Pfizer Vaccine Research, Ottawa, ON, Canada.
Int Immunopharmacol. 2013 May;16(1):50-6. doi: 10.1016/j.intimp.2013.03.021. Epub 2013 Apr 2.
Tobacco smoking is one of the most preventable causes of morbidity and mortality, but current smoking cessation treatments have relatively poor long term efficacy. Anti-nicotine vaccines offer a novel mechanism of action whereby anti-nicotine antibodies (Ab) in circulation prevent nicotine from entering the brain, thus avoiding the reward mechanisms that underpin nicotine addiction. Since antibody responses are typically long lasting, such vaccines could potentially lead to better long-term smoking cessation outcomes. Clinical trials of anti-nicotine vaccines to date have not succeeded, although there was evidence that very high anti-nicotine Ab titers could lead to improved smoking cessation outcomes, suggesting that achieving higher titers in more subjects might result in better efficacy overall. In this study, we evaluated CpG (TLR9 agonist) and aluminum hydroxide (Al(OH)3) adjuvants with a model anti-nicotine antigen comprising trans-3'aminomethylnicotine (3'AmNic) conjugated to diphtheria toxoid (DT). Anti-nicotine Ab titers were significantly higher in both mice and non-human primates (NHP) when 3'AmNic-DT was administered with CpG/Al(OH)3 than with Al(OH)3 alone, and affinity was enhanced in mice. CpG also improved functional responses, as measured by nicotine brain levels in mice after intravenous administration of radiolabeled nicotine (30% versus 3% without CpG), or by nicotine binding capacity of NHP antisera (15-fold higher with CpG). Further improvement should focus on maximizing Ab function, which takes into account both titer and avidity, and this may require improved conjugate design in addition to adjuvants.
吸烟是导致发病率和死亡率的最可预防原因之一,但目前的戒烟治疗方法长期效果相对较差。抗尼古丁疫苗提供了一种新的作用机制,即循环中的抗尼古丁抗体 (Ab) 阻止尼古丁进入大脑,从而避免了支撑尼古丁成瘾的奖励机制。由于抗体反应通常是持久的,因此这种疫苗可能会导致更好的长期戒烟效果。迄今为止,抗尼古丁疫苗的临床试验并未成功,尽管有证据表明非常高的抗尼古丁 Ab 滴度可能导致戒烟效果改善,这表明在更多受试者中达到更高的滴度可能会导致整体效果更好。在这项研究中,我们评估了 CpG(TLR9 激动剂)和氢氧化铝(Al(OH)3)佐剂与包含反式-3'氨基甲基尼古丁(3'AmNic)与白喉类毒素(DT)偶联的模型抗尼古丁抗原的组合。当 3'AmNic-DT 与 CpG/Al(OH)3 一起给药时,无论是在小鼠还是非人类灵长类动物(NHP)中,抗尼古丁 Ab 滴度均显著高于单独使用 Al(OH)3,并且在小鼠中亲和力增强。CpG 还改善了功能反应,如通过静脉内给予放射性标记的尼古丁后小鼠的尼古丁脑水平(用 CpG 为 30%,不用 CpG 为 3%)或 NHP 抗血清的尼古丁结合能力(用 CpG 为 15 倍)来衡量。进一步的改进应侧重于最大限度地提高 Ab 功能,这既要考虑滴度又要考虑亲和力,除了佐剂外,这可能还需要改进缀合物设计。