| properties of two isolated antigens associated with bovine leukemia virus infection. | we isolated an ether-resistant internal antigen and an ether-sensitive antigen previously described in relation to bovine leukemia virus infection. these two antigens have now been isolated by isoelectric focusing and concanavalin a affinity chromatography, respectively. the ether-resistant antigen exhibited isoelectric heterogeneity with a major peak at ph 7.2 and a minor peak at ph 6.2. its molecular weight, estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page), was ... | 1976 | 10447 |
| pseudotype particles of vesicular stomatitis virus with surface antigens of bovine leukaemia virus--vsv (blv) -- as a sensitive probe for detecting antibodies in the sera of spontaneously infected cattle. | phenotypically mixed particles containing the genome of vesicular stomatitis virus (vsv) and envelope antigen corresponding to bovine leukaemia virus (blv) -- the vsv (blv) pseudotypes -- can be employed as a rapid, specific and sensitive probe for detecting blv-neutralizing antibodies in bovine sera. | 1978 | 26209 |
| immunological nature of the inhibition of blv-induced early polykaryocytosis by bovine sera. | a quantitative in vitro assay (epi) was developed for the serological detection of bovine leukemia virus (blv) infection in cattle. positive sera inhibit early polykaryocytosis (ep) induced by blv. we report herein experiments which demonstrate that blv-induced antibodies are responsible for this inhibition. serum fractionation by gel filtration and affinity chromatography indicate that ep-inhibiting activity is mediated only by immunoglobulins of the igg class. furthermore, on the basis of thei ... | 1978 | 28296 |
| [proceedings: some biochemical properties of bovine leukemia virus]. | | 1975 | 50808 |
| further studies on the antigenic properties and distribution of the putative bovine leukemia virus. | the c-type viruses found in long-term cultures. new bolton center (nbc) cell lines, of peripheral lymphocytes from leukemic cattle and in short-term cultures of bovine buffy coat(bc) cells share an immunofluorescent(if)antigen detected in the cytoplasm of infected cells as well as an antigen demonstrable in gel diffusion experiments. therefore the viruses from these cultures most likely represent different isolates of the putative bovine leukemia virus (blv). the blv precipitin antigen is analog ... | 1975 | 51637 |
| biochemical approach to bovine leukemia. | many bovine leukemic lymphocytes produce virus particles when kept in survival cultures in eagle's minimum essential medium supplemented with 20 percent of inactivated fetal calf serum. virus particles equilibrate at a density of 1.16 g/ml in sucrose gradients and at a density of 1.12 g/ml in metrizamide gradients. simultaneous detection tests show that a high molecular weight rna-reverse transcriptase complex exists in these viruses. hybridizations between total rna from bovine leukemic lymphoc ... | 1975 | 52980 |
| characteristics of the major internal protein and rna-dependent dna polymerase of bovine leukaemia virus. | a virus designated bovine leukaemia virus (blv), associated with leukaemia in cattle and previously demonstrated to induce the disease in sheep, was purified from chronically infected sheep cell cultures. electrophoretic analysis showed a major protein of mol. wt. about 24,000 (p24) which reacted in gel diffusion and complement-fixation tests with sera from naturally infected cattle, experimentally infected sheep, and guinea pigs immunized with p24. blv p24 has an isoelectric point of 8-6. inter ... | 1975 | 54405 |
| an ether-sensitive antigen associated with bovine leukemia virus infection. | an ether-sensitive antigen (es-ag) associated with bovine leukemia virus infection was detected by immunodiffusion tests. this antigen was sensitive to ether, sodium periodate, and trypsin treatment. based on column chromatography, es-ag was a larger molecule than that of ether-resistant antigen (gs-ag). with infection, precipitating antibody against es-ag developed earlier than the precipitating antibody against the gs-ag. | 1975 | 54435 |
| 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 |
| in vitro transmission and propagation of the bovine leukemia virus in monolayer cell cultures. | this study demonstrates that the bovine leukemia virus (blv) can infect in vitro cells of human, simian, bovine, canine, caprine, ovine, and bat origin. cultures of these cells, cocultivated with blv-infected cells or inoculated with cell-free blv preparations, continuoously showed the presence of cells with the internal blv antigen as well as blv-induced syncytia. virus replication was abundant and increased with passage in bat lung cells and was moderate but constant in fetal canine thymus cel ... | 1976 | 61801 |
