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Characteristics of a persistent rubella infection in a human cell line
Abstract:
A persistent infection of the human MCF-7 cell line (MCF-7RV) was established with the DBS strain of rubella virus at a low multiplicity of infections. Fluorescent antibody staining revealed that 100% of the cells were positive for rubella antigens. The infected cells were refractory to superinfection with vesicular stomatitis virus (VSV) but were susceptible to herpes simplex virus type 2 (HSV-2). No interferon could be detected in infected cell culture fluid, and continuous passage in the presence of antibody did not lead to a decrease in the percentage of infected cells. Virus production in the persistently infected cells represented a 5- to 10-fold increase over primary infection. Plaque assays at 30 and 39 degree C of the virus produced at 37 degree C revealed the presence of temperature-sensitive (ts) mutants. If MCF-7RV cells were maintained at 30 degree C, significant increases in virus production were observed, leading to cytopathic effect and destruction of the monolayer. If maintained at 39 degree C, MCF-7RV cells produced less virus and demonstrated normal morphology. These data suggest that the naturally selected population of ts mutants being produced by these cells represents the mechanism by which persistence is maintained.
Insights
Persistent rubella virus infection in human cells (MCF-7RV) was established. The study suggests that naturally selected temperature-sensitive (ts) mutants maintain this rubella virus persistence.
Area of Science:
- Virology
- Cell Biology
- Immunology
Background:
- Persistent viral infections can evade host immune responses.
- Understanding the mechanisms of viral persistence is crucial for developing effective treatments.
Purpose of the Study:
- To establish and characterize a persistent rubella virus infection in a human cell line.
- To investigate the mechanisms underlying rubella virus persistence.
Main Methods:
- Establishing a persistent rubella virus infection in MCF-7 cells (MCF-7RV).
- Assessing viral antigen expression using fluorescent antibody staining.
- Evaluating susceptibility to superinfection with other viruses (VSV, HSV-2).
- Detecting interferon in cell culture fluid.
- Analyzing virus production and characteristics at different temperatures.
Main Results:
- 100% of MCF-7RV cells showed rubella viral antigens.
- Infected cells were resistant to vesicular stomatitis virus (VSV) but susceptible to herpes simplex virus type 2 (HSV-2).
- No interferon was detected; continuous passage with antibody did not reduce infection rates.
- Persistent infection led to a 5- to 10-fold increase in virus production compared to primary infection.
- Temperature-sensitive (ts) mutants were identified in the produced virus.
- Lower temperatures (30°C) increased virus production and caused cell damage, while higher temperatures (39°C) reduced production and maintained normal cell morphology.
Conclusions:
- The study established a model for persistent rubella virus infection in human MCF-7 cells.
- The findings indicate that the production of temperature-sensitive (ts) rubella virus mutants is a key mechanism for maintaining persistent infection.
- This persistent infection model provides insights into viral evasion strategies and potential therapeutic targets.