| polypeptides of mammalian oncornaviruses. ii characterization of murine leukemia virus polypeptide (p 15) bearing interspecies reactivity. | | 1975 | 46125 |
| zinc reverse transcriptases from mammalian rna type c viruses. | | 1975 | 46146 |
| editorial: as in cats, so in man? | | 1975 | 46966 |
| inhibition of oncornavirus functions by 2'-azido polynucleotides. | the 2'-azido analogs of poly(u) and poly(c), poly(duz) [poly(2'-azido-2'-deoxyuridylic acid)], and poly-(dcz [poly(2'-azido-2'-deoxycytidylic acid)], were found to inhibit the rna-directed dna polymerase (reverse transcriptase) activity of murine leukemia (moloney, rauscher) and sarcoma (moloney) virus, and feline leukemia (theilen) and sarcoma (gardner) virus, while under the same conditions the unsubstituted parent compounds failed to do so. in addition, poly(duz) and poly(dcz) inhibited the r ... | 1975 | 47174 |
| the oncogene hypothesis and the search for human cancer virusus. | | 1975 | 47649 |
| a p60 polypeptide in the feline leukemia virus pseudotype of moloney sarcoma virus with murine leukemia virus p30 antigenic determinants. | a 60,000-dalton polypeptide (p60) has been identified in the feline leukemia virus (felv) pseudotype of moloney sarcoma virus [msv(felv)]. this polypeptide is present in the purified virus complex in concentrations greater than either the murine p30 or the feline p27. purified p60 crossreacts immunologically with murine p30 group antiserum and contains several interspecies determinants, whereas the group specific determinant of felv p27 is not detected. comparison of peptide fingerprints of p60 ... | 1975 | 49060 |
| isolation of mammalian type c rna virus cross-reactive antigen and antibody by immuno-affinity chromatography. | | 1975 | 49291 |
| multiple species-specific and interspecific antigenic determinants of a mammalian type c rna virus internal protein. | | 1975 | 49292 |
| interspecies antigenic determinants of the reverse transcriptases and p30 proteins of mammalian type c viruses. | the major internal structural proteins (p30) of type c viruses isolated from several mammalian species were studied by radioimmunoprecipitation and competitive radioimmunoassays. three antigenically distinguishable sets of interspecies determinants could be demonstrated by both methods. one set of determinants shared by viruses of rodent origin (mouse and rat) can be detected readily in feline leukemia viruses but not in other type c viral groups. the p30 proteins of murine viruses also contain ... | 1975 | 49443 |
| antibody in cats to mammalian rna tumor virus interspecies antigens. | the studies were undertaken to determine whether the cat, a mammalian species that carries xenotropic endogenous c-type virus(es) and in addition undergoes horizontally transmitted oncogenic c-type rna tumor virus infections, responds immunologically to the mammalian c-type virus interspecies antigens. sera from normal cats and from cats with spontaneous or virus-induced neoplasms were examined for antibodies to interspecies antigen antigen by complement-fixation inhibition, by inhibition of the ... | 1975 | 50133 |
| [proceedings: some biochemical properties of bovine leukemia virus]. | | 1975 | 50808 |
| partial characterization of c-type particles in a cell line (wr-9) derived from a rat epidermoid carcinoma of spontaneous origin. | a c-type virus continuously released from a cell line (wr-9) derived from a spontaneous epidermoid carcinoma was purified by means of large-scale tissue culture techniques and high-volume zonal centrifuges. with the use of relatively pure virus concentrates, partial characterization of the virus has been accomplished. up to 60 liters of spent culture medium from relatively low virus-yielding cultures were processed at a time through the model k ultracentrifuge in order to obtain quantities of vi ... | 1975 | 50883 |
| antigenic determinants of the 70,000 molecular weight glycoprotein of woolly monkey type c rna virus. | the 70,000 molecular weight glycoprotein (gp70) of a type-c rna virus originally isolated from a woolly monkey has been partially purified and immunologically characterized. evidence that this viral protein is viral coded was derived from studies showing its antigenic properties to be unaltered by virus passage in cells of different species. a broadly reactive competition immunoassay was developed utilizing antiserum prepared against feline leukemia virus to precipitate 125i-labeled woolly monke ... | 1975 | 51882 |
| essential arginyl residues in reverse transcriptase. | | 1975 | 52361 |
| evolution of type c viral genes: origin of feline leukemia virus. | reiterated gene sequences related to the rna of feline leukemia virus (felv) are detected in all tissues of domestic cats and their close felis relatives but not in more distantly related felis species. partially homologous viral gene sequences are found in rodent, and particularly rat, dna. together with the immunologic relationships observed between felv and endogenous rodent type c viruses, the results lead to the conclusion that felv-related genes were transmitted from a rodent to cat ancest ... | 1975 | 52892 |
