First complete and productive cell culture model for members of the genus Iridovirus

Abstract

Chilo iridescent virus (CIV; the type strain of the genus Iridovirus) replicates productively in larvae of the boll weevil, Anthonomus grandis. This study focuses on characterizing productive infections of a boll weevil cell line, BRL-AG-3A (AG3A), starting with CIV reared in the waxworm, Galleria mellonella. We show that CIV can be continually and productively passaged to high titer in AG3A cells. The replication of larval-derived CIV in AG3A was analyzed by observing viral DNA replication and restriction endonuclease digestion profiles, morphogenesis, and infectivity using TCID(50) assays with AG3A as an indicator cell line. The data showed that virus passaged in the AG3A host is stable. AG3A cells are more efficient than previously utilized CF-124T cells from Choristoneura fumiferana. This system constitutes a superior model for cellular and molecular studies on CIV; it represents the first complete, productive cell culture model for the replication of CIV or any member of the genus Iridovirus.

Invertebrate Iridescent Virus 6, a DNA Virus, Stimulates a Mammalian Innate Immune Response through RIG-I-Like Receptors

“…The presence of viral factories in the cytoplasm of infected cells is a classical indication of productive Iridovirus infection [62]. After demonstrating activation of the immune response by IIV-6 infection, we performed transmission electron microscopy (TEM) to investigate the presence of viral particles inside mammalian cells.…”

“…We observed IIV-6 particles in a low percentage of MEFs at 72 hours post-infection, indicating viral entry (Fig 4, bottom row). The IIV-6 particles in S2 cells were organized in typical viral factories showing the expected pattern of Iridovirus morphogenesis including complete, developing, and empty particles [62] (Fig 4 top row). IIV-6 particles in infected MEFs did not arrange into factory structures (Fig 4, bottom row).…”