Experimental evolution of immunological specificity
Experimental evolution of immunological specificity
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DOI：
10.1073/pnas.1904828116
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发表时间：
2019-10-08
影响因子：
11.1
通讯作者：
Kurtz, Joachim
中科院分区：
文献类型：
--
作者：
Ferro, Kevin;Peuss, Robert;Kurtz, Joachim
记忆和特异性是适应性免疫系统的标志。与先前的观点相反，先天免疫系统也可以提供免疫记忆的形式，例如无脊椎动物的免疫启动和脊椎动物的训练免疫。免疫启动甚至可以是特异性的，但在细胞和分子功能上与脊椎动物的适应性免疫系统有显著差异。到目前为止，免疫启动的特异性水平是否以及如何在进化过程中适应自然选择还不清楚。我们测试的进化引发特异性的无脊椎动物模型，甲虫赤拟谷盗。使用控制进化实验，我们选择甲虫对细菌荧光假单胞菌，乳酸乳球菌，和4株昆虫病原体苏云金芽孢杆菌的特异性或非特异性免疫启动。在14代宿主选择后，在选择特异性的品系中引发的特异性并不普遍较高，而是取决于用于引发和攻击的细菌。昆虫病原体B。苏云金杆菌引发效应最强。进化群体之间的差异反映在转录组学反应中，揭示了免疫、代谢和转录修饰基因的参与。最后，我们证明了一组差异表达的免疫基因的诱导强度预测了感染后进化系的生存概率。我们的结论是，高特异性的免疫启动可以迅速发展为某些细菌，最有可能是由于免疫基因的调节变化。
Memory and specificity are hallmarks of the adaptive immune system. Contrary to prior belief, innate immune systems can also provide forms of immune memory, such as immune priming in invertebrates and trained immunity in vertebrates. Immune priming can even be specific but differs remarkably in cellular and molecular functionality from the well-studied adaptive immune system of vertebrates. To date, it is unknown whether and how the level of specificity in immune priming can adapt during evolution in response to natural selection. We tested the evolution of priming specificity in an invertebrate model, the beetle Tribolium castaneum. Using controlled evolution experiments, we selected beetles for either specific or unspecific immune priming toward the bacteria Pseudomonas fluorescens, Lactococcus lactis, and 4 strains of the entomopathogen Bacillus thuringiensis. After 14 generations of host selection, specificity of priming was not universally higher in the lines selected for specificity, but rather depended on the bacterium used for priming and challenge. The insect pathogen B. thuringiensis induced the strongest priming effect. Differences between the evolved populations were mirrored in the transcriptomic response, revealing involvement of immune, metabolic, and transcription-modifying genes. Finally, we demonstrate that the induction strength of a set of differentially expressed immune genes predicts the survival probability of the evolved lines upon infection. We conclude that high specificity of immune priming can evolve rapidly for certain bacteria, most likely due to changes in the regulation of immune genes.