| pathogenicity of some clones from field isolates of avian leukosis viruses. | | 1972 | 4344