| species and interspecies radioimmunoassays for rat type c virus p30: interviral comparisons and assay of human tumor extracts. | the major internal protein, p30, of rat type c virus (ralv) was purified and utilized to establish intra- and interspecies radioimmunoassays. three rat viruses were compared in homologous and heterologous intraspecies assays with no evidence of type specificity. the only heterologous viruses to give inhibition in these species assays were the feline (felv) and hamster (halv) type c viruses; these reactions were incomplete and required high virus concentrations. an interspecies assay using a goat ... | 1975 | 54444 |
| properties of mouse leukemia viruses. x. occurrence of viral structural antigens on the cell surface as revealed by a cytotoxicity test. | | 1976 | 54978 |
| properties of mouse leukemia viruses. xi. immunoelectron microscopic studies on viral structural antigens on the cell surface. | | 1976 | 54979 |
| immune response to leukemia virus and tumor-associated antigens in cats. | cats represent an unusually valuable model for studying the role of the immune response to leukemia, lymphoma, and other mesodermal neoplasms. the agents that cause spontaneous feline leukemias, lymphomas, and fibrosarcomas, the feline leukemia and sarcoma viruses, are well characterized. a specific tumor cell membrane antigen, designated the feline oncornavirus-associated cell membrane antigen (focma) has also been described. feline leukemia and feline sarcoma viruses are antigenically indistin ... | 1976 | 56224 |
| purification and serological characterization of the major envelope glycoprotein from akr murine leukemia virus and its reactivity with autogenous immune sera from mice. | the major envelope glycoprotein (gp71) from akr murine leukemia virus (mulv) was purified and its serological reactivity with heterologous and autogenous immune mouse sera was examined. homologous and interspecies competition radioimmunoassays using antisera to rauscher-mulv gp69/71 or friend-mulv gp71 or antisera to feline leukemia virus to precipitate 125i-labeled gp71 from various mulv showed that distinct differences exist between rauscher- or friend-mulv and akr-mulv glycoproteins. characte ... | 1976 | 56459 |
| felv-related sequences in dna from a felv-free cat colony. | | 1976 | 56809 |
| isolation and characterization of an antigen of the bovine c-type virus. | by means of gel filtration and isoelectric focusing, an antigen of the bovine c-type leukemia virus was isolated in a highly purified form from extracts of infected cells. the antigen has a molecular weight of approximately 25,000 daltons and an isoelectric point of 6.4 to 6.6. in immunodiffusion experiments, the antigen forms a line of identity with an antigen extracted from highly purified bovine c-type leukemia virus by treatment with ether or triton x-100. as determined by immunodiffusion an ... | 1976 | 56993 |
| bovine leukemia virus: an exogenous rna oncogenic virus. | short-term cultures of bovine leukemic lymphocytes release virus particles with biochemical properties of rna oncogenic viruses. these particles, tentatively called bovine leukemia virus (blv), have a high molecular weight rna-reverse transcriptase complex and a density of 1.155 g/ml in sucrose solutions. molecular hybridizations between blv/[3h]cdna and several viral rnas show that blv is not related to mason-pfizer monkey virus, simian sarcoma associated virus, feline leukemia virus, or avian ... | 1976 | 57616 |
| infectious proviral dna in human cells infected with transformation-defective type c viruses. | | 1976 | 57665 |
| neutralization of homologous and heterologous oncornaviruses by antisera against the p15(e) and gp71 polypeptides of friend murine leukemia virus. | | 1976 | 58469 |
| type c viruses from kirsten sarcoma-transformed mink cells co-cultivated with primate cells and expressing p30 antigens related to feline leukemia virus. | two type c viruses with new antigenic and biological properties were isolated by co-cultivating secondary cell strains established from the kidneys of a baboon (papio papio) and a patas monkey (erythrocebus patas) with mink cells non-productively transformed by kirsten sarcoma virus. both new isolates (designated pp-1r and ep-1r) contain major structural proteins (p30) that are immunologically most closely related to the p30 proteins of feline leukemia viruses. the reverse transcriptases of both ... | 1976 | 60495 |
| endogenous type-c rna viruses of mammalian cells. | | 1976 | 62589 |
| bvr-1, a restriction locus of a type c rna virus in the feline cellular genome: identification, location, and phenotypic characterization in cat x mouse somatic cell hybrids. | somatic cell hybrids were constructed between balb/c-rag mouse cells and feline lymphoma cells by the hypoxanthine-aminopterin-thymidine selection scheme. rag cells spontaneously produce an endogenous b-tropic type c virus. cat-mouse hybrids preferentially segregate feline chromosomes and retain murine chromosomes-demonstrable by karyotypic and isozyme analyses. despite the presence of the complete mouse genome, including the viral genome, virus production was diminished to 1-5% of the levels ob ... | 1976 | 63949 |
| [feline leukosis and sarcoma viruses]. | | 1976 | 64021 |
