[Production and characterization of some mouse embryo cellular substrates in vitro]

Cell cultures with a different multiplication potential in vitro, depending upon the strain source used, were obtained from mouse embryos belonging to the CVA, C57 Black A2G and Swiss strains. Only the Swiss 12 culture underwent spontaneous transformation and was carried through more than 50 passages in vitro. The Swiss-12 substrate proved not to be contaminated either by viruses or micoplasma. It is less sensitive than other elective cell substrates to infection with attenuated polioviruses, cytopathogenic Coxsackie A9 virus and vaccinia virus, but its sensitivity to infection with Herpes simplex type 1 virus is similar to that of human embryo fibroblasts. After a high number of passages the Swiss-12 substrate permits, in comparison to other cell substrates (human heteroploid Hep-2 line, human embryo fibroblasts), a highly efficient qualitative differentiation between the growth media and calf serum.