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Venter E, van der Merwe CF, Buys AV, Huismans H, van Staden V. Comparative ultrastructural characterization of African horse sickness virus-infected mammalian and insect cells reveals a novel potential virus release mechanism from insect cells. J Gen Virol 2014; 95:642-651. [PMID: 24347494 DOI: 10.1099/vir.0.060400-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
African horse sickness virus (AHSV) is an arbovirus capable of successfully replicating in both its mammalian host and insect vector. Where mammalian cells show a severe cytopathic effect (CPE) following AHSV infection, insect cells display no CPE. These differences in cell death could be linked to the method of viral release, i.e. lytic or non-lytic, that predominates in a specific cell type. Active release of AHSV, or any related orbivirus, has, however, not yet been documented from insect cells. We applied an integrated microscopy approach to compare the nanomechanical and morphological response of mammalian and insect cells to AHSV infection. Atomic force microscopy revealed plasma membrane destabilization, integrity loss and structural deformation of the entire surface of infected mammalian cells. Infected insect cells, in contrast, showed no morphological differences from mock-infected cells other than an increased incidence of circular cavities present on the cell surface. Transmission electron microscopy imaging identified a novel large vesicle-like compartment within infected insect cells, not present in mammalian cells, containing viral proteins and virus particles. Extracellular clusters of aggregated virus particles were visualized adjacent to infected insect cells with intact plasma membranes. We propose that foreign material is accumulated within these vesicles and that their subsequent fusion with the cell membrane releases entrapped viruses, thereby facilitating a non-lytic virus release mechanism different from the budding previously observed in mammalian cells. This insect cell-specific defence mechanism contributes to the lack of cell damage observed in AHSV-infected insect cells.
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Affiliation(s)
- E. Venter
- Department of Genetics, University of Pretoria, Pretoria 0002, South Africa
| | - C. F. van der Merwe
- Laboratory for Microscopy and Microanalysis, University of Pretoria, South Africa
| | - A. V. Buys
- Laboratory for Microscopy and Microanalysis, University of Pretoria, South Africa
| | - H. Huismans
- Department of Genetics, University of Pretoria, Pretoria 0002, South Africa
| | - V. van Staden
- Department of Genetics, University of Pretoria, Pretoria 0002, South Africa
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Ito Y, Tanaka Y, Inaba Y, Omori T. Electron microscopy of Ibaraki virus. ARCHIV FUR DIE GESAMTE VIRUSFORSCHUNG 1973; 40:29-46. [PMID: 4120843 DOI: 10.1007/bf01242633] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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