| [clinical aspects of infection with feline leukemia virus in cats]. | the leukemia-sarcoma complex constitutes the most common group of malignancies in the cat. epizootiology of felv infections and pathogenesis, which can be divided into three stages, are described. diagnosis can be made by immunofluorescent, elisa and virus isolation techniques, as well as focma-antibody tests. symptomatology of felv related illnesses is presented. feline lymphoma can be categorized into four anatomic types: thymic, alimentary and multicentric type and true leukemia. forms, which ... | 1984 | 6098972 |
| transcription and expression of the herpes simplex virus tk gene inserted into proviral sequences of feline leukemia virus. | recombinant dna molecules containing the herpesvirus tk gene inserted near the middle of a cloned feline leukemia virus proviral genome, in the same transcriptional orientation as the long terminal redundancies (ltrs), were used to transform human tk- cells. analysis of rna from cloned lines indicates that the 5' ltr promotes a high level of transcription which, as a result of differing rna splicing and polyadenylation pathways, results in three large, abundant rnas, two of which contain the ent ... | 1984 | 6099323 |
| transformation by feline retroviruses. | | 1984 | 6099894 |
| cell cycle kinetics of uninfected and feline leukemia virus-infected canine lymphoma cell lines: effects of methotrexate treatment. | the cell cycle kinetics of uninfected and feline leukemia virus-infected canine lymphoma cell lines were determined by autoradiography (plm method) as follows: dt-5: generation time (tc), 15.2 h; pre-synthetic gap phase (tg1), 3.2 h; dna-synthetic phase (ts), 8.2 h; post-synthetic gap ph se (tg2), 3.3 h; visible mitotic phase (tm), 0.5 h. 11028: tc, 13.6 h; tg1, 1.9 h; ts, 7.7 h; tg2, 3.4 h; tm, 0.6 h. 11028+felv (11028 productively infected with feline leukemia virus): tc, 11.2 h; tg1, 0.2 h; t ... | 1980 | 6109397 |
| immune-mediated disorders of cats. | immune-mediated disorders in cats share many clinical and pathologic similarities with their counterparts in other species. cats, however, are unique among domestic animals owing to the involvement of feline leukemia virus. in addition, a number of other infectious organisms can produce immune-mediated sequelae--that is, fip virus, fesfv, and h. felis. therefore, the diagnostic and therapeutic aims in the management of feline immune-mediated disorders must take into account the probability of a ... | 1984 | 6149649 |
| biochemical and immunological characterization of polyproteins coded for by the mcdonough, gardner-arnstein, and snyder-theilen strains of feline sarcoma virus. | the mcdonough (sm), gardner-arnstein (ga), and snyder-theilen (st) strains of feline sarcoma virus (fesv) code for high-molecular-weight polyproteins that contain varying amounts of the amino-terminal region of the felv gag gene-coded precursor protein and a polypeptide(s) of an as yet undetermined nature. the sm-fesv primary translational product is a 180,000-dalton polyprotein which is immediately processed into a highly unstable 60,000-dalton molecule containing the p15-p12-p30 fragment of th ... | 1980 | 6154148 |
| effect of chemical modification and fragmentation on antigenic determinants of internal protein p30 and surface glycoprotein gp70 of type c retroviruses. | the effects of protein modification on the antigenic determinants of p30 and gp70 of type c retroviruses were investigated by using solid-phase competition radioimmunoassays. proteins were modified by reduction with 2-mercaptoethanol and subsequent carboxymethylation of sh groups with iodoacetamide or by amidination of alpha and epsilon amino groups with methylacetimidate. the type-specific determinants of gp70 were found to be conformational in nature, as they were destroyed by these chemical m ... | 1980 | 6154154 |
| biochemical and immunological properties of the dna polymerase and rnaase h activities of purified feline leukemia virus reverse transcriptase. | feline leukemia virus dna polymerase was purified by ion-exchange and nucleic acid affinity chromatographies. the enzyme consists of a single polypeptide chain of mol. wt. approx. 72,000 as determined by both glycerol density gradient centrifugation and sds-polyacrylamide gel electrophoresis. the preferred divalent cation for dna synthesis is mn2+ on a variety of template-primers, and its optimum concentration appears to be significantly lower than reported results of other mammalian type-c vira ... | 1980 | 6159069 |
| antiviral properties of polyinosinic acids containing thio and methyl substitutions. | polyinosinic acids containing methyl and sulphur substitutions are potent inhibitors of reverse transcriptase. substitution of sulphur for oxygen at the 6 position produces significant effects on the properties of polyinosinic acid: the kinetics of inhibition change from competitive to mixed-type and the inhibition constant falls by three orders of magnitude. in contrast, 1-methyl substitution produces no such effects. poly(1-methyl-6-thioinosinic acid) or poly(m1s6i) inhibits irreversibly, inhi ... | 1981 | 6169784 |
| feline leukemia - unique and cross-relating antigens on individual virus-producing tumors identified by complement-dependent antibody. | following exposure to feline leukemia virus (felv), cats that resist leukemia produce complement dependent antibodies (cda) which lyse leukemia cells in the presence of cat complement. the cda activity has been shown to be directed to feline oncornavirus-associated cell membrane antigen (focma) found on the surface of most feline leukemias. despite the retrovirus etiology of feline leukemia, and the ubiquity of focma expression by individual tumors, we found that cda activity did not cross-react ... | 1981 | 6172390 |
