L cell virus: infectivity for type N and B mouse embryo cells.

The efficiency of focus formation of four L cell virus populations was significantly higher on type N mouse embryo fibroblast cultures than on type B cells. [5-3H]uridine-incorporating material sedimenting at a density of 1.158/g/cm3 was observed in the supernatant fluids of type N and B cultures infected with the four viral populations.