| mcdonough feline sarcoma virus: characterization of the molecularly cloned provirus and its feline oncogene (v-fms). | the genetic structure of the mcdonough strain of feline sarcoma virus (sm-fesv) was deduced by analysis of molecularly cloned, transforming proviral dna. the 8.2-kilobase pair sm-fesv provirus is longer than those of other feline sarcoma viruses and contains a transforming gene (v-fms) flanked by sequences derived from feline leukemia virus. the order of genes with respect to viral rna is 5'-gag-fms-env-3', in which the entire feline leukemia virus env gene and an almost complete gag sequence ar ... | 1982 | 6281462 |
| detection of transient and persistent feline leukaemia virus infections. | a study was made of cats persistently or transiently viraemic with feline leukaemia virus (felv) following experimental oronasal infection. cats of two ages were exposed to the virus. one group was infected when eight weeks old in the expectation that most of the cats would become persistently viraemic, and the second group when 16 weeks old, so that some would show signs of a transient infection and then recover. the periods following infection when virus was detectable in the blood and in the ... | 1982 | 6281958 |
| a comparison of three methods of feline leukaemia virus diagnosis. | samples of blood from pet cats were examined for evidence of feline leukaemia virus (felv) by three techniques: virus isolation, immunofluorescence and an enzyme-linked immunosorbent assay (elisa) leukassay f. there was good agreement between the results from virus isolation and immunofluorescence. however, about 30 per cent of cats which were positive for felv antigen by elisa were negative by either of the other tests. the status of most of these cats was unchanged four or 12 weeks later. | 1982 | 6281960 |
| detection of feline leukemia virus infection in tokyo area by enzyme-linked immunosorbent assay (elisa). | | 1981 | 6283220 |
| reactivation of latent feline leukaemia virus infection. | in most cats exposed to the contagious feline leukemia virus (felv), viral replication is contained in target haematopoietic tissues and elicits humoral immunity to felv and to the feline oncornavirus-associated cell membrane antigen (focma). recently, we and others have considered that these ostensibly self-limiting infections might be persistent nonproductive (latent) infections in certain haematopoietic cells. this hypothesis could account for the relapsing viraemias, protracted incubation pe ... | 1982 | 6283387 |
| dna sequence relationship of the baboon endogenous virus genome to the genomes of other type c and type d retroviruses. | baboon endogenous virus (baev) is a type c retrovirus present in multiple proviral copies in the dna of baboons. although interspecies antigenic determinants present on reverse transcriptase and gag proteins are shared among all mammalian type c viruses, no nucleic acid homology between baev and other type c viruses (except rd-114) has been found in conventional liquid hybridization experiments. in this study, we used restriction fragments of cloned baev dna immobilized on nitrocellulose to test ... | 1982 | 6284972 |
| retroviruses as etiologic agents of some animal and human leukemias and lymphomas and as tools for elucidating the molecular mechanism of leukemogenesis. | | 1982 | 6286010 |
| neutralization of feline leukemia virus with feline antisera to leukocyte alloantigens. | the possibility that normal cellular antigens might serve as targets for antibody neutralization of the feline leukemia virus was investigated. xenospecific antiserum directed to normal feline cells was shown to inactivate feline leukemia virus grown in fibroblasts. cat antisera to normal feline leukocyte alloantigens were then prepared, after which persistent viremia was induced in the donor cats. such alloantisera neutralized virus taken from plasma of the appropriate cat but did not neutraliz ... | 1982 | 6286102 |
| natural killer activity against retrovirus infected cells: dichotomy in nk sensitivity of infected t and b cells. | | 1982 | 6286194 |
| search for evidence of feline leukemia virus infection in humans with leukemias, lymphomas, or soft tissue sarcomas. | two-hundred and thirty-nine patients, including 66 with soft tissue sarcomas and 173 with hematologic cancers, were investigated for evidence of infection with feline leukemia virus (felv). included in this group were 2 patients with acute lymphocytic leukemia who had lived in the same household with leukemic cats. none of the patients demonstrated measurable levels of neutralizing antibody to felv or had detectable felv antigens in peripheral blood normal leukocytes or leukemic cells. in a smal ... | 1982 | 6287075 |
| feline leukemia: a naturally occurring cancer of infectious origin. | | 1982 | 6291969 |
| immune response to tumor cells in domestic animals. | | 1982 | 6294028 |
| structural and antigenic analysis of the nucleic acid-binding proteins of bovine and feline leukemia viruses. | the nucleic acid-binding proteins of bovine leukemia virus (blv) and feline leukemia virus (felv) were isolated in a high state of purity with chloroform-methanol extraction followed by reversed-phase liquid chromatography. selective solubilization and purity of blv p12 and felv p10 was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. the compositions and molecular weights were determined by amino acid analysis. an abundance of lysine and arginine residues along with their ... | 1983 | 6298455 |
| circulating levels of feline leukemia and sarcoma viruses and fibrosarcoma regression in persistently viremic cats. | | 1983 | 6299527 |
| role of suppressor cells in feline leukemia virus-associated immunosuppression. | protein from detergent-disrupted feline leukemia virus was found to suppress lymphocyte blastogenic responsiveness of peripheral blood mononuclear cells from normal cats. when suppressive doses of this protein were substituted for mitogen in the preactivation step of the concanavalin a-induced suppressor cell assay, significant suppression was observed in five of eleven cats tested. these results suggest that feline leukemia virus-associated immunosuppression may be mediated by a virus-induced s ... | 1983 | 6299534 |
| effects of retrovirus protein on the feline one-way mixed leukocyte reaction. | the objective of this study was to evaluate the effects of feline retrovirus protein on cat lymphocyte recognition of allogeneic cells in the mixed leukocyte reaction (mlr), using u.v.-inactivated feline leukaemia virus (felv) and a non-disease-producing endogenous cat virus (rd-114). twenty micrograms of u.v.-inactivated virus protein from each virus were added to mixed leukocyte cultures. felv induced significant suppression of the mlr (p less than 0.005) whereas no significant suppression was ... | 1983 | 6300313 |