| antibodies against feline and gibbon ape reverse transcriptase on surface of spleen cells in human myelogenous leukemia. | | 1981 | 6175523 |
| nucleotide sequences of feline retroviral oncogenes (v-fes) provide evidence for a family of tyrosine-specific protein kinase genes. | the nucleotide sequences encoding the transforming polyproteins of the snyder-theilen and gardner-arnstein strains of feline sarcoma virus (fesv) have been determined. these sequences include a viral transforming gene (v-fes), derived from cellular proto-oncogene sequences (c-fes) of domestic cats by recombination with feline leukemia virus (felv). the v-fes sequences are predicted to encode a polypeptide domain strikingly similar to that specified by the transforming gene (v-fps) of the avian f ... | 1982 | 6183005 |
| monoclonal antibodies specific to transforming polyproteins encoded by independent isolates of feline sarcoma virus. | hybridomas secreting monoclonal antibodies directed against polyprotein gene products of the gardner, snyder-theilen, and mcdonough strain of feline sarcoma virus have been isolated. antibody produced by one hybridoma recognizes immunological determinants localized within a feline leukemia virus gag gene structural component (p15) common to polyproteins encoded by each feline sarcoma virus isolate while antibody produced by a second is specific for p30 determinants unique to p170gag-fms. additio ... | 1982 | 6183442 |
| feline oncornavirus-associated cell membrane antigen: a viral and not a cellularly coded transformation-specific antigen of cat lymphomas. | the feline oncornavirus-associated cell membrane antigen (focma) was defined as a tumor antigen common to cat lymphomas and fibrosarcomas induced by feline leukemia virus (felv) and feline sarcoma virus (fesv), respectively. the antigen was recognized by sera from cats thought to be resistant to leukemogenesis. we report here that a common denominator in the activity of naturally occurring viremic cat antisera to focma is, in fact, their reactivity to felv c antigenic determinants. the cat antis ... | 1983 | 6186079 |
| monoclonal antibodies to three epitopic regions of feline leukemia virus p27 and their use in enzyme-linked immunosorbent assay of p27. | three different monoclonal antibodies were developed against the major core protein (p27) of feline leukemia virus (felv). each antibody was directed against a different epitope of the species-specific portion of felv-p27. the 3 antibodies reacted with 5 different isolates of felv but not with 7 other retroviruses (mulv (rauscher), mulv (akr), mpmv, mmtv, smrv, baev, rd 114). these monoclonal antibodies could readily be adapted to an enzyme-linked immunosorbent assay (elisa) for the specific mea ... | 1983 | 6186744 |
| immunopathology induced by the feline leukemia virus. | | 1982 | 6195744 |
| feline leukemia virus envelope gp70 of subgroups b and c defined by monoclonal antibodies with cytotoxic and neutralizing functions. | nine murine monoclonal antibodies (mab) to the envelope proteins of feline leukemia virus (felv) are described. eight mab are directed to epitopes of the same molecular species of gp70 and the other mab is directed to the p15e moiety. six of the gp70 epitopes are discrete; two are closely associated or overlapping. four anti-gp70 mab (2 of igg2a and 2 of igg2b subclasses) were directly cytotoxic for felv-producer lymphoma cells with cat or with rabbit complement (c). another mab (igg2b), which w ... | 1983 | 6196410 |
| granules of blood eosinophils are stained directly by anti-immunoglobulin fluorescein isothiocyanate conjugates. | direct staining of the granules of blood eosinophils by anti-immunoglobulin fluorescein isothiocyanate (fitc) conjugates was observed when feline blood smears were tested for presence of feline leukemia virus (felv) antigen by immunofluorescent antibody. when blood smears of other species including swine, horses, cattle, dogs, sheep, birds, and human beings were examined, direct staining of eosinophils by fitc conjugates was also detected. this fitc staining was restricted to eosinophils and was ... | 1983 | 6196994 |
| hamster endogenous retrovirus (haer)--distinct properties of structural proteins and dna polymerase. | the structural proteins as well as some features of the rna-dependent dna polymerase of the hamster endogenous retrovirus (haer) were examined. the polypeptide pattern of this virus is substantially different from that of other known retroviruses in containing major polypeptides with molecular weights of 68,000, 59,000, 27,000 and 24,000 daltons. double antibody competitive radioimmunoassays showed that the haer particles do not share any detectable antigenic relatedness with the murine viruses' ... | 1983 | 6197953 |
| characterization of structural and immunological properties of specific domains of friend ecotropic and dual-tropic murine leukemia virus gp70s. | a detailed comparison of the gp70 proteins of cloned ecotropic friend murine leukemia virus (flv) and dual-tropic friend mink focus-forming virus (frmcf) was performed by analyzing the structural and immunological properties of amino- and carboxy-terminal domains of these molecules generated upon controlled trypsinization. the two gp70s gave characteristic fragmentation patterns; the amino-terminal fragments of frmcf gp70 were smaller than the corresponding fragments of flv and contained a tryps ... | 1984 | 6198530 |
| purification of a specific inhibitor of reverse transcriptase from human placenta. | human placental extracts contain a factor which specifically and reversibly inhibits the reverse transcriptase of mammalian retroviruses. this placental inhibitor has been partially purified and characterized. it elutes at 0.1-0.2 m phosphate on hydroxyapatite chromatography and can be further purified by phosphocellulose chromatography where it elutes at 0.4 m kcl. by these purification procedures, specific activities of 40-70,000 units of inhibitor per mg of protein were obtained. the size of ... | 1984 | 6200446 |
