| molecular cloning of a feline leukemia provirus integrated adjacent to the c-myc gene in a feline t-cell leukemia cell line and the unique structure of its long terminal repeat. | this paper reports the molecular cloning of a rearranged c-myc region from the ft-1 cell line, which was derived from a spontaneous feline t-cell leukemia carrying the feline leukemia virus (felv). an abnormal c-myc ecori fragment of about 18 kilobases, detected by southern blotting, was molecularly cloned from the dna of the ft-1 cell line. the c-myc rearrangement in ft-1 was due to direct integration of the felv provirus genome immediately upstream of the c-myc gene in the opposite transcripti ... | 1989 | 2539700 |
| feline leukemia virus-induced immunodeficiency syndrome in cats as a model for evaluation of antiretroviral therapy. | severe progressive immunodeficiency syndrome can be induced experimentally with a molecularly cloned isolate of feline leukemia virus (felv-faids). the resultant disease syndrome is characterized by persistent viremia, lymphopenia, progressive weight loss, persistent diarrhea, enteropathy, and opportunistic infections. the onset of clinical immunodeficiency disease is prefigured by the replication of the felv-faids variant virus in bone marrow and other tissues. the felv-faids system can be used ... | 1989 | 2540109 |
| testing of nucleoside analogues in cats infected with feline leukemia virus: a model. | in the present communication we evaluate the feline leukemia virus (felv) infection of cats as a model for antiretroviral chemotherapy studies. additionally, we report the results of testing the antiviral effect of the compounds, 3'-azido-3'-deoxythymidine (azt), 2',3'-dideoxycytidine, 2',3'-dideoxyinosine and 2',3'-dideoxyadenosine against felv replication in vitro. cumulative data from experiments in which felv-infected cats were treated with azt at different stages of experimental infection a ... | 1989 | 2540111 |
| negative control region at the 5' end of murine leukemia virus long terminal repeats. | using in vitro protein binding and in vivo functional studies, we have identified novel regulatory sequences near the 5' end of murine leukemia virus (mulv) long terminal repeats (ltrs). these sequences are highly conserved in all mulv ltrs as well as in feline leukemia virus and gibbon ape leukemia virus ltrs. in this upstream conserved region (ucr), gel retardation assays detected two overlapping but distinct binding sites (ucr-u and ucr-l) for nuclear proteins (ucrf-u and ucrf-l). three lines ... | 1989 | 2540425 |
| prevalence of feline calicivirus, feline leukaemia virus and antibodies to fiv in cats with chronic stomatitis. | the prevalence of feline calicivirus (fcv), feline leukaemia virus (felv) and feline immunodeficiency virus (fiv) antibodies were assessed in 78 british and 18 north american household cats with chronic stomatitis and in appropriate controls. in british cats, fcv was significantly (p less than 0.005) more prevalent in both hospital (92 per cent) and general practice (79 per cent) cases compared to their controls (19 per cent in both cases). a similar difference in prevalence of fcv was noted in ... | 1989 | 2541529 |
| atypical localised viral expression in a cat with feline leukaemia. | | 1989 | 2541530 |
| free gp70 from felv: enrichment from cell culture fluid by ferric oxide-agarose chromatography. | a new chromatographic material based on beads of macroporous crosslinked agarose containing ferric oxide particles was used for enrichment of gp70--the envelope glycoprotein of feline leukemia virus (felv). free gp70 was purified from cell culture fluid in one step with a recovery of 50 to 60% and a purification of about 60 times. the described procedure is a suitable first step for the purification of gp70 from large volumes of cell culture fluid. | 1989 | 2541738 |
| retroviruses and malignant lymphoma. | retroviruses are single stranded rna viruses that possess a unique enzyme, reverse transcriptase. this enzyme facilitates the synthesis of double stranded dna intermediates able to integrate into the genome of the host cell. although primarily a means of remaining latent, this integration can have the effect of transforming the cell to malignant growth, either by activation of growth control genes in cis or trans, or by insertion of an integrated oncogene. malignant lymphomas caused by retroviru ... | 1989 | 2541838 |
| remission of felv-associated lymphosarcoma and persistent viral infection after extracorporeal immunoadsorption of plasma using staphylococcal protein a columns: details of immune response. | sixteen feline leukemia virus (felv)-infected cats with lymphosarcoma (lsa) were treated by extracorporeal immunoadsorption using staphylococcal protein a columns in order to remove immunoglobulin g (igg) and circulating immune complexes (cic) from plasma. complete viral clearance and long-lasting tumor regression were achieved in nine of the cats and tumor regression without virus clearance was observed in two other cats. since lsa cats rarely go into spontaneous remission, and since other form ... | 1989 | 2543084 |
| modulation of immunity in patients with autoimmune disease and cancer treated by extracorporeal immunoadsorption with prosorba columns. | extensive animal studies and clinical observations support an immunosuppressive role for certain antibodies and circulating immune complexes (cic) in malignant and autoimmune diseases. investigators have attempted to correct or modulate dysfunction by removal of antibodies or cic from plasma. extra-corporeal immunoadsorption of plasma over columns containing a silica matrix and covalently attached highly purified staphylococcal protein a (prosorba column) is a procedure that specifically removes ... | 1989 | 2543085 |
| hematologic effects of short-term oral diethylcarbamazine treatment given to chronically feline leukemia virus-infected cats. | diethylcarbamazine (n,n-diethyl-4-methyl-1-piperazine carboxamide [dec]) is widely used, especially in tropical regions, to prevent and treat filariasis. the antifilarial effect of this drug has been attributed to immunomodulation. evidence is accumulating to indicate that dec may mitigate the course of feline leukemia virus infection (felv) in cats. previous studies have suggested that continuous oral dec treatment given shortly after evidence of felv infection prevents or delays lymphopenia an ... | 1989 | 2543497 |
