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Friend leukemia
About: Friend leukemia is a research topic. Over the lifetime, 319 publications have been published within this topic receiving 7463 citations.
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TL;DR: Results showed that the T-cell deficits may be at least partly attributable to a derangement of the signal transduction pathway leading to activation, and suggests that the alterations in signalTransduction are not caused by primary defect of the responder-T cells but may result from an extrinsic suppressive mechanism.
Abstract: Proliferative and interleukin responses to T-cell mitogens such as concanavalin A (Con A) were rapidly and progressively reduced in BALB/c mice infected with the Friend leukemia complex (F...
3 citations
TL;DR: The greatest degree of interference (reduction of splenomegaly) occurred when Cocal virus was administered 24-48 hr prior to Friend leukemia virus.
Abstract: SummaryIn studying the inhibitory effect of a single infectious or UV-inactivated arbovirus (Cocal) dose on Friend leukemia virus-induced leukemia in DBA/2J mice, the greatest degree of interference (reduction of splenomegaly) occurred when Cocal virus was administered 24-48 hr prior to Friend leukemia virus. The percentage and duration of splenomegaly inhibition was dependent on the dose and state (infectious or inactivated) of the Cocal virus.
3 citations
TL;DR: It could be shown that marrow of C57BL/6 origin loses its FV-P resistance in allogeneic leukemic lethally irradiated recipients and is transformed by the surviving virus.
Abstract: After lethal irradiation (800 R) Friend virus (FV-P)-infected leukemic DBA/2 mice were transplanted with normal bone marrow cells. Isogeneic transplantation led to an immediate relapse of leukemia. Therefore, allogeneic bone marrow cells were taken from almost FV-P resistant C57BL/6 mice. A measure of leukemia development was given by the number of erythropoietin-independent erythroid colonies (CFU-EI) in bone marrow and spleen, characteristic for the Friend leukemia. Even after allogeneic transplantation leukemia recurred after 5 to 19 days. By an electrophoretic analysis of the hemoglobin, it could be shown that the transformed erythropoiesis was donor derived. Thus, marrow of C57BL/6 origin loses its FV-P resistance in allogeneic leukemic lethally irradiated recipients and is transformed by the surviving virus.
3 citations
TL;DR: It was shown by Southern blot hybridization that SV40 DNA was integrated in multiple copies in the chromosomal DNA of several clones of Friend leukemia cell clones analyzed were able to undergo induced erythroid differentiation.
Abstract: Thymidine kinase-negative Friend leukemia cells were cotransfected with simian virus 40 (SV40) DNA and thymidine kinase gene DNA of herpes simplex virus type 1. The transfected thymidine kinase-positive cells were selected in HAT medium, and SV40 T-antigen expression was observed over many months in cells cultured under selective conditions, and after adaptation to normal growth medium under nonselective conditions. It was shown by Southern blot hybridization that SV40 DNA was integrated in multiple copies in the chromosomal DNA of several clones. All SV40 DNA-containing Friend leukemia cell clones analyzed were able to undergo induced erythroid differentiation. Induced cultures still expressed SV40 T-antigen to the same extent that untreated control cultures did.
3 citations
Journal Article•
TL;DR: The kind of cellular resistance induction used in this experiment enabled us to obtain an MDR cell line in three months of culture, and showed a high expression on the membrane surface of P-glycoprotein in the MELC-DRTL line, but the fact that it was impossible to obtain a complete reversal of the resistance, even when using high concentrations of verapamil suggests the presence of other mechanisms unrelated to the presence.
Abstract: BACKGROUND Resistance of tumor cells to cytotoxic agents can be due to the overexpression of the mdr 1 gene, which encodes a plasma membrane protein (P-glycoprotein). To understand the molecular basis of multidrug resistance, several laboratories have isolated cell lines resistant to doxorubicin, actinomycin D, vinca alkaloids and related agents. Many months or years of culture with gradually increasing concentrations of cytotoxic agents are necessary to obtain a resistant cell line. METHODS We selected a new multidrug resistant cell line (MELC-DRTL) by 24-hour cycles of exposure to relatively high concentrations of daunorubicin from sensitive Friend Leukemia cells. After each cycle, the residual live cells were expanded up to the density of 1 x 10(6) cells/ml. RESULTS The assay conducted with MoAb C-219 showed a high expression on the membrane surface of P-glycoprotein in the MELC-DRTL line, but the fact that it was impossible to obtain a complete reversal of the resistance, even when using high concentrations of verapamil, suggests the presence of other mechanisms unrelated to the presence of P-glycoprotein. CONCLUSIONS The kind of cellular resistance induction used in this experiment enabled us to obtain an MDR cell line in three months of culture.
3 citations