| method to map antigenic determinants recognized by monoclonal antibodies: localization of a determinant of virus neutralization on the feline leukemia virus envelope protein gp70. | a method is presented whereby antigenic determinants recognized by specific monoclonal antibodies can be mapped to specific sites on a protein sequence with high resolution. short dnase i-generated dna fragments encoding portions of the protein of interest are molecularly cloned into the ecori site of the beta-galactosidase gene of phage lambda charon 16 so as to obtain expression of random protein fragments as fusion proteins. the monoclonal antibody is used to screen the phage library to isola ... | 1984 | 6203125 |
| the immunobiology of the feline leukemia virus. | | 1984 | 6204435 |
| remission of leukemia and loss of feline leukemia virus in cats injected with staphylococcus protein a: association with increased circulating interferon and complement-dependent cytotoxic antibody. | we have injected purified staphylococcus aureus protein a intraperitoneally into leukemic cats infected with feline leukemia virus, into cats persistently infected with feline leukemia virus but without hematologic or cytologic abnormalities, and into healthy cats without feline leukemia virus infection. pre- and post-treatment serum samples were evaluated sequentially for interferon activity and for complement-dependent cytotoxic antibody. our results indicate that serum interferon increased dr ... | 1984 | 6208551 |
| [detection of antigenic determinants of the major structural proteins of various mammalian type c retroviruses in the leukocytes of patients with hemoblastoses and in healthy donors by the elisa method]. | using the enzyme-labelled antibodies it was shown that extracts from leukocytes of patients with leukemias and healthy donors contain antigenic determinants related to major virus protein of mammalian c type oncornaviruses ssv/ssav, baev, felv and rlv. the highest antigen activity in patients was detected in the feline leukemia (felv) system, and the least one--in the system of murine leukemia (rlv). common antigenic determinants of major virus protein of the viruses under study were detected in ... | 1984 | 6209091 |
| degenerative myelopathy in a cat. | degenerative myelopathy was diagnosed in a 6-year-old cat that had progressive ataxia, posterior paresis, and loss of conscious proprioception over a period of 8 months. corticosteroid therapy did not alleviate clinical signs, and the cat was euthanatized. microscopic examination of the spinal cord revealed diffuse degeneration of myelin attended by marked astrocytosis. the degenerative changes were most marked in the thoracolumbar segment. the cause of the degenerative lesions was not apparent. | 1980 | 6243272 |
| differential expression of two distinct endogenous retrovisus genomes in developing tissues of the domestic cat. | | 1980 | 6243723 |
| feline oncogenic viruses. | | 1980 | 6243737 |
| lysis of retroviruses with monoclonal antibodies against viral envelope proteins. | | 1980 | 6243827 |
| search for mammalian type-c retrovirus polypeptides on infected animal cells and human tumor cell lines using interspecies-reacting antibodies. | cells producing endogenous and exogenous type-c retroviruses of murine, feline and primate origin were evaluated for expression of those virus-specific cell-surface antigens which cross-react with antibodies to interspecies determinants of mammalian type-c viral polypeptides. surface polypeptides of cells replicating endogenous and exogenous type-c retroviruses were iodinated by the lactoperoxidase method. labelled antigens were immunoprecipitated and analyzed in polyacrylamide gel electrophores ... | 1980 | 6244200 |
| increased risk for lymphoma and glomerulonephritis in a closed population of cats exposed to feline leukemia virus. | feline leukemia virus (felv)-associated diseases were observed in a household in eastern connecticut having 134 cats over a period of five and a half years. felv-positive cats had a much higher mortality rate (34.6 deaths per 1000 cat-months of follow-up) than did felv-negative cats (8.9 deaths per 1000 cat-months of follow-up). the leading cause of death was glomerulonephritis followed by lymphoma. the relative risk for virus-positive cats as compared to virus-negative cats for the two diseases ... | 1980 | 6244730 |
| animal model of human disease: leukemic lymphoma. | | 1980 | 6244738 |
| translational products encoded by newly acquired sequences of independently derived feline sarcoma virus isolates are structurally related. | polyproteins encoded by several independent isolates of feline sarcoma virus (fesv) were analyzed with respect to molecular weight, extent of phosphorylation, and tryptic peptide composition. as previously reported, cells nonproductively transformed by the gardner strain of fesv express a polyprotein which has a molecular weight of approximately 115,000 and contains feline leukemia virus p15, p12, and minor portion of p30. in addition, a major 72,000-dalton possible cleavage product can be ident ... | 1980 | 6245259 |
| a summary of responses to cancer therapy in cats. | | 1980 | 6245346 |
| molecular cloning of snyder-theilen feline leukemia and sarcoma viruses: comparative studies of feline sarcoma virus with its natural helper virus and with moloney murine sarcoma virus. | extrachromosomal dna obtained from mink cells acutely infected with the snyder-theilen (st) strain of feline sarcoma virus (feline leukemia virus) [fesv(felv)] was fractionated electrophoretically, and samples enriched for felv and fesv linear intermediates were digested with ecori and cloned in lambda phage. hybrid phages were isolated containing either fesv or felv dna "inserts" and were characterized by restriction enzyme analysis, r-looping with purified 26 to 32s viral rna, and heteroduplex ... | 1980 | 6246254 |