| treatment of felv-induced immunodeficiency syndrome (felv-faids) with controlled release capsular implantation of 2',3'-dideoxycytidine. | 2',3'-dideoxycytidine (ddc) inhibits replication of the immunodeficiency inducing strain of feline leukemia virus (felv-faids) in vitro at concentrations ranging from 1-10 micrograms/ml. additive antiviral effect is achieved when ddc is combined with either human recombinant alpha interferon (ifn alpha) or tumor necrosis factor (tnf) plus ifn alpha. initial in vivo pharmacokinetic studies in cats, utilizing bolus intravenous administration of ddc (20 mg/kg), resulted in peak plasma concentration ... | 1989 | 2544137 |
| feline cytotoxic large granular lymphocytes induced by recombinant human il-2. | large granular lymphocytes (lgl) have been characterized phenotypically and functionally as cytotoxic t lymphocytes, nk cells or lymphokine-activated killer cells. the most prominent morphologic feature of lgl is large cytoplasmic granules that are thought to contain the molecules responsible for cell lysis. in this study, we describe the morphologic and functional characteristics of il-2-dependent cytotoxic lymphocytes derived from feline pbl. stimulation of feline pbl with con a followed by cu ... | 1989 | 2544649 |
| concentration and purification of feline leukaemia virus (felv) and its outer envelope protein gp70 by aqueous two-phase systems. | the major protective antigens of retroviruses are considered to be their glycosylated envelope proteins. however, the methods commonly employed to enrich and purify virus from culture media such as pelleting and density-gradient centrifugation result in a low recovery of the viral external glycoproteins. this is an obvious drawback when the virus is intended for use in a vaccine. in search for alternative methods to concentrate and purify felv, we have attempted extraction in two-phase systems b ... | 1989 | 2547820 |
| diagnosis of feline leukemia virus and feline immunodeficiency virus infections. | feline leukemia virus is an oncogenic retrovirus that can result in a wide variety of neoplastic and non-neoplastic diseases, including immunosuppression. diagnosis of felv infection can be achieved by several methods, including virus isolation; ifa assay of a peripheral blood smear; and detection of a viral protein (called p27) by elisa testing of whole blood, plasma, serum, saliva, or tears. commercially available elisa kits have revolutionized felv testing and have become very popular as "in- ... | 1989 | 2549672 |
| feline immunodeficiency virus infection. | feline immunodeficiency virus (fiv) (formerly feline t-lymphotropic lentivirus or ftlv) was first isolated from a group of cats in petaluma, california in 1986. the virus is a typical lentivirus in gross and structural morphology. it replicates preferentially but not exclusively in feline t-lymphoblastoid cells, where it causes a characteristic cytopathic effect. the major structural proteins are 10, 17 (small gag), 28 (major core), 31 (endonuclease?), 41 (transmembrane?), 52 (core precursor pol ... | 1989 | 2549690 |
| felv-faids-induced immunodeficiency syndrome in cats. | findings are reviewed, relevant to elucidation of the pathogenic, genetic and biochemical properties of a single, genetically heterogeneous isolate of feline leukemia virus (felv-faids) shown to induce fatal immunodeficiency disease in nearly 100% of inoculated cats. hypotheses are suggested which pertain to the mechanism of t-cell killing by this virus, and which extrapolate findings in the felv-faids animal model to aids induced in humans by human immunodeficiency virus (hiv). | 1989 | 2549691 |
| immunodeficiency in latent feline leukemia virus infections. | challenge of naive experimental animals with a retroviral inoculum may result in one of two broad sequelae. the first is the establishment of an appropriate humoral and cellular immune response leading to a condition of immunity to subsequent infection with the retrovirus. alternatively, the host may fail to develop a successful immune response, resulting in a chronic viremia associated with immunosuppression and ultimately death due to secondary pathogens. an alternate disease course is the est ... | 1989 | 2549692 |
| felv-induced immunosuppression through alterations in signal transduction: changes in intracellular free calcium levels. | feline leukemia virus (felv) is a retrovirus with immunosuppressive properties. the mechanism(s) of immunosuppression is unknown. calcium has been shown to be a second messenger in cellular activation and regulation. this study was designed to determine whether felv alters intracellular free calcium (ifc) levels in an felv-infected feline lymphoid cell line. control cells and felv-infected cells were exposed to concanavalin a, formyl-l-methionyl-l-leucyl-l-phenylalanine, and leukotriene b4. the ... | 1989 | 2549693 |
| felv-induced immunosuppression through alterations in signal transduction: down regulation of protein kinase c. | activation of protein kinase c by a phorbol ester, 12-o-tetradecanoylphorbol-13-acetate (tpa), was shown to stimulate the respiratory burst in normal cat neutrophils. neutrophils from feline leukemia virus (felv)-exposed viremic and nonviremic cats had significant suppression of their respiratory burst when stimulated with tpa. the addition of whole ultraviolet light-inactivated felv and felv proteins to normal cat neutrophils produced no significant suppression of the respiratory burst. these d ... | 1989 | 2549694 |
| control of feline leukaemia virus. | feline leukaemia virus (felv) usually occurs in its natural species, the domestic cat. felv is also important to human individuals as a comparative model, as it may cause a variety of diseases, some malignant and some benign, such as immunosuppression, which bears a resemblance to aids (acquired immune deficiency syndrome) in man. felv is transmitted among cats by contagion. the main sources of infection are persistently infected carrier cats which continuously excrete virus. dissemination of fe ... | 1989 | 2549695 |