| type c virogenes: modes of transmission and evolutionary aspects. | | 1976 | 64381 |
| bovine leukemia virus: an exogenous rna oncogenic virus? | short term cultures of bovine leukemic lymphocytes release virus particles with biochemical properties of rna oncogenic viruses. these particles, tentatively called bovine leukemia virus (blv) have a high molecular weight-reverse transcriptase complex and a density averaging 1.155 g/ml in sucrose solutions. molecular hybridizations between blv-3h cdna and several viral rnas show that blv is not related to mason-pfizer monkey virus (mpmv) simian sarcoma associated virus (ssv-1) feline leukemia vi ... | 1976 | 64382 |
| interspecies determinants of friend leukemia virus antigens involved in cytolysis of virus-pfoducing cells. | the cytolytic reactivity of a complex goat anti-feline leukemia virus (felv) antiserum for mouse cells (eveline) releasing large quantities of friend leukemia virus (flv) was analyzed by the sensitive [14c]nicotinamide release microcytotoxicity assay. whereas this interspecies killing reactivity could be blocked by absorption of the goat anti-felv serum with a preparation of disrupted flv, absorption with purified flv gp71, the major envelope glycoprotein, had no effect. subsequent serum absorpt ... | 1977 | 64623 |
| cells transformed by certain strains of moloney sarcoma virus contain murine p60. | it was previously demonstrated that the 60,000 dalton (p60) precursor-like polyprotein containing murine p30 was a constituent of the feline leukemia virus pseudotype of moloney sarcoma virus [m1msv(felv)]. it is now shown that p60 is detected in cells of five mammalian species transformed by m1msv, indicating that p60 is specified by this genome. moreover, little or no murine p30 is detected in the m1msv-transformed cells, suggesting that the murine group p30 antigenic reactivity of s + l- cel ... | 1977 | 65230 |
| expression of antigenic crossreactivity to rd114 p 30 protein in a human fibrosarcoma cell line. | an antigen crossreacting with the 30,000-molecular-weight protein (p30) of the feline endogenous oncornavirus (rd114) was detected in a well-characterized human fibrosarcoma cell line, ht1080, by indirect immunofluorescence. three antisera against rd114 p30 gave similar positive results, while two antisera prepared against simian sarcoma virus p30, one antiserum prepared against murine leukemia virus p30, and one antiserum prepared against feline leukemia virus p30 gave no immunofluorescence. th ... | 1977 | 66679 |
| abrogation of resistance to feline oncornavirus disease by immunization with killed feline leukemia virus. | four-week-old specific-pathogen-free cats were immunized with a combined vaccine composed of killed feline leukemia virus and killed feline oncornavirus-associated cell membrane antigen-containing tumor cells. immunization induced feline oncornavirus-associated cell membrane antigen antibody titers ranging from 1:32 to 1:256 but did not elicit detectable virus-neutralizing antibody titers. kittens immunized with tumor cells alone developed higher feline oncornavirus-associated cell membrane anti ... | 1977 | 67886 |
| morphologic and immunologic studies of human prostatic carcinoma. | benign and malignant prostatic tissue was removed in surgery and partitioned for (a) ultrastructural study, (b) tissue culture, and (c) (c) immunochemical study. fourteen malignant and 18 benign prostatic cancer specimens were examined by transmission electron microscopy (tem) for the presence of viruses or virus-like particles. viruses could not be identified with assurity in thin sections. acinar cells of normal, benign prostatic hypertrophy (bph), and neoplastic prostate tissue were examined ... | 1977 | 68819 |
| mammalian c-type oncornaviruses: relationships between viral structural and cell-surface antigens and their possible significance in immunological defense mechanisms. | | 1977 | 68853 |
| expression of feline leukaemia virus antigens on cat lymphoma cells: kinetics of biosynthesis. | | 1977 | 69678 |
| phosphorylation and nucleic acid binding properties of m1 moloney murine sarcoma virus-specific pp60gag. | the pp60gag polyprotein of the feline leukemia virus pseudotype of m1 moloney murine sarcoma virus [m1msv(felv)] was previously shown to be msv specific and to contain murine p30 and smaller structural polypeptides. this protein was detected in m1msv-transformed cells, and in pulse-chase studies it was found to be stable. in this study virion p60 was shown to contain murine pp12, to be phosphorylated, and to bind to nucleic acids. 32p-labeled m1msv[felv) was fractionated by guanidine agarose chr ... | 1977 | 69721 |
| characterization of a feline leukemia viral cell membrane antigen reactive with feline sera. | | 1977 | 72119 |
| feline malignant mammary tumors. iii. presence of c-particles and intracisternal a-particles and their relationship with feline leukemia virus antigens and rd-114 virus antigens. | thirty-six feline mammary tumors were examined by the electron microscope, and by the indirect immunofluorescence (ifa) test with anti-felv and anti-rd-114 serum. in 11 (30.6%) tumors intracisternal a-particles (iap) were found. one of these tumors contained a few particles with an electron-dense nucleoid in the cisternae of the endoplasmic reticulum. in 7 (19.4%) other tumors c-particles were found and in the remaining 18 (50.0%) no particles at all could be detected. in 11 (30.6%) tumors felv ... | 1977 | 72739 |