| protection of cats against feline leukemia virus-positive and virus-negative tumors by complement-dependent antibody. | | 1980 | 6246303 |
| light and electron microscopic evaluation of thymuses from feline leukemia virus-infected kittens. | light microscopic and electron microscopic findings in thymuses from 4-week old feline leukemia virus-infected and 4- and 9-week old noninfected kittens were evaluated and found to be morphologically similar to each other. thymuses from 9-week old feline leukemia virusinfected kittens were markedly atrophied and individual lobules within each thymus varied in the severity of atrophy. loubules having the least severe atrophy had a moderate thinning of the cortex and a heterogeneous thymuses inclu ... | 1980 | 6247186 |
| characterization of the endogenous feline leukemia virus-related dna sequences in cats and attempts to identify exogenous viral sequences in tissues of virus-negative leukemic animals. | | 1980 | 6247824 |
| differential association of transfer rnas with the genomes of murine, feline and primate retroviruses. | the trnas that are bound to the genomic rnas of several murine, feline, and primate retroviruses have been identified. transfer rnas were divided into those loosely bound and those tightly bound by stepwise thermal dissociation of the 70 s rna. they were then identified and semiquantitated by aminoacylation. proline trna is the most tenaciously bound trna in several strains of murine leukemia virus, two strains of feline leukemia virus, and the primate viruses simian sarcoma, baboon endogenous, ... | 1980 | 6248115 |
| treatment of feline leukemia and reversal of felv by ex vivo removal of igg: a preliminary report. | cats that were spontaneously infected with feline leukemia virus (felv) were treated with a combination of low-dose irradiation and extracorporeal immunosorption using formalin and heat-fixed s. aureus as a non-specific immunosorbent to remove plasma igg and immune complexes. the treatment resulted in reduction of circulating lymphoblasts within two weeks and clinical improvement of three of the five animals. a reversal of the felv status is reported in five of five cats. two of the five cats re ... | 1980 | 6249487 |
| in vitro activation of feline complement by feline leukemia virus. | incubation of normal feline serum with purified feline leukemia virus (felv) at 37 degrees c for 30 min resulted in the activation of the complement system via the classical pathway as demonstrated by consumption of the c1, c4, c2, c3, and, to a lesser extent, the later c components. a similar finding was observed when normal human serum was substituted for normal cat serum. in contrast, complement-dependent lysis of felv with normal feline serum as assayed by the release of ribonucleic acid-dep ... | 1980 | 6249754 |
| feline chronic progressive polyarthritis. | twenty cats with a chronic progressive polyarthritis were studied. the disorder occurred exclusively in male cats, and all but six of the cats were between 1.5 and 5.0 years of age. there were two forms of the disease as determined by radiographic changes: joint instability and deformity, and clinical course. the most prevalent form of the disease was characterized by osteopenia and periosteal new bone formation surrounding affected joints. marginal periarticular erosions and collapse of the joi ... | 1980 | 6250422 |
| feline leukemia. | | 1980 | 6251017 |
| characterization of a 170,000-dalton polyprotein encoded by the mcdonough strain of feline sarcoma virus. | in this study, we demonstrated the expression of a 170,000-mr polyprotein in each of several mcdonough feline sarcoma virus (fesv)-transformed mink cell clones and one mcdonough fesv-transformed rat clone. this polyprotein designated mcdonough fesv p170, contained feline leukemia virus (felv) p15, p12, and p30 immunological determinants and shared two of its five [35s]methionine-labeled tryptic peptides with felv pr180gag-pol. both of these peptides were shown to be specific to the p30 component ... | 1980 | 6251265 |
| three independent isolates of feline sarcoma virus code for three distinct gag-x polyproteins. | cells nonproductively transformed by the snyder-theilen, gardner-arnstein, and mcdonough strains of feline sarcoma virus synthesize gag-x polyproteins of 78,000, 100,000, and 180,000 daltons, respectively. these feline sarcoma virus-coded products were precipitated by antisera to polypeptides encoded by the gag gene of feline leukemia virus and by rat antisera raised to feline sarcoma virus-transformed rat tumor cells. precipitation with rat antisera absorbed with feline leukemia virus showed th ... | 1980 | 6251274 |
| current concepts in veterinary neuro-ophthalmology. | | 1980 | 6251595 |
| polypeptides of feline leukemia virus: a glycosylated gag-related protein is released into culture fluids. | | 1980 | 6251608 |
| feline leukemia in israel: prevalence of antibody to feline oncornavirus-associated cell membrane antigen in stray cats. | feline lymphoma was recorded for the first time in pet cats in israel. furthermore, a serological survey in urban stray cats was carried out to determine the prevalence of antibody to feline oncornavirus-associated cell membrane antigen (focma). a total of 91 cats was tested and only 5 has antibody to focma. of these 5 positive cats, 4 originated from an area where a feline leukemia virus-positive cat had been detected prior to the survey. the prevalence of stray cats with antibody to focma is l ... | 1980 | 6252115 |