| diseases associated with spontaneous feline leukemia virus (felv) infection in cats. | more than 2000 cats sent for necropsy in order to provide a diagnosis were investigated immunohistologically using paraffin sections for the presence of a persistent infection with feline leukemia virus (felv). the spectrum of neoplastic and non-neoplastic diseases associated significantly with felv infection was determined statistically. three-quarters of the cats with persistent felv infections died of non-neoplastic diseases and about 23% died of tumors, nearly exclusively those of the leukem ... | 1989 | 2549696 |
| false-positive reactions associated with anti-mouse activity in serotests for feline leukemia virus antigen. | false-positive reactions were observed in commercial test kits designed to detect felv infections in cats. the false-positive reactions were associated with heterophilic antibody in cat serum directed primarily against mouse immunoglobulins. of 2,830 sera tested, 579 were considered felv positive or equivocal via elisa; of these, 10 were found that did not have felv antigen but did have anti-mouse antibody. with 95% confidence, 0.14% to 0.57% of cats would have such false-positive reactions in e ... | 1989 | 2551863 |
| sensitivity and specificity of blood test kits for feline leukemia virus antigen. | enzyme-linked immunosorbent assay (elisa) test kits have been used widely to diagnose felv infection. several companies have licensed such kits, but because these test kits are designed somewhat differently, a demonstration of their relative merits was needed. differences in the sensitivity and specificity of 7 commercial test kits were determined by testing sera that induce false-negative (limiting dilution of felv group specific antigen, p27), and false-positive (cat anti-mouse antibody) test ... | 1989 | 2551864 |
| interpreting feline leukemia test results. | routine prevaccinal screening for felv has inherent statistical limitations owing to the magnification of false-positive test errors by the low prevalence of felv viremia in the general cat population. positive elisa test results obtained in a screening program should be interpreted with caution, because a high proportion--approximately 72%--of such are likely to be false-positive results. on the other hand, routine screening is an excellent method for ruling out felv viremia, because a false-ne ... | 1989 | 2551866 |
| induction of aplastic anemia by intra-bone marrow inoculation of a molecularly cloned feline retrovirus. | intra-bone marrow inoculation of cells infected with molecularly cloned feline retrovirus (felv-c-sarma [fsc]) associated with aplastic anemia was examined to test the hypothesis that cell-to-cell transmission of virus might facilitate marrow cell infection and anemogenesis, a possibility suggested by in-vitro co-culture experiments. ibm inoculation of either fsc-infected feline marrow cells or fibroblasts of weanling cats bypassed age-related restriction of fsc replication, initiated viremia, c ... | 1989 | 2552228 |
| [cat retroviruses and human retroviruses: elements of comparison]. | following emotional head-lines of certain articles in the press, making believe that the cat could be susceptible to the aids virus, the authors present elements of comparison between principal feline retroviruses (the feline leucosis virus and the feline immunodeficiency virus) and the two human immunodeficiency viruses (hiv). the feline leucosis virus in differentiated from the human and the feline immunodeficiency viruses by its virological, pathological and epidemiological characteristics. b ... | 1989 | 2553219 |
| scrambled duplications in the feline leukemia virus gag gene: a putative pattern for molecular evolution. | the present study is a detailed computer-assisted analysis of the feline leukemia virus gag gene nucleotide sequence together with its flanking sequences (st-felv gag) that is compared with the aligned sectors of the moloney strain of murine leukemia virus (mo-mulv gag) and of three strains of feline sarcoma virus. it shows that perfectly matched repeated oligomers up to 13 nucleotides long are overrepresented and scattered throughout both st-felv gag and mo-mulv gag, in noncoding and coding sec ... | 1989 | 2553988 |
| prevalence of feline leukaemia virus and antibodies to feline immunodeficiency virus in cats in the united kingdom. | a representative sample of the pet cat population of the united kingdom was surveyed. blood samples from 1204 sick and 1007 healthy cats of known breed, age and sex were tested for antibodies to feline immunodeficiency virus (fiv) and feline leukaemia virus (felv). the prevalence of fiv was 19 per cent in sick cats and 6 per cent in healthy cats, and the prevalence of felv was 18 per cent in sick cats and 5 per cent in healthy cats; both infections were more common in domestic cats than in pedig ... | 1989 | 2554556 |
| lymphoid and mesenchymal tumors in transgenic mice expressing the v-fps protein-tyrosine kinase. | src, abl, and fps/fes are prototypes for a family of genes encoding nonreceptor protein-tyrosine kinases. the oncogenic potential of the v-fps protein-tyrosine kinase was investigated by introduction of the gag-fps coding sequence of fujinami sarcoma virus into the mouse germ line. transgenic mice with v-fps under the transcriptional control of a 5' human beta-globin promoter (gf) or with both 5' and 3' beta-globin regulatory sequences (gef) were viable. unexpectedly, both gf and gef transgenes ... | 1989 | 2555699 |
| animal models of aids. | animal models of aids are essential for understanding the pathogenesis of retrovirus-induced immune deficiency and encephalopathy and for development and testing of new therapies and vaccines. aids and related disorders are etiologically linked to members of the lentivirus subfamily of retroviruses; these lymphocytopathic lentiviruses are designated human immuno-deficiency virus type 1 (hiv-1) and human immuno-deficiency virus type 2 (hiv-2). the only animals susceptible to experimental hiv-1 in ... | 1989 | 2556312 |
| on interpretation of feline leukemia test results. | | 1989 | 2557312 |
| a survey of the feline leukaemia virus in singapore. | in this survey for the presence of the feline leukaemia virus (felv) in the singapore domestic cat population, the sera of two different groups of unvaccinated mainly short haired cats which were over 6 months old were sampled. the felv enzyme-linked immunoadsorbent assay (elisa) diagnostic test kit was used to detect the presence of the felv group specific (gs) antigens in the blood of cats. of the 345 clinically healthy cats surveyed, 34 sera (9.9%) were found to be positive and of the group o ... | 1989 | 2560357 |
