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Anti-lymphoma natural resistance (NR) has been detected in DBA/2 mice inoculated intravenously (iv) with syngeneic Friend leukemia cells (FLC). Interferon-sensitive 745 or interferon-resistant 3Cl-8 clones, passaged in vitro and exhibiting "low" tumorigenicity in syngeneic DBA/2 mice, were used. NR, measured as rapid clearance of radiolabeled cells from lung and liver of recipient mice, was age-dependent, was boosted by host pretreatment with polyinosinic-polycytidylic (poly I:C) acid or Friend leukemia virus, and was decreased by mice pretreatment with cyclophosphamide or i-carrageenan. Treatment of "target" FLC with interferon suppressed the susceptibility of 745 FLC, but not that of 3Cl-8 FLC to host's NR. These data suggest that the "low" in vivo tumorigenicity of in vitro passaged FLC is, at least in part, due to host's NR directed against target structures associated with leukemia cells. 相似文献
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Experiments were designed to test the presence of antitumor natural resistance (NR) in DBA/2 mice against highly oncogenic in vivo passaged histocompatible Friend leukemia cells (FLC-V). NR was measured in vivo as rapid clearance of radiolabeled cells from different organs or as growth inhibition in lethally irradiated mice. Interferon-sensitive (745) or interferon-resistant (3C18) lines were used. Organ clearance studies showed that young recipients eliminate cells more rapidly than old mice. Moreover, depressive (e.g., cyclophosphamide or carrageenen) or enhancing (e.g., poly (I:C) or Friend leukemia virus infection) agents of NR function modulate accordingly leukemia cell clearance. Similar results were obtained testing tumor growth in lethally irradiated hosts, although modulating agents were substantially less effective in this system. Both FLC-745-V and FLC-3C18-V lines were equally susceptible to NR. Therefore, these data provide further support to the hypothesis that exogenous IFN capable of suppressing the growth of both lines could act via enhancement of the NR function. 相似文献
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F F Wang A N Chiang Y J Wang 《Proceedings of the National Science Council, Republic of China. Part B, Life sciences》1988,12(2):57-61
It has been shown that radiolabeled erythropoietin (epo) specifically binds to homogeneous epo-responsive spleen cells from mice infected with the anemic variant of the Friend virus. We now report that membranes isolated from these cells retain the ability to specifically bind epo. Spleen cells were swollen in ice-cold 10 mM Tris-Cl pH 7.4 containing 0.2 mM phenylmethyl sulfonylfluoride for 5 minutes, after which the cells were homogenized and centrifuged to remove nuclear fraction. Membranes were collected by centrifuging the supernatant at 75,000 g for 90 min. Utilizing 3H-epo labeled at the terminal sialic acids of the carbohydrate moieties or 125I-epo labeled at the tyrosine residues, it was shown that the isolated membranes contained specific epo binding sites. About 90% of the binding could be inhibited by the presence of unlabeled epo whereas no inhibition was seen with other glycoproteins and growth factors. Equilibrium could be reached in approximately 2.5 hr at 25 degrees C or 1.5 hr at 37 degrees C. Binding could be saturated at an epo concentration of about 3 nM, Scatchard analysis indicated a single class of receptors with a Kd of approximately 1.5 nM. 相似文献
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Retroviral interference is manifested in chronically infected cells as a decrease in susceptibility to superinfection by virions using the same cellular receptor. The pattern of interference reflects the cellular receptor specificity of the chronically infecting retrovirus and is mediated by the viral envelope glycoprotein, which is postulated to bind competitively all cellular receptors available for viral attachment. We established retroviral interference in mice by infecting them with Friend murine leukemia virus and them measured susceptibility to superinfection by challenging the mice with the erythroproliferative spleen focus-forming virus. Infection of approximately 10% of nucleated splenocytes rendered mice 1% as susceptible to superinfection as untreated controls. The magnitude of this effect was the same in mice incapable of producing neutralizing antibodies or genetically deficient for T cells. The results indicated that retroviral interference in vivo was established rapidly with infection of a fraction of the host cell population and that the decrease in susceptibility to superinfection occurred without a detectable contribution by immunologic factors. 相似文献