| a new class of genetically transmitted retravirus isolated from mus cervicolor. | the cocultivation of spleen cells from the southeast asian mouse, mus cervicolor, with heterologous cell lines has permitted the isolation of a new retravirus (designated m432) that can be transmitted to tissue culture cells of the laboratory mouse, m. musculus. cells infected with m432 contain cytoplasmic type a particles and budding forms with compact,spherical nucleoids; extracellular virions lack surface spikes and have a condensed, central core surrounded by an intermediate line. like other ... | 1976 | 62362 |
| detection, quantitation, and characterization of the major internal virion antigen of the bovine leukemia virus by radioimmunoassay. | the major internal polypeptide of the bovine leukemia virus (blv) was purified to homogeneity with the use of gel filtration and affinity chromatography. like previous results, the protein had a molecular weight of 25,000 daltons as determined by electrophoresis in polyacrylamide gels with sodium dodecyl sulfate. more than 90% of the 125i-labeled protein was precipitated by bovine sera that reacted in immunofluorescence tests with acetone-fixed blv-infected cells. in contrast, minimal precipitat ... | 1976 | 63563 |
| 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 |
| isolation and characterisation of oncornavirus from primary cultures of tissues from cattle with leukemia. | the purpose of this investigation was to search for oncornavirus in primary cell cultures obtained from leukemic cattle organs and lymphocytes and to study their molecular-biological properties and role in the etiology of cattle leukemia. the investigation was carried out on 25 primary trypsinized cell culutres of lymph nodes, spleens, kidneys and lymphocytes from cattle with acute and chronic leukemia. it was demonstrated that all cell cultures from leukemic cattle (in contrast to cell cultures ... | 1977 | 66913 |
| inhibition of the reverse transcriptase of bovine leukemia virus by antibody in sera from leukemic cattle and immunological characterization of the enzyme. | sera from some leukemic cattle contain an antibody that inhibits the reverse transcriptase activity of the bovine leukemia virus. the antibody is not directed against the synthetic template or the major internal and envelope viral antigens. the antibody failed to inhibit the dna polymerases of the murine leukemia virus, simian sarcoma-associated virus, avian myeloblastosis virus, or escherichia coli. conversely, the bovine leukemia virus enzyme was not inhibited by antibody against the reverse t ... | 1977 | 66983 |
| purification and characterization of the major internal protein (p24) of bovine leukemia virus [proceedings]. | | 1977 | 68745 |
| metrizamide, a new reagent for purification of rna oncogenic viruses associated with bovine enzootic leukemia and human leukemias [proceedings]. | | 1977 | 68746 |
| evaluation of radioimmunoprecipitation for the detection of bovine leukemia virus infection in domestic cattle. | the potential application of a recently developed radioimmunoprecipitation test for antibody directed against the major structural protein of bovine leukemia virus was evaluated for use in detection of blv-infection in domestic cattle. this technique was found to be considerably more sensitive than serologic procedures currently being utilized for this purpose. radioimmunoprecipitation was also shown to have distinct advantages as compared to hematologic criteria, such as specified by bendixen's ... | 1977 | 68975 |
| characterization of a retravirus isolated from squirrel monkeys. | a new retravirus (smrv) isolated from a squirrel monkey, saimiri sciureus, has an mg2+-dependen reverse transcriptase and a buoyant density of 1.17 g/cm3 in sucrose and 1.21 g/cm3 in cesium chloride, similar to the mouse mammary tumor virus and the mason-pfizer monkey virus. the polypeptide patter of smrv as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis was distinct from the reported polypeptide patterns of known retraviruses. four major polypeptides of molecular weight ... | 1977 | 69728 |
| biochemical and immunological characterization of the major envelope glycoprotein of bovine leukemia virus. | the major envelope glycoprotein of bovine leukemia virus was isolated by lectin-bound sepharose and deae-cellulose column chromatography. this protein was shown to have a molecular weight of about 41,000 and to lack detectable immunological cross-reactivity with glycoproteins of other oncornaviruses. sera obtained from 100% of cattle examined with clinically diagnosed lymphosarcoma contained high-titered antibody to 125i-labeled bovine leukemia virus glycoprotein, whereas sera from animals in a ... | 1977 | 69730 |
| a reverse transcriptase assay for detection of the bovine leukemia virus. | an rna-dependent dna polymerase or reverse transcriptase has been demonstrated in highly purified bovine leukemia virus (blv) particles. the viral enzyme responded very effectively to the exogenous template primer polyneucleotide (poly) (ra)-oligonucleotide (oligo) (dt). unlike the reverse transcriptases of most mammalian c type rna viruses, and of the ubliquitous foamy-like bovine syncytial virus, the blv enzyme prefers magnesium rather than manganese for optimal activity. the identification of ... | 1977 | 73357 |