| transforming genes of avian (v-fps) and mammalian (v-fes) retroviruses correspond to a common cellular locus. | the gardner (ga) and snyder-theilen (st) isolates of feline sarcoma virus (fesv) represent genetic recombinants between feline leukemia virus (felv) and transformation-specific sequences (v-fes gene) of cat cellular origin. a related transforming gene (v-fps), common to the fujinami, prc ii, and ur 1 strains of avian sarcoma virus has also been described. translational products of each of these recombinant virus isolates are expressed in the form of polyproteins exhibiting protein kinase activit ... | 1983 | 6301150 |
| ferrokinetic and erythrocyte survival studies in healthy and anemic cats. | erythrocyte survival and ferrokinetic studies were adapted to the cat. for 5 clinically healthy 4- to 9-month-old cats, mean 51cr-labeled erythrocyte survival was 144 hours, and mean plasma 59fe-labeled transferrin disappearance halftime was 51 minutes. erythrocyte use of radioiron was rapid and efficient, with 50% to 80% of labeled iron incorporated into the erythron by 100 hours after injection into the cat. six cats with feline leukemia virus infection were studied. for 2 cats with erythroid ... | 1983 | 6301316 |
| the parodi-irgens feline sarcoma virus and simian sarcoma virus have homologous oncogenes, but in different contexts of the viral genomes. | we have identified the oncogene and the putative transforming protein of the parodi-irgens feline sarcoma virus (pi-fesv). the pi-fesv is defective and needs a helper virus for its replication. the v-onc sequences in the pi-fesv were found to be related to the v-sis sequences of the simian sarcoma virus (ssv). pi-fesv nonproducer cells express two viral rnas, a 6.8-and a 3.3-kilobase rna. the 6.8-kilobase rna contains gag, sis, and env sequences but lacks the pol gene. the 3.3-kilobase rna, on t ... | 1983 | 6302323 |
| suppression of the humoral antibody response in natural retrovirus infections. | the feline leukemia virus (felv) frequently causes death by predisposing the host to acute infections by other pathogens rather than by inducing leukemia. in a previous study, cats infected with felv were found to have prolonged homograft rejection responses but there was no evidence that the humoral immune response was impaired. in the present study, the humoral response to the synthetic multichain polypeptide (l-tyrosine-l-glutamic acid)-poly-dl-alanine-poly-l-lysine, denoted (t.g)al, was foun ... | 1983 | 6302837 |
| molecular cloning and characterization of endogenous feline leukemia virus sequences from a cat genomic library. | recombinant bacteriophage lambda clones from a cat genomic library derived from placental dna of a specific pathogen-free cat were screened to identify endogenous feline leukemia virus (felv) sequences. 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-l ... | 1983 | 6304345 |
| nucleotide sequence of the envelope gene of gardner-arnstein feline leukemia virus b reveals unique sequence homologies with a murine mink cell focus-forming virus. | the nucleotide sequence of the envelope gene and the adjacent 3' long terminal repeat (ltr) of gardner-arnstein feline leukemia virus of subgroup b (ga-felv-b) has been determined. comparison of the derived amino acid sequence of the gp70-p15e polyprotein to those of several previously reported murine retroviruses revealed striking homologies between ga-felv-b gp70 and the gp70 of a moloney virus-derived mink cell focus-forming virus. these homologies were located within the substituted (presuma ... | 1983 | 6304347 |
| haemopoietic colony formation (bfu-e, gm-cfc) during the development of pure red cell hypoplasia induced in the cat by feline leukaemia virus. | the gm-cfc assay for granulocyte-macrophage progenitors and the bfu-e and cfu-e assay for early and late erythroid progenitors from cat bone marrow were characterized. gm-cfc gave 59 +/- 4 to 118 +/- 6 colonies per 10(5) bone marrow cells using colony stimulating factors (csf) from cat, mouse or human sources. the cfu-e and bfu-e assays gave 114 +/- 7 and 58 +/- 7 colonies respectively with optimum doses of erythropoietin. irradiated cat bone marrow cells were good sources of csf and of burst pr ... | 1983 | 6304428 |
| active immunization with feline leukemia virus envelope glycoprotein suppresses growth of virus-induced feline sarcoma. | the efficiency was examined of immunization with feline leukemia virus glycoprotein complexes (gp85 rosettes) to protect cats against tumors induced by feline sarcoma virus (fesv). the glycoprotein was isolated from feline leukemia virus (felv). young cats were vaccinated with the purified viral glycoprotein and challenged with fesv (felv). felv gp85 antibody levels were measured by enzyme-linked immunosorbent assay and tumor volumes were determined. in immunized animals tumor development was re ... | 1983 | 6304480 |
| recovery of feline leukaemia virus from non-viraemic cats. | the persistence of virus in the bone marrow of cats which had ostensibly recovered from feline leukaemia virus (felv) infection was investigated. nineteen cats were exposed to felv by natural, contact infection and 36 weeks later three were found to be persistently viraemic while the remainder were non-viraemic and had virus neutralising serum antibodies. virus was isolated in bone marrow cultures established from nine of the 16 non-viraemic cats which were considered, therefore, to have latent ... | 1983 | 6304986 |
| cell culture density modulates the incorporation of hla antigens by enveloped viruses. | uninfected, as well as feline leukemia virus (felv) infected human cells cultured under high cell density conditions undergo changes in the expression of major histocompatibility complex (mhc) antigens, as determined by indirect trace binding radio immunoassay (ria) using monoclonal anti-hla antibodies and by decreased sensitivity to complement mediated cytotoxicity by anti-hla alloantibodies. felv particles produced by the viral infected cells are also sensitive to neutralization by anti-hla an ... | 1983 | 6305890 |