| deposition of retrovirus associated antigens (p30 and gp70) on cell membranes of feline and murine leukaemia virus infected cells. | a quantitative estimation of retrovirus associated cell membrane antigens of murine and feline cells infected with their respective type c leukosis virus is presented. using a radio-immune assay with three broadly reactive antisera, the minimum estimated number of retrovirus associated antigenic determinants on yac [moloney leukaemia virus (mulv) infected murine] and fl-74 [feline leukaemia virus (felv) infected feline] cells was 1.3 x 10(6) and 1.6 x10(6) determinants per cell respectively. the ... | 1978 | 75945 |
| experimental horizontal transmission of feline leukemia viruses of subgroups a, b, and c. | experiments were conducted with cats in metal cages inside plastic isolators to determine whether feline leukemia virus (felv) of the three known antigenic subgroups (a, b, and c) is transmitted horizontally from infected cats to normal "contact" cats. blood smears collected at weekly intervals were examined by the fixed-cell, indirect immunofluorescence test for felv internal p30 to follow the spread of infection from inoculated cat to contact cats. these studies established that viruses of all ... | 1978 | 75981 |
| endogenous mink (mustela vison) type c virus isolated from sarcoma virus-transformed mink cells. | a previously described type virus stock (designated pp-1r), isolated by cocultivating baboon cells with mink cells transformed by kirsten sarcoma virus (64j1), has been further cloned and characterized. end point-diluted stocks of pp-1r have been obtained that are free of focus-forming activity and lack both kirsten sarcoma and primate type c viral sequences. nucleic acid hybridization experiments show that the cloned virus (milv) is an endogenous, genetically transmitted virus of the mink (mus ... | 1978 | 76684 |
| rd-114 virus: characterization and identification. | | 1978 | 77028 |
| multiple rnase h activities in mammalian type c retravirus lysates. | lysates of moloney murine sarcoma-leukemia virus [m-msv(mlv)], a virus complex grown in the rat cell line 78a-1, were found to contain three rnase h species separable by polycytidylic acid[poly(c)]-agarose chromatography. rnase h activity (rnase h i) associated with rna-directed dna polymerase eluted at 0.23 m kci from poly(c)-agarose. rnase h ii, which eluted from poly(c)-agarose at 0.12 m kci and was not associated with dna polymerase activity, was shown to be identical to an rnase h species ( ... | 1978 | 77333 |
| the biosynthesis of oncovirus proteins. | the patterns of oncovirus protein biosynthesis are essentially similar for avian and mammalian viruses. in each case the four major internal structural proteins are synthesized as a precursor polypeptide of about 75 000 daltons, the product of the gag gene. translation occurs on genome-sized mrna. this polyprotein is cleaved in a series of steps to give the mature proteins. the mechanism and localization of cleavage have not yet been clarified. viral reverse transcriptase, the product of the pol ... | 1978 | 77678 |
| radioimmunologic characterization of rd-114 reverse transcriptase: evolutionary relatedness of mammalian type c viral pol gene products. | | 1978 | 78564 |
| surface antibodies of human myelogenous leukaemia leukocytes reactive with specific type-c viral reverse transcriptases. | purified immunoglobin g (igg) from patients with chronic myelogenous leukaemia specifically neutralised rt from feline leukaemia virus while purified igg from other types of leukaemias and from normal blood cells were less reactive and in some cases preferentially reacted with rt from horizontally transmitted primate type-c viruses (simian sarcoma virus-gibbon ape leukaemia virus group). this indicates the presence of a heterogeneous immune response to rt or to an rt-like molecule in humans. | 1978 | 82207 |
| antibody response in cats to feline leukemia virus reverse transcriptase under natural conditions of exposure to the virus. | | 1978 | 84436 |
| [immunotherapy of malignant growths (author's transl)]. | our knowledge of antigens which are associated with different types of malignant tumours is steadily increasing. these antigens exist in considerable numbers, but, so far with few exceptions, only their presence can be demonstrated by certain methods; to isolate and identify them has not yet been possible. these antigens are, therefore, suitable not so much for the primary diagnosis, but rather, like the carcinoembryonic antigen, the tissue-polypeptide antigen or the alpha-feto-protein, for asse ... | 1979 | 88728 |
| sarcoma virus-induced transformation specific antigen: presence of antibodies in cats that were naturally exposed to leukemia virus. | | 1979 | 88797 |
| characterization of reverse transcriptase from filine leukemia virus by radioimmunoassay. | | 1979 | 91258 |