| biosynthesis of bovine leukemia virus (blv) major internal protein (p24) in infected cells and x. laevis oocytes microinjected with blv 60-70s rna [proceedings]. | | 1977 | 79394 |
| distribution of bovine leukemia virus proviral dna sequences in tissues of animals with enzootic bovine leukosis [proceedings]. | | 1977 | 79401 |
| the retrovirus particles in human myeloma cells rpmi8226: morphological, biochemical, immunological and infective transmission studies. | the retrovirus designated rpmi8226v (isolated from human myeloma cells rpmi8226) has been characterized with respect to its morphological, biochemical and immunological properties as well as its propagation in various animal and human cells. the myeloma cells rpmi8226 produce intracytoplasmatic a-type particles and extracellular particles. the extracellular particles have been classified as immature particles with translucent core center, typical mammalian c-type virus particles and c-type parti ... | 1978 | 80755 |
| [detection of common antigenic determinants in the envelopes of mammalian type d (mason--pfizer) and type c virions by using the virion precipitation reaction]. | immune sera to mason-pfizer virus (m-pmv) are capable of precipitating type c viruses of mice (nih-mulv, g-mulv, and to a lower degree r-mulv), cats (felv, rd-114), and monkeys (ssv-1, galv, bev). the immune sera to rd-114, bev, ssv-1 and galv viruses can precipitate m-pmv virions. the adsorption analysis suggests that cross-reactions between m-pmv, rd-114, nih-mulv, and g-mulv viruses depend on common virus-specific antigenic determinants in the envelopes of the virions. the relationship betwe ... | 1978 | 80888 |
| identification and behavior of the precipitating blv antibodies in sera of leukotic cattle. | precipitating bovine leukemia virus antibodies isolated from bovine leukemic sera by ion-exchange chromatography, gel filtration and affinity chromatography were identified as immunoglobulins of the igg1 subclass and iga class. they proved to be different with regard to molecular size and electrical charge. immunoglobulins igg2 and igm as well as low-molecular components ranging in the microglobulin regions (less than 4s) failed to precipitate blv antigens. individual bovine leukemic sera showed ... | 1978 | 81182 |
| bovine leukemia virus involvement in enzootic bovine leukosis. | | 1978 | 81603 |
| detection of complement-dependent lytic antibodies in sera from bovine leukemia virus-infected animals by the 51cr-release assay [proceedings]. | | 1978 | 84644 |
| induction of c-type virus in cell lines derived from calf form bovine lymphosarcoma. | for attempt to detect an etiological agent, cultures from bovine lymphosarcoma cases (adult form (als), calf form (cls), and thymic form (tls) were maintained in vitro for over a 18 month period. in two cultures from als, bovine leukemia virus (blv) antigen was constantly detected. on the other hand, blv antigen remained negative in cultures from two cls and one tls cases up to 40 passages. the rna dependent dna polymerase activities in these cultures were also negative. treatment of a culture f ... | 1978 | 85238 |
| a new virion precipitation test for oncovirus envelope antigens which detects common antigenic determinants in mammalian type-c viruses and mason-pfizer monkey virus. | a method for the study of oncovirus envelope antigens was developed, bases on the precipitation of intact virions by a double antibody technique. the amount of precipitated virus was then measured as reverse transcriptase activity. the method was designated the virion precipitation test (vpt). it has been used for titration of antibodies to envelope antigens of oncoviruses. the study of envelop antigens of 11 different oncoviruses permitted their differentiation into the following groups: (1) mu ... | 1979 | 86521 |
| ["revertase" project: results of carrying out the scientific program]. | the article summarizes the data obtained within the scope of the "revertase" project organized in 1972 under the guidance of scientific councel on molecular biology. the scientific program included four main topics: synthesis of complementary dna via reverse transcription on the various rna templates and their use as tools in molecular biology, enzymatic synthesis of structural genes in double dna-polymerase system and their propagation by means of genetic engineering, enzymology of reverse tran ... | 1979 | 86943 |
| translation of bovine leukemia virus virion rnas in heterologous protein-synthesizing systems. | bovine leukemia virus 60 to 70s rna was heat denatured, the polyadenylic acid-containing species were separated by velocity sedimentation, and several size classes were translated in a micrococcal nuclease-treated cell-free system from rabbit reticulocytes. the major rna species sedimented at 38s and migrated as a single component of molecular weight 2.95 x 10(6) when analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. the predominant polypeptides of the in vitro translation o ... | 1979 | 87518 |