| circulating antibodies to the feline leukemia virus and focma in cats. | presence of antibodies to the structural proteins of the feline leukemia virus and the feline oncornavirus-associated cell membrane antigen focma was analyzed in sera of 120 cats from household environments. in our experiments 35% of the sera tested were positive with the viable cells of fl-74 feline lymphoma cell line. on the other hand, only 5% of the feline sera reacted with felv from fl-74 cells in the solid phase ria. selected positive sera were analyzed for the presence of antibodies to th ... | 1983 | 6306490 |
| virus-associated liposarcoma and malignant lymphoma in a kitten. | | 1983 | 6307955 |
| feline cytotoxic immune mechanisms against virus-associated leukemia and fibrosarcoma. | humoral and cellular cytotoxic immune mechanisms of cats were compared against feline leukemia virus (felv)- and feline sarcoma virus (fesv)-transformed cells. the groups of animals studied were nonexposed control cats; felv-infected immune or viremic tumor-bearing cats; fesv-inoculated tumor progressor or regressor cats, and cats immunized with fesv-transformed autochthonous fibroblasts (atf). sera containing complement-dependent antibodies (cda), which lysed felv-producer lymphoma lines, had n ... | 1983 | 6311439 |
| the mechanism of retrovirus suppression of human t cell proliferation in vitro. | immunosuppression is commonly associated with retrovirus-induced animal tumors. studies in the murine and feline retrovirus systems suggest that the 15,000-dalton envelope protein (p15e) of the virion may contribute to immunosuppression by interfering with normal lymphocyte function. we examined the effect of inactivated feline leukemia virus (uv-felv) and p15e derived from this virus on concanavalin a (con a) driven human t cell proliferation. virus and p15e markedly suppressed mononuclear cell ... | 1983 | 6311904 |
| molecular cloning of integrated gardner-rasheed feline sarcoma virus: genetic structure of its cell-derived sequence differs from that of other tyrosine kinase-coding onc genes. | gardner-rasheed feline sarcoma virus (gr-fesv) is an acute transforming retrovirus which encodes a gag-onc polyprotein possessing an associated tyrosine kinase activity. the integrated form of this virus, isolated in the charon 21a strain of bacteriophage lambda, demonstrated an ability to transform nih/3t3 cells at high efficiency upon transfection. foci induced by gr-fesv dna contained rescuable sarcoma virus and expressed gr-p70, the major gr-fesv translational product. the localization of lo ... | 1983 | 6312085 |
| inhibition of feline leukemia virus replication by human leukocyte interferon. | the replication of feline leukemia virus (felv) is inhibited by treatment of cat cell cultures with crude human leukocyte interferon (huifn-alpha) as evidenced by titration of the infectious progeny. the inhibition can be demonstrated in three different cell lines in which the production of hemagglutinin by encephalomyocarditis (emc) virus, and plaque formation by vesicular stomatitis virus (vsv) are also inhibited by the huifn-alpha. the dose dependency of the inhibition of emc virus by the hui ... | 1983 | 6312876 |
| immunosuppressive properties of a feline retrovirus 15,000 dalton protein. | | 1983 | 6314348 |
| serum erythropoietin changes in cats with feline leukemia virus-induced erythroid aplasia. | erythropoietin concentrations were increased significantly (p less than 0.025) in nine cats with natural feline leukemia virus infection and associated erythroid aplasia compared to six clinically normal cats. adult cats experimentally inoculated with the kawakami-theilen isolate of feline leukemia virus developed a progressive simultaneous increase in erythropoietin activity and decrease in packed cell volume. these findings indicate that erythroid aplasia associated with feline leukemia virus ... | 1983 | 6314629 |
| erythrocyte macrocytosis in feline leukemia virus associated anemia. | using erythrocyte volume distribution histograms (erythrograms), erythrocyte macrocytosis and anisocytosis were quantitated in 139 cats tested for feline leukemia virus group-specific antigen. feline leukemia virus-negative cats with non-regenerative anemia or normal packed cell volumes had normal mean corpuscular volume values. uninfected cats with regenerative anemia had prominent significantly increased macrocytosis and anisocytosis (p less than 0.01). ninety percent of 62 feline leukemia vir ... | 1983 | 6316617 |
| course of feline leukemia virus infection and its detection by enzyme-linked immunosorbent assay and monoclonal antibodies. | monoclonal antibodies specific for 3 distinct epitopes of the species-specific determinants of feline leukemia virus (felv) p27 were used in an enzyme-linked immunosorbent assay (elisa) for measurement of serum p27 in cats infected with felv. group-specific antigen (gsa) of felv in peripheral blood leukocytes was also determined by an immunofluorescence assay. antibodies to felv and the feline oncornavirus-associated cell membrane antigen (focma) were also measured. thirty-six cats were surveyed ... | 1983 | 6316819 |
| the feline oncornavirus-associated cell membrane antigen (focma) is related to, but distinguishable from, felv-c gp70. | the feline oncornavirus-associated cell membrane antigen (focma) on the surface of feline lymphosarcoma (lsa) cells is defined as the target(s) recognized in immunofluorescence (ifa) tests by antibody in sera of cats relatively resistant to development of felv (feline leukemia virus) lsa and fesv (feline sarcoma virus) fibrosarcoma. the specificities of antibodies in cat focma-typing sera and the nature of the lsa antigens recognized were investigated in the present study. focma sera obtained fr ... | 1983 | 6318434 |
| comparison of feline leukemia virus-infected and normal cat t-cell lines in interleukin 2-conditioned medium. | following mitogen stimulation (phytohemagglutinin or concanavalin a), feline lymphocytes were maintained in medium containing feline interleukin 2. lymphocyte lines derived from the blood of feline leukemia virus-infected cats contained cells 50 to 90% of which expressed virus antigens, but lymphocyte lines derived from uninfected cats remained virus free. leukemia virus-positive and -negative lymphocyte lines retained total dependence upon the presence of interleukin 2 for finite life spans of ... | 1984 | 6318972 |