| isolation and characterisation of a myeloid leukaemia inducing strain of feline leukaemia virus. | | 1989 | 2560447 |
| the mutated, myeloid cell-specific growth factor receptor v-fms transforms avian erythroid but not myeloid cells. | in avian hematopoietic cells, transformation by tyrosine kinase oncogenes is restricted to the erythroid lineage. to study the mechanism of this striking target cell specificity, we constructed an avian retrovirus correctly expressing the feline v-fms protein, an oncogenic version of the myeloid-specific csf-1 receptor. similar to other tyrosine kinase oncogenes (erbb, src, fps, sea), the v-fms oncogene induced progenitor cells to self-renew in an erythropoietin-independent manner. spontaneous d ... | 1989 | 2560752 |
| feline immunodeficiency virus infection in a population of pet cats from southeastern florida. | blood samples from 95 randomly selected pet cats that were brought to veterinarians in southeastern florida were tested for antibodies to feline immunodeficiency virus (fiv). virus-specific antibodies (indicative of virus infection) were found in 8 of the 95 (8.4%) cats tested. all of the virus-infected cats were males (statistically significant, p less than or equal to 0.016) and were at least 1 year of age. the 3 most severely ill cats infected with fiv were also infected with feline leukemia ... | 1989 | 2562225 |
| identification, using synthetic peptides, of the minimum amino acid sequence from the retroviral transmembrane protein p15e required for inhibition of lymphoproliferation and its similarity to gp21 of human t-lymphotropic virus types i and ii. | synthetic peptides containing portions of a highly conserved region of retroviral transmembrane proteins of human and animal retroviruses were tested for their ability to inhibit lymphoproliferation to determine the minimum amino acid sequence required. the previously reported immunosuppression mediated by the peptide cks-17 was confirmed and further localized to a sequence of eight residues essentially identical to the sequence present in the transmembrane protein gp21 of human t-lymphotropic v ... | 1989 | 2746730 |
| serological responses in cats vaccinated with felv iscom and an inactivated felv vaccine. | various approaches have been considered for generation of effective and safe vaccines against retroviruses, including hiv, with limited success. in the present vaccination study, encompassing 137 household cats, we have composed an experimental iscom subunit vaccine containing gp70 of feline leukaemia virus (felv)--the external glycosylated envelope protein, and the transmembrane protein p15e, with a commercial available inactivated felv vaccine (leukocell). the two vaccines were estimated to co ... | 1989 | 2750271 |
| formation and characterization of felv iscoms. | immunostimulating complexes (iscoms) have been prepared from feline leukaemia virus (felv) envelope proteins. the iscoms were characterized biochemically in sds-polyacrylamide gel electrophoresis showing the presence of proteins of estimated molecular weights of 15,000, 27,000 and 70,000. immunoblotting showed that both the transmembrane protein p15e and the external glycoprotein gp70 (making up the gp85 protein) were present in the iscom. furthermore, a degradation product of gp70 with an estim ... | 1989 | 2750272 |
| use of 8-methoxypsoralen and long-wavelength ultraviolet radiation for decontamination of platelet concentrates. | transmission of viral diseases through blood products remains an unsolved problem in transfusion medicine. we have developed a psoralen photochemical system for decontamination of platelet concentrates in which platelets are treated with long wavelength ultraviolet radiation (uva, 320-400 nm) in the presence of 8-methoxypsoralen (8-mop). bacteria, rna viruses, and dna viruses ranging in genome size from 1.2 x 10(6) daltons, encompassing the size range of human pathogens, were inoculated into pla ... | 1989 | 2752129 |
| clinical feline toxoplasmosis. serologic diagnosis and therapeutic management of 15 cases. | clinical toxoplasmosis was diagnosed in 15 cats by correlating serologic evidence of infection and clinical signs to either response to therapy or histopathologic demonstration of the organism. ophthalmic manifestations, primarily involving the anterior segment, were common. other common physical examination abnormalities included muscle hyperesthesia, fever, and weight loss. response to therapy was variable, but administration of clindamycin hydrochloride resulted in resolution of all clinical ... | 1989 | 2778747 |
| investigation of immunosuppressive properties of inactivated human immunodeficiency virus and possible neutralization of this effect by some patient sera. | retroviral infections are accompanied by immunosuppression in a variety of species. for feline leukemia virus, the immunosuppression has been ascribed to the transmembrane envelope protein, p15e, which suppresses the proliferative responses of cat, mouse, and human lymphocytes. a similar suppressive effect has been shown for a lysate of human immunodeficiency virus (hiv), strain htlv-iiib. here we determined that detergent-disrupted htlv-iiib lystate exerted a strong suppressive effect on pha-st ... | 1989 | 2786762 |
| [the distribution of feline leukemia virus (felv) in switzerland]. | | 1987 | 2820053 |
| effects of treatment with cobra venom factor on experimentally induced feline leukemia. | five- to six-month-old specific-pathogen-free cats were exposed to cobra venom factor (cvf) alone (4 cats), rickard feline leukemia virus (felv; 9 cats), or cvf and felv (6 cats). host-virus relationships were evaluated by monitoring the development of viremia, production of antibody against feline oncornavirus-associated cell membrane antigen, and amount of circulating immune complexes (cic). exposure to cvf induced complement depletion, which lasted 8 to 15 days. however, complement depletion ... | 1987 | 2820273 |
| influence of inactivated feline retrovirus on feline alpha interferon and immunoglobulin production. | the effect of ultraviolet-inactivated feline leukaemia virus (uv-felv) on the development of feline immunoglobulin-secreting cells (isc) was investigated using a reverse haemolytic plaque assay. low concentrations of uv-felv at 2 x 10(-4) to 2.0 micrograms/ml stimulated the production of isc. by contrast, the same concentration of uv-felv suppressed the development of pokeweed mitogen (pwm)-driven isc. maximum suppression of isc occurred at 50 micrograms/ml of uv-felv. the generation of an inter ... | 1987 | 2820639 |