| placenta-bound immunoglobulins. | low ph eluates were prepared from trophoblasts derived from 8 term human placentas. a qualitative analysis for immunoglobulins revealed the presence of igg, iga, and igm in these eluates. igc-rich fractions were obtained by deae-cellulose chromatography of ammonium sulfate-concentrated eluates. these fractions were able to neutralize, in vitro, the catalytic activity of reverse transcriptases (rt) from several retroviruses. rt from baboon endogenous virus (bev) seemed to be more susceptible to t ... | 1979 | 92319 |
| studies on antibodies against feline leukaemia virus (felv) in cat sera and rabbit anti-felv sera: cross reaction and differences. | the indirect immunoferritin technique (ift) that enables us to distinguish clearly whether an antibody reacts with a virus particle or only with the cell membrane, was used to study 25 cat sera and one rabbit anti-feline leukaemia virus (felv) serum using fl-74 cells as target. (1) all sera contained antibodies against felv even though 11 of the cats were viraemic at the same time; (2) from the effect of glutaraldehyde fixation of the fl-74 cells on the reaction with cat sera and the results of ... | 1979 | 93140 |
| enhancement of feline leukemia virus-induced leukemogenesis in cats exposed to methylnitrosourea. | the effect of methylnitrosourea (mnu), a potent resorptive carcinogen, was evaluated for its influence on the susceptibility of adult cats to infection and induction of oncornavirus disease by feline leukemia virus (felv). young adult cats at an age previously demonstrated to be highly resistant to felv, were injected intravenously with moderately toxic doses (15-20 mg/kg) of mnu alone or with infections felv (rickard strain). following exposure to virus and chemical, cats were monitored for ant ... | 1979 | 93586 |
| tumor immunology in domestic animals. | | 1979 | 95155 |
| the effects of methylnitrosourea on the immune system and hematopoietic system of adult specific pathogen free cats. | the effects of a single non-carcinogenic dose of 15 mg/kg methylnitrosourea (mnu) on the immune and hematopoietic systems of adult specific-pathogen-free (spf) cats were determined. the cell-mediated-immune (cmi) system was markedly suppressed, as evidenced by: (i) prolonged cutaneous allograft retention time (41-84 days); (ii) decreased lymphocyte blast transformation response to mitogens (2% of pretreatment response to pokeweed mitogen or concanavalin a) and antigen (12% of untreated control c ... | 1979 | 162045 |
| association of feline leukemia virus with lymphosarcoma and other disorders in the cat. | two hundred fifty boston cats with disorders such as lymphosarcoma, myeloproliferative disease, anemia, glomerulonephritis, pregnancy abnormalities, feline infectious peritonitis, toxoplasmosis, and various bacterial infections were examined for feline leukemia virus (felv) by immunofluorescence. antibody titers against feline oncornavirus-associated cell membrane antigen (focma) were tested in 133 of these cats. the tests for felv and focma antibody were also conducted among healthy cats not kn ... | 1975 | 163223 |
| anemia associated with feline leukemia virus infection in cats. | the types of anemia associated with natural and experimental feline leukemia virus (felv) infection in cats were investigated. in one experiment, 10 kittens were inoculated neonatally with jarrett felv-1, an isolate of subgroup a; 6 developed anemia a few weeks later. this anemia was characterized by macrocytosis, normoblastosis, increased erythropoiesis in the bone marrow, and extramedullary hematopoiesis in the spleen. anemia was transient and nonfatal and occurred before the onset of lympoid ... | 1975 | 163317 |
| phosphoproteins: structural components of oncornaviruses. | oncornaviruses, which contain a virion-associated protein kinase, were found to possess phosphoproteins as virion structural components. one major phosphoprotein common to strains of laboratory and wild mouse oncornaviruses and a strain of feline leukemia virus was shown to be a polypeptide of about 12, 000 mol wt. in addition to this, the kirsten strain of murine sarcoma virus contained a second major phosphoprotein of about 10, 000 mol wt, and mouse erythroblastosis virus contained a second ma ... | 1975 | 163371 |
| feline leukaemia virus and its clinical effects in cats. | feline leukemia virus (felv) infection is common among cats where contact is high. the virus can be transmitted readily between cats. it causes a variety of haemopoietic and lymphoid neoplasms; the most common types are alimentary, multicentric and thymic lymphosarcoma and lymphatic leukaemia. the virus is involved in the aetiology of certain other diseases including anaemia, glomerulonephritis and an immunosuppressive syndrome which predisposes cats to intercurrent infections. many infected cat ... | 1975 | 163515 |
| a mixed-immunoglobulin rosette technique for detection of antibody to feline oncornavirus-associated cell membrane antigen. | a mixed-immunoglobulin rosette technique has been developed for the detection of antibodies to feline oncornavirus-associated cell membrane antigens. lymphoblastoid cells infected with feline leukemia virus were incubated with test sera and then fixed in paraformaldehyde. they were then exposed to a rabbit anti-cat immunoglobulin g serum. antigen-antibody reactions were detected by mixing the cells with sheep erythrocytes sensitized with cat anti-sheep red blood cell serum; the presence of cat a ... | 1975 | 163696 |
