Disease relevance of Leukemia Virus, Feline

• Unlike experimentally induced virus-negative leukaemias and sarcomas of other species, LSA cells from FeLV-negative LSA cats lack any FeLV proteins, including p15 or p12, and complete functional copies of FeLV provirus and thus do not produce FeLV when grown in cell culture [1].
• Infectious helper feline leukemia virus (FeLV) was detected in the blood of all cats after FeSV challenge, but the duration and magnitude of this viremia were reduced in animals that had been previously vaccinated with live, freeze-thawed, or paraformaldehyde-fixed cells [2].
• Because p85 contains antigens related to two structural proteins (p15 and p12) of feline leukemia virus (FeLV), antibodies directed to these were adsorbed with purified FeLV proteins [3].
• Thymic lymphomas induced by the Rickard strain of FeLV (FeLV-R) are of prothymocyte or (immature) cortical thymocyte origin, as these express terminal deoxynucleotidyl transferase, the guinea pig erythrocyte rosette receptor, Ia antigens, partial cortisone sensitivity, and nonspecific esterase [4].
• Selective solubilization and purity of BLV p12 and FeLV p10 was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis [5].

Psychiatry related information on Leukemia Virus, Feline

• HC, which has been shown to enhance the in vivo FeLV susceptibility of cats, also enhanced the permissiveness of M theta from cats to FeLV in vitro (600-fold for M theta from adult cats and 200-fold for M theta) from kittens [6].

High impact information on Leukemia Virus, Feline

• By using monoclonal antibodies to FL-74 cells and to components of FeLV, the cytotoxic antibody was shown to be directed against gp70, a glycoprotein of Mr 70,000, but not against p27 of FeLV or other membrane antigen(s) of FL-74 cells [7].
• Of these, at least 400-500 base pairs located near the 5' end of v-fes encode a portion of the GA-FeSV polyprotein; the remaining 1.2 kilobases are derived from the FeLV env gene but do not appear to encode any detectable product related to the FeLV envelope glycoprotein [8].
• The close homology of the v-fes sequences shows that GA- and ST-FeSV were formed by recombination of FeLV with similar portions of a cat cellular gene (c-fes) [8].
• All three antigens are helper virus-independent and are encoded by the FeSV genome, FOCMA, p15, and p12 antigens cochromatograph as phosphorylated molecules of 85,000 molecular weight (pp85), adsorb to immunoadsorbant columns prepared with antibodies to feline leukemia virus (FeLV), and are precipitated with antisera to FeLV or FOCMA [9].
• Antibodies to FOCMA can be adsorbed with fractions containing pp85 but not with FeLV proteins, including p15 and p12 [9].

Chemical compound and disease context of Leukemia Virus, Feline

• Interestingly, this arginine is not found in endogenous FeLV sequences or in recombinant viruses recovered from feline cells infected with FeLV-A [10].
• The remaining McDonough FeSV P170 methionine-containing peptides were not represented within either FeLV Pr180gag-pol or Pr82env [11].
• The results of pactamycin gene ordering experiments indicated that the small structural proteins of FeLV are ordered p11-p15-p10-p30 [12].
• The gag protein is expressed and shed into the medium of infected cells as particles which have a buoyant density on sucrose gradients and appearance by electron microscopy similar to those of authentic FeLV virions [13].
• Previous experimental studies utilizing human recombinant interferon-alpha-2b (IFN alpha-2b) alone or with zidovudine (AZT) to treat established feline leukemia virus (FeLV) infection resulted in a significant reduction in circulating virus throughout a 49-day treatment period [14].

Biological context of Leukemia Virus, Feline

• These results indicate that FeLV-C has tropism for macrophages, FeLV expression is positively correlated with TNF-alpha expression in macrophages, and TNF-alpha enhances FeLV replication in fibroblasts [15].
• Two ALVAC (canarypox virus)-based recombinant viruses expressing the feline leukemia virus (FeLV) subgroup A env and gag genes were assessed for their protective efficacy in cats [16].
• The LTR enhancer sequences of FeLV contain identical binding sites for some of the transcription factors that are known to affect the lymphomagenicity of SL3 [17].
• Restriction endonuclease mapping of four different clones indicates that there are a number of similarities among them, notably the presence of a 6.0- to 6.4-kilobase pair (kbp) EcoRI hybridizing fragment containing portions of sequences homologous to the gag, pol, env, and long terminal repeat-like elements of the infectious FeLV [18].
• Unlike their exogenous FeLV counterparts, neither nearly full-length endogenous FeLV molecular clones (CFE-6 and CFE-16) nor their isolated LTRs were able to activate collagenase IV gene or MCP-1 expression in transient transfection assays [19].

Anatomical context of Leukemia Virus, Feline

• Moreover, a positive correlation was shown between cell-associated FeLV surface glycoprotein gp70 and TNF-alpha expression in FeLV-C-infected macrophages by immunofluorescence (r = .6; P = .001), measured with a computer-assisted, laser-based digital imaging system [15].
• In an investigation of the role of macrophages in FeLV-C-induced diseases, the concentrations of FeLV and tumor necrosis factor-alpha (TNF-alpha) were compared between feline peritoneal macrophages incubated with FeLV of subgroup A or C [15].
• This suggests that FeLV does not block CTLL-20 proliferation by absorbing or inactivating IL 2, or by occluding IL 2 receptors, and that T lymphocytes develop an insensitivity to lymphokines after contact with FeLV-UV, which may be caused by a metabolic, rather than an immunologic, defect [20].
• To compare the infectivity of the demineralized bone matrix with that of mineralized bone particles in cell cultures and in animals in which they had been implanted, we measured FeLV p27 antigen and (pro)viral nucleic acids as well as antiviral antibodies [21].
• Cats that were aviremic 12 to 16 weeks after challenge exposure were examined for reactivation of latent FeLV infection; 4 weekly doses of methylprednisolone were administered, followed by in vitro culture of bone marrow cells [22].

Gene context of Leukemia Virus, Feline

• Activation of mitogen-activated protein kinase kinases 1 and 2 (MEK1 and -2) by the LTR is an intermediate step in the FeLV LTR-mediated induction of AP-1 activity [23].
• In this report, we show that the U3 region of exogenous FeLV LTRs can induce transcription from collagenase IV (matrix metalloproteinase 9) and monocyte chemotactic protein 1 (MCP-1) promoters up to 12-fold [23].
• The vaccine consisting of FeLV DNA with the IL-12 and IL-18 genes conferred significant immunity, protecting completely against transient and persistent viremia, and in five of six kittens protecting against latent infection [24].
• The 5' 1.9 kb in the HZ2-FeSV are colinear with 5' FeLV sequences, and the 3' 3.5 kb are colinear with 3' FeLV sequences, with the exception of a 0.85-kb deletion in the env gene [25].
• Development of antibodies to feline IFN-gamma as tools to elucidate the cellular immune responses to FeLV [26].

Analytical, diagnostic and therapeutic context of Leukemia Virus, Feline

• Portions of the purified RSV and MuMTV preparations, from which light-scattering samples were obtained, and portions of the actual FeLV light-scattering samples were examined by negatively stained, catalase crystal-calibrated electron microscopy [27].
• During 1989 and 1990, 2,229 feline serum samples were tested for FeLV antigen (gsa p27); positive ELISA results were obtained for 204 (9%) of the samples [28].

References