Expression of virus-like particles in normal and transformed gerbil cells.

Three types of virus-like particles (VLP) were observed in three of seven gerbil cell lines. One of these cultures was in a non-transformed state and contained R and C-type VLP, while the two others began to express R-type or intracisternal A-type VLP only after spontaneous transformation. These particles seem to be endogenous to the gerbil but do not appear to be directly involved in cell transformation.