RB virus: a strain of Friend virus that produces a ‘Friend virus-like’ disease in Fν-2rr mice (original) (raw)
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Enhancement of spleen focus formation and virus replication in Friend virus-infected mice
Cancer research, 1969
Spleen focus formation, induced by a member [spleen focus forming virus (SFFV)] of the Friend virus complex, was en hanced in mice that had been infected 2 days previously with Newcastle disease virus or lactic dehydrogenase-elevating virus. Enhancement was also observed in mice treated with erythro poietin or maintained in 10 percent oxygen for 48 hours be fore SFFV infection. Sublethally irradiated mice were able to synthesize 30 times as much SFFV after treatment with S. typhosa endotoxin. Evidence is presented which indicates that these treatments exert their effects, at least in part, by increas ing the number or susceptibility of target cells for SFFV. The data are consistent with the hypothesis that a major portion of the target cells for SFFV are primitive erythroid cells, possibly erythropoietin-sensitive cells.
International Journal of Cancer, 1981
The biological properties of the virus synthesized by I8 clones of a line of mouse bone-marrow hematopoietic cells transformed in vitm by the polycythemic strain of Friend leukemia virus (FLV-P) were compared. In vitro assays were performed to determine whether the virus released into the culture fluids was ecotropic or xenotropic, and in vivoassays were carried out to determine spleen focus formation and leukemogenicity in susceptible DBNZJ and BALBlc mice. A number of clones released virus which reproduced the entire range of effects typial of the FLV-P complex. However, in other clones, there appeared to be no correlation between the assays for leukemogenicity and the assays for either ecotropic virus, reverse transcriptase activity, or virus antigens. Xenotropic virus was not detected in any of the cultures. These results suggest that the FLV-P complex contains a heterogeneous population of viruses, but the possibility that the differences observed may be due to the inability of FLV-P to be expressed fully in some clones cannot be excluded.
Proceedings of the …, 1979
We have recently demonstrated that normal hemopoietic cells express RNA sequences that are homologous to sequences specific for the Friend erythroleukemia virus genome [Bernstein, A., Gamble, C., Penrose, D. & Mak, T. W. (1979) Proc. NatL Acad. Sci. USA 76, 4455-4459]. In this communication, we report that the Fv-2 locus, the major genetic determinant controlling host susceptibility to erythroleukemia induction by Friend leukemia virus, also controls the expression of endogenous sequences related to the replication-defective component of Friend leukemia virus, Friend spleen focus-forming virus (SFFV), in normal uninfected mice. Two independent congeneic pairs of mice [C57BL/6 (B6) and B6.S; B6 and
Infection of Haematopoietic Stem Cells In Mice With Friend Virus Induced Erythroleukaemia
Cell Proliferation, 1986
Animals infected with conventional anaemia (FVA) or polycythemiainducing (FVP) strains of the Friend virus develop lethal erythroleukaemia. A variant strain, RFV, induces an initially identical disease except that it spontaneously regresses in 50% of infected mice. To determine whether pluripotent stem cells as measured by spleen colony forming units (CFU-s) in leukaemic mice are productively infected with virus and whether their infection influences the outcome of the disease, we tested CFU-s from leukaemic mice for susceptibility to cytotoxicity by monospecific antiviral gp70 antiserum. Spleen CFU-s from progressively leukaemic (FVP, FVA and RFV) mice were productively infected with virus. CFU-s in RFV progressors became infected by 40 days post-virus inoculation. FVA and FV P progressors became infected between 15 and 21 days post virus. Infection of CFU-s was accompanied by an increase in the proportion of replicating (S phase) CFU-s in these populations. Spleen CFU-s from fully regressed RFV regressor mice were uninfected and remained so throughout the course of their disease. Bone marrow CFU-s in both regressors and progressors remained uninfected and were not induced to increased cell cycling.
Journal of Virology, 1984
The pathogenic Friend virus complex is of considerable interest in that, although members of this group are genetically related, they differ markedly in biochemical and biological properties. Heteroduplex mapping of molecular clones of the Friend virus complex, which includes the replication-competent ecotropic Friend murine leukemia virus (F-MuLV) and mink cell focus-forming virus (F-MCF) and replication-defective polycythemia- and anemia-inducing strains of spleen focus-forming virus (SFFVp and SFFVa, respectively), was employed to provide insight into the molecular basis of their relationships. In heteroduplexes of F-MuLV X F-MCF, a major substitution of 0.89 kilobases in the env gene of F-MCF was discerned. Heteroduplexes of SFFVp X F-MuLV or F-MCF and SFFVa X F-MuLV or F-MCF showed several major deletions in the pol gene region and a single major deletion in the 3' half of the env gene region of SFFVp and SFFVa. A major substitution of 0.89 kilobases was mapped to the 5'...
Journal of Virology, 1979
The spleen focus-forming virus (SFFV), a rapidly transforming, replication-defective virus in Friend virus (FV) complex that is readily neutralized by antisera directed against its helper virus, was examined for the presence of SFFV-specific antigens. Antisera prepared in Fisher rats against an SFFV-infected Fisher rat embryo fibroblast line (SFFV-FRE) neutralized SFFV effectively, but not Friend-associated murine leukemia virus (F-MuLV) whether the latter was tested alone or was mixed with SFFV in the FV complex. In contrast, serum from mice immunized with SFFV-infected nonproducer mouse cells had little or no neutralizing activity against SFFV. Both absorption and immunoprecipitation studies indicate that the SFFV-specific antigen is immunologically related to xenotropic murine leukemia virus antigens. The role of both SFFV- and F-MuLV-specific antigens in the neutralization of SFFV suggests that this defective virus could be an antigenic mosaic and that viruses in the FV complex ...
Journal of Virology, 1992
Although Fv-2r homozygous mice are resistant to leukemias induced either by an erythropoietin-encoding virus or by wild-type Friend virus (FV) (M. E. Hoatlin, S. L. Kozak, F. Lilly, A. Chakraborti, C. A. Kozak, and D. Kabat, Proc. Natl. Acad. Sci. USA 87:9985-9989, 1990), they are susceptible to some variants of FV (R. A. Steeves, E. A. Mirand, A. Bulba, and P. J. Trudel, Int. J. Cancer 5:349-356, 1970; R. W. Geib, M. B. Seaward, M. L. Stevens, C.-L. Cho, and M. Majumdar, Virus Res. 14:161-174, 1989). To localize the virus gene involved in influencing the host range, we cloned and sequenced the env gene of the BB6 variant of FV (Steeves et al., Int. J. Cancer 5:349-356, 1970). In comparison with the wild-type env gene, the BB6 variant contains a 159-bp deletion that eliminates the membrane-proximal portion of the extracellular domain and 58 point mutations resulting in 13 amino acid changes. Substitution of the variant env gene for the wild-type env gene resulted in a recombinant vi...