Mechanisms of Humoral Immune Protection Induced by Anthrax Vaccine Adsorbed

项目摘要 为了减轻生物恐怖主义造成的炭疽感染的持续威胁，现役军人接种了疫苗 吸附炭疽疫苗(AVA)。然而，一些AVA接受者可能仍未受到保护 炭疽病感染和更好地理解导致疫苗反应受损和迅速的机制 需要逐渐减弱的豁免权。在现实世界中最大的AVA疫苗接种者队列(2900人)中，不到 50%的AVA疫苗接种者在体外显示出显著的致死毒素中和作用，抗体水平和 接种疫苗后，中和能力迅速减弱。因此，这个项目的目标是确定 AVA疫苗接种后中和不良的机制。AVA的主要抗原是保护性抗原 (帕)。我们之前的研究已经确定了血清抗PA识别的共同序列表位，并且 已经显示出中和和非中和反应的不同表位结合。中和性差 应答也与抗PA亲和力受损和IgG4产生增加有关。在……里面 此外，非洲裔美国人与欧洲裔美国人的疫苗接种者相比，次优AVA反应更为常见。 初步数据表明，非裔美国人对非中和的反应更丰富。 AVA疫苗接种后的表位在免疫细胞亚群和免疫途径上有显著差异 与欧洲裔美国人相比。关键问题仍然存在，以了解的机制 成人疫苗接种反应迅速减弱或受损，如针对AVA的反应。本项目致力于 比较高、低水平抗PA抗体探讨AVA免疫后免疫保护受损的机制 上述AVA队列中的中和者以及新招募的领域特异性、抗PA亲和力、 和抗PA IgG4反应，所有这些反应都可能抑制保护性人类炭疽杆菌免疫(目标1)。 其他保护性反应的机制将通过中和PA特异性的人来剖析 先前由我们实验室产生的单抗。此外，尽管抗PA结构域的特异性是 与中和能力有关，与中和剂血清结合的PA构象表位没有 已被阐明。因此，本项目采用了新颖的氢-氚交换质谱学技术。 Niques使用来自高中和剂和低中和剂的血清在PA上绘制抗PA结合位点图(目标2)。最后，机甲- 将评估非洲裔美国人与欧洲裔美国人接种疫苗后AVA反应受损的失调症。 (目标3)。抗体、免疫细胞图谱和调节途径将通过质量细胞术进行比较。 AVA疫苗接种后不同时间的细胞周期、细胞内细胞因子产生、流式细胞仪和ELISpot检测。 将测试抗原表位特异性和对受损的抗PA反应的遗传易感性。这些研究将 提供新的见解，以优化未来的炭疽疫苗和其他跨种族成人疫苗接种。

Project Summary To mitigate the ongoing threat of anthrax infection due to bioterrorism, active military members are vaccinated with Anthrax Vaccine Adsorbed (AVA). However, some AVA recipients may remain unprotected against anthrax infection and a better understanding of mechanisms leading to impaired vaccine response and rapidly waning immunity are needed. In the largest real-world cohort of AVA vaccinees (>2,900 individuals), less than 50% of AVA vaccinees showed significant in vitro lethal toxin neutralization, and both antibody levels and neutralization capacity waned quickly after vaccination. Therefore, the goal of this project is to identify mechanisms of poor neutralization after AVA vaccination. The primary antigen in AVA is protective antigen (PA). Our previous studies have identified common sequential epitopes recognized by serum anti-PA, and have shown differential epitope binding of neutralizing vs. non-neutralizing responses. Poorly neutralizing responses have also been associated with impaired avidity of anti-PA and enhanced IgG4 production. In addition, suboptimal AVA responses are more common in African American vs. European American vaccinees. Preliminary data suggest that African American individuals have enriched responses against non-neutralizing epitopes after AVA vaccination and have marked differences in immune cell subsets and immune pathways compared to European American individuals. Critical questions remain in understanding the mechanisms of rapidly waning or impaired adult vaccination responses, such as those against AVA. This project addresses mechanisms of impaired protection after AVA immunization by comparing anti-PA antibodies from high and low neutralizers in the AVA cohort described above as well as new recruits for domain specificity, anti-PA avidity, and anti-PA IgG4 responses, all of which may inhibit protective human Bacillus anthracis immunity (Aim 1). Additional mechanisms of protective responses will be dissected using neutralizing PA-specific human monoclonal antibodies previously generated by our lab. In addition, although anti-PA domain specificity is related to neutralizing capacity, the conformational epitopes of PA bound by the serum of neutralizers have not been elucidated. Therefore, this project uses novel hydrogen-deuterium exchange mass spectrometry tech- niques to map anti-PA binding sites on PA using sera from high and low neutralizers (Aim 2). Finally, mech- anisms of impaired AVA responses will be evaluated in African American vs. European American vaccinees (Aim 3). Antibodies, immune cell profiles, and regulatory pathways will be compared by mass cytometry (CyTOF), intracellular cytokine production, flow cytometry and ELISpot at various times after AVA vaccination. Epitope specificity and genetic predisposition to impaired anti-PA responses will be tested. These studies will provide new insights to optimize future anthrax vaccines and other adult vaccinations across racial groups.