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Component of strain MC29 avian leukosis virus with the property of defectiveness
Abstract:
Three clones of morphologically altered cells (L(-)MC29) of singular properties were isolated from MC29 (subgroup A) leukosis virus-infected chick embryo cells. Supernatant fluids from cultures of the cloned cells produced no transforming or interfering activity on chick embryo cells susceptible to known avian leukosis-sarcoma viruses. No virus associated with the cells was demonstrable by fluorescent-antibody staining or by electron microscopy. All L(-)MC29 clone cells were activated, however, by four strains of Rous-associated viruses (RAV) representative of A, B, C, and D subgroup avian leukosis viruses and by two strains of MC29 virus. Virus L(-)MC29 cells activated by superinfection with RAV-1 and RAV-2 was characterized by helper-dependent and helper-independent properties. These findings suggest that the strain MC29 leukosis virus, or a component thereof, possesses properties of defectiveness similar to those of the Bryan high-titer Rous sarcoma virus.
Insights
Researchers isolated unique altered cells (L(-)MC29) from avian leukosis virus-infected cells. These cells, activated by other viruses, suggest MC29 leukosis virus may be defective, similar to Rous sarcoma virus.
Area of Science:
- Virology
- Cell Biology
- Oncology
Background:
- MC29 virus is an avian leukosis virus subgroup A.
- Morphologically altered cells were isolated from infected chick embryo cells.
Purpose of the Study:
- To characterize the properties of isolated L(-)MC29 cell clones.
- To investigate the potential defectiveness of MC29 leukosis virus.
Main Methods:
- Isolation and culture of morphologically altered cell clones (L(-)MC29).
- Assays for transforming and interfering activity of cell-free supernatants.
- Activation studies using various Rous-associated virus (RAV) strains and MC29 virus.
- Characterization of activated virus properties (helper-dependent/independent).
Main Results:
- Isolated L(-)MC29 clones showed no transforming or interfering activity.
- No associated virus was detected by immunofluorescence or electron microscopy.
- L(-)MC29 cells were activated by RAV strains (subgroups A, B, C, D) and MC29 virus.
- Activated virus exhibited both helper-dependent and helper-independent characteristics.
Conclusions:
- The MC29 leukosis virus, or a component, displays properties of defectiveness.
- These properties are analogous to those observed in Bryan high-titer Rous sarcoma virus.
- Further research is warranted to elucidate the nature of MC29 virus defectiveness.