| biological behavior of tumors and associated retroviremia in cats inoculated with snyder-theilen fibrosarcoma virus and the phenomenon of tumor recurrence after primary regression. | the fate of tumors and associated retroviremia was studied in 111 cats infected with the snyder-theilen strain of feline sarcoma virus (fesv). tumors appeared at the site of inoculation within 7 to 10 days. a retroviremia, due mainly to the associated feline leukemia virus helper virus (felv-helper), developed at the same time as tumors. of the cats, 44 developed progressively growing tumors and therefore had to be killed, and 67 developed tumors that regressed. there was a strong correlation be ... | 1984 | 6319286 |
| location of human t-cell leukemia virus (htlv) p19 antigen on virus-producing cells. | mouse monoclonal antibody to htlv p19 was used to locate htlv p19 on the surface of cells and virions by immunofluorescence microscopy (ifm) and immunoelectron microscopy (iem). when htlv-producing cells hut 102 (b2 clone), mt-2 and strain a were used as target cells, htlv p19 was detected on the surface of cells and virions as spots or small sectors by both ifm and iem. cells infected with animal type-c retroviruses, e.g., gibbon ape leukemia virus, simian sarcoma virus, feline leukemia virus, ... | 1984 | 6319298 |
| clearance of feline leukemia virus from persistently infected pet cats treated by extracorporeal immunoadsorption is correlated with an enhanced antibody response to felv gp 70. | six persistently feline leukemia virus (felv)-infected pet cats were treated by extracorporeal immunoadsorption with staphylococcus aureus cowan i (sac) to remove circulating immune complexes and immunoglobulin g (igg) from plasma. in three of these cats, the felv infection was eliminated, whereas in the other three cats the infection persisted. the amounts of peripheral blood leukocyte (pbl)-associated felv, soluble felv envelope glycoprotein (gp70) antigens in serum, and felv-gp70-specific ant ... | 1984 | 6319496 |
| nucleotide sequences of the envelope genes of two isolates of feline leukemia virus subgroup b. | we determined the nucleotide sequences of the envelope genes of the snyder-theilen and gardner-arnstein isolates of feline leukemia virus subgroup b. comparison of the deduced amino acid sequences of the envelope gene products revealed regions of sequence divergence, which we relate to structural features of the viral protein. we also examined nucleotide sequences within the long terminal repeats of these related isolates of feline leukemia virus subgroup b. | 1984 | 6319767 |
| naturally occurring retroviruses (rna tumor viruses). ii. | this is the second of two papers describing the biology of the naturally occurring rna tumor viruses (oncoviruses). it will appear in two parts. in the first paper [cancer investigation 1(1):67-83 (1983)] the general properties of this class of viruses and the biology of the retroviruses of the "lower" vertebrates was discussed. in this paper the oncoviruses of the "higher" animals are described. part one deals with cat retroviruses. | 1983 | 6320991 |
| association of the transforming proteins of the st and ga strains of feline sarcoma virus and their in vitro associated protein kinase activities with cellular membranes. | the translation products of the snyder-theilen (st) and gardner-arnstein (ga) strains of feline sarcoma virus (fesv), termed gag-fes proteins, are high molecular weight polyproteins containing different amounts of the amino terminus of the feline leukemia virus (felv) gag gene-coded precursor protein linked to a similar sarcoma virus-specific polypeptide. both polyproteins are phosphoproteins with indistinguishable in vitro associated tyrosine-specific protein kinase activities. the polyproteins ... | 1983 | 6320992 |
| acute transforming feline retroviruses. | | 1983 | 6321109 |
| sequence analysis of gardner-arnstein feline leukaemia virus envelope gene reveals common structural properties of mammalian retroviral envelope genes. | we have sequenced the envelope (env) gene and most of the adjacent 3' long terminal repeat (ltr) of gardner-arnstein feline leukaemia virus subtype b. the ltr of this virus contains, at corresponding positions, all signal sequence elements known from other retroviral ltrs. the deduced amino acid sequence of the longest open reading frame was compared with env polypeptide sequences of several murine leukaemia viruses. this allowed us to predict the positions of both p12/15env and gp70 polypeptide ... | 1983 | 6321156 |
| transcriptional control of the bovine leukemia virus genome: role and characterization of a non-immunoglobulin plasma protein from bovine leukemia virus-infected cattle. | using cloned bovine leukemia virus (blv) dna as a probe in the dot blot hybridization technique, we demonstrated that the expression of the blv genome in infected lymphocytes is blocked in vivo at the transcriptional level. this blocking effect is due to a non-immunoglobulin protein present in the plasma but not in the serum of blv-infected cattle. the plasma blv-blocking protein also blocks the expression of the blv genome in fibroblast cells of bovine and nonbovine origin infected with blv in ... | 1984 | 6321796 |
| indirect leukocyte migration inhibition in breast cancer and benign breast disease patients by mouse mammary tumor virus grown in feline kidney cells. | indirect migration inhibition assays were performed with normal and mammary tumor-bearing c3h/hen mice and patients with breast disease to assess cellular immunity against three different mouse mammary tumor virus (mtv) preparations grown in feline kidney cell cultures and against a mouse-derived mtv preparation. mtv obtained after passage through feline kidney cells and the mouse-derived mtv were capable of eliciting macrophage migration inhibitory factor production by mouse spleen cells obtain ... | 1984 | 6321840 |
| complete amino acid sequence of the basic nucleic acid binding protein of feline leukemia virus. | the complete amino acid sequence of the nucleic acid binding protein p10 of the rickard strain of feline leukemia virus (felv) has been determined. fragments obtained by enzymatic digestion were purified by reverse-phase liquid chromatography and subjected to semiautomated edman degradation. felv p10 is a basic polypeptide composed of 57 amino acids with mr = 6604. the structure of p10 is compared to the structures of other retroviral nucleic acid binding proteins, and an analysis of a highly co ... | 1984 | 6322425 |
| viruses and bone marrow failure. | | 1984 | 6322884 |
| inhibition of erythroid colony-forming cells by a mr 15,000 protein of feline leukemia virus. | the effects of concentrated ultraviolet-inactivated feline leukemia virus (felv), the purified mr 15,000 envelope protein (p15e) of felv, or the purified mr 27,000 structural protein (p27) of felv on feline bone marrow mononuclear cells were studied in vitro in methylcellulose cultures. whole virus and purified viral proteins were from the kawakami-theilen isolate of felv, which induces erythroid aplasia in cats. bone marrow mononuclear cells from felv-negative young adult cats were preincubated ... | 1984 | 6322979 |