| retrovirus-induced feline pure red cell aplasia: the kinetics of erythroid marrow failure. | cats viremic with feline leukemia virus subgroup c (felv-c) develop pure red cell aplasia (prca) characterized by the loss of detectable late erythroid progenitors (cfu-e) in marrow culture. normal numbers of early erythroid progenitors (bfu-e) and granulocyte-macrophage progenitors (cfu-gm) remain, suggesting that the maturation of bfu-e to cfu-e is impaired in vivo. we have examined the cell cycle kinetics of bfu-e and their response to hematopoietic growth factor(s) to better characterize ery ... | 1987 | 2821017 |
| retrovirus-induced feline pure red cell aplasia. hematopoietic progenitors are infected with feline leukemia virus and erythroid burst-forming cells are uniquely sensitive to heterologous complement. | feline leukemia virus subgroup c/sarma (felv-c) induces pure red cell aplasia (prca) in cats. just before the onset of anemia, erythroid colony-forming cells (cfu-e) become undetectable in marrow culture, yet normal frequencies of erythroid burst-forming cells (bfu-e)- and granulocyte-macrophage colony-forming cells (cfu-gm) persist. to determine if erythroid progenitors were uniquely infected with retrovirus, marrow mononuclear cells from cats viremic with felv-c were labeled with monoclonal an ... | 1987 | 2821071 |
| molecular cloning of an endogenous cat retroviral element (ece 1)--a recombinant between rd-114 and felv-related sequences. brief report. | a lambda l 47.1 clone library was constructed from bamhi digests of cellular cat dna and was screened with cdna probes specific for the 3'-terminus of the replication competent rd-114 virus. the first analysis of one clone (lambda-ece 1) shows that it consists at least of a 3'-ltr and a 5' adjacent env gene. the ltr nucleotide sequences of the rd-114 cdna clones and ece 1 are identical within the r region and unrelated to felv. otherwise, the region upstream from the 3'-ltr of ece 1 shows homolo ... | 1987 | 2821968 |
| structural abnormality and over-expression of the myc gene in feline leukemias. | tumor cells of feline leukemia were examined for structural abnormality and expression of the myc gene. four of 12 spontaneous leukemia cases showed structural abnormalities of the myc gene detected by southern blotting analysis. of these 4 cases, one (case 1) showed a dna rearrangement in the 5' portion of the c-myc locus associated with integration of feline leukemia virus (felv) genome. another case had a newly inserted myc gene which was transduced by felv. in the 2 other cases, no relation ... | 1987 | 2822586 |
| nucleotide sequence analysis of the ltrs and env genes of sm-fesv and ga-fesv. | the nucleotide sequences of the env genes and the ltrs of sm- and ga-fesv lambda recombinants have been determined by the maxam and gilbert method and/or the dideoxy method with specific sequencing primers. comparison of the two sequences reveals a homology of 93%, the differences being randomly distributed. two frameshift mutations are observed in the ga-fesv isolate which close the reading frame and would prevent the synthesis of the env protein. comparison of these two fesv sequences with the ... | 1987 | 2823466 |
| experimental transmission and pathogenesis of immunodeficiency syndrome in cats. | we describe the identification, experimental transmission, and pathogenesis of a naturally occurring powerfully immunosuppressive isolate of feline leukemia virus (designated here as felv-faids) which induces fatal acquired immunodeficiency syndrome (aids) in 100% (25 of 25) of persistently viremic experimentally infected specific pathogen-free (spf) cats after predictable survival periods ranging from less than 3 months (acute immunodeficiency syndrome) to greater than one year (chronic immunod ... | 1987 | 2823940 |
| cryptosporidiosis in a feline leukemia virus-positive cat. | a 4-year-old felv-positive cat with a 1-year history of intermittent diarrhea and subsequent anorexia, depression, and weight loss had enteric cryptosporidiosis at necropsy. cryptosporidium sp is an important cause of gastroenteritis and diarrhea in various species, including human beings with acquired immunodeficiency syndrome. a major determinant of the severity of the disease caused by cryptosporidium sp is the immunologic status of the affected animal. cryptosporidiosis should be included in ... | 1987 | 2824411 |
| low-dose cytosine arabinoside-induced remission of lymphoblastic leukemia in a cat. | low-dose cytosine arabinoside (10 mg/m2, q 12 h), an antimetabolite chemotherapeutic agent, was administered subcutaneously to a cat with aleukemic lymphoblastic leukemia. after several weeks of this treatment, there was marked improvement in the neutrophil count and pcv, as well as restoration of adequate numbers of normal bone marrow cells. the remission lasted 10 weeks. | 1987 | 2824412 |
| comparison of serological responses in cats vaccinated with two different felv vaccine preparations. | | 1987 | 2825396 |
| the role of feline leukaemia virus in naturally occurring leukaemias. | | 1987 | 2825985 |
| feline leukemia virus: current status of the feline induced immune depression and immunoprevention. | this is a review of the current knowledge of feline leukemia virus (felv) associated with immune depression observed in cats. it will focus on the clinical and experimental observations associated with feline retroviral infection and presence in vivo and in vitro. we will briefly describe retroviral-associated acquired immune deficiency syndrome associated with felv infection in the cat and specific cellular pathology associated with felv latency. in addition, we will focus on the action of felv ... | 1987 | 2826030 |
| non-lymphoid hematopoietic neoplasia in cats: a retrospective study of 60 cases. | sixty cats with hematologic abnormalities indicative of non-lymphoid hematopoietic neoplasia were classified into two groups, myelodysplastic syndromes (mds) and acute myelogenous leukemias (aml), using criteria developed for human patients with similar diseases. cats with myeloblast counts in bone marrow of less than 30% were classed as mds and cats with myeloblast counts of 30% or greater were classed as aml. the clinical, laboratory, and postmortem findings in each group were described and co ... | 1988 | 2826080 |
