Hill Sarah C, Manvell Ruth J, Schulenburg Bodo, Shell Wendy, Wikramaratna Paul S, Perrins Christopher, Sheldon Ben C, Brown Ian H, Pybus Oliver G
Department of Zoology, University of Oxford, Oxford OX1 3PS, UK.
Department of Virology, Animal and Plant Health Agency (APHA), Weybridge KT15 3NB, UK.
Proc Biol Sci. 2016 Dec 28;283(1845). doi: 10.1098/rspb.2016.2159.
For viruses such as avian influenza, immunity within a host population can drive the emergence of new strains by selecting for viruses with novel antigens that avoid immune recognition. The accumulation of acquired immunity with age is hypothesized to affect how influenza viruses emerge and spread in species of different lifespans. Despite its importance for understanding the behaviour of avian influenza viruses, little is known about age-related accumulation of immunity in the virus's primary reservoir, wild birds. To address this, we studied the age structure of immune responses to avian influenza virus in a wild swan population (Cygnus olor), before and after the population experienced an outbreak of highly pathogenic H5N1 avian influenza in 2008. We performed haemagglutination inhibition assays on sampled sera for five avian influenza strains and show that breadth of response accumulates with age. The observed age-related distribution of antibody responses to avian influenza strains may explain the age-dependent mortality observed during the highly pathogenic H5N1 outbreak. Age structures and species lifespan are probably important determinants of viral epidemiology and virulence in birds.
对于禽流感等病毒而言，宿主群体内的免疫力可通过选择具有新型抗原、能避免免疫识别的病毒，推动新毒株的出现。据推测，随着年龄增长获得性免疫力的积累会影响流感病毒在不同寿命物种中的出现和传播方式。尽管了解禽流感病毒的行为非常重要，但对于该病毒的主要宿主——野生鸟类中与年龄相关的免疫力积累情况，我们却知之甚少。为解决这一问题，我们研究了一个野生天鹅种群（大天鹅）在2008年经历高致病性H5N1禽流感疫情前后，针对禽流感病毒免疫反应的年龄结构。我们对采集的血清进行了针对五种禽流感毒株的血凝抑制试验，结果表明反应广度随年龄增长而积累。观察到的针对禽流感毒株的抗体反应与年龄相关的分布情况，可能解释了在高致病性H5N1疫情期间观察到的年龄依赖性死亡率。年龄结构和物种寿命可能是鸟类病毒流行病学和毒力的重要决定因素。
