Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
Vet Microbiol. 2010 May 19;142(3-4):242-53. doi: 10.1016/j.vetmic.2009.10.015. Epub 2009 Oct 28.
Equine herpesvirus 1 (EHV1) replicates in the respiratory tract of horses, after which infected leukocytes transport virus throughout the body, resulting in abortion or nervous system disorders. Two EHV1 strains circulate in the field: neurovirulent and non-neurovirulent. To investigate differences in replication in the upper respiratory tract (URT), an experimental inoculation study in ponies was performed with both strains. Two groups of six ponies, were inoculated intranasally with 10(6.5) TCID(50) of either strain. Clinical signs, nasal shedding and viremia were evaluated. At early time points post-inoculation (pi), one pony of each group was euthanized. Tissues were collected for titration and immunostainings. Number and size of EHV1-induced plaques were calculated, and individual EHV1-infected cells were quantified and characterized. Inoculation with either strain resulted in nasal shedding and replication in several tissues of the URT. Both strains replicated in a plaquewise manner in epithelium of the nasal mucosa, but replication in epithelium of the nasopharynx was largely limited to non-neurovirulent EHV1. Plaques were never able to cross the basement membrane, but individual infected cells were noticed in the connective tissue of all examined tissues for both strains. The total number of these cells however, was 3-7 times lower with non-neurovirulent EHV1 compared to neurovirulent EHV1. CD172a(+) cells and CD5(+) lymphocytes were important target cells for both strains. Interestingly, in lymph nodes, B-lymphocytes were also important target cells for EHV1, irrespective of the strain. Viremia was detected very early pi and infected cells were mainly CD172a(+) for both strains. In summary, these results are valuable for understanding EHV1 pathogenesis at the port of entry, the URT.
马疱疹病毒 1 型（EHV1）在上呼吸道的马体内复制，随后受感染的白细胞将病毒运送到全身，导致流产或神经系统紊乱。两种 EHV1 株在野外循环：神经毒力型和非神经毒力型。为了研究在上呼吸道（URT）中的复制差异，在小马中进行了两种毒株的实验性接种研究。两组六匹小马，分别用 10（6.5）TCID（50）的两种毒株经鼻腔接种。评估临床症状、鼻分泌物和病毒血症。在接种后的早期时间点（pi），每组一匹小马被安乐死。收集组织进行滴定和免疫染色。计算 EHV1 诱导的斑块数量和大小，并对单个 EHV1 感染的细胞进行定量和特征描述。用两种毒株接种均导致了 URT 中鼻分泌物和复制。两种毒株均以斑块样方式在鼻黏膜上皮中复制，但鼻咽上皮中的复制主要限于非神经毒力型 EHV1。斑块从未能够穿过基底膜，但在两种毒株的所有检查组织的结缔组织中均注意到了单个感染细胞。然而，与神经毒力型 EHV1 相比，非神经毒力型 EHV1 的这些细胞总数低 3-7 倍。CD172a（+）细胞和 CD5（+）淋巴细胞是两种毒株的重要靶细胞。有趣的是，在淋巴结中，B 淋巴细胞也是 EHV1 的重要靶细胞，与毒株无关。pi 时非常早期就检测到病毒血症，感染细胞主要为 CD172a（+），两种毒株均如此。总之，这些结果对于了解 EHV1 在入口处即上呼吸道的发病机制非常有价值。
