccine in Male Sprague Dawley Rats

“…The World Health Organization estimates that up to half of all lifetime smokers of tobacco will die as a result of smoking; therefore, developing a novel and effective anti-nicotine vaccine is crucial. We previously published the AFPL1-conjugate nicotine vaccine, demonstrating that it is able to bind to nicotine and prevent it from entering the brain in a mouse model [4]. To the best of our knowledge, we were the first group to report a nicotine vaccine that induced both mucosal (IgA, IgG) and systemic anti-nicotine antibodies [5] with no preliminary signs of toxicity.…”

“…Previous investigations of the mouse model for the AFPL1-conjugate nicotine vaccine have demonstrated that the vaccine induces anti-nicotine antibodies [4,5]. However, these models use inbred mice, which represents a limitation for assessing heterogeneic responses that would be expected during preclinical trials.…”

“…Anti-nicotine IgG antibodies in sera samples were measured by an indirect ELISA using MaxiSorp (Nunc) microtiter plates as previously described [4]. Briefly, biotinylated goat anti-rat IgG was used as secondary antibody to detect the nicotine-specific systemic antibodies in the sera obtained over the course of the vaccination protocol.…”

“…We have been developing a conjugate-nicotine vaccine that combines the hapten with the adjuvant Finlay proteoliposome (AFPL1) nanoparticle adjuvant [4]. Using a heterologous vaccination strategy, where the initial priming event consisted of an intramuscular (IM) and an intranasal (IN) vaccination with two subsequent IN boosts, the vaccine formulation was able to significantly induce anti-nicotine antibodies in both the lung and in the sera of mice, resulting in two levels of protection [5].…”

“…Importantly, we continued to utilize the heterologous vaccination strategy to assess the safety of the vaccine with this alternative administration route. While doses are usually only doubled when moving from mice to rats [12], we increased the dose of the vaccine to be 5 times greater than what was administered to BALB/c mice in previous studies [4,5]. In addition, we also increased the number of boost events from two to three.…”