| [infection with feline leukemia virus: immunology and serodiagnosis as the basis for control. 1]. | | 1984 | 6324337 |
| [infection with feline leukemia virus: immunology and serodiagnosis as a basis for the prevention of infection. 2]. | | 1984 | 6324338 |
| a new package for an old oncogene. | | 1984 | 6325919 |
| transduction and rearrangement of the myc gene by feline leukaemia virus in naturally occurring t-cell leukaemias. | evidence of myc gene transduction by feline leukaemia virus in several spontaneous lymphoid tumours of cats suggests that recombinant viruses carrying oncogenes may be much more involved in oncogenesis in natural conditions than previously recognized. | 1984 | 6325920 |
| isolation of a feline leukaemia provirus containing the oncogene myc from a feline lymphosarcoma. | the molecular mechanism by which feline leukaemia virus (felv) induces lymphoid malignancy in domestic cats is largely unknown. using the insertional activation model of c-myc by avian leukosis virus in the induction of bursal lymphoma in chickens, we have now characterized the c-myc locus in feline tissues and investigated the possibility that felv may also insert within feline c-myc. we used the 1.5 kilobase (kb) psti fragment of mc29 v-myc in southern blot analysis to characterize the structu ... | 1984 | 6325921 |
| viral transduction of c-myc gene in naturally occurring feline leukaemias. | feline leukaemia virus (felv) is epidemiologically associated with induction of the majority of lymphoid tumours of the domestic cat. however, about one-third of these tumours are devoid of exogenous virus or show evidence of virus integration only after tumour outgrowth. to help define the genetic mechanisms of feline lymphomagenesis we have explored here the possibility that cellular oncogenes (c-onc genes) are rearranged in tumour cell dna. of 16 felv-positive t-cell tumours among 31 naturall ... | 1984 | 6325922 |
| nucleotide sequence of the gag gene and gag-pol junction of feline leukemia virus. | the nucleotide sequence of the gag gene of feline leukemia virus and its flanking sequences were determined and compared with the corresponding sequences of two strains of feline sarcoma virus and with that of the moloney strain of murine leukemia virus. a high degree of nucleotide sequence homology between the feline leukemia virus and murine leukemia virus gag genes was observed, suggesting that retroviruses of domestic cats and laboratory mice have a common, proximal evolutionary progenitor. ... | 1984 | 6328019 |
| appearance of cytotoxic antibody to viral gp70 on feline lymphoma cells (fl-74) in cats during ex vivo immunoadsorption therapy: quantitation, characterization, and association with remission of disease and disappearance of viremia. | fifty cats with feline leukemia virus (felv) infection and leukemia-lymphoma complex were treated by ex vivo immunoadsorption with staphylococcus protein a-bound filters. most cats responded to therapy. twelve showed tumor regression, including disappearance of tumor cells, but died later of other complications. three have had long-term remission of more than 1 year and remain healthy. a consistent finding in these three cats was the appearance during treatment of a complement-dependent cytotoxi ... | 1984 | 6328520 |
| infection with feline leukemia virus associated with induction of humoral response to a normal cell protein. | selected populations of cats that were naturally exposed to the feline leukemia virus (felv) were found to have humoral antibodies to a normal cell protein designated ncp105. earlier studies revealed that cats exposed to felv often had serum antibodies to the feline oncornavirus-associated cell membrane (focma) as well as to a feline sarcoma virus (fesv) -specific transforming protein designated gag-fes. cats with no history of exposure to felv or fesv lacked antibodies to all three antigens: nc ... | 1984 | 6329486 |
| characterization of the expression of cellular retrovirus genes and oncogenes in feline cells. | expression of endogenous retrovirus genes and two different cellular oncogenes (c-onc genes) was examined at the transcriptional level in a variety of normal and lymphoma/leukemia tissues of the domestic cat. the two oncogenes, c-myb(related to avian myeloblastosis virus) and c-myc(related to avian myelocytomatosis virus) were selected for their association with the induction of hematopoietic malignancies, when present in the transforming retroviruses. tissue-specific expression of endogenous fe ... | 1983 | 6329934 |
| retroviruses in human leukemia. | after decades of work, a retrovirus of true human origin has been isolated first from a u.s. adult case of t-cell lymphoma and then from cases from various regions of the world. this virus, named htlv-i, is strongly associated with a malignant leukemia-lymphoma of mature t-cells. this disease was first clinically characterized in japan but subsequently found to cluster in the caribbean region, areas of the u.s. and in other countries. this retrovirus-associated malignancy has an adult onset and ... | 1983 | 6329935 |
| characterization of monoclonal antibodies directed against the envelope proteins of feline leukemia virus. | monoclonal antibodies directed against the feline leukemia virus (felv) envelope proteins, gp70 and p15e, were identified by radioimmunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. six of these monoclonal antibodies were specific for the gp70; two for the p15e. enzyme-linked immunosorbent assay binding assays against felv subtypes a, b, and c showed that most of the monoclonal antibodies bound to more than one subtype but have a greater affinity for subtype b. one ... | 1984 | 6331649 |
| nucleotide sequence of the feline retroviral oncogene v-fms shows unexpected homology with oncogenes encoding tyrosine-specific protein kinases. | the nucleotide sequence encoding the transforming polyprotein of the mcdonough strain of feline sarcoma virus was determined. this sequence includes 231 nucleotides specifying a leader peptide, 1,377 nucleotides encoding most of the feline leukemia virus-derived gag gene, and 2,969 nucleotides representing the viral transforming gene v-fms. a single open reading frame was predicted to encode a fusion polyprotein of 160,000 daltons (p160gag-fms). fourteen potential sites for glycosylation were pr ... | 1984 | 6582485 |