| leukogenic properties of purified blv and possible routes of its transmission with blood cells present in milk. | the results of five years studies on the possibility of experimental induction of bovine leukemia with purified blv and different blv-containing materials demonstrated that inoculation of calves with purified blv (structures of 1.14-1.17 g/ml density in 20-60% sucrose gradient) can induce oncornavirus infection and bovine leukemia. from 41 experimentally infected calves 9 showed evidence of bovine leukemia. 5 of these 9 animals were from a group of 22 calves inoculated with purified blv. diagnos ... | 1978 | 89827 |
| studies on cell lines derived from calf, thymic and skin forms of bovine lymphosarcoma. | the etiology of sporadic bovine leukosis (sbl) is not known. long-term monolayer cultures were made from calf (cls), thymic (tls) and skin (sls) forms, and serological tests, electron microscopic observations and reverse transcriptase assays were employed for the detection of an etiological agent. bovine leukosis virus (blv) antigen and reverse transcriptase activities remained negative in cultures from sbl cases. treatment of a culture from cls 3178 with 5'-iodo-2'-deoxyuridine and dexamethason ... | 1978 | 89828 |
| [biochemical characteristics of a calf leukemia virus in chronically infected cells]. | studied were the conditions of cultivation of flk cells chronically infected with a calf leucosis virus. the gradient values of density were compared to those of the murine sarcoma virus--1.14--1.15 vs, 1.17--1.18/cm3. established were the parameters of the reverse transcriptase reaction for the calf leukosis virus (magnesium-dependent reverse transcriptase). data showed that the calf leucosis virus may not resolutely be referred either to the b- or the the c-type of retroviruses. | 1979 | 92095 |
| integration site of bovine leukemia virus dna in the bovine genome [proceedings]. | | 1979 | 93923 |
| phosphonoformate inhibits reverse transcriptase. | the new antiviral substance phosphonoformate (pfa) has been tested in a cell-free system for its effect on reverse transcriptases from an avian retrovirus (avian myeloblastosis virus, amv) and from mammalian retroviruses (rauscher leukaemia virus, rmulv; bovine leukaemia virus; baboon endogenous virus; simian sarcoma virus; visna virus). the observed inhibitory effect of pfa has been compared with that of a structurally related substance, phosphonoacetate (paa). phosphonoformate, at a concentrat ... | 1979 | 94344 |
| biochemical and epidemiological studies on bovine leukemia virus (blv). | | 1979 | 94578 |
| tumor immunology in domestic animals. | | 1979 | 95155 |
| a critical comparison of the virus neutralizaiton, radioimmunoprecipitation and immunodiffusion tests for the serological diagnosis of blv infection. | several serological tests are available for the detection of antibodies to blv. thus far, only the virus neutralization antibody (vna) test, the immunofluorescence test, and the immunodiffusion test with the major internal virion protein have been critically evaluated as diagnostic methods for the identification of blv-infected cattle. of these tests, the vna test is the most sensitive and specific. therefore, in the present study the vna test has been applied to evaluate the reliability of the ... | 1978 | 112908 |
| inhibition of bovine leukemia virus release. | sera from 3 cows with the adult form of lymphosarcoma inhibited release of leukemia virus from a cell line of fetal lamb spleen infected with bovine leukemia virus (blv). sera from 5 to 7 cattle experimentally infected with blv also suppressed virus release. the inhibition of virus release was reversible. sera from cattle with the calf form and the thymic form of lymphosarcoma and normal bovine control sera did not repress virus release. | 1975 | 165311 |
| survey for antibodies to leukemia (c-type) virus in cattle. | serums from 4,394 dairy cattle in 100 herds and from 2,794 beef cattle in 50 herds were tested for antibody to the bovine (c-type) leukemia virus (blv), using the agar gel immunodiffusion test. reactors were found in 66% of the dairy herds (10.2% of the cattle) and in 14% of the beef herds (1.2% of the cattle). the prevalence of reactors was examined with respect to age, herd size, and sex. few of the reactors were less than 2 years old. there was a high percentage of reactors in small dairy her ... | 1975 | 166060 |
| a leukovirus isolated from cells obtained from leukemic calf lymph nodes. | | 1975 | 167904 |
| seroepidemiological evidence for horizontal transmission of bovine c-type virus. | thirty colostrum-deprived calves from leukemia-free herds were foster nursed for 10 weeks on cows infected with bovine c-type virus (blv) from multiple-case herds or on cows from leukemia-free herds. after weaning, the calves were raised in continuous contact with blv-infected animals of approximately the same ages. sera collected at 6 to 18 and 43 to 48 months of age were examined for the presence of antibodies to blv by the immunofluorescent antibody test. at 6 to 18 months of age, only 1 of t ... | 1975 | 168965 |
