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Helper specificity for retrieval of defective friend virus
Abstract:
A Friend virus-induced reticulum-cell sarcoma from BALB/c mice has been cultivated in vitro in our laboratory for more than 11 years and contains no detectable evidence of virus. However, Friend virus could be retrieved readily from the tissue cultures by any of several lymphatic leukemia viruses belonging to the Friend-Moloney-Rauscher (FMR) group, as long as the helper viruses were actively replicating in a culture. Helper activity appeared to be highly specific and limited to the FMR group including the B-tropic Tennant leukemia virus which produced a B-tropic Friend virus pseudotype. The naturally occurring type AKR murine leukemia viruses and the related Gross passage A virus failed both in vivo and in vitro to retrieve the Friend virus genome from the virus-free tumor cells.
Insights
Friend virus can be recovered from long-term mouse tumor cell cultures using specific helper viruses from the Friend-Moloney-Rauscher group. Other leukemia viruses could not retrieve the Friend virus genome.
Area of Science:
- Virology
- Oncology
- Murine Models
Background:
- Friend virus causes reticulum-cell sarcoma in BALB/c mice.
- Tumor cell lines can be maintained in vitro for extended periods.
- Virus retrieval from cell cultures is crucial for studying viral genomes.
Purpose of the Study:
- To investigate the possibility of retrieving the Friend virus genome from long-term in vitro cultivated tumor cells.
- To determine the specificity of helper viruses in the retrieval process.
- To compare the efficacy of different leukemia viruses in recovering Friend virus.
Main Methods:
- Culturing a Friend virus-induced reticulum-cell sarcoma from BALB/c mice in vitro for over 11 years.
- Testing various lymphatic leukemia viruses for their ability to retrieve the Friend virus genome from the established tumor cell line.
- Assessing helper virus activity in vitro and in vivo.
Main Results:
- Friend virus was readily retrievable from the virus-free tumor cultures when helper viruses from the Friend-Moloney-Rauscher (FMR) group were actively replicating.
- Helper activity was specific to the FMR group, with B-tropic Tennant leukemia virus producing a B-tropic Friend virus pseudotype.
- Naturally occurring AKR murine leukemia viruses and Gross passage A virus failed to retrieve the Friend virus genome.
Conclusions:
- The Friend virus genome can persist in a non-infectious form within long-term tumor cell cultures.
- Specific helper viruses within the FMR group are essential for the rescue and replication of the Friend virus genome.
- This study highlights the host-range and specificity of helper virus activity in viral genome retrieval.