| characterization of a differentiated cat melanoma cell line. | we have established several long-term cultures of a naturally occurring metastatic melanoma of a domestic cat. the cells are fully differentiated as indicated by the fontana-masson staining of the melanin in the perinuclear region and by electron microscopy of the cytoplasmic melanosomes in various stages of development. the melanoma cells do not produce virus particles or the major core proteins (i.e., protein with a molecular weight of 30,000) of the feline leukemia virus or the endogenous cat ... | 1983 | 6850643 |
| cellular immune response in the blood of cats is restricted to autochthonous feline sarcoma virus-transformed cells. | the blood-borne cytotoxic cellular immune response of cats to autochthonous fibroblasts transformed with feline sarcoma virus (fesv) was examined. peripheral blood lymphocytes (pbl) from immune animals were assayed for cytotoxic activity using a 51cr release microcytotoxicity assay. the time courses for appearance of cytotoxic cells were similar for all cats: effector lymphocytes appeared in the blood 7 days after immunization; peak activity occurred about day 16, and cytotoxic pbl were no longe ... | 1983 | 6852979 |
| leukemic cell targeting and therapy by monoclonal antibody in a mouse model system. | a monoclonal antibody prepared against the rauscher virus envelope glycoprotein with a molecular weight of 70,000 targeted to neoplastic cells and cured the rauscher leukemia virus-induced erythroleukemia in balb/c mice. this antibody, 103a, specifically reacted with the rauscher and friend erythroleukemia viruses and erythroleukemic cells but did not react with other murine ecotropic or xenotropic viruses or feline leukemia virus or with normal spleen cells, thymocytes, or fibroblasts, as measu ... | 1982 | 6947860 |
| neoplastic transformation of rabbit cells by murine sarcoma viruses. | neoplastic transformation of rabbit cells by kirsten murine sarcoma virus (ki-msv), the ki-msv pseudotype of baboon endogenous virus (ki-msv[baev]) and the moloney-msv pseudotype of feline leukemia virus (m-msv[felv]) is reported. rabbit cells can be readily transformed by ki-msv, ki-msv(baev) and m-msv(felv). rabbit cells transformed by ki-msv and m-msv(felv) were found to be virus producers, whereas those transformed by ki-msv(baev) were nonproducers (np). the np cells were obtained by simply ... | 1982 | 7129681 |
| detection of felv antigen. | | 1995 | 7483231 |
| erythroleukemia in two cats naturally infected with feline leukemia virus in the same household. | erythroleukemia was observed in two unrelated cats infected with feline leukemia virus (felv) from the same household. case 1, a 1-year-old neutered male cat developed erythroleukemia (m6) after a diagnosis of myelodysplastic syndrome (mds-er) on the criteria of fab classification of acute leukemias. case 2, a 1-year-old neutered female cat, which had close contact with case 1, also developed erythroleukemia (m6er). in both cases, marked proliferation of erythroid progenitor cells with dispropor ... | 1995 | 7492633 |
| ultrasensitive retrovirus detection by a reverse transcriptase assay based on product enhancement. | reverse transcriptase (rt) is an indispensable component of infectious retroviruses. we have developed an ultrasensitive rt test in which rna of bacteriophage ms2 serves as the template for rt-mediated cdna synthesis. a fragment of the cdna is selectively amplified by polymerase chain reaction and the amplification product is analyzed by southern blot hybridization or enzyme immunoassay. the procedure was 10(6) to 10(7) times more sensitive than a conventional rt test and detected as little as 1 ... | 1994 | 7509077 |
| engineering of the human-immunodeficiency-virus-type-1 (hiv-1) reverse transcriptase gene to prevent dimerization of the expressed chimaeric protein: purification and characterization of a monomeric hiv-1 reverse transcriptase. | we report here a human-immunodeficiency-virus-type-1 (hiv-1) recombinant reverse transcriptase (rt) engineered to contain a 26-amino-acid linker insertion from the tether domain of feline leukaemia virus (flv) rt. the chimaeric protein was expressed in escherichia coli and migrated on sds/page as a 68 kda band. a monomeric form of the chimaeric hiv-1 rt has been prepared by the coordinated applications of immobilized-metal-affinity chromatography and gel filtration on superose 12 columns. the mo ... | 1994 | 7514879 |
| the c-kit proto-oncogene receptor is expressed on a subset of human cd3-cd4-cd8- (triple-negative) thymocytes. | the c-kit receptor is a tyrosine-kinase transmembrane receptor first identified as an oncogene in the hz4-feline leukemia virus and later found to be important in hematopoiesis in mice. the ligand for this receptor (steel factor) can stimulate hematopoiesis both in vitro and in vivo. to study the pattern of c-kit receptor expression in normal human hematopoietic progenitor cells, we prepared a monoclonal antibody (9b9) against human c-kit receptor by using a synthetic peptide (amino acids 476-50 ... | 1994 | 7522182 |
| differential antiviral activities and intracellular metabolism of 3'-azido-3'-deoxythymidine and 2',3'-dideoxyinosine in human cells. | dideoxynucleosides such as 3'-azido-3'-deoxythymidine (azt) and 2',3'-dideoxyinosine (ddi) can effectively inhibit the replication of human immunodeficiency virus (hiv) in t lymphoid cells. there is evidence that hiv can infect and replicate in other cells including monocytoid cells and macrophages. the present study compared the antiretroviral activities of ddi and azt in three lineages of human cells, i.e., molt4 (t lymphocytoid, cd4+), u937 (monocytoid, cd4+), and ht1080 (fibroblastoid, cd4-) ... | 1994 | 7526781 |
| uses of flow cytometry in virology. | this article reviews some of the published applications of flow cytometry for in vitro and in vivo detection and enumeration of virus-infected cells. sample preparation, fixation, and permeabilization techniques for a number of virus-cell systems are evaluated. the use of flow cytometry for multiparameter analysis of virus-cell interactions for simian virus 40, herpes simplex viruses, human cytomegalovirus, and human immunodeficiency virus and its use for determining the effect of antiviral comp ... | 1994 | 7530594 |
