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Are endogenous feline leukemia viruses really endogenous?
H Stewart1, O Jarrett, M J Hosie
1MRC-University of Glasgow Centre for Virus Research, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Bearsden Road, Glasgow G61 1QH, United Kingdom. h.stewart.1@research.gla.ac.uk
Veterinary Immunology and Immunopathology
|July 1, 2011
Summary
Endogenous feline leukemia viruses (FeLV) may transmit between cats by acquiring exogenous LTRs, forming novel FeLV-B viruses. This research identifies two field isolates suggesting the between-host transmission of endogenous FeLV.
Area of Science:
- Virology
- Genetics
- Molecular Biology
Background:
- Endogenous feline leukemia virus (FeLV) proviruses are integrated into the genomes of many domestic cats.
- The possibility of a transmissible exogenous form of endogenous FeLV exists.
- Recombinant FeLV-B subgroup viruses arise from recombination between exogenous FeLV-A and endogenous FeLV.
Purpose of the Study:
- To assess the potential for between-host transmission of endogenous FeLV.
- To identify FeLV isolates containing only subgroup B virus lacking FeLV-A.
Main Methods:
- Examination of primary FeLV field isolates using classical interference assays.
- Sequencing of the env gene and U3 region of the 3' long terminal repeat (LTR).
- Analysis of viral genomes and co-packaged viral genomes.
Main Results:
- Two primary field isolates (2518 and 4314) were identified, appearing to contain only subgroup B virus.
- Sequencing confirmed endogenous viral env genes in both isolates, but with exogenous 3' LTRs.
- FeLV-2518 contained a truncated FeLV-A genome, while FeLV-4314 lacked a helper subgroup A genome.
Conclusions:
- The data suggest endogenous FeLVs can be mobilized by acquiring exogenous LTRs.
- This mobilization can yield novel viruses that are biologically typed as FeLV-B.
- The findings support the possibility of between-host transmission of endogenous FeLV.
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