School of Biological Sciences, University of Bristol, Bristol, United Kingdom.
Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, United Kingdom.
PLoS Biol. 2018 Apr 13;16(4):e2003538. doi: 10.1371/journal.pbio.2003538. eCollection 2018 Apr.
The immune state of wild animals is largely unknown. Knowing this and what affects it is important in understanding how infection and disease affects wild animals. The immune state of wild animals is also important in understanding the biology of their pathogens, which is directly relevant to explaining pathogen spillover among species, including to humans. The paucity of knowledge about wild animals' immune state is in stark contrast to our exquisitely detailed understanding of the immunobiology of laboratory animals. Making an immune response is costly, and many factors (such as age, sex, infection status, and body condition) have individually been shown to constrain or promote immune responses. But, whether or not these factors affect immune responses and immune state in wild animals, their relative importance, and how they interact (or do not) are unknown. Here, we have investigated the immune ecology of wild house mice-the same species as the laboratory mouse-as an example of a wild mammal, characterising their adaptive humoral, adaptive cellular, and innate immune state. Firstly, we show how immune variation is structured among mouse populations, finding that there can be extensive immune discordance among neighbouring populations. Secondly, we identify the principal factors that underlie the immunological differences among mice, showing that body condition promotes and age constrains individuals' immune state, while factors such as microparasite infection and season are comparatively unimportant. By applying a multifactorial analysis to an immune system-wide analysis, our results bring a new and unified understanding of the immunobiology of a wild mammal.
野生动物的免疫状态在很大程度上是未知的。了解这一点以及什么因素会影响它，对于理解感染和疾病如何影响野生动物是很重要的。野生动物的免疫状态对于了解其病原体的生物学也很重要，这与解释物种间（包括人类）病原体的溢出直接相关。与我们对实验室动物的免疫生物学的精细了解相比，野生动物的免疫状态知识非常匮乏。产生免疫反应是有代价的，许多因素（如年龄、性别、感染状况和身体状况）已经单独表明会限制或促进免疫反应。但是，这些因素是否影响野生动物的免疫反应和免疫状态、它们的相对重要性以及它们如何相互作用（或不相互作用）尚不清楚。在这里，我们以野生家鼠为例，研究了野生哺乳动物的免疫生态学，以确定其适应性体液、适应性细胞和先天免疫状态。首先，我们展示了免疫变异在鼠群中的结构如何，发现相邻种群之间可能存在广泛的免疫不一致性。其次，我们确定了导致小鼠之间免疫差异的主要因素，表明身体状况促进和年龄限制个体的免疫状态，而微寄生虫感染和季节等因素则相对不重要。通过对免疫系统进行多因素分析，我们的结果为理解一种野生哺乳动物的免疫生物学带来了新的统一认识。