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P J Dawson A H Fieldsteel 《Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N.Y.)》1975,149(1):61-63
Prior inoculation of 7-wk-old A/He mice with the Graffi pseudotype of Friend virus protected the animals against subsequent challenge with Friend virus. Graffi leukemia virus itself did not induce protection, probably because it failed to replicate in these mice. 相似文献
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Tissue-specific replication of Friend and Moloney murine leukemia viruses in infected mice. 总被引:4,自引:12,他引:4 下载免费PDF全文
We have studied the replication of ecotropic murine leukemia viruses (MuLV) in the spleens and thymuses of mice infected with the lymphocytic leukemia-inducing virus Moloney MuLV (M-MuLV), with the erythroleukemia-inducing virus Friend MuLV (F-MuLV), or with in vitro-constructed recombinants between these viruses in which the long terminal repeat (LTR) sequences have been exchanged. At 1 week after infection both the parents and the LTR recombinants replicated predominantly in the spleens with only low levels of replication in the thymus. At 2 weeks after infection, the patterns of replication in the spleens and thymuses were strongly influenced by the type of LTR. Viruses containing the M-MuLV LTR exhibited a remarkable elevation in thymus titers which frequently exceeded the spleen titers, whereas viruses containing the F-MuLV LTR replicated predominantly in the spleen. In older preleukemic mice (5 to 8 weeks of age) the structural genes of M-MuLV or F-MuLV predominantly influenced the patterns of replication. Viruses containing the structural genes of M-MuLV replicated efficiently in both the spleen and thymus, whereas viruses containing the structural genes of F-MuLV replicated predominantly in the spleen. In leukemic mice infected with the recombinant containing F-MuLV structural genes and the M-MuLV LTR, high levels of virus replication were observed in splenic tumors but not in thymic tumors. This phenotypic difference suggested that tumors of the spleen and thymus may have originated by the independent transformation of different cell types. Quantification of polytropic MulVs in late-preleukemic mice infected with each of the ecotropic MuLVs indicated that the level of polytropic MuLV replication closely paralleled the level of replication of the ecotropic MuLVs in all instances. These studies indicated that determinants of tissue tropism are contained in both the LTR and structural gene sequences of F-MuLV and M-MuLV and that high levels of ecotropic or polytropic MuLV replication, per se, are not sufficient for leukemia induction. Our results further suggested that leukemia induction requires a high level of virus replication in the target organ only transiently during an early preleukemic stage of disease. 相似文献
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Animals infected with conventional anaemia (FVA) or polycythemia-inducing (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 FVP 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. 相似文献
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Genetic diversity in leukemia-prone feral house mice infected with murine leukemia virus 总被引:3,自引:0,他引:3
The Lake Casitas (LC) mouse population located in south western Ventura county in California is unusual insofar as 85% of these mice are persistently viremic with congenitally transmitted murine leukemia virus (MuLV). The virus has been identified as the etiological agent responsible for lymphoma and neuromotor paralysis in large numbers of the mice. The majority of other wild mouse populations are generally free of infectious MuLV despite the presence of endogenous cellular DNA sequences homologous to infectious virus isolated from wild mice. Electrophoretic variation in 46 gene-enzyme systems was surveyed using mice from Lake Casitas and from a virus-negative population located in Bouquet Canyon (BC) approximately 40 miles from Lake Casitas. The LC and BC populations are genetically very similar to each other and to feral mouse populations previously studied in California and Europe. In the LC population 24% of the loci are polymorphic compared to 17% in the BC population. The average heterozygosities for the LC and Bc populations are 0.094 and 0.073, respectively. The large amount of genic variation in LC fails to support the concept of the derivation of the colony from a small number of founders. Tests for linkage disequilibrium and/or selective association of viremia and polymorphism at 15 loci located on nine mouse chromosomes did not reveal any nonrandom assortments. The viremic LC population, then, appears indistinguishable within the limits of experimental resolution from the virus-negative BC population in its population genetic structure. 相似文献