| naturally occurring persistent feline oncornavirus infections in the absence of disease. | healthy feline leukemia virus (felv)-infected cats from leukemia cluster environments were followed for up to 23 months for development of disease and evidence of alteration in the hemogram. the incidence of disease development in felv-postive cats was more than fivefold higher than the incidence for felv-negative cats. ten cases of leukemia developed in 69 infected cats, whereas one case of leukemia occurred in 59 uninfected cats. the incidence for development of diseases other than leukemia wa ... | 1975 | 163793 |
| editorial: advances in leukaemia virus research. | | 1975 | 164081 |
| feline oncornavirus-associated cell membrane antigen. ii. antibody titers in healthy cats from household and laboratory colony environments. | antibody titers to the feline oncornavirusassociated cell membrane antigen (focma) were determined for 447 healthy cats from laboratory colony and household environments. only 2.7 percent of 221 cats from colony environments were antibody positive as compared to 50.4 percent of 256 cats from household environments. incidence of focma antibody and geometric mean antibody titer for pet cats from new york city representing single cat apartment habitats were substantially lower than values for unscr ... | 1975 | 164562 |
| feline oncornavirus-associated cell membrane antigen. iii. antibody titers in cats from leukemia cluster households. | serum samples from 182 healthy cats residing in environments known to have a natural exposure to feline leukemia virus (felv) were examined for the presence of antibody to the feline oncornavirus-associated cell membrane antigen. the number included 138 cats from leukemia-"cluster" households. such cats previously showed greatly increased frequencies of felv infection, as determined by the virus group-specific antigen (gasa) in peripheral blood leukocytes and platelets. the geometric mean antibo ... | 1975 | 164563 |
| aberrant viruses in cells infected with murine sarcoma virus-feline leukemia virus. | this study describes an unusual type of virus seen when a feline leukemia virus (felv) pseudotype of murine sarcoma virus (musv) obtained by cocentrifugation procedures infected feline embryo cells (fef) and two crandell cat cell lines (crfk1, crfk2). when all three cell cultures were infected with musv-felv, only fef and crfk2 were transformed and only these showed normal and aberrant virus. the crfk1 infected with musv-felv did not transform but did replicate normal type-c virus with a 50-a in ... | 1975 | 164569 |
| viral-related information in oncornavirus-lik particles isolated from cultures of marrow cells from leukemic patients in relapse and remission. | characterization of ribonucleic acid content of particles released from cultures of marrow cells of leukemic patients indicates the presence of rna molecules of size and base sequence characteristic of oncornarviruses. seventeen marrow samples obtained from leukemic patients in relapse or in a chronic phase of the disease yielded particles containing high-molecular-weight rna with a sedimentation velocity (about 70 s) similar to that obtained for murine oncornavirus rna. eight of nine marrow sam ... | 1975 | 164662 |
| demonstration of feline leukemia virus antibody in cats by passive hemagglutination (38583). | two felv fractions from sephadex g-150 gel filtration were used to sensitize rbc for the pha test. when the cells were coated with the fraction from the second peak consisting mostly of a mojor gs antigen of felv, no antibodies could be detected either in hyperimmunized cat sera or sera from leukemic cats, whereas antibodies were readily detectable in immunized rabbits. using cells coated with the first peak eluants or tween-ether disrupted felv, pha antibodies were detected in cat sera. there e ... | 1975 | 164675 |
| affinity chromatography of viral dna polymerases on pyran-sepharose. | pyran covalently linked to cyanogen bromide-activated sepharose has been shown to be an effective affinity matrix for several viral dna polymerases. differential salt elution of viral compared with cellular polymerases, as well as substrate elution, suggests the affinity nature for the matrix. unlike some other affinity systems described, pyran-sepharose is totally resistant to nuclease digestion and is stable at 4 degrees for several months. dna polymerases isolated from several viruses by dete ... | 1975 | 165485 |
| infectious spread and control of feline leukemia virus. | | 1975 | 165603 |
| differential host range of viruses of feline leukemia-sarcoma complex. | | 1975 | 166488 |
| amino-terminal sequence of baboon type c virus p30. | | 1975 | 166494 |
