Production of R-type virus-like particles in hamster cells.

The production and release of R-type virus-like particles (VLP) was studied in several Syrian hamster cell lines. Most but not all hamster cell lines contain detectable levels of R-type VLP. However, only BHK-21 clone F (CF) cells would release the VLP into culture fluids. Treatment with dexamethasone enhanced to a limited extent the production and release of VLP from BHK-21 CF cells. Actinomycin D inhibited the production and release of R-type VLP in hamster cells, suggesting that some transcription from DNA is necessary for VLP production. Furthermore, 5-iododeoxyuridine induced the production of R-type VLP in Syrian hamster embryo cells. These results suggest that R-type VLP are endogenous to Syrian hamsters.