| demonstration of retroviral proteins associated with erythroid progenitors of cats with feline leukemia virus-induced erythroid aplasia. | feline erythroid aplasia is a fatal retrovirus-induced disease related to infection with feline leukemia virus of subgroup c. when bone marrow cells from cats inoculated with felv were incubated with polyvalent antibody to felv and cultured for erythroid colony formation, a complement-dependent inhibition of erythroid progenitors was demonstrated with virtually complete suppression of erythroid colony-forming units (cfu-e) and burst-forming units (bfu-e) evident from post-inoculation week 4 unti ... | 1987 | 2826931 |
| o-linked glycosylation of retroviral envelope gene products. | treatment of [3h]glucosamine-labeled friend mink cell focus-forming virus (frmcf) gp70 with excess peptide:n-glycanase f (pngase f) resulted in removal of the expected seven n-linked oligosaccharide chains; however, approximately 10% of the glucosamine label was retained in the resulting 49,000-mr (49k) product. for [3h]mannose-labeled gp70, similar treatment led to removal of all the carbohydrate label from the protein. prior digestion of the pngase f-treated gp70 with neuraminidase resulted in ... | 1988 | 2828650 |
| strong sequence conservation among horizontally transmissible, minimally pathogenic feline leukemia viruses. | we report the first complete nucleotide sequence (8,440 base pairs) of a biologically active feline leukemia virus (felv), designated felv-61e (or f6a), and the molecular cloning, biological activity, and env-long terminal repeat (ltr) sequence of another felv isolate, felv-3281 (or f3a). f6a corresponds to the non-disease-specific common-form component of the immunodeficiency disease-inducing strain of felv, felv-faids, and was isolated from tissue dna of a cat following experimental transmissi ... | 1988 | 2828667 |
| feline leukemia virus infection in street cats in tokyo area. | | 1987 | 2828737 |
| murine monoclonal antibodies cross-reactive with feline peripheral blood mononuclear cells. | twelve murine monoclonal antibodies (mab), specific for canine, human, and mouse cell surface determinants on lymphohemopoietic cells, were tested for reactivity (using indirect immunofluorescence) with peripheral blood mononuclear cells (pbmc) from 3 normal cats and 3 felv-positive cats with lymphoblastic leukemia. mab dly6 and 1h3, specific for canine lymphocytes, mab hb57s, specific for human mu(igm) chain, mab j-118 40.164.3 and h81.98.71, specific for murine and human ia, all had higher bin ... | 1987 | 2829413 |
| effect of diethylcarbamazine on cats given feline leukaemia virus vaccine. | leukocell (norden laboratories, lincoln, ne, usa), a commercially available retroviral vaccine, is given to protect susceptible cats against feline leukaemia virus. oral diethylcarbamazine, an immunomodulator used in the treatment of filariasis, when given with 1 ml i.m. leukocell, increased titres and duration of serum antibodies to feline oncornavirus-associated cell membrane antigen and transient average monocyte counts in treated/vaccinated cats as compared to cats that received vaccine with ... | 1987 | 2829454 |
| feline leukemia virus and pneumocystis carinii infection. | | 1987 | 2830393 |
| idiotype networks in the immune response to feline leukemia virus. | | 1987 | 2830503 |
| suppression of feline bone marrow fibroblast colony-forming units by feline leukemia virus. | bone marrow fibroblast colony-forming units (cfu-f) were evaluated in cats experimentally infected with feline leukemia virus (felv). cats that developed persistent viral infection and anemia (progressor cats) had a progressive decrease in the number of cfu-f at 2, 4, 6, 8, and 10 weeks after inoculation with felv. this suppression of cfu-f number in progressor cats ranged from 16 to 44% of the preinoculation cfu-f value. cats that did not develop persistent viral infection or anemia (regressor ... | 1988 | 2831764 |
| epidemiology of feline leukaemia virus infections. | in cats the commonest cause of leukaemia and lymphomas is infection with feline leukaemia virus (felv). following infection with this retrovirus some cats eliminate the virus and produce neutralizing antibody whereas others remain latently infected. a final group become persistently infected, and eventually succumb to neoplastic or non-neoplastic diseases induced by the virus. the proportion of cats falling into these different post-infection states depends on the age of exposure and the dose of ... | 1987 | 2832022 |
| viral transduction of host genes in naturally occurring feline t-cell leukaemias: transduction of myc and a t-cell antigen receptor beta-chain gene. | | 1987 | 2832272 |
| pathogenic and host range determinants of the feline aplastic anemia retrovirus. | feline leukemia virus (felv) c-sarma (or fsc) is a prototype of subgroup c felvs, which induce fatal aplastic anemia in outbred specific-pathogen-free (spf) cats. felv c isolates also possess an extended host range in vitro, including an ability, unique among felvs, to replicate in guinea pig cells. to identify the viral determinants responsible for the pathogenicity and host range of fsc we constructed a series of proviral dnas by exchanging gene fragments between fsc and felv-61e (or f6a), the ... | 1988 | 2833751 |
| myelofibrosis in cats with myelodysplastic syndrome and acute myelogenous leukemia. | bone marrow sections from 44 cats with myelodysplastic syndrome (mds) or acute myelogenous leukemia (aml) were graded for reticulin content using light microscopic methods. twenty-seven (61%) of the cats had slight to marked reticulin myelofibrosis. the association of myelofibrosis with possible pathogenetic factors, including megakaryocyte count, intramedullary lymphoid follicles, hemosiderin content, and felv antigenemia, was examined. no evidence was found that indicated a causal relationship ... | 1988 | 2834859 |
