In Vitro Host Range of Feline Leukemia Virus

2015 ◽  
pp. 489-492
Author(s):  
P. S. Sarma ◽  
D. Jain ◽  
P. R. Hill
Keyword(s):  
Host Range ◽  
Leukemia Virus ◽  
Feline Leukemia Virus

Recombination between feline leukemia virus subgroup B or C and endogenous env elements alters the in vitro biological activities of the viruses.

1992 ◽  
Vol 66 (6) ◽  
pp. 3976 ◽  
Author(s):  
R Pandey ◽  
A K Ghosh ◽  
D V Kumar ◽  
B A Bachman ◽  
D Shibata ◽  
...  
Keyword(s):  
Biological Activities ◽  
Leukemia Virus ◽  
Feline Leukemia Virus

scholarly journals Adaptation of Chimeric Retroviruses In Vitro and In Vivo: Isolation of Avian Retroviral Vectors with Extended Host Range

2001 ◽  
Vol 75 (11) ◽  
pp. 4973-4983 ◽  
Author(s):  
Eugene V. Barsov ◽  
William S. Payne ◽  
Stephen H. Hughes
Keyword(s):  
Host Range ◽  
Mammalian Cells ◽  
Leukemia Virus ◽  
Retroviral Vectors ◽  
Retroviral Vector ◽  
General Strategy ◽  
Coding Region ◽  
Chimeric Viruses

ABSTRACT We have designed and characterized two new replication-competent avian sarcoma/leukosis virus-based retroviral vectors with amphotropic and ecotropic host ranges. The amphotropic vector RCASBP-M2C(797-8), was obtained by passaging the chimeric retroviral vector RCASBP-M2C(4070A) (6) in chicken embryos. The ecotropic vector, RCASBP(Eco), was created by replacing theenv-coding region in the retroviral vector RCASBP(A) with the env region from an ecotropic murine leukemia virus. It replicates efficiently in avian DFJ8 cells that express murine ecotropic receptor. For both vectors, permanent cell lines that produce viral stocks with titers of about 5 × 106 CFU/ml on mammalian cells can be easily established by passaging transfected avian cells. Some chimeric viruses, for example, RCASBP(Eco), replicate efficiently without modifications. For those chimeric viruses that do require modification, adaptation by passage in vitro or in vivo is a general strategy. This strategy has been used to prepare vectors with altered host range and could potentially be used to develop vectors that would be useful for targeted gene delivery.

FLVCRb: a Mitochondrial FLVCR Isoform Important for Erythropoiesis

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 4243-4243
Author(s):  
Deborah Chiabrando ◽  
Sonia Mercurio ◽  
Samuele Marro ◽  
Sharmila Fagoonee ◽  
Erika Messana ◽  
...  
Keyword(s):  
Cell Membrane ◽  
Mouse Model ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Leukemia Virus ◽  
Feline Leukemia Virus ◽  
Knock Out ◽  
Skeletal Malformations ◽  
Fetal Erythropoiesis