| circulating immune complexes associated with naturally occurring lymphosarcoma in pet cats. | cats were classified into 4 categories by immunofluorescence antibody assay for the presence of feline leukemia virus (felv) and histologically as a) normal, felv-, b) normal, felv+, c) lymphosarcoma (lsa), felv+, and d) lsa, felv-. determinations by raji cell radioimmunoassay modified for cat serum revealed circulating immune complex (cic) levels of healthy cats to be less than or equal to 50 micrograms equivalent aggregated cat immunoglobulin/ml (microgram/ml). in contrast, sera of cats in gro ... | 1980 | 6253567 |
| protection of cats against progressive fibrosarcomas and persistent leukemia virus infection by vaccination with feline leukemia cells. | young cats (3-6 mo old) were challenged with oncogenic snyder-theilen feline sarcoma virus (fesv) after vaccination with live or killed fl74 cat lymphoma cells. compared with controls immunized with normal cat fibroblasts, the fl74-vaccinated cats exhibited increased resistance to fesv-induced progressive primary and disseminated secondary tumors. maximum protection was achieved by vaccination with live fl74 cells or with a low dose of freeze-thawed cells, but tumor cells inactivated by glutaral ... | 1980 | 6253714 |
| development of virus non-producer lymphosarcomas in pet cats exposed to felv. | naturally occurring oncoviruses of several species are transmitted contagiously and cause lymphosarcoma (lsa) or leukaemia in their hosts. all naturally occurring oncoviruses replicate in vivo in the tumours they induce or, as with bovine leukaemia virus, can be isolated from tumour cells grown in short-term cell culture. however, we have shown that feline leukemia virus (felv) is not present in a significant minority of pet cats that develop lsa. unlike experimentally induced virus-negative leu ... | 1980 | 6253821 |
| origin and functional properties of the major gene product of the snyder-theilen strain of feline sarcoma virus. | the only known product of the snyder-theilen strain of feline sarcoma virus (st-fesv) is a 85,000-dalton protein, designated st p85, that contains feline leukemia virus gag gene encoded proteins (p15, p12, and a fragment of p30) and a sarcoma virus-specific polypeptide. antibodies directed against the latter immunoprecipitated a 92,000-dalton phosphoprotein (ncp 92) expressed at low levels in normal feline embryo fibroblasts as well as in feline cells of epithelial or lymphoid origin. normal cel ... | 1980 | 6254060 |
| feline leukaemia virus diagnosis. | | 1980 | 6254235 |
| humoral immune reactivity to feline leukemia virus and associated antigens in cats naturally infected with feline leukemia virus. | | 1980 | 6254637 |
| in defense of leukoassay f. | | 1980 | 6254939 |
| comparative analysis of the genomes of feline leukemia viruses. | the genomes of several strains of feline leukemia virus (felv) were compared by two-dimensional polyacrylamide gel electrophoresis of the large rnase t1-resistant oligonucleotides of the 70s rna. differences between each strain of felv tested were detected by this method. we estimate that the degree of sequence identity between the viruses is: felv a (glasgow-1) to felv b (snyder-theilen), 52%; felv a (glasgow-1) to felv c(sarma), 66%; felv b(snyder-theilen) to felv c (sarma), 37%. the fingerpri ... | 1980 | 6255191 |
| sequence organization of feline leukemia virus dna in infected cells. | a restriction site map has been deduced of unintegrated and integrated felv viral dna found in human rd cells after experimental infection with the gardner-arnstein strain of felv. restriction fragments were ordered by single and double enzyme digests followed by southern transfer (1) and hybridization with 32p-labeled viral cdna probes. the restriction map was oriented with respect to the 5' and 3' ends of viral rna by using a 3' specific hybridization probe. the major form of unintegrated vira ... | 1980 | 6255412 |
| infection of feline embryo adherent cells with feline leukemia virus: feline oncornavirus-associated cell membrane antigen expression and morphologic transformation. | feline embryo adherent cells were infected with the richard or kawakami-theilen strains of feline leukemia virus (felv) and examined for feline oncornavirus-associated cell membrane antigen (focma), viral group-specific antigen (gsa) production, and in vitro evidence of transformation. as early as 10 days after infection, when more than half of the infected cells were gsa positive, focma was detected on 5-10 percent of the cells. transitory morphologic alterations (epithelioid appearance and rou ... | 1981 | 6256575 |
| biological, immunological, and molecular properties of revertants of cat cells transformed by murine sarcoma virus. | | 1981 | 6257388 |
| polypeptides of feline leukaemia virus: identification of p15(e) and p12(e). | antiserum to the p15(e) polypeptide of rauscher murine leukaemia virus (r-mulv) precipitated two proteins from purified virions of feline leukaemia virus (felv) with apparent mol. wt. of 18500 and 155000 on sds-polyacrylamide gels. these proteins have been designated p15(e) and p12(e), in line with the nomenclature for mulv proteins. like the analogous protein of mulv, felv p15(e) was found to be disulphide-linked to the virion glycoprotein, gp70. felv p15(e) was sensitive to digestion of intact ... | 1980 | 6257828 |
| induction of retinal degeneration in cats by methylnitrosourea and ketamine hydrochloride. | persistent mydriasis seen in cats used in an oncology study apparently was not related to neoplasia. ophthalmoscopically, the cats had severely atrophic retinas and clinically observable visual impairment. these findings were confirmed by electroretinographic and histologic examination. cats with these retinal lesions had received combinations of methylnitrosourea, ketamine hydrochloride, and feline leukemia virus. retinopathy was not seen in ketamine-anesthetized cats receiving feline leukemia ... | 1981 | 6258283 |
