Abstract
Rabbit embryo tissue was grown in a thin plasma clot and after some days the cultures were submitted to a trypsin solution strong enough to digest the clot and free the cells that had extended into it. 1 By repeated pipettings and filtrations through lens paper, alternated with differential washings in gelatin-Tyrode solution, suspensions were obtained of the living cells as individuals. They were mixed at room temperature with suspensions of virus, and after an interval the cells were recovered with the centrifuge, again washed repeatedly, treated in various ways and inoculated into rabbits. The viruses used were vaccinia and the filterable agent causing the rabbit fibroma described by Shope. 2
Cells exposed to virus and repeatedly washed invariably gave rise to lesions in susceptible animals. The briefest exposure at room temperature permitted by the conditions resulted in an association of the virus with the cells, which withstood many washings of the latter. The fixation thus indicated took place not only upon living cells but upon those killed by heat, ultraviolet light, and water respectively, and often was as considerable. Incubation of the material with immune serum in vitro, followed by repeated washings prior to infection, resulted in neutralization of the virus associated with dead cells, whereas these procedures were without effect when the cells were alive. The possibility that serum antibodies accumulated on the dead cells and were carried into the final inoculum was ruled out by appropriate tests.
Suspensions of individual, washed cells procured from cultures of Shope tumor tissue, or from rabbit embryo cultures inoculated with vaccinia, were found to carry the virus.
Get full access to this article
View all access options for this article.