| long-term renal and hematologic effects of uninephrectomy in healthy feline kidney donors. | to assess long-term hematologic and renal effects associated with a solitary kidney, 16 healthy cats undergoing uninephrectomy for kidney donation between may 1987 and january 1991 were evaluated by use of physical examination, cbc, serum biochemical analysis, urinalysis, and urine protein:creatinine ratio. results of preoperative cbc, serum biochemical analysis, and urinalysis were within reference limits in all donors. median age at surgery and at follow-up evaluation was 34 and 72 months, res ... | 1995 | 7559043 |
| enhanced expression of novel cd57+cd8+ lak cells from cats infected with feline immunodeficiency virus. | as a model for lymphokine-activated killer (lak) function in hiv infection, we studied lak cells in cats infected with feline immunodeficiency virus (fiv), which causes an acquired immunodeficiency syndrome. peripheral blood mononuclear cells cultured in concanavalin a and interleukin-2 developed lak cytotoxicity against chronically fiv-infected crfk cells and acutely infected cd4+ lymphocytes but not uninfected cells. lak cells from fiv+ cats were more cytotoxic than lak cells from uninfected c ... | 1995 | 7561518 |
| lentivirus infection in an african lion: a clinical, pathologic and virologic study. | in may 1991, clinical, pathologic, and virologic investigations were carried out on an 8-yr-old male lion (panthera leo), with recurrent infections, in captivity with two lionesses in the zoological garden of pistoia, tuscany, italy. the lion had severe pneumonia, neutropenia, thrombocytopenia, and an increase in blood urea nitrogen and creatininemia; in spite of therapy, it died within 3 months. at necropsy, the animal had a lymphoma and other lesions similar to those described in feline immuno ... | 1995 | 7563428 |
| cdna encoding a functional feline liver/bone/kidney-type alkaline phosphatase. | feline alkaline phosphatase (fealp) was copurified with the putative 70-kda feline leukemia virus subgroup-a (felv-a) receptor protein from feline t-lymphocyte cells (fet) by two-dimensional gel electrophoresis. the sequence of the n-terminal 17 amino acids and five other internal tryptic peptides revealed that it is homologous to the liver/bone/kidney (l/b/k)-type alkaline phosphatase of other mammalian species. corresponding oligonucleotides were synthesized and used for amplification of a 1.2 ... | 1995 | 7574682 |
| is it possible to catch leukemia from a cat? | | 1995 | 7616826 |
| feline retroviruses. proceedings of an international symposium. research triangle park, north carolina, 6-9 october 1993. | | 1995 | 7618249 |
| recombinant felv vaccine: long-term protection and effect on course and outcome of fiv infection. | the efficacy and the long-term protection of a recombinant feline leukemia virus (felv) vaccine were determined in 30 specified pathogen free cats for over 3 years. at the same time, in order to specify the effects of feline immunodeficiency virus (fiv) on the immune system, one half of the cats (n = 15) were previously infected with the swiss isolate fiv zurich 2. the second half of the animals (n = 15) served as non-infected controls. eighteen (nine fiv-negative, nine fiv-positive) vaccinated ... | 1995 | 7618252 |
| therapeutic effects of diethylcarbamazine and 3'-azido-3'-deoxythymidine on feline leukemia virus lymphoma formation. | twenty-four specific pathogen-free kittens were infected with the rickard strain of feline leukemia virus (felvr). the kittens were divided into four equal groups and were orally administered either a high dose of diethylcarbamazine (dech, 12 mg kg-1), a low dose of diethylcarbamazine (decl, 3 mg kg-1), 3'-azido-3'-deoxythymidine (azt, 15 mg kg-1, b.i.d.), or a placebo (250 mg granular dextrose) daily for 10 weeks. blood was collected at 2-week intervals for complete blood counts (cbc) and flow ... | 1995 | 7618257 |
| panleukopenia-like syndrome of felv caused by co-infection with felv and feline panleukopenia virus. | to study the effect of interferon on feline leukemia virus (felv) infection, 30 specific pathogen free (spf) cats were infected with the apathogenic felv a glasgow. unexpectedly, between 5 and 8 weeks after felv infection, all 19 cats with persistent felv infection but not the felv-negative cats died from a panleukopenia-like syndrome. no feline panleukopenia virus (fplv) antigen was found in feces by latex agglutination, enzyme-linked immunosorbent assay (elisa) or immunoelectron microscopy. no ... | 1995 | 7618258 |
| identification of differentially expressed genes in t-lymphoid malignancies in an animal model system. | the molecular events characterizing lymphoid malignancy have been examined in an animal model system, specifically, the retroviral induction of leukemia and lymphoma in the domestic cat following infection with feline leukemia virus (felv). genes differentially expressed in felv-induced lymphomas were isolated using a strategy of differential hybridization. six genes were identified which demonstrate a higher level of expression in an felv-induced feline thymic tumor as compared with normal thym ... | 1995 | 7628875 |
| sequence similarities between latent membrane protein lmp-1 of epstein-barr virus, integral membrane protein p12i of human t cell leukemia/lymphotropic virus type 1, e5 transformation protein of bovine papillomavirus, and the transmembrane proteins of slowly transforming retroviruses. | | 1995 | 7632458 |
| feline leukemia virus infection downmodulates the production of growth-inhibitory activity by marrow stromal cells. | to determine the role of infected marrow accessory cells in the pathogenesis of viral-associated hematologic disorders, we evaluated whether feline leukemia virus (felv) infection alters the cytoadhesive properties of long-term marrow culture (ltmc) stromal cells, the support of stromal-associated progenitors in ltmcs, and the production of progenitor growth-promoting and -inhibiting activities by marrow stromal cells. our previous studies demonstrated that ltmcs containing felv-infected stromal ... | 1995 | 7656928 |
| detection of felv antigen by indirect immunofluorescence in elisa/cite negative cats. | | 1995 | 7660550 |
| haematological disorders associated with feline retrovirus infections. | feline oncornavirus and lentivirus infections have provided useful models to characterize the virus and host cell factors involved in a variety of marrow suppressive disorders and haematological malignancies. exciting recent progress has been made in the characterization of the viral genotypic features involved in felv-associated diseases. molecular studies have clearly defined the causal role of variant felv env gene determinants in two disorders: the t-lymphocyte cytopathicity and the clinical ... | 1995 | 7663052 |
