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Expression of infectious murine leukemia viruses by RAW264.7 cells, a potential complication for studies with a
Janet W Hartley1, Leonard H Evans, Kim Y Green
1Laboratory of Immunopathology, NIAID, NIH, Bethesda, MD 20892, USA. jhartley@niaid.nih.gov
Abstract:
The mouse macrophage-like cell line RAW264.7, the most commonly used mouse macrophage cell line in medical research, was originally reported to be free of replication-competent murine leukemia virus (MuLV) despite its origin in a tumor induced by Abelson MuLV containing Moloney MuLV as helper virus. As currently available, however, we find that it produces significant levels of ecotropic MuLV with the biologic features of the Moloney isolate and also MuLV of the polytropic or MCF class. Newborn mice developed lymphoma following inoculation with the MuLV mixture expressed by these cells. These findings should be considered in interpretation of increasingly widespread use of these cells for propagation of other viruses, studies of biological responses to virus infection and use in RNA interference and cell signalling studies.
Insights
The widely used RAW264.7 mouse macrophage cell line unexpectedly produces infectious murine leukemia virus (MuLV), posing risks for research. This viral contamination can lead to lymphoma in newborn mice, impacting various biological studies.
Area of Science:
- Virology
- Immunology
- Cancer Research
Background:
- The RAW264.7 cell line is a standard model for mouse macrophage research.
- It was presumed to be free of replication-competent murine leukemia virus (MuLV).
Purpose of the Study:
- To investigate the presence and characteristics of MuLV in currently available RAW264.7 cells.
- To assess the pathogenic potential of the detected MuLV in vivo.
Main Methods:
- Detection and characterization of retroviral particles produced by RAW264.7 cells.
- Inoculation of newborn mice with the viral mixture to assess oncogenic potential.
Main Results:
- RAW264.7 cells produce significant levels of ecotropic and polytropic/MCF-class MuLV.
- Inoculation of newborn mice with this MuLV mixture resulted in lymphoma development.
Conclusions:
- Current RAW264.7 cell lines harbor replication-competent MuLV, contrary to previous reports.
- The presence of MuLV in RAW264.7 cells has critical implications for research using these cells, including viral propagation and studies of immune responses.