| natural feline leukemia virus infection and the immune response of cats of different ages. | forty-two kittens and 28 adult cats were placed as tracers in leukemia cluster environments in contact with resident cats, 30% of which were persistently infected with feline leukemia virus (felv). after 7 months exposure, felv viremia had been detected in 71% of the tracer kittens, although only 55% of these remained persistently infected; in the same period, 11% of tracer adults became infected, but by 2 years the figure reached 43%. mean latent periods before detection of viremia were 3.4 +/- ... | 1980 | 6258787 |
| feline leukaemia diagnosis. | | 1981 | 6259801 |
| activation of the alternative complement pathway by normal and transformed cells in homologous and heterologous sera. | a variety of both normal and viral transformed or infected cells have been tested for their ability to activate the alternative pathway of complement in either homologous or heterologous sera. normal cell lines fail to produce alternative pathway activation in homologous sera but readily activate the alternative pathway in heterologous sera. in contrast, human cells, persistently infected with measles virus or chicken cells transformed with oncogenic avian viruses, produce a marked activation in ... | 1981 | 6260511 |
| cellular transformation by subgenomic feline sarcoma virus dna. | the genome of the snyder-theilen strain of feline sarcoma virus (st-fesv) is a 4.3-kilobase-pair (kbp) rna molecule that contains a 1.5-kbp cellular insertion (fes gene) flanked by feline leukemia virus sequences at its 5' end (1.6 kbp) and 3' end (1.2 kbp) (sherr et al., j. virol. 34:200-212, 1980). dna transfection techniques have been utilized to determine the regions of the st-fesv genome involved in malignant transformation. i have found that the 3.7-kbp 5'-end fragment of the st-fesv provi ... | 1981 | 6261000 |
| three sizes of subunits in rnas from feline sarcoma-leukaemia virus mixtures. | rna from the snyder-theilen feline sarcoma-leukaemia virus complex (st-fesv-felv) sedimented in a double-peaked band between 50 and 70s, but gardner-arnstein (ga) fesv-felv rna sedimented in a single 70s peak. felv isolated from the st virus mixture contained rna which sedimented in a 70s band like ga-fesv-felv rna, but f422 felv rna sedimented more slowly, at 50 to 60s. after thermal denaturation, resedimentation revealed three classes of rna subunits in st-fesv-felv rna: the first class, 35 to ... | 1980 | 6262439 |
| shared interspecies antigenic reactivities among hamster and feline oncoviruses. | group-reactive antisera against the major internal protein p30 of the hamster sarcoma virus (hasv) showed interspecies reactivity in immunodiffusion even with sera of low titer against hasv. antisera were prepared by sc injection of virus into male new zealand white rabbits. the cross-reactivity between interspecies antigens of feline and hamster rna tumor viruses was stronger than between either virus with murine leukemia virus. molecular hybridization data, obtained from nucleic acid hybridiza ... | 1981 | 6262550 |
| feline oncovirus-associated cell membrane antigen and feline leukemia virus group-specific antigen expression in bone marrow and serum. | feline retrovirus-induced possible preneoplastic lesions were identified by detection of feline oncovirus-associated cell membrane antigen (focma) in bone marrow (bm) and mesenteric lymph nodes of noninbred, domestic short- or long-hair kittens. cell-bound focma was detected 1-3 weeks after feline leukemia virus (felv) infection and at least 6 months before a tumor was evident. bm focma was detected earlier and reached higher levels at early periods in cats that became persistently viremic. seru ... | 1981 | 6262553 |
| feline leukemia virus and hepatitis b virus: a comparison of late manifestations. | | 1981 | 6262865 |
| hematologic abnormalities preceding apparent recovery from feline leukemia virus infection. | a 5-month-old domestic short-haired cat was referred to the western college of veterinary medicine because of hemorrhage from the mouth. neutropenia and bone marrow dyscrasia developed within 2 weeks, and results of a fluorescent antibody test for feline leukemia virus (felv) were positive. during the next 6 months, the feline oncornavirus cell membrane-associated antibody titer increased, the hematologic abnormalities regressed, and the cat became negative to the felv fluorescent antibody test ... | 1981 | 6263848 |
| sequence arrangement and biological activity of cloned feline leukemia virus proviruses from a virus-productive human cell line. | we examined 14 different feline leukemia virus proviruses from the productively infected human cell line rd(felv)-2 after cloning in the modified lambda vector charon 4a. each isolate was characterized by restriction digestion and southern blot analysis. the dna of each isolate was tested for competence to express virus after uptake by sensitive animal cells (transfection). all but one isolate contained an apparently complete provirus, but only four were infectious. seven isolates (four noninfec ... | 1981 | 6264136 |
| biochemical characterization of cells transformed via transfection by feline sarcoma virus proviral dna. | murine fibroblasts transformed by transfection with dna from mink cells infected with the snyder-theilen strain of feline sarcoma virus and subgroup b feline leukemia virus were analyzed for the presence of integrated proviral dna and the expression of feline leukemia virus- and feline sarcoma virus-specific proteins. the transformed murine cells harbored at least one intact feline sarcoma virus provirus, but did not contain feline leukemia virus provirus. the transformed murine cells expressed ... | 1981 | 6264144 |