| induction of feline leukaemia virus-neutralizing antibodies by immunization with synthetic peptides derived from the felv env gene. | the surface glycoprotein, gp70, of feline leukaemia virus (felv) contains sites which are important in inducing neutralizing antibodies. using synthetic peptides corresponding to nucleotide sequence 729-957 (amino acid sequence 243-319) of felv-a/glasgow-1, the antigenicity and immunogenicity of this part of the viral surface glycoprotein were investigated. the region contains two highly conserved domains separated by a variable region (vr4), when compared with felv of subgroups b and c, and an ... | 1993 | 7692683 |
| comparison of fibrosarcomas that developed at vaccination sites and at nonvaccination sites in cats: 239 cases (1991-1992). | questionnaires were sent to veterinarians who had submitted a fibrosarcoma from a cat to the surgical pathology services of the veterinary schools of the university of pennsylvania and tufts university between jan 1, 1991 and june 30, 1992. questionnaire items included signalment, felv and feline immunodeficiency virus status, site of sarcoma, vaccination site, vaccines used, treatment, biologic behavior of the tumor, and final outcome. data were analyzed, using student's t-test for continuous d ... | 1994 | 7698923 |
| induction of feline acquired immune deficiency syndrome by feline leukemia virus: alteration in response to hormones in the hypothalamic-pituitary-gonadal system. | male kittens who were infected with the feline leukemia virus (felv) were found at various times after exposure to contain a sequence of dysfunction in their hypothalamic-pituitary-gonadal (hpg) system. to understand whether the involved endocrine glands in this system were damaged by felv, the hypothalamus, pituitary, and testes were tested for hormonal responsiveness in vivo and in vitro. the infected cats were administered with luteinizing hormone-releasing hormone (lhrh) and human chorionic ... | 1995 | 7700890 |
| molecular analysis of tumours from feline immunodeficiency virus (fiv)-infected cats: an indirect role for fiv? | five tumours, which arose in cats naturally or experimentally infected with feline immunodeficiency virus (fiv), were examined with molecular probes to establish tumour cell lineage and to screen for integrated viral sequences. three of the tumours were classed as b-cell lymphomas on the basis of morphology, immunocytochemistry, rearrangement of immunoglobulin heavy chain genes and lack of rearrangement of t-cell receptor (tcr) beta-chain genes. two of these b-cell tumours arose in specific path ... | 1995 | 7705953 |
| acute feline leukemia virus infection causes altered energy balance and growth inhibition in weanling cats. | naturally occurring retroviral infections cause progressive weight loss, immune suppression, invasion by opportunistic organisms, and eventual death. feline leukemia virus (felv) inhibited growth and decreased energy intake in seven experimentally infected weanling cats compared with age- and sex-matched controls. remarkably, changes in energy intake, energy expenditure, and weight gain occurred in the acute phase of infection prior to the systemic/productive bone marrow phase of felv infection. ... | 1995 | 7712229 |
| conversion of human fibroblasts to tissue macrophages by the snyder-theilen feline sarcoma virus (st:fesv(felv)): productive infection by leishmania major. | the decisive role of macrophages in t-cell differentiation is best exemplified by cutaneous leishmaniasis. during infection, leishmania attach to macrophages, the only site of replication for the parasite. we have recently demonstrated the conversion of human fibroblasts to tissue macrophages (tm) by transduction with the snyder-theilen feline sarcoma virus (st:fesv-(felv)). since leishmania have tropism only for macrophages, we have used the parasite to ascertain the functional phenotype of the ... | 1994 | 7721332 |
| function of a unique sequence motif in the long terminal repeat of feline leukemia virus isolated from an unusual set of naturally occurring tumors. | feline leukemia virus (felv) proviruses have been characterized from naturally occurring non-b-cell, non-t-cell tumors occurring in the spleens of infected cats. these proviruses exhibit a unique sequence motif in the long terminal repeat (ltr), namely, a 21-bp tandem triplication beginning 25 bp downstream of the enhancer. the repeated finding of the triplication-containing ltr in non-b-cell, non-t-cell lymphomas of the spleen suggests that the unique ltr is an essential participant in the deve ... | 1995 | 7745680 |
| seroepidemiological survey of feline retrovirus infections in cats in taiwan in 1993 and 1994. | in order to investigate the prevalence of infections with three feline retroviruses feline immunodeficiency virus (fiv), feline leukemia virus (felv) and feline syncytial virus (fsv) in taiwan, we collected a total of 75 blood samples from cats from veterinary hospitals, a breeding cattery and a homeless shelter in 1993 and 1994. we examined the presences of anti-fiv and fsv antibodies and felv-p27 antigen in these samples by the indirect immunofluorescence and/or enzyme-linked immunosorbent ass ... | 1995 | 7756412 |
| coccidioidomycosis in 48 cats: a retrospective study (1984-1993) | coccidioidomycosis was diagnosed in 48 cats. forty-one cases were identified within a period of 3 years. coccidioides immitis was revealed by cytological or histopathological examinations, or culture in 70% of cats. the remaining 30% of cases were diagnosed by appropriate clinical signs, radiographic lesions, and serological test results. the average age of affected cats was 6.2 years with a median age of 5.0 years. fifty-four percent (n = 26) were female and 46% (n = 22) were male. domestic sho ... | 1995 | 7760314 |
| increased insensible water loss in feline retrovirus-infected cats. | feline retroviruses such as feline leukemia virus (felv) adversely affect the regulation of many vital host systems such as the immune response, erythropoiesis, and nutrient metabolism. in this paper, we describe the disruption of an additional homeostatic mechanism-evaporative water loss-by felv. viremic cats had greater evaporative water losses (24.0 +/- 1.4 gm water/kg per day) at low relative humidity levels (19% to 25% relative humidity) when compared to age- and sex-matched control cats (1 ... | 1995 | 7770670 |
| thoughts on retroviruses. | | 1995 | 7782231 |