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arXiv 2402.07252q-bio.PE
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适应型病原体与宿主免疫的生态-进化动力学

Eco-evolutionary dynamics of adapting pathogens and host immunity

Pierre Barrat-Charlaix, Richard A. Neher

AI总结:

本研究用Susceptible/Infected模型揭示,病原体逃逸变异株在动态宿主免疫压力下初始指数增长但迅速丧失优势,后续轨迹不可预测,解释了流感病毒抗原进化的适应性与高频变异株准中性动力学的矛盾。

摘要:

随着病原体在宿主群体中传播,免疫力逐渐建立,易感个体池随之耗竭。这产生了选择压力,许多人类RNA病毒(如流感病毒或SARS-CoV-2)通过快速抗原进化和频繁出现免疫逃逸变异株来应对。然而,宿主免疫系统会适应且旧的免疫反应会衰退,使得逃逸变异株仅在有限时间内享有增长优势。若变异株增长动力学与宿主免疫重塑在相近时间尺度上运作,病毒适应则由固定环境下快速进化模型无法捕捉的生态-进化相互作用决定。在此,我们使用Susceptible/Infected模型描述动态但免疫多样的宿主群体中进化病毒群体的相互作用。我们表明,取决于毒株交叉免疫、宿主群体异质性及免疫反应持久性,逃逸变异株初始呈指数增长,但在达到高频前失去增长优势。其后续动力学遵循由未来逃逸变异株决定的异常随机游走,导致变异株轨迹不可预测。该模型可解释抗原进化明显适应性特征与流感病毒高频变异株准中性动力学之间的表面矛盾。

英文摘要:

As pathogens spread in a population of hosts, immunity is built up and the pool of susceptible individuals is depleted. This generates selective pressure, to which many human RNA viruses, such as influenza virus or SARS-CoV-2, respond with rapid antigenic evolution and frequent emergence of immune evasive variants. However, the host's immune systems adapt and older immune responses wane, such that escape variants only enjoy a growth advantage for a limited time. If variant growth dynamics and reshaping of host-immunity operate on comparable time scales, viral adaptation is determined by eco-evolutionary interactions that are not captured by models of rapid evolution in a fixed environment. Here, we use a Susceptible/Infected model to describe the interaction between an evolving viral population in a dynamic but immunologically diverse host population. We show that depending on strain cross-immunity, heterogeneity of the host population, and durability of immune responses, escape variants initially grow exponentially, but lose their growth advantage before reaching high frequencies. Their subsequent dynamics follows an anomalous random walk determined by future escape variants and results in variant trajectories that are unpredictable. This model can explain the apparent contradiction between the clearly adaptive nature of antigenic evolution and the quasi-neutral dynamics of high frequency variants observed for influenza viruses.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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