Frequent and seasonally variable sublethal anthrax infections are accompanied by short-lived immunity in an endemic system
Frequent and seasonally variable sublethal anthrax infections are accompanied by short-lived immunity in an endemic system
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DOI：
10.1111/1365-2656.12207
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发表时间：
2014-09-01
影响因子：
4.8
通讯作者：
Getz, Wayne M.
中科院分区：
文献类型：
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作者：
Cizauskas, Carrie A.;Bellan, Steven E.;Getz, Wayne M.
1. 很少有研究从免疫学角度研究野生动物中宿主与病原体的相互作用，特别是在季节性和纵向动态的背景下。此外，虽然大多数生态免疫学研究采用血清学抗体测定，但终点滴度测定通常基于主观标准，需要更加客观。2．尽管炭疽是一种古老且新兴的人畜共患传染病，在世界范围内都有发现，但其自然生态仍不清楚。特别是，人们对野生食草动物宿主对炭疽杆菌的适应性免疫反应知之甚少。3．在纳米比亚埃托沙国家公园的天然炭疽系统中，我们在 2-3 年内收集了来自平原斑马 (Equus quagga) 的 154 个血清样本、来自跳羚 (Antidorcas marsupialis) 的 21 个血清样本和来自非洲象 (Loxodonta africana) 的 45 个血清样本，并在可能的情况下对个体进行了重新采样，以进行季节性和纵向比较。我们使用酶联免疫吸附测定法来测量抗炭疽抗体滴度，并开发了三种日益保守的模型来通过更严格、客观的测定来确定终点滴度。4． 52% 至 87% 的斑马、0-15% 的跳羚和 3-52% 的大象具有可测量的抗炭疽抗体滴度，具体取决于所使用的模型。虽然大象和跳羚发起抗炭疽适应性免疫反应的能力仍然模棱两可，但我们的结果表明，ENP 中的斑马通常能在亚致死性炭疽感染中存活下来，在雨季遇到大多数炭疽杆菌，并可以部分增强它们对炭疽杆菌的免疫力。5。因此，炭疽不仅是一种致命疾病，而且在一些易感宿主中经常作为亚致死感染发生。尽管我们发现对炭疽的适应性免疫力迅速减弱，但随后和频繁的亚致死性炭疽芽孢杆菌感染会导致抗炭疽免疫力的成熟。通过触发宿主免疫反应，这些常见的亚致死感染可能充当免疫调节剂，并通过间接免疫和共感染效应影响种群动态。 6．此外，通过我们的三个终点滴度模型，我们将更严格的测定引入血清学抗体测定中，即使是在将实验室免疫学方法适应野生系统所带来的经常限制性条件下。通过这些方法，与之前使用不太全面的滴度分析的研究相比，我们发现了更多对炭疽有免疫反应的斑马。
1. Few studies have examined host-pathogen interactions in wildlife from an immunological perspective, particularly in the context of seasonal and longitudinal dynamics. In addition, though most ecological immunology studies employ serological antibody assays, endpoint titre determination is usually based on subjective criteria and needs to be made more objective.2. Despite the fact that anthrax is an ancient and emerging zoonotic infectious disease found world-wide, its natural ecology is not well understood. In particular, little is known about the adaptive immune responses of wild herbivore hosts against Bacillus anthracis.3. Working in the natural anthrax system of Etosha National Park, Namibia, we collected 154 serum samples from plains zebra (Equus quagga), 21 from springbok (Antidorcas marsupialis) and 45 from African elephants (Loxodonta africana) over 2-3 years, resampling individuals when possible for seasonal and longitudinal comparisons. We used enzyme-linked immunosorbent assays to measure anti-anthrax antibody titres and developed three increasingly conservative models to determine endpoint titres with more rigourous, objective mensuration.4. Between 52 and 87% of zebra, 0-15% of springbok and 3-52% of elephants had measurable anti-anthrax antibody titres, depending on the model used. While the ability of elephants and springbok to mount anti-anthrax adaptive immune responses is still equivocal, our results indicate that zebra in ENP often survive sublethal anthrax infections, encounter most B. anthracis in the wet season and can partially booster their immunity to B. anthracis.5. Thus, rather than being solely a lethal disease, anthrax often occurs as a sublethal infection in some susceptible hosts. Though we found that adaptive immunity to anthrax wanes rapidly, subsequent and frequent sublethal B. anthracis infections cause maturation of antianthrax immunity. By triggering host immune responses, these common sublethal infections may act as immunomodulators and affect population dynamics through indirect immunological and co-infection effects.6. In addition, with our three endpoint titre models, we introduce more mensuration rigour into serological antibody assays, even under the often-restrictive conditions that come with adapting laboratory immunology methods to wild systems. With these methods, we identified significantly more zebras responding immunologically to anthrax than have previous studies using less comprehensive titre analyses.