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pH-dependent hemolysis and cell fusion of rhabdoviruses
Abstract:
Human erythrocytes pretreated with fungal semialkali protease or trypsin became susceptible to hemagglutination by vesicular stomatitis virus (VSV) and rabies virus. Both viruses exhibited extensive hemolytic and fusion activities against erythrocytes pretreated with these enzymes. The hemolysis and fusion were pH dependent and the activities were most apparent at pH 5.0 and decreased with increase in pH. However, VSV still exhibited slight hemolytic activity at neutral pH. Hemolysis was also dependent on the dose of virus and was inhibited by treatment of the viruses with antiviral antibody. Results of sodium dodecyl sulfate polyacrylamide gel electrophoresis of erythrocyte membranes suggested that most of the carbohydrates were removed from the membrane proteins by the treatment with proteolytic enzymes.
Insights
Fungal protease or trypsin treatment makes human red blood cells susceptible to vesicular stomatitis virus (VSV) and rabies virus. These viruses cause hemolysis and fusion, particularly at acidic pH, by removing erythrocyte membrane carbohydrates.
Area of Science:
- Virology
- Biochemistry
- Cell Biology
Background:
- Vesicular stomatitis virus (VSV) and rabies virus are known to interact with host cells.
- Erythrocyte membranes possess specific surface structures that may mediate viral interactions.
Purpose of the Study:
- To investigate the effect of proteolytic enzymes on human erythrocyte susceptibility to VSV and rabies virus.
- To characterize the hemolytic and fusion activities of these viruses on treated erythrocytes.
- To elucidate the role of erythrocyte membrane carbohydrates in viral interactions.
Main Methods:
- Human erythrocytes were pretreated with fungal semialkali protease or trypsin.
- Treated erythrocytes were incubated with VSV and rabies virus.
- Hemagglutination, hemolysis, and fusion assays were performed.
- pH-dependency and virus dose-dependency were analyzed.
- Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was used to analyze membrane protein changes.
Main Results:
- Protease or trypsin pretreatment rendered erythrocytes susceptible to hemagglutination by VSV and rabies virus.
- Both viruses exhibited significant hemolytic and fusion activities on treated erythrocytes, most pronounced at pH 5.0.
- VSV showed slight hemolytic activity at neutral pH.
- Viral hemolysis was dose-dependent and inhibited by antiviral antibodies.
- SDS-PAGE indicated removal of carbohydrates from erythrocyte membrane proteins post-enzyme treatment.
Conclusions:
- Proteolytic removal of carbohydrates from erythrocyte membranes enhances susceptibility to VSV and rabies virus-induced hemolysis and fusion.
- Viral interaction and subsequent cell damage are pH-dependent.
- These findings highlight the role of specific erythrocyte surface carbohydrates in mediating viral entry and cytopathic effects.