In vitro isolation and characterization of the GA strain of feline sarcoma virus.

Abstract

The Gardner-Arnstein strain of feline sarcoma virus (GA-FSV) present in a naturally-occurring feline fibrosarcoma, was isolated in feline embryo fibroblast cultures. Virus isolation was successfully accomplished by co-infecting the feline embryo cultures with helper feline leukemia virus. Cultures inoculated with tumor concentrate alone contained a nontransforming feline-C-type virus which was identified as a GA-FSV associated virus (GA-FeLV). Both the GA-FSV as well as the accompanying GA-FeLV were serially propagated in feline and canine embryo cultures. The foci of cell transformation induced by GA-FSV consisted of aggregates of refractile fibroblasts in parallel and crisscross orientations. Evidence was obtained that the development of foci in feline and canine embryo cultures depended on the multiplication of transformed cells rather than in the local spread of virus to adjoining cells. GA-FSV stocks containing high titers of the associated feline leukemia virus gave “one-hit” focus titration patterns in feline and canine embryo cultures. Exogenous “helper” FeLV failed to enhance the focus titers in feline and canine embryo cultures. The GA-FSV and GA-FeLV were classified as members of the subgroup B of the feline leukemia-sarcoma complex.