Roberts Katherine E, Hughes William O H
School of Biology, University of Leeds, Leeds LS2 9JT, UK.
School of Life Sciences, University of Sussex, Brighton BN1 9QG, UK.
J Invertebr Pathol. 2014 Sep;121:1-6. doi: 10.1016/j.jip.2014.06.004. Epub 2014 Jun 19.
Immunosenescence, the systemic reduction of immune efficiency with age, is increasingly recognised as having important implications for host-parasite dynamics. Changes in the immune response can impact on the ability of an individual to resist or moderate parasite infection, depending on how and when it encounters a parasite challenge. Using the European honey bee Apis mellifera and its microsporidian parasite Nosema ceranae, we investigated the effects of host age on the ability to resist parasite infection and on baseline immunocompetence, assessed by quantifying constitutive (PO) and potential levels (PPO) of the phenoloxidase immune enzyme as general measures of immune function. There was a significant correlation between the level of general immune function and infection intensity, but not with survival, and changes in immune function with age correlated with the ability of individuals to resist parasite infection. Older individuals had better survival when challenged with a parasite than younger individuals, however they also had more intense infections and lower baseline immunocomptence. The ability of older individuals to have high infection intensities yet live longer, has potential consequences for parasite transmission. The results highlight the need to consider age in host-parasite studies and show the importance of choosing the correct measure when assaying invertebrate immunity.
免疫衰老,即随着年龄增长免疫效率的系统性降低,越来越被认为对宿主 - 寄生虫动态关系具有重要影响。免疫反应的变化会影响个体抵抗或减轻寄生虫感染的能力,这取决于个体遭遇寄生虫挑战的方式和时间。我们以欧洲蜜蜂意大利蜜蜂及其微孢子虫寄生虫蜜蜂微孢子虫为研究对象,通过量化酚氧化酶免疫酶的组成水平(PO)和潜在水平(PPO)作为免疫功能的一般指标,来评估宿主年龄对抵抗寄生虫感染能力和基线免疫能力的影响。一般免疫功能水平与感染强度之间存在显著相关性,但与生存率无关,且免疫功能随年龄的变化与个体抵抗寄生虫感染的能力相关。与年轻个体相比,老年个体在受到寄生虫挑战时具有更高的生存率,然而,它们也有更严重的感染和更低的基线免疫能力。老年个体感染强度高但寿命更长的这种能力,对寄生虫传播具有潜在影响。研究结果强调了在宿主 - 寄生虫研究中考虑年龄的必要性,并表明在检测无脊椎动物免疫时选择正确指标的重要性。