Trans-Species Rescue of Defective Genomes of Murine Sarcoma Virus from Hamster Tumor Cells with Helper Feline Leukemia Virus

Abstract

Abstract. This report describes a trans-species rescue of defective MSV genome with helper leukemia virus derived from cats. This rescue was achieved by in vitro co-cultivation of hamster tumor cells with feline embryo cells in the presence of helper feline leukemia virus (FeLV), or by inoculation of tumor cells into FeLV-infected newborn cats.The rescued focus-forming viruses produced foci in feline embryo cultures but not in cultures of mouse, rat, and hamster species. One isolate was tested and found to induce sarcoma in a kitten. Antigenic and viral interference studies indicated that the focus-forming virus has the viral envelope of FeLV. Virus stocks consisted of a mixture of focus-forming particles and a 1000-fold excess of helper FeLV. Virus assay patterns in feline embryo cultures with or without added helper FeLV indicated that this helper virus is required for the transformation of feline cells.

Cytochemistry, Cytogenetics and Ultrastructure of Hamster Tumour Cells Carrying Mouse Sarcoma Viral Genome (HT-1 Cells)

“…It was apparent then, that the HT-1 cells were carrying the MSV genome though initially not producing the virus-a state which could be compared with that of the non-producing (NP) cells previously described for Rous sarcoma virus (RSV) (Hanafusa et al, 1964 (Sarma et al, 1965). Recent trans-species rescue of the MSV genome from HT-1 cells by feline leukaemia virus (Sarma et al, 1970) Since most HT-1 cells grew in suspension, the cells had to be spun down for the preparation of spreads on glass slides. After fixation the cells were stained using the foRowing staining techniques (Hayhoe and Flemans, 1969): Leishman, May-Grunwald-Giemsa (MGG), acid phosphatase periodic acid-Schiff (PAS), Sudan black and alkaline phosphatase.…”

In Vitro Isolation and Characterization of the GA Strain of Feline Sarcoma Virus

“…ference tests using the focus-forming GA-FSV and FeLV pseudotypes of MSV (12,13) showed that the noncytopathogenic, C-type virus accompanying the GA-FSV, designated herein as GA-FeLV, could be assayed by a viral interference technique ( 12). Focus induction by the GA-FSV was interfered with by prior infection of FEF cultures with GA-FeLV and FeLV strains of the subgroup B, but not by FeLV of the subgroups A and C of the feline leukemia-sarcoma viruses ( 12).…”

“…Secondary and tertiary monolayer cultures of F E F were propagated in disposable plastic Falcon dishes in a humidified COz incubator as previously described (6,7,(12)(13)(14). The original, naturallyoccurring fibrosarcoma, as well as tumors experimentally induced by GA-FSV in cats and dogs (9), were used in infectivity studies.…”

Gazdar Strain of Murine Sarcoma Virus. Biologic and Antigenic Interactions with the Heterologous Hamster Host

“…MSV induced hamster sarcomas and tissue culture cell lines of MSV transformed hamster cells usually do not contain detectable quantities of infectious or noninfectious virus but contain defective MSV genome rescuable in techniques using helper leukemia viruses (6,10,13). However, the species-specific group-specific antigen (gs-1 antigen) of the viruses of the murine leukemia-sarcoma complex ( 6, 7, 14-1 7 ) which serves as an antigenic marker for the viruses of this group, is not present in detectable amounts in such hamster cells.…”