Abstract Abstract 4243 Feline Leukemia Virus subgroup C Receptor (FLVCR) was originally identified and cloned as a cell-surface protein receptor for feline leukemia virus subgroup C, causing pure red blood cell aplasia in cats. Recent studies have demonstrated that FLVCR is a heme exporter which is essential for erythropoiesis. The heme efflux via FLVCR was shown to be essential for erythroid differentiation in K562 cells as well as in CD34+ precursors cells1. Moreover, Keel and co-authors have reported that Flvcr-null mice die in utero due to the failure of fetal erythropoiesis; also post-natal mice lacking FLVCR showed severe anemia. In addition to the erythroid defect, Flvcr-null embryos display defective growth and developmental anomalies2. We have identified an alternative transcription start site giving rise to a novel FLVCR isoform (FLVCRb). Flvcr-b transcript completely lacks the first exon of the canonical isoform (FLVCRa) and code for a putative 6 transmembrane domain containing protein ubiquitously expressed. In vitro over-expression of FLVCRa and FLVCRb showed that the two proteins display different subcellular localization. As expected, FLVCRa is localized at the cell membrane while FLVCRb is in the mitochondrial compartment. The mitochondrial localization of this novel isoform is further confirmed by the identification of a N-terminal mitochondrial sorting presequence. The mitochondrion is the site in which heme biosynthesis occurs. Although all the enzymatic reactions involved in heme synthesis are well characterized, how heme is exported to the cytosol is largely unknown. Because of FLVCRa is a heme exporter at the cell membrane, we hypothesized that FLVCRb could be the mitochondrial heme exporter. According to this hypothesis, FLVCRb expression increased following the stimulation of heme biosynthesis in vitro, in correlation with the increase in hemoglobin production. The ability of FLVCRb to bind and export heme out of the mitochondria is still under investigation. To gain insights into the specific roles of the two isoforms, we have generated Flvcr mutant mice different from those previously reported2. Keel and co-author generated a mouse model in which both FLVCRa and FLVCRb have been deleted. In our mouse model, FLVCRa has been specifically deleted while FLVCRb is still expressed (FLVCRa-null mice). Flvcr-a +/− mice were grossly normal, fertile and indistinguishable from their wild-type littermates. When Flvcr-a +/− mice were intercrossed, no Flvcr-a homozygous knock-out newborns were obtained. The analysis of the embryos from timed Flvcr-a +/− intercrosses showed that the Flvcr-a homozygous knock-out genotype was lethal between E14.5 and the birth. E13.5 Flvcr-a-null embryos showed multifocal and extended hemorrhages, visible in the limbs, head and throughout the body wall, as well as subcutaneous edema. Imcomplete vasculogenesis in the Flvcr-a-null embryos was observed at E11.5, a developmental stage in which hemorrhages were not still evident. This suggests that hemorrhages arise from a defect in the development of embryonic vasculature. Moreover, FLVCRa-null embryos showed skeletal abnormalities as demonstrated by Alcian blue-alizarin red staining. Skeletal malformations were evident in the limb where digits did not form properly and in the head where Meckel's cartilage was incomplete. It is interesting to note that this kind of malformations also occurs in Diamond Blackfan Anemia (DBA) patients. Surprisingly, flow cytometric analyses of E14.5 fetal liver cells double-stained for Ter119 (erythroid-specific antigen) and CD71 (transferrin receptor) showed normal erythropoiesis in Flvcr-a-null embryos, in opposition to what occurs in the previously reported Flvcr-null mice2. Taken together, these data demonstrated that FLVCRb is sufficient to support fetal erythropoiesis when the expression of FLVCRa is loss, likely exporting heme out of the mithocondrion for hemoglobin synthesis. Moreover, the loss of FLVCRa leads to incomplete vasculogenesis, hemorrhages and skeletal malformations highlighting new roles of FLVCRa in these processes. 1. Quigley JG et al. Identification of a human heme exporter that is essential for erythropoiesis. Cell 2004 2. Keel SB et al. A heme export protein is required for red blood cell differentiation and iron homeostasis. Science 2008. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Properties of Feline Leukemia Virus II. In Vitro Labeling of the Polypeptides 1

1974 ◽  
Vol 14 (3) ◽  
pp. 700-703 ◽  
Author(s):  
Leland F. Velicer ◽  
Donald C. Graves
Keyword(s):  
Leukemia Virus ◽  
Feline Leukemia Virus

scholarly journals Retrovirus-induced feline pure red blood cell aplasia: pathogenesis and response to suramin

Blood ◽  
1991 ◽  
Vol 77 (7) ◽  
pp. 1442-1451
Author(s):  
JL Abkowitz
Keyword(s):  
Blood Cell ◽  
Red Blood Cell ◽  
Mononuclear Cells ◽  
Leukemia Virus ◽  
Transcriptase Inhibitor ◽  
Feline Leukemia Virus ◽  
Erythroid Progenitors ◽  
Marrow Cultures