| [complement-fixing antibody in cattle with persistant lymphocytosis. preliminary results with french livestock]. | | 1975 | 170012 |
| serological diagnosis of infection with the putative bovine leukemia virus. | we report on an accurate, rapid and inexpensive test for the identification of animals infected with the bovine c-type virus (blv). the test involves the detection of serum antibodies to blv using the immunofluorescent (if) technique on acetone-fixed, infected cells. the specificity of the test was demonstrated by the fact that virus was found by electron microscopy in 90% of cattle showing positive reactions. in contrast, virus was not found despite extensive examination in antibody negative an ... | 1975 | 172279 |
| [further studies on the occurrence of antibodies against c-type virus specific antigen in sera of cattle from leukosis infected, suspicious, and non-suspicious herds]. | | 1975 | 173115 |
| [experiments upon the cultivation of an agent of bovine leukosis in bovine leukocyte cultures. 3. leukosis transmission to calves with cell-free culture medium]. | | 1975 | 173117 |
| induction of syncytia by the bovine c-type leukemia virus. | bovine buffy coat cells infected with the bovine leukemia virus (blv) induce syncytia formation in human diploid embryonic lung cells as well as in monolayer cell cultures of bovine, simian, ovine, bat, and caprine origin, but not in mouse fibroblast cells, normall rat kidney cells, or rsv-transformed rat cells. syncytia were not observed in diploid embryonic lung cells inoculated with bovine buffy coat cells free of blv. the syncytia-induction effect is associated with the synthesis of complete ... | 1976 | 175949 |
| development of an in vitro infectivity assay for the c-type bovine leukemia virus. | the ability of the bovine c-type leukemia virus to induce syncytia formation in monolayer cell cultures has been used to develop a specific and simple infectivity assay for the virus. using bovine embryonic spleen cells or human diploid embryonic lung cells as indicator cells, the results of the assay can be evaluated in 4 to 6 or 6 to 8 days, respectively. pretreatment of the indicator cells with deae-dextran greatly increases the sensitivity of the assay. the assay is quantitative and can be a ... | 1976 | 175950 |
| lack of infectivity of bovine leukemia (c-type) virus to rats. | sprague-dawley rats were given ip injections of bovine culture and sheep cultures of bovine leukemia virus (blv) and gross passage-a leukemia virus [mulv(g)]. sera were tested to blv antigens. blv did not induce tumors in sprague-dawley rats, but the rats were susceptible to mulv(g) at low doses. | 1976 | 176402 |
| bovine leukemia virus genes in the dna of leukemic cattle. | reverse transcripts of the rna genome of the bovine leukemia virus (blv) as well as 125i-labeled blv rna hybridize to the dna of tissues from leukemic cattle with the adult form of the disease but not to bovine thymic lymphoma or normal bovine tissues. | 1976 | 179141 |
| pathology of lymphosarcoma in sheep induced with bovine leukemia virus. | sixty-nine sheep were infected with bovine leukemia virus from bovine lymphosarcoma materials. twenty-four developed lymphosarcoma and died from 13 to 66 (average, 29) months later. circulating lymphocytes were increased to leukemia levels (70,000 to 403,000/cu mm blood) in only eight sheep within 2 to 3 months of death. various lymph nodes and visceral organs including heart, abomasum, uterus, kidneys, and urinary tract were commonly affected as in cattle with the adult form of lymphosarcoma. i ... | 1976 | 179703 |
| [enzootic bovine leukaemia, diagnosis, distribution and control in the netherlands (author's transl)]. | the results of studies on the incidence of enzootic bovine leukaemia in the netherlands from 1968 to 1975 inclusive are given. the serological methods used (fluorescent antibody technique, immunoperoxidase test, micro complement fixation test and gel diffusion test) were found to be of great value especially for the early diagnosis of the disease. antibodies to bovine leukaemia virus are already detected long before the onset of persistent lymphocytosis. the results obtained so far with serologi ... | 1976 | 180631 |
| diagnostic tests of bovine leukemia: comparison between an hematological test and the serological diagnosis. | | 1976 | 182441 |
| studies on bovine leukaemia ii. haematological, serological, virological and electron microscopical diagnosis. | | 1976 | 183425 |
| serologic response of cattle following inoculation with bovine leukemia virus. | | 1975 | 183668 |
| natural mode of transmission of the bovine c type leukemia virus (blv). | | 1975 | 183677 |
| seroepidemiologic testing in man for evidence of antibodies to feline leukemia virus and bovine leukemia virus. | | 1975 | 183678 |