| epidemiological studies on feline leukaemia virus infection. i. a serological survey in urban cats. | a survey of the incidence of feline leukaemia virus (felv) infection in cats in a large urban area was made by studying the prevalence of antibodies to feline leukaemia virus-associated cell membrane antigens. two serological tests were used, immunofluorescence and a mixed immunoglobulin rosette technique. the overall incidence of cats with antibodies was 40%, contrasting with 6% in the surrounding rural area. only 6% of urban kittens were positive while 50% of adults had antibodies. the inciden ... | 1975 | 166947 |
| an unusual case of feline leukemia and an associated syncytium-forming virus. | a 3-year-old female siamese cat was admitted to a local animal hospital with a history of recent extreme lethargy and anorexia. a hemorrhagic tumor was removed from an area of oral buccal skin and diagnosed histopathologically as lymphosarcoma. rapid physical deterioration occurred, and the cat became moribund 2 weeks after surgical operation. necropsy revealed at least 200 spherical hemorrhagic neoplastic nodules attached to the omentum, mesentery, and peritoneum. examination of histopathologic ... | 1975 | 167623 |
| electron microscope studies of tumor virus rna. | | 1975 | 169036 |
| amino acid sequence homology of mammalian type c rna virus major internal proteins. | the nh2-terminal amino acid sequence of the major group-specific antigen, the major internal virion protein (p30; approximate molecular weight 30,000) of several mammalian type c rna viruses was determined by the edman degradation procedure using an automated protein sequenator. all of the proteins analyzed show a high degree of over-all sequence homology and also contain specific regions or single residues. all p30s begin with the sequence prolyl-leucylarginyl (pro-leu-arg) and have an invarian ... | 1975 | 169234 |
| establishment of two canine sarcoma cell lines: productive infection with feline leukemia virus. | two canine sarcoma cell lines (11028, 11031) were established in vitro and have been transferred 213 and 306 times, respectively, since 1970. these cell lines had a chromosome pattern consistent with their canine origin. both cultures were infected with feline leukemia virus (felv), which caused a morphologic and karyotypic changes. the cells became rounded after infection with felv and both cultures showed the presence of a single, large, acrocentric chromosome considered to be a marker chromos ... | 1975 | 169374 |
| feline oncornavirus-associated cell membrane antigen. iv. antibody titers in cats with naturally occurring leukemia, lymphoma, and other diseases. | cats with naturally occurring leukemia and lymphoma had low or negative humoral antibody titers to the feline oncornavirus-associated cell membrane antigen (focma). geographic differences were seen in the relative frequencies of various forms of lymphoproliferative neoplasms. lymphatic leukemia and thymic lymphoma were most common in boston, whereas alimentary lymphoma was most frequent in glasgow. no significant differences were found in geometric mean focma antibody titers for the various form ... | 1975 | 169377 |
| properties of feline leukemia virus. iii. analysis of the rna. | the kinetics of virus labeling was used to study the maturation of viral rna in the rickard strain of feline leukemia virus. viral rna labeled over differing intervals was characterized by gel electrophoresis and velocity sedimentation in sucrose gradients made up in aqueous buffer and 99% dimethyl sulfoxide. labeled virus was found within 30 min after adding radioactive uridine to the cells and production of labeled virus reached a maximum at 4 to 5 h after pulse labeling. native rna from felin ... | 1975 | 169389 |
| editorial: leukaemia in animals and man. | | 1975 | 169460 |
| viral leukaemia in domestic cats. | | 1975 | 169461 |
| [the incidence of lymphosarcoma (leukaemia) and feline leukaemia virus (felv) in cats in the netherlands (author's transl)]. | seven different groups of cats were examined to study the incidence and distribution of feline leukaemia virus (felv) in the netherlands. the indirect fluorescent antibody (ifa) technique was used to detect felv antigen. of the cats with lymphosarcoma (leukaemia), 73.2 per cent and of those with infectious peritonitis, 32.4 per cent were found to be positive for felv antigen. of the sixty-six cats with other tumours, only one, a cat with carcinoma of the mammary gland; was positive for felv anti ... | 1975 | 169604 |
| complement-fixation-inhibition as a test for antibodies in cats and humans to c-type rna tumor virus antigen. | the complement-fixation-inhibition (cfi) test was evaluated as a means of detecting humoral antibodies in cat sera and in human sera to mammalian c-type rna virus interspecies antigen(s). cfi antibody titers of greater than or equal 1:2 were detected in sera from all tumor bearing (23) and normal cats (23), however, sera from most germ free cats were negative. when the same cat sera were tested for blocking antibody by the paired radioiodine labeled antibody technique the correlation between the ... | 1975 | 169819 |