Feline leukemia virus, subgroup C/Sarma (FeLV-C/Sarma) induces pure red blood cell aplasia in cats. Although erythroid (BFU-E and CFU-E) and granulocyte/macrophage (CFU-GM) progenitors are infected with this virus, only erythropoiesis is impaired. Two to 3 weeks before the onset of anemia, CFU-E become undetectable in marrow cultures while earlier erythroid progenitors (BFU-E) persist, suggesting that FeLV-C/Sarma (presumably via its envelope glycoprotein gp70) inhibits the differentiation of BFU-E to CFU-E in vivo. To correlate in vitro observations with the progression of disease, prospective studies were performed in six cats. These studies showed that at the time that the frequencies of CFU-E decreased in marrow cultures, BFU-E no longer responded to hematopoietic growth factor(s), although the responses of CFU-GM were unchanged. In further studies, anemic cats received suramin, a reverse-transcriptase inhibitor with other diverse effects. Within 4 to 14 days, erythropoiesis improved and up to 1,616 CFU-E were detected per 10(5) marrow mononuclear cells. However, progenitor cells remained infected, suggesting that suramin modulated erythroid differentiation without inhibiting progenitor infection. These observations led to the hypothesis that the gp70 of FeLV-C/Sarma impairs BFU-E differentiation by interference with ligand/receptor interactions or signal transduction pathways unique to erythroid cells. Understanding this mechanism should provide insights into the interactions controlling early erythropoiesis.

scholarly journals Studies in feline long-term marrow culture: hematopoiesis on normal and feline leukemia virus infected stromal cells

Blood ◽  
1992 ◽  
Vol 80 (3) ◽  
pp. 651-662
Author(s):  
ML Linenberger ◽  
JL Abkowitz
Keyword(s):  
Stromal Cells ◽  
Mononuclear Cells ◽  
Clonal Selection ◽  
Leukemia Virus ◽  
Feline Leukemia Virus ◽  
Erythroid Progenitors ◽  
Gag Protein ◽  
Cell Engraftment

To study the effects of feline leukemia virus (FeLV) on the hematopoietic microenvironment, a two-step feline long-term marrow culture (LTMC) system was developed and characterized. The adherent, stromal layer of these cultures is composed of fibroblastoid cells (50% to 80%), macrophages (10% to 30%), fat cells (10% to 20%), and large, polygonal cells that express muscle actin (1% to 2%). When fresh, enriched marrow mononuclear cells (MMNC) were added to 3-week-old irradiated stromal cultures, nonadherent erythroid progenitors (BFU-E) and granulocyte/macrophage progenitors (CFU-GM) could be detected for up to 5 and 12 weeks, respectively. LTMC stromal layers established from marrow cells from cats viremic with either a nonpathogenic strain of FeLV (FeLV-A/61E) or the anemogenic strain FeLV-C/Sarma were morphologically equivalent to uninfected LTMC stromal layers, although more than 80% of the stromal cells expressed FeLV gag protein. When FeLV-infected stromal cultures were recharged with uninfected MMNC, altered patterns of hematopoiesis were observed, compared with recharged, uninfected stromal cultures. In cultures with infected stroma, fewer nonadherent cells (NAC), nonadherent BFU-E, and nonadherent CFU-GM were detected during the first 4 to 5 weeks after recharge. In contrast, greater numbers of NAC and nonadherent CFU-GM were found from weeks 5 to 12 after recharge. When FeLV-infected stromal cultures were recharged with MMNC from a cat heterozygous for the X-chromosome-linked enzyme glucose-6-phosphate dehydrogenase (G-6- PD), the percentage of nonadherent CFU-GM expressing the domestic type G-6-PD isoenzyme remained stable over time (mean % domestic [%d], 53% +/- 3%), and was equivalent to that of nonadherent CFU-GM maintained in uninfected cultures (mean %d, 56% +/- 3%), indicating that clonal drift or clonal selection was not responsible for the enhanced maintenance of CFU-GM. Furthermore, as only 10% to 20% of recharged hematopoietic cells became infected with FeLV in vitro, it is unlikely that the altered pattern was due to progenitor infection. We hypothesize that the increase in NAC and nonadherent CFU-GM in FeLV-infected cultures resulted from enhanced growth factor production by stromal cells. The two-step LTMC system may facilitate the characterization of stromal- derived factors that affect progenitor cell engraftment and proliferation.

