Comparative ultrastructural characterization of African horse sickness virus-infected mammalian and insect cells reveals a novel potential virus release mechanism from insect cells
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Date
Authors
Venter, Eduard
Van der Merwe, Christiaan F.
Buys, A.V. (Antonia Vergina)
Huismans, H. (Henk), 1942-
Van Staden, Vida
Journal Title
Journal ISSN
Volume Title
Publisher
Society for General Microbiology
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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Keywords
Comparative ultrastructural characterization, Virus-infected, Insect cells, Reveals, Potential virus, African horse sickness virus (AHSV)
Sustainable Development Goals
Citation
Venter, E, Van der Merwe, CF, Buys, AV, Huismans, H & Van Staden, V 2014, 'Comparative ultrastructural characterization of African horse sickness virus-infected mammalian and insect cells reveals a novel potential virus release mechanism from insect cells', Journal of General Virology, vol. 95, no. 3, pp. 642-651.