| immune response of healthy and leukemic cats to the feline oncornavirus-associated cell membrane antigen. | feline leukemia is an infectious disease caused by a horizontally transmitted virus. infection of animals or cultured cells with feline oncornaviruses results in the expression of a specific cell membrane antigen, feline oncornavirus-associated cell membrane antigen (focma). the humoral antibody response to focma is directly correlated with tumor progression. the measurement of this antibody is a useful tool for determining virus exposure. using this procedure it was determined that cats living ... | 1975 | 169820 |
| in vitro host range of feline leukemia virus. | | 1975 | 169821 |
| horizontal transmission of feline leukemia virus in cats. | traditionally, cancer has not been considered an infectious disease although some multiple cases of leukemia in man and cattle have been reported. the discovery that feline lymphosarcoma was associated with an rna virus (feline leukemia virus(felv)) meant that infectious transmission of the disease was a possibility. the critical question was whether the predominant method of transmission from one animal to another was 'vertical' (via the gametes) or 'horizontal' (via contagion or infection). a ... | 1975 | 169834 |
| in vitro transformation of cells from human neoplasms. | the possible involvement of rna tumor virus genomes in human cell transformation was investigated. forty-nine cell cultures from neoplastic, normal, or embryo tissues were examined for transformation, following inoculation of murine leukemia virus (mulv), feline leukemia virus (felv) grown in human cells, or bone marrow aspirates from leukemia patients. five cultures exhibited transformation (1 after inoculation of mulv grown in human cells; 4 after inoculation of human leukemic bone marrow), an ... | 1975 | 169838 |
| sarcomas induced in rats by feline rna virus. | | 1975 | 169839 |
| vaccination against feline leukaemia virus using a cell membrane antigen system. | cats inoculated with live feline lymphoblastoid cells of the fl74 line developed high titres of antibody to feline oncornavirus-associated cell membrane antigen (focma). eight cats were subsequently challenged with a large dose of feline leukaemia virus (felv) of a highly pathogenic strain. all resisted infection while 10 cats given the challenge virus alone became infected. the felv produced by fl74 cells was shown to be of extremely low infectivity in cats and in cultured feline cells. cats in ... | 1975 | 170211 |
| natural history of feline leukaemia virus. | | 1975 | 170454 |
| segregation of rd-114 and fel-v-related sequences in crosses between domestic cat and leopard cat. | | 1975 | 170535 |
| human serum lyses rna tumour viruses. | | 1975 | 170540 |
| an in vitro focus-induction assay for xenotropic murine leukemia virus, feline leukemia virus c, and the feline--primate viruses rd-114/ccc/m-7. | | 1975 | 170737 |
| the relation of immune response to pathogenesis, vaccination and epidemiology in virus induced leukaemia. | the antigenic systems of oncornaviruses and particularly feline leukaemia virus (felv) are reviewed briefly. the use of immunological methods in studying the epidemiology of the disease is described. the incidence of felv infection as judged by a serological survey is at least 100 times greater than that of leukaemia in the cat population. horizontal transmission, due to virus replication in respiratory and alimentary epithelial cells, is common. a method of producing high titres of antibody aga ... | 1975 | 170952 |
| electrophoretic mobilities of rna tumor viruses. studies by doppler-shifted light scattering spectroscopy. | we have used laser beat frequency light scattering spectroscopy to measure, at several ph values, the electrophoretic mobilities of purified avian myeloblastosis (amv), murine leukemia (mulv), murine mammary tumor (mumtv), and feline leukemia (felv) viruses. the mobilities of these viruses are similar at ph greater than or equal to7 (-2.7 to -3.2 x 10(-4) (cm/sec)/(v/cm). the isoelectric points of mulv and amv are apparently less than ph 3, whereas for felv the data could be interpreted to indic ... | 1975 | 170961 |
| characterization of non-producer human cells induced by kirsten sarcoma virus. | non-producer (np) human cells induced by the kirsten sarcoma virus were characterized. these morphologically altered np cells produced neither infectious virus nor complement-fixing antigens of the murine sarcoma-leukemia virus complex. the np cells did not release rna-dependent dna polymerase and type-c virus particles with a density of approximately 1.15 g/ml in sucrose gradients by 3h-uridine labelling. the np cells produced tumors when transplanted subcutaneously into athymic nude mice. the ... | 1975 | 171229 |
| symposium: characterization of oncornaviruses and related viruses--a report. | | 1975 | 171431 |
| serological analysis of an oncornavirus (pmf virus) detected in malignant permanent human cell lines. | immunodiffusion analysis of the pmf virus which was detected in malignant permanent human cell lines revealed positive reactions with antisera against the mason-pfizer monkey virus (mpmv). no cross-reactivity was demonstrated with murine leukemia virus (mulv), rat leukemia virus (ralv), hamster leukemia virus (halv), feline leukemia virus (felv), simian (woolly monkey) sarcoma virus (ssv-1) and mouse mammary tumor virus (mtv). the cross-reactive antigens of the pmf virus and the mpmv are conside ... | 1975 | 171892 |