| the role of viruses in the development of ocular tumors. | the role of viruses as a cause of human cancer has been investigated by a variety of techniques in recent years. while no definitive answer exists at present, several lines of evidence indicating a viral role in human tumors and reviewed. these include the well-documented role of viruses in causing animal tumors; evidence for an association of certain viruses with human tumors; and virally induced animal models of human tumors, melanoma, retinoblastoma, and ocular malignant melanoma. | 1980 | 6264364 |
| epidemiologic association between virus-negative feline leukemia and the horizontally transmitted feline leukemia virus. | about two-thirds of the natural cases of feline leukemia-lymphoma are assumed to be caused by the feline leukemia virus (felv) because they occur in cats, which harbor this agent, and felv will induce the disease under laboratory conditions. epidemiological evidence is presented which associates cases of naturally occurring 'virus negative' feline leukemia with exposure to felv. | 1981 | 6268292 |
| evaluation of the parameters of the elisa procedure for feline type c retroviral antigens: assay of felv antigens in chronically infected or nonproducer transformed cells. | the successful application of an improved enzyme-linked immunosorbent assay (elisa) to the specific detection and quantitation of feline leukemia virus (felv) is presented. the methods described can detect felv antigens at the picogram/milliliter level using a fluorometric assay for peroxidase-linked antibody. the use of a fluorogenic substrate resulted in at least a 9-fold increase in sensitivity of the peroxidase assay. felv antigens could be specifically detected in chronically infected cells ... | 1981 | 6268565 |
| determinants of susceptibility and resistance to feline leukemia virus infection. i. role of macrophages. | the role of autochthonous peritoneal feline macrophages (m theta) in the age-related resistance of cats to feline leukemia virus (felv) was investigated by a study of the functional properties and felv susceptibility of m theta from kittens and adult cats and the effect of hydrocortisone (hc) and silica on m theta-felv interactions. although the phagocytic functions of isolated m theta from kittens and adults were equivalent, the mean felv susceptibility of m theta from kittens was five times th ... | 1981 | 6268885 |
| determinants of susceptibility and resistance to feline leukemia virus infection. ii. susceptibility of feline lymphocytes to productive feline leukemia virus infection. | the interplay between feline leukemia virus (felv) and feline lymphocytes (lc) infected in vitro or in vivo was investigated. surface marker analysis and viral infectivity (vi) assays of lc populations were used to determine susceptibility of lc subsets to felv. the principal felv-replicating cell in the mesenteric lymph node of persistently infected, preleukemic cats was a nonadherent, complement receptor (cr)-bearing lc (b-cell). the lymph nodes of preleukemic cats also had increased numbers o ... | 1981 | 6268886 |
| isolation of feline leukemia virus from a leopard cat cell line and search for retrovirus in wild felidae. | a strain of feline leukemia virus (felv), subgroup a, was isolated in early subpassage of a testicular fibroblast culture obtained from a captive asian leopard cat. neither felv nor rd-114 virus was recovered from cultured tissues of 15 other animals, representing eight species of wild felidae. | 1981 | 6268887 |
| characterization of sarcoma-positive, leukemia-negative (s+l-) human cells induced by the feline leukemia virus pseudotype of moloney sarcoma virus. | | 1981 | 6269117 |
| a micro-enzyme-linked immunosorbent assay (elisa) test for detection of feline leukemia virus in cats. | | 1981 | 6269798 |
| selective host range restriction of goat cells for recombinant murine leukemia virus and feline leukemia virus type a. | we isolated a strain of normal goat fibroblasts which was uniquely selective in that it allowed the replication of xenotropic murine leukemia virus but not polytropic recombinant murine leukemia virus. in addition, feline leukemia virus type a replication was severely diminished in these goat cells, whereas feline leukemia virus type b and feline endogenous rd114-ccc viruses replicated efficiently. no other known cells exhibit this pattern of virus growth restriction. these goat cells allow the ... | 1981 | 6270364 |
| trends in veterinary immunology. developments in immunoprophylaxis. | | 1981 | 6270523 |
| diagnosis of feline leukemia virus infections. | | 1981 | 6270524 |
| recombinant bacteriophages containing the integrated transforming provirus of gardner--arnstein feline sarcoma virus. | the integrated dna provirus of the gardner-arnstein (ga) strain of feline sarcoma virus (fesv) was molecularly cloned in a bacteriophage lambda vector. the cloned dna fragment is 14.4 kilobase pairs long and contains a 6.7-kilobase provirus flanked by cellular sequences derived from nonproductively transformed mink cells. transfection of mouse nih/3t3 cells with the cloned dna fragment induced foci of transformation at efficiencies of 10(4) focus-forming units/pmol of sarcoma virus dna. restrict ... | 1981 | 6270655 |
| serology in feline leukaemia virus infections. | | 1981 | 6270875 |
| isolation via transfection of feline leukemia viruses from dna of naturally occurring feline lymphomas. | | 1981 | 6270898 |