scholarly journals Cell lines produce factors that induce fetal hemoglobin in human BFUe- derived colonies

Blood ◽  
1992 ◽  
Vol 80 (10) ◽  
pp. 2650-2655
Author(s):  
P Constantoulakis ◽  
M Walmsley ◽  
R Patient ◽  
T Papayannopoulou ◽  
T Enver ◽  
...  
Keyword(s):  
Cell Lines ◽  
Leukemia Virus ◽  
Fetal Hemoglobin ◽  
Feline Leukemia Virus ◽  
In Vitro Translation ◽  
Expression Cloning ◽  
Bladder Cell ◽  
Relative Production ◽  
Established Cell

Established cell lines were screened for secretion of activities than can stimulate fetal hemoglobin (HbF) production in adult burst-forming unit-erythroid (BFUe) cultures. Conditioned media from four cell lines, a human teratocarcinoma, an osteosarcoma, a bladder cell carcinoma, and feline leukemia virus (FeLV) A-infected feline fibroblasts (FEF-A cells), consistently increased the relative production of fetal globin in BFUe-derived colonies. In vitro translation of RNA from these cells in Xenopus oocytes yielded products that increased the gamma to gamma+beta ratio in adult erythroid colonies. These results demonstrate that a variety of cell lines produce factors that stimulate the production of HbF in vitro. The genes of such factors could be isolated by expression cloning of cDNA from cell lines using the Xenopus oocyte system.

scholarly journals Subtle Mutational Changes in the SU Protein of a Natural Feline Leukemia Virus Subgroup A Isolate Alter Disease Spectrum

2005 ◽  
Vol 79 (3) ◽  
pp. 1351-1360 ◽  
Author(s):  
Chandtip Chandhasin ◽  
Patricia N. Coan ◽  
Laura S. Levy
Keyword(s):  
T Cell ◽  
Host Range ◽  
Leukemia Virus ◽  
Point Mutations ◽  
Feline Leukemia Virus ◽  
Surface Glycoprotein ◽  
Envelope Gene ◽  
Disease Spectrum ◽  
Functional Differences ◽  
Multicentric Lymphoma

ABSTRACT FeLV-945 is a representative isolate of the natural feline leukemia virus (FeLV) variant predominant in non-T-cell malignant, proliferative, and degenerative diseases in a geographic cohort. The FeLV-945 surface glycoprotein (SU) is closely related to natural horizontally transmissible FeLV subgroup A (FeLV-A) but was found to differ from a prototype to a larger extent than the members of FeLV-A differ among themselves. The sequence differences included point mutations restricted largely to the functional domains of SU, i.e., VRA, VRB, and PRR. Despite the sequence differences in these critical domains, measurements of receptor utilization, including host range and superinfection interference, confirmed the assignment of FeLV-945 to subgroup A. Other proviruses isolated from the cohort contained similar sequence hallmarks and were assigned to FeLV subgroup A. A provirus from cat 1046 contained a histidine-to-proline change at SU residue 6 within an SPHQ motif that was previously identified as a critical mediator of fusion events during virus entry. The 1046 pseudotype virus entered cells only in the presence of the soluble cofactor FeLIX provided in trans, but it retained an ecotropic host range even in the presence of FeLIX. The mutational changes in FeLV-945 were shown to confer significant functional differences compared to prototype FeLV-A viruses. The substitution of FeLV-945 envelope gene sequences for FeLV-A/61E sequences conferred a small but statistically significant replicative advantage in some feline cells. Moreover, substitution of the unique FeLV-945 long terminal repeat and envelope gene for those of FeLV-A/61E altered the disease spectrum entirely, from a thymic lymphoma of a T-cell origin to an as yet uncharacterized multicentric lymphoma that did not contain T cells.

Host cell range of T-lymphotropic feline leukemia virus in vitro

2006 ◽  
Vol 345 (4) ◽  
pp. 1466-1470 ◽  
Author(s):  
Takayuki Shojima ◽  
Risa Nakata ◽  
Takayuki Miyazawa
Keyword(s):  
Host Cell ◽  
Leukemia Virus ◽  
Feline Leukemia Virus ◽  
Cell Range
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