State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
Beijing Institutes of Life Science, Chinese Academy of Sciences, Beijing 100101, China.
Proc Natl Acad Sci U S A. 2022 Feb 8;119(6). doi: 10.1073/pnas.2120835119.
Changes in population density lead to phenotypic differentiation of solitary and gregarious locusts, which display different resistance to fungal pathogens; however, how to regulate their cellular immune strategies remains unknown. Here, our stochastic simulation of pathogen proliferation suggested that humoral defense always enhanced resistance to fungal pathogens, while phagocytosis sometimes reduced defense against pathogens. Further experimental data proved that gregarious locusts had significantly decreased phagocytosis of hemocytes compared to solitary locusts. Additionally, transcriptional analysis showed that gregarious locusts promoted immune effector expression ( and ) and reduced phagocytic gene expression () and the cytokine tumor necrosis factor (TNF). Interestingly, higher expression of the cytokine TNF in solitary locusts simultaneously promoted expression and inhibited and expression. Moreover, inhibition of TNF increased the survival of solitary locusts, and injection of TNF decreased the survival of gregarious locusts after fungal infection. Therefore, our results indicate that the alerted expression of TNF regulated the immune strategy of locusts to adapt to environmental changes.
种群密度的变化导致独居和群居蝗虫表型分化，表现出对真菌病原体不同的抗性；然而，它们如何调节细胞免疫策略尚不清楚。在这里，我们对病原体增殖的随机模拟表明，体液防御总是增强对真菌病原体的抗性，而吞噬作用有时会降低对病原体的防御。进一步的实验数据证明，群居蝗虫的血细胞吞噬作用明显低于独居蝗虫。此外，转录分析表明，群居蝗虫促进了免疫效应因子的表达（和），并降低了吞噬基因的表达（）和细胞因子肿瘤坏死因子（TNF）。有趣的是，独居蝗虫中细胞因子 TNF 的高表达同时促进了表达，并抑制了和的表达。此外，抑制 TNF 增加了独居蝗虫的存活率，而 TNF 的注射降低了真菌感染后群居蝗虫的存活率。因此，我们的结果表明，TNF 的警报表达调节了蝗虫的免疫策略，以适应环境变化。
