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Mouse Elberfeld (ME) virus determines the cell surface alterations when mixedly infecting poliovirus-infected cells
Abstract:
The surface alterations of HEp-2 cells induced by mixed infection with two different picornaviruses (poliovirus and ME virus) were compared by scanning electron microscopic and transmission electron microscopic studies and by 51Cr-release assay. The contribution of each of the viruses to the resulting surface changes was discernible, as investigations on the chronology of the cytopathic alterations demonstrated that the changes were distinct for either virus. The surface of ME virus-infected cells was characterized by large membranous structures ('sheets' and blebs) representing huge vacuoles. These sheets were not seen in poliovirus-infected cells. Poliovirus induced more prominent cell pycnosis, elongation of filopodia and condensation of collapsed microvilli on the cell surface than ME virus. Mixed infection with these two viruses led to surface alterations typical for ME virus. These ME virus-specific changes occurred irrespective of poliovirus reproduction or its inhibition by guanidine. ME virus-specific alterations also predominated in cytolytic membrane damage as expressed by 51Cr-release from infected cells. 51Cr-release was more pronounced from ME virus than from poliovirus-infected cells, even when ME virus reproduction was suppressed by interfering poliovirus. However, alteration of the internal structures of the infected cells was only dominated by ME virus when the reproduction of poliovirus was suppressed.
Insights
Mixed picornavirus infections show ME virus dominates cell surface changes, causing distinct alterations like large vacuoles. Poliovirus induces different changes, but ME virus effects prevail in mixed infections.
Area of Science:
- Virology
- Cell Biology
- Microscopy
Background:
- Picornaviruses are small RNA viruses known to cause various cytopathic effects in host cells.
- Understanding viral interactions during mixed infections is crucial for deciphering disease pathogenesis.
- HEp-2 cells are a commonly used human epithelial cell line for studying viral infections.
Purpose of the Study:
- To compare the distinct surface alterations induced by poliovirus and ME virus in HEp-2 cells.
- To investigate the outcome of mixed infections on cellular surface morphology and integrity.
- To determine the dominant virus in dictating cytopathic effects during co-infection.
Main Methods:
- Scanning and transmission electron microscopy to visualize cellular surface changes.
- 51Cr-release assay to quantify cytolytic membrane damage.
- Chronological analysis of cytopathic alterations in singly and dually infected cells.
Main Results:
- ME virus infection caused large membranous structures (vacuoles, sheets, blebs) not observed with poliovirus.
- Polio virus induced cell pycnosis, filopodia elongation, and microvilli condensation.
- Mixed infections predominantly displayed ME virus-specific surface alterations, irrespective of poliovirus replication.
- ME virus-specific cytolytic damage and 51Cr-release were more pronounced than poliovirus-induced damage.
Conclusions:
- ME virus dictates the characteristic surface alterations during mixed infections with poliovirus in HEp-2 cells.
- ME virus-induced cytopathic effects, particularly membrane damage, are dominant even when poliovirus replicates.
- Cellular internal structure alterations are primarily influenced by ME virus when poliovirus replication is suppressed.