| feline haemobartonellosis: clinical, haematological and pathological studies in natural infections and the relationship to infection with feline leukaemia virus. | haemobartonella felis infection was demonstrated in 38 cats which could be divided into four groups as follows: group a, feline leukaemia virus (felv) free cats with h felis infection alone; group b, felv free cats with h felis infection and other clinical conditions; group c, felv positive cats with h felis infection but no clinical manifestation of felv related or any other intercurrent disease; and group d, felv positive cats with h felis infection and clinical manifestations of felv related ... | 1988 | 2834861 |
| use of a subunit feline leukemia virus vaccine in exotic cats. | three adult bengal tigers, 2 immature white tigers, and 3 adult servals were vaccinated im with three 1-ml doses of a subunit felv vaccine with dosage interval guidelines of the manufacturer. all cats had increased antibody titers to felv gp 70 capsular antigen and feline oncornavirus cell membrane-associated antigen during the vaccination trial. three weeks after the third vaccination, 7 of the 8 cats had gp70 antibody titers greater than 0.2 (optical density), and all 8 cats had feline oncorna ... | 1988 | 2835347 |
| effect of diethylcarbamazine on serum antibody to feline oncornavirus-associated cell membrane antigen in feline leukemia virus cats. | diethylcarbamazine (n,n-diethyl-4-methyl-1-piperazine carboxamide; dec) is a drug frequently used for prevention and treatment of the filariases. an opsonic action of dec may generate increased immune responses to microfilariae. we tested the hypothesis that dec treatment could result in higher antibody levels to other infectious agents. a retroviral animal model was studied, in light of the consideration that use of dec as an antifilarial agent could conceivably alter seroepidemiologic surveys ... | 1988 | 2836593 |
| a case of feline large granular lymphoma. | | 1988 | 2838677 |
| [serological survey of feline leukemia virus infection and the outcome of antibody-positive cats]. | a serological survey was carried out to examine the presence of antibodies against feline leukemia virus (felv) and feline oncornavirus-associated cell membrane antigen (focma) in 208 cat sera collected at teikyo university school of medicine. seven cats (3.4%) were positive for felv antibodies by enzyme-linked immunosorbent assay whereas no cat was positive for focma antibody by indirect membrane immunofluorescent test. anemia, leukemia and/or lymphoma formation were not observed in these felv ... | 1988 | 2840305 |
| effects of increasing cyclic amp or calcium on feline erythroid progenitors in vitro: normal cells are stimulated while cells from retrovirus-infected cats are suppressed. | pharmacologic modulators of cyclic 3',5'-adenosine monophosphate (camp) and calcium were added to cultures of bone marrow cells from normal cats and cats with retrovirus-induced erythroid aplasia (ea). treatment with the following reagents increased the number of erythroid progenitors (cfu-e and bfu-e) in cells from normal cats: isoproterenol, dibutyryl camp, forskolin, ro-20-1724 and a23187. however, treatment of cells collected from viremic cats not only failed to enhance cfu-e and bfu-e but i ... | 1988 | 2840470 |
| structure and function of endogenous feline leukemia virus long terminal repeats and adjoining regions. | the nucleotide sequence of the 5' long terminal repeat (ltr) of three independent loci (cfe-6, cfe-16, and cf-14) of endogenous feline leukemia virus (felv) dnas of the domestic cat genome was determined. the 3' ltr of the cfe-6 clone was also sequenced. the endogenous felv ltrs, which were very similar to each other in sequence and in organization of the functional domains, differed considerably from the exogenous felv ltr in the u3 region. the major differences in u3 included variations in set ... | 1988 | 2843665 |
| a feline model for the myelodysplastic syndrome: pre-leukaemic abnormalities caused in cats by infection with a new isolate of feline leukaemia virus (felv), ab/gm1. | | 1988 | 2844635 |
| sir william weipers commemorative lecture. cancer and aids; the contribution of comparative medicine. | | 1988 | 2845627 |
| fluorometric enzyme immunoassay for measurement of infectious feline leukemia virus and its neutralization. | a fluorometric enzyme immunoassay using an alkaline phosphatase-conjugated monoclonal antibody was developed to quantitate feline leukemia virus (felv) infection. monoclonal antibodies, directed against the felv structural protein p27, were conjugated with alkaline phosphatase using a modified maleimide method. the enzyme immunoassay requires only 4 days to reproducibly measure felv production instead of the 12 days required for the commonly used transformation assay using c81 cells. a linear co ... | 1988 | 2846700 |
| protein immunoassay based on agglutination of antibody-coated ferric oxide particles. | a novel immunoassay is described based on the agglutination by antigens of antibody-coated ferric oxide (fe2o3) particles. the procedure for attachment of antibodies to the ferric oxide particles is simple and fast. the assay was used for identification and quantification of gamma-globulin in human serum and in chromatographic fractions as well as of gp70 (an envelope protein from feline leukemia virus) in the culture medium and for identification of the thyroid-stimulating hormone (tsh). | 1988 | 2846702 |
| tumorigenic potential of a myc-containing strain of feline leukemia virus in vivo in domestic cats. | the oncogenic capacity of a myc-containing strain of feline leukemia virus (felv), termed lc-felv, has been examined after inoculation of the virus into neonatal kittens. like other myc-containing strains of felv, lc-felv may induce with relatively short latency, but does not necessarily induce, thymic lymphosarcoma in viremic animals. naturally occurring and experimentally induced tumors are t-cell lymphomas which contain clonally integrated lc-felv proviral dna and which cannot readily be cult ... | 1988 | 2846887 |
| clinical and immunologic aspects of felv-induced immunosuppression. | cats exposed to the feline leukemia virus (felv) may mount an effective immune response and eliminate the virus, develop a non-viremic, latent infection or become persistently infected and shed the virus. persistently infected cats commonly die of secondary opportunistic infections that result from felv-induced immunosuppression. the acquired immunosuppression is the most frequent and most devastating consequence of felv infection in the cat. immunosuppression is targeted primarily to the cell-m ... | 1988 | 2847393 |