| cell cycle-related morphological changes of feline lymphoid cells as revealed by electron microscopy. | the aim of this study was to correlate morphological changes in cells to known phases of the cell cycle. for this purpose, feline lymphoblastoid cells (fl74) chronically infected with feline leukemia virus were synchronized and examined by scanning and transmission electron microscopy. scanning electron microscopy revealed that the cell surface underwent distinct changes which were found to be cell cycle specific. morphological changes shown by transmission electron microscopy were used as ultra ... | 1981 | 6272982 |
| feline leukemia virus-induced erythroid aplasia: in vitro hemopoietic culture studies. | colony forming unit (cfu) assays were developed for feline granulocyte-macrophage (cfugm), early erythroid (day 2 cfue), and late erythroid (day 7 cfue) colonies in methylcellulose medium. feline cfugm and both day 2 and day 7 cfue were enhanced by feline macrophage conditioned medium and late cfue often were intimately associated with macrophages. kittens were inoculated with the kawakami-theilen (kt) strain of feline leukemia virus (felv) and sequential changes in marrow cfu determined. erythr ... | 1981 | 6273200 |
| feline leukaemia virus infection. | all aspects, including aetiology, incidence, transmission, immunity, clinical signs, pathogenesis, pathology and diagnosis of feline leukaemia virus infection in domestic cats are considered with a bias towards the more clinical aspects for the benefit of private practitioners. non-neoplastic disease and possible methods of control are also discussed. | 1981 | 6273557 |
| role of viruses in the etiology of naturally occurring feline leukemia. | | 1981 | 6274762 |
| relationship of the feline oncornavirus associated cell membrane antigen to a feline sarcoma virus encoded polyprotein. | | 1981 | 6274763 |
| feline leukemia virus nonproducer lymphosarcomas of cats as a model for the etiology of human leukemias. | | 1981 | 6274764 |
| prevalence and sequelae of feline leukemia virus infection in laboratory cats. | over a 4-year period, 1,683 pound-source cats received at a research institution were screened for feline leukemia virus (felv) infection, using an indirect fluorescent antibody test. viremia was detected in 83 of the cats, for a prevalence of 4.9%. during this period, felv infection was detected in 5 kittens on a research project; lymphoma or anemia developed 6 to 17 months after the infections were detected. it was concluded that apparently healthy cats infected with felv may not be appropriat ... | 1981 | 6276347 |
| protection against feline leukemia by vaccination with a subunit vaccine. | an effective vaccine against feline leukemia virus infection has been developed by the collection and concentration of tissue culture medium harvested from a tumor cell line. lymphoid cells were grown to near saturation density in a normal growth medium and then transferred to a serum-free medium. the serum-free medium was collected, concentrated, and evaluated for its vaccine potential. cats receiving the vaccine emulsified in complete freund adjuvant developed high antiviral and antitumor tite ... | 1981 | 6277792 |
| selective effect of feline leukaemia virus on early erythroid precursors. | | 1982 | 6278316 |
| feline leukaemia virus testing. | | 1981 | 6278376 |
| the u3 portion of feline leukemia virus dna identifies horizontally acquired proviruses in leukemic cats. | the presence and location of dna sequences related to the u3 and u5 portions of the infectious exogenous feline leukemia virus (felv) long terminal repeat (ltr) in various cat dnas have been determined by hybridization experiments. in uninfected cat dnas, the u5 ltr segment from the gardner-arnstein strain b virus is present at approximately 150 copies per cell. this level is approximately 10-fold greater than that of endogenous internal felv sequences. the u5 sequences differ in copy number and ... | 1981 | 6278488 |
| loss of the short-lived suppressive function of peripheral leukocytes in feline retrovirus-infected cats. | normal feline peripheral blood mononuclear cells demonstrated increased phytomitogen blast transformation after a 24 hr delay in mitogen addition as compared to 0 hr mitogenesis. increased stimulation after 24 hr which is not due to enhancing factors accumulating in the culture medium has been attributed to a short-lived suppressor cell which loses its effect after 24 hr in culture. this short-lived suppressive phenomenon was studied in normal specific-pathogen-free cats and compared to experime ... | 1982 | 6279852 |
| primary structure analysis of the major internal protein p24 of human type c t-cell leukemia virus. | a human type c retrovirus [human t-cell leukemia (lymphoma) virus; htlv], recently isolated from young adult patients with cutaneous t-cell lymphoma or leukemia, was not detectably related to other known animal retroviruses in molecular hybridization studies, by comparison of reverse transcriptase and the major core protein p24. the p24 core protein was purified to homogeneity. the amino acid composition, the cooh-terminal amino acid, and the nh(2)-terminal amino acid sequence of the first 25 re ... | 1982 | 6280175 |
| isolation and characterization of circulating feline leukemia virus-immune complexes from plasma of persistently infected pet cats removed by ex vivo immunosorption. | igg and circulating igg immune complexes (cic) were purified from plasma of three pet cats persistently infected with feline leukemia virus (felv) by adsorption to, and elution from, staphylococcus aureus cowan i. cic were then separated from free igg by sucrose gradient ultracentrifugation and were analyzed for the presence of felv structural proteins and corresponding specific antibodies. radioimmunoprecipitation analysis indicated that felv envelope (gp70) and major core (p30) proteins, along ... | 1982 | 6281336 |