Department of Health Sciences, Wilfrid Laurier University, Waterloo, ON N2L 3C5, Canada.
Department of Biology, Wilfrid Laurier University, Waterloo, ON N2L 3C5, Canada.
Viruses. 2019 Jan 23;11(2):93. doi: 10.3390/v11020093.
Frog virus 3 (FV3) is the type species of the genus (family Iridoviridae). FV3 and FV3-like viruses are globally distributed infectious agents with the capacity to replicate in three vertebrate classes (teleosts, amphibians, and reptiles). At the cellular level, FV3 and FV3-like viruses can infect cells from virtually all vertebrate classes. To date, the cellular receptors that are involved in the FV3 entry process are unknown. Class A scavenger receptors (SR-As) are a family of evolutionarily conserved cell-surface receptors that bind a wide range of chemically distinct polyanionic ligands and can function as cellular receptors for other DNA viruses, including vaccinia virus and herpes simplex virus. The present study aimed to determine whether SR-As are involved in FV3 cellular entry. By using well-defined SR-A competitive and non-competitive ligand-blocking assays and absolute qPCR, we demonstrated that the SR-A competitive ligands drastically reduced the quantities of cell-associated viral loads in frog cells. Moreover, inducing the expression of a human SR-AI in an SR-A null cell line significantly increased FV3⁻cell association. Together, our results indicate that SR-As are utilized by FV3 during the cellular entry process.
蛙病毒 3（FV3）是虹彩病毒科虹彩病毒属的模式种。FV3 和 FV3 样病毒是在全球范围内分布的传染性病原体，能够在三个脊椎动物类群（硬骨鱼、两栖动物和爬行动物）中复制。在细胞水平上，FV3 和 FV3 样病毒可以感染来自几乎所有脊椎动物类群的细胞。迄今为止，参与 FV3 进入过程的细胞受体尚不清楚。A 类清道夫受体（SR-As）是一组进化上保守的细胞表面受体，可结合广泛的化学性质不同的多阴离子配体，并且可以作为其他 DNA 病毒（包括牛痘病毒和单纯疱疹病毒）的细胞受体。本研究旨在确定 SR-As 是否参与 FV3 细胞进入。通过使用明确的 SR-A 竞争性和非竞争性配体阻断测定和绝对 qPCR，我们证明了 SR-A 竞争性配体大大降低了蛙细胞中与细胞相关的病毒载量。此外，在 SR-A 缺失细胞系中诱导人 SR-AI 的表达显著增加了 FV3-细胞结合。总之，我们的结果表明，SR-As 在 FV3 的细胞进入过程中被利用。