| epizootiology of natural infection with bovine leukemia virus. | | 1975 | 183681 |
| replication of bovine leukemia virus in monolayer cell cultures. | | 1975 | 183699 |
| biochemical characterization of bovine leukemia virus. | | 1975 | 183700 |
| incidence and persistence of bovine leukemia virus antibody in calves fed pooled sour colostrum. | | 1975 | 183701 |
| induction of lymphoid tumors in sheep with cell-free preparations of bovine leukemia virus. | | 1975 | 183702 |
| studies on bovine leukaemia. iii. the haematological and serological response of sheep and goats to infection with whole blood from leukaemic cattle. | | 1976 | 186987 |
| ultrastructural comparison of bovine leukemia virus (blv) with c-type particles of other species. | | 1976 | 187149 |
| bovine leukosis. v. epidemiological study of bovine c-type virus by the use of the complement fixation test. | persistent levels of serum antibodies to bovine c-type virus were demonstrated by the complement fixation test in cattle of a leukosis herd during an observation period of one and one half years. using the same method, no antibodies were detected in a control herd. | 1976 | 187302 |
| effect of pasteurization and heat treatment on bovine leukemia virus. | four sheep inoculated with mixtures of bovine leukemia virus (blv) and milk that was treated by a simulated high-temperature short-time pasteurization procedure did not become infected with blv or develop tumor. four sheep inoculated with unpasteurized blv-mil mixtures became infected with blv and 3 died with tumor at 15, 21, and 27 months, respectively, after inoculation. fluid from a blv-infected cell culture was heated to 56, 60, 65, and 73 c for 1/2 minute and 1 minute (in separate trials) a ... | 1976 | 187564 |
| bovine lymphosarcoma: development of a radioimmunologic technique for detection of the etiologic agent. | a highly sensitive and specific radioimmunoassay has been developed for the major structural protein of an oncornavirus etiologically associated with bovine lymphosarcoma. this test can be used to identify cattle which have been exposed to the bovine leukemia virus and may thus develop or transmit the disease. analysis of randomly obtained serums indicates that infection that infection with this virus is widespread among cattle. | 1976 | 188129 |
| presence of trypanosoma theileri in herds with a high incidence of enzootic bovine leukosis. | | 1976 | 189704 |
| proteins of bovine leukemia virus. i. characterization and reactions with natural antibodies. | the bovine leukemia virus (blv) was purified from a chronically infected fetal lamb kidney cell line. sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of this virus revealed the presence of eight distinguishable viral components with molecular weights ranging from 80,000 to 11,000. the major component is a non-glycosylated protein having a molecular weight of 24,000 (p24). at least three heavier polypeptides were found, one of them representing a glycoprotein (gp 60). in additi ... | 1977 | 191635 |
| [examination for evidence of infection of humans with bovine leukemia virus]. | | 1977 | 191952 |
| cross-neutralization of ovine and bovine c-type leukemia virus-induced syncytia formation. | ovine leukemia virus (olv) could not be distinguished from bovine leukemia virus (blv) morphologically. both c-type rna tumor virus-producing cells induced syncytia when cocultivated with several indicator cells including xc and kc cells. syncytia formation could be blocked by antibodies against olv and blv, indicating that fusion was virus mediated. furthermore, antibodies against olv and blv exhibited reciprocal syncytial blocking properties, suggesting that olv and blv were closely related vi ... | 1977 | 192452 |
| concanavalin a and the production of bovine leukemia virus antigen in short-term lymphocyte cultures. | the influence of the mitogen concanavalin a (con a) on the production of bovine leukemia virus (blv) antigen in short-term lymphocyte cultures was determined by means of a single radial immunodiffusion test. con a did not affect viral antigen production in peripheral blood lymphocytes from 60% of both experimentally and naturally infected cattle. antigen production was stimulated by con a in lymphocytes from 28% of the cattle, but it was inhibited in lymphocytes from 12%. similar results were al ... | 1977 | 192904 |
| isolation of a p15 polypeptide from bovine leukemia virus and detection of specific antibodies in leukemic cattle. | | 1977 | 193251 |
| early syncytium formation induced by bovine leukemia virus in mixed cultures. | early syncytium formation was obtained in mixed cultures in the presence of blv (bovine leukemia virus). the phenomenon is specifically dependent upon the presence of blv. | 1977 | 193590 |
