Rabies is a lethal viral infection that can affect almost all mammals, including humans. To better understand the replication of Rabies lyssavirus, we investigated if the viral load in brains naturally infected with rabies influences viral internalization and viral growth kinetics in neuroblastoma cells, and if the viral load affects mortality in mice after intradermal infection. We noted that high initial viral loads in brains (group II) were unfavourable for increasing viral titers during serial passages in neuroblastoma cells when compared to low initial viral loads in brains (group I). In addition, group I strains showed higher viral growth and enhanced internalization efficiency in neuroblastoma cells than group II strains. However, we observed that the dominant virus subpopulation in group II promoted efficient viral infection in the central nervous system in the new host, providing a selective advantage to the virus. Our data indicate that rabies infection in animal models depends on not only the virus strain but also the amount of virus. This study may serve as a basis for understanding the biologic proprieties of Rabies lyssavirus strains with respect to the effects on viral replication and the impact on pathogenesis, improving virus yields for use in vaccine development.

狂犬病是一种致命的病毒感染，可以影响几乎所有的哺乳动物，包括人类。为了更好地了解狂犬病狂犬病毒的复制，我们调查了自然感染狂犬病的大脑中的病毒载量是否会影响神经母细胞瘤细胞中的病毒内在化和病毒生长动力学，以及病毒载量是否会影响皮内感染后小鼠的死亡率。我们注意到，与低初始病毒载量（第一组）相比，高初始病毒载量（第二组）不利于神经母细胞瘤细胞连续传代期间病毒滴度的增加。此外，与II组相比，I组菌株在神经母细胞瘤细胞中显示出更高的病毒生长和更高的内在化效率。但是，我们观察到第二组中的主要病毒亚群在新宿主的中枢神经系统中促进了有效的病毒感染，为病毒提供了选择性优势。我们的数据表明，动物模型中的狂犬病感染不仅取决于病毒株，还取决于病毒的数量。这项研究可作为了解其生物学特性的基础。关于狂犬病狂犬病病毒株对病毒复制的影响和对发病机理的影响，提高了用于疫苗开发的病毒产量。