| feline leukemia virus vaccine: new developments. | | 1988 | 2847394 |
| lymphotropic retroviruses of animals and man. | | 1988 | 2847502 |
| feline leukemia/sarcoma viruses and immunodeficiency. | | 1988 | 2847504 |
| antithymocyte globulin treatment of retrovirus-induced feline erythroid aplasia: in vivo and in vitro studies. | the kawakami-theilen strain of feline leukemia virus (felv-kt) was used experimentally to produce erythroid aplasia in cats. the in vivo effects of goat anti-feline-thymocyte globulin (atg) on hematopoiesis were investigated in felv-negative normal and felv-positive anemic cats. treatment was initiated in anemic cats between 4 and 6 weeks postinoculation (pi) when erythroid progenitors were reduced to 10% of normal levels. during the first 2 weeks of treatment, atg significantly increased the nu ... | 1988 | 2847891 |
| [critical application of the cite-felv test, a new concept elisa for the study of feline leukemia virus in blood samples from cats]. | | 1988 | 2848490 |
| feline immunodeficiency syndrome--a comparison between feline t-lymphotropic lentivirus and feline leukemia virus. | a feline t-lymphotrophic lentvirus (ftlv) has recently been isolated from a domestic cat free of feline leukemia virus (felv). this virus is distinct from felv (an oncornavirus), although they share a common denominator, namely, the ability to cause immunosuppression and induce lymphadenopathy and anemia. their differences can be revealed by examining the following: the metal requirement for reverse transcriptase activity, the antigenic comparison by western blot analysis, the different suscepti ... | 1988 | 2848998 |
| activation of the feline c-fms proto-oncogene: multiple alterations are required to generate a fully transformed phenotype. | the v-fms oncogene is capable of producing tumors in vivo and transforming cells in culture; in contrast, the c-fms proto-oncogene is nontransforming. in this report we present the complete nucleotide sequence of a feline c-fms cdna, the progenitor of the v-fms oncogene. comparison of this sequence with that of v-fms shows that the proteins encoded by these two genes differ by nine amino acid substitutions and the replacement of 50 c-terminal amino acids present in c-fms by 11 unrelated residues ... | 1988 | 2849512 |
| igg-fc-receptor positive and negative t cells from feline leukemia virus-infected cats. | | 1988 | 2850387 |
| feline leukemia virus infection in a captive cheetah and the clinical and antibody response of six captive cheetahs to vaccination with a subunit feline leukemia virus vaccine. | | 1986 | 2851578 |
| feline leukemia virus vaccines. | | 1986 | 2853437 |
| effect of continuous oral diethylcarbamazine treatment on lymphocyte counts of feline leukemia virus-infected cats. | in previous studies, administration of diethylcarbamazine (dec) resulted in increased serum antibody titers to feline oncornavirus-associated cell membrane antigen (focma) in cats infected with feline leukemia virus (felv). felv infection of cats frequently results in immunosuppression associated with lymphopenia. the present investigation demonstrated that chronic administration of dec prevented or delayed severe lymphopenia in two felv-infected offspring of an felv-infected queen as compared t ... | 1988 | 2855080 |
| receptor-mediated leukaemogenesis: hypothesis revisited. | the discovery of the first example of retroviral transduction of an immunological effector molecule has led us to reconsider the possible importance of cell surface receptors of the immune system in leukaemia development. antigen receptors on lymphoid cells not only bind external ligands but are crucial in the control of cellular proliferation. the concept of autocrine stimulation in oncogenesis is already well established and we see no reason to exclude the possibility of analogous mechanism op ... | 1988 | 2855466 |
| colony stimulating factor-1 induced growth stimulation of v-fms transformed fibroblasts. | the v-fms oncogene, which is capable of transforming fibroblasts, was derived by recombination of a feline leukemia virus with a cellular gene (c-fms) that encodes the receptor for colony stimulating factor 1 (csf-1). we examined the capacity of recombinant human csf-1 (produced in a yeast expression system) to stimulate the growth of v-fms transformed rat fibroblasts. recombinant human csf-1 bound to v-fms transformed fibroblasts with high affinity (apparent kd = 6.0 x 10(-10) m); only non-spec ... | 1988 | 2856249 |
| structure and origins of the hz2-feline sarcoma virus. | the hz2-feline sarcoma virus (hz2-fesv) is a replication-defective acute transforming feline retrovirus with oncogene homology to abelson murine leukemia virus (a-mulv) (p. besmer, w.d. hardy,jr., e. e. zuckerman, p. j. bergold, l. lederman, and h. w. snyder, jr. (1983) nature (london) 303, 825-828). in contrast to a-mulv which was isolated from a hematopoietic tumor, the hz2-fesv derives from a multicentric fibrosarcoma. we have molecularly cloned the hz2-fesv provirus from mink hz2-fesv nonpro ... | 1987 | 2884777 |
| molecular cloning of a feline leukemia virus that induces fatal immunodeficiency disease in cats. | a replication-defective variant of feline leukemia virus was molecularly cloned directly from infected tissue and found to induce a rapid and fatal immunodeficiency syndrome in cats. studies with cloned viruses also showed that subtle mutational changes would convert a minimally pathogenic virus into one that would induce an acute form of immunodeficiency. the data suggest that acutely pathogenic viruses may be selected against by current methods for isolation of the human and simian immunodefic ... | 1988 | 2893454 |
| transduction of endogenous envelope genes by feline leukaemia virus in vitro. | feline leukaemia viruses (felv) are exogenous retroviruses that can be detected in most cats with leukaemia, aplastic anaemia, myeloproliferative diseases and fatal immunosuppression. felv isolates have been divided into three subgroups, based on the viral envelope-determined properties of interference and host range in vitro. felv-a is present in all natural isolates and is generally minimally pathogenic. felv-b is found with felv-a in isolates from approximately 40% of natural infections and i ... | 1988 | 2895894 |
| retroviruses: leukemia and immunosuppression. the yohei ito memorial lecture. | | 1988 | 2904514 |