Baker Institute for Animal Health, Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Hungerford Hill Road, Ithaca, NY 14853, USA.
J Virol. 2010 May;84(10):5329-35. doi: 10.1128/JVI.02469-09. Epub 2010 Mar 10.
The patterns and dynamics of evolution in acutely infecting viruses within individual hosts are largely unknown. To this end, we investigated the intrahost variation of canine influenza virus (CIV) during the course of experimental infections in naïve and partially immune dogs and in naturally infected dogs. Tracing sequence diversity in the gene encoding domain 1 of the hemagglutinin (HA1) protein over the time course of infection provided information on the patterns and processes of intrahost viral evolution and revealed some of the effects of partial host immunity. Viral populations sampled on any given day were generally characterized by mean pairwise genetic diversities between 0.1 and 0.2% and by mutational spectra that changed considerably on different days. Some observed mutations may have affected antigenicity or host range, including reversions of CIV host-associated mutations. Patterns of sequence diversity differed between naïve and vaccinated dogs, with some presumably antigenic mutations transiently reaching high frequency in the latter. CIV populations are therefore characterized by the rapid generation and clearance of genetic diversity. Potentially advantageous mutations arise readily during the course of single infections and may give rise to antigenic escape or host range variants.
在个体宿主内急性感染病毒的进化模式和动态在很大程度上是未知的。为此，我们研究了在未感染和部分免疫的犬以及自然感染的犬中，犬流感病毒（CIV）在实验感染过程中的宿主内变异。通过追踪感染过程中血凝素（HA1）蛋白编码结构域 1 的基因序列多样性，提供了有关宿主内病毒进化模式和过程的信息，并揭示了部分宿主免疫的一些影响。在任何给定的一天采样的病毒群体通常具有 0.1%至 0.2%的平均成对遗传多样性特征，并且突变谱在不同的日子变化很大。一些观察到的突变可能影响了抗原性或宿主范围，包括 CIV 与宿主相关的突变的回复。未感染和接种疫苗的犬之间的序列多样性模式不同，后者中的一些假定的抗原性突变暂时达到高频率。因此，CIV 群体的特点是快速产生和清除遗传多样性。在单次感染过程中，有利的突变很容易产生，可能导致抗原逃逸或宿主范围变体。