| bovine leukemia virus specific antibodies among french cattle. i. comparison of complement fixation and hematological tests. | complement fixation (cf) and hematological studies were performed on 517 cows living in normal conditions in different geographical areas of france. the animals belonged to three different categories: (1) multiple or single case herds, in which lymphosarcomas had been detected in the past five years. (2) leukemia free herds of high risk regions. (3) leukemia free and apparently unexposed herds. positive animals were found with both methods in the first two categories but not in the third. persis ... | 1977 | 194846 |
| evidence that b-lymphocytes carry the nuclear pocket abnormality associated with bovine leukemia virus infection. | peripheral blood lymphocytes from 3 cows with persistent lymphocytosis were separated on nylon wool columns into nylon wool-adherent and nonadherent populations. the percentage of cells coated with surface immunoglobulin (b-cells) and the frequency of lymphocytic nuclear pockets in each sub-population were then determined. in each case the adherent population consisted predominantly of b-cells with an increased nuclear pocket frequency, whereas the nonadherent cells were 98.99% negative for surf ... | 1977 | 195072 |
| morphogenesis of bovine leukemia virus. | | 1977 | 195397 |
| purification of a glycoprotein from bovine leukemia virus (blv). | a precipitating antigen of bovine leukemia virus was isolated by isoelectric focusing and sephadex gel filtration. in sds-polyacrylamide gel electrophoresis it was found to be a homogeneous protein with a relative molecular weight of 69000 daltons. because of its relative molecular weight and staining characteristics it was designated as blv gp69. a protein with the same molecular weight could also be demonstrated in blv particles. in 34 out of 35 sera from cattle affected by enzootic bovine leu ... | 1977 | 195414 |
| study on the diagnosis of enzootic bovine leukosis by complement fixation. | | 1977 | 195423 |
| evidence for the replication of bovine leukemia virus in the b lymphocytes. | bovine peripheral blood lymphocytes from a cow with persistent lymphocytosis were separated on nylon wool columns into nylon-adherent and nonadherent populations. nylon-adherent cells were highly enriched for surface immunoglobulin (sig) bearing b lymphocytes (95.5%) and nonadherent cells for sig negative non-b cells, presumably t lymphocytes (96.3%). the b lymphocytes were found to be the major producers for bovine leukemia virus. a total of 39% of the b-enriched cells, surviving after 72 hours ... | 1977 | 195501 |
| tumor-associated antigen in bovine and ovine lymphosarcoma. | specific tumor-associated antigens were found on the membrane and in the cytoplasm of lymph node cells and peripheral blood lymphocytes (pbl) from cattle and sheep with lymphosarcoma by immunofluorescence tests. materials from 15 cattle with the adult form of lymphosarcoma were examined. cytoplasmic antigen was detected in fixed tumor cells from all 15 cases and in pbl from 9 cases tested. membrane antigen was detected in living cells from 10 of the cases tested. in 3 calf-type cases, cytoplasmi ... | 1977 | 195721 |
| cellular basis of persistent lymphocytosis in cattle infected with bovine leukemia virus. | peripheral blood lymphocytes from 14 cattle infected with the bovine leukemia virus (blv) and 14 blv-free cattle were examined by the membrane immunofluorescent antibody technique to detect surface immunoglobulin (s-ig) and by the erythrocyte-antibody-complement (eac) rosette test for the detection of complement receptors. direct comparisons of the percentages of s-ig-bearing cells and eac rosette-forming cells in both infected and blv-free animals showed no evidence for the presence of a substa ... | 1977 | 197011 |
| properties of density gradient-fractionated peripheral blood leukocytes from cattle infected with bovine leukemia virus. | discontinuous bovine serum albumin gradients were used to fractionate peripheral blood leukocytes from bovine leukemia virus (blv)-free and blv-infected cows. the release of infectious blv and spontaneous incorporation of [3h]thymidine were not properties of density gradient-fractionated leukocytes from a blv-free cow. when leukocytes from blv-infected cattle were fractionated, b lymphocytes which spontaneously incorporated [3h]thymidine could be separated as a distinct subpopulation from b lymp ... | 1977 | 197012 |
| seroepidemiologic studies on the possible relationships of human and bovine leukemia: brief communication. | a seroepidemiologic study was conducted in an attempt to identify antibodies against the bovine leukemia virus (blv) in people exposed to cattle with lymphosarcoma. farm families, farm employees, and veterinarians in contact with cow herds having documented cases of lymphosarcoma were tested for precipitating antibodies to the blv with the agar gel immunodiffusion test. the cattle also were tested serologically. information was collected form the farm families regarding consumption of unpasteuri ... | 1977 | 197245 |
| bovine lymphosarcoma in twin calves. | lymphosarcoma in twin female calves, apparently the first to be observed in canada, is reported here. peripheral blood and cultured mononuclear cells of one of the calves showed aneuploidy of the chromosomes. no hematological or serological evidence of bovine leukemia virus infection was observed in the other members of the herd. bovine leukemia virus infection of the leukemic cells could not be detected by electron microscopy or by tissue culture procedures. there is a need to clarify the relat ... | 1977 | 198076 |
| fetal infection with bovine leukemia virus in sheep. | several sheep fetuses were thymectomized, and their tails were removed at 58 to 65 days of gestation for tissue culture. bovine leukemia virus (blv) antigens were detected in serial culture of tissues from fetuses whose dams and sires were both blv positive. however, no blv antigens were detected in serial cultures of tissues from fetuses whose dams were negative but whose sire was positive. precolostral serums from 3 of 16 neonatal lambs, whose sire and dams were both blv positive, were blv ant ... | 1977 | 198128 |
| b-lymphocytes and t-lymphocytes in three types of bovine lymphosarcoma. | lymphoid cells of peripheral blood, lymph nodes, and thymus from clinically normal cattle, cattle infected with bovine leukemia virus (blv), and cattle with lymphosarcoma were characterized for t- and b-cell surface markers. b-cells were detected by the erythrocyte-antibody-complement (eac) rosette test and the surface immunoglobulin (sig) immunofluorescence assay. peripheral blood from blv-infected cattle had a higher than normal percentage of b-cells by both eac rosette and sig immunofluoresce ... | 1977 | 198556 |
| detection of bovine leukemia virus in b-lymphocytes by the syncytia induction assay. | bovine peripheral blood lymphocytes (pbl's) from 3 cows and 1 steer infected with bovine leukemia virus (blv) were separated by fractionation through nylon wool columns into nylon-adherent and nonadherent cell populations. nylon-adherent cells were enriched in b-lymphocytes, as determined by the presence of surface membrane immunoglobulins (slg), whereas nylon-nonadherent cells or "non-b-lymphocytes" contained few slg-bearing cells. pbl's and separated b- and non-b-lymphocyte populations were as ... | 1977 | 198558 |
| [serologic diagnosis of bovine leukosis using complement binding reaction]. | | 1977 | 199004 |
| bovine leukemia virus specific antibodies among french cattle. ii. radioimmunoassay with the major structural protein (blv p24). | a radioimmunoassay (ria) for the major internal protein of the bovine leukemia virus (blv p24) was established using anti-blv p24 natural antibodies and purified 125i-labelled blv p24. the final precipitation of the immune complexes was realized by a preparation of inactivated staphylococcus aureau cowan i. sera from 363 cows belonging to (1) leukemic herds, (2) non-leukemic but blv-exposed herds, and (3) apparently unexposed herds were studied comparatively in blv p24 ria, complement fixation a ... | 1977 | 199546 |
| location of antigens associated with bovine leukemia virus. | antigens associated with bovine leukemia virus (blv) infection (gp 44/55 and p23) were identified by neutralization and immunofluorescent antibody (fa) tests. only serums containing antibody to gp 45/55 neutralized the virus; antibody to p23 did not. these results indicate that gp 44/55 may be located in the virus envelope. in indirect fa tests, both a cytoplasmic fluorescence and a membrane fluorscence were detected in blv-infected cells. the serum used in the fa test was then absorbed with eit ... | 1977 | 200198 |
| inhibition of bovine leukemia virus release by antiviral antibodies. | peripheral blood lymphocytes from bovine leukemia virus (blv) infected cattle were grown in vitro with serums from blv-infected and uninfected cattle, sheep and rabbits. only serums from infected animals which had antibody to gp 45/55, the major glycoprotein antigen, inhibited the release of virus from the cells. although viral antigens could be detected in the cells themselves, none were detected in the supernatants of cultures grown with these serums. normal serums and serums with antibody onl ... | 1977 | 200199 |
| expression of the bovine leukemia virus and its internal antigen in blood lymphocytes. | | 1977 | 200953 |
| [etiology of bovine leukemia]. | | 1977 | 201082 |
| bovine leukemia virus-associated antigens in lymphocyte cultures. | short-term lymphocyte cultures from bovine leukemia virus (blv)-infected cattle were tested for blv-associated antigens at various times after incubation. several immunologic methods were used, including fluorescent antibody tests, immunodiffusion, and radial immunodiffusion. antigens were not detected in uncultured lymphocytes. the blv-associated antigens were detected as early as 3 hours, with maximum antigen production occurring at 18 to 24 hours after incubation. these results indicate that ... | 1977 | 201202 |
| a new notifiable disease. | | 1977 | 202054 |
| comparative study of four diagnostic methods of enzootic bovine leukosis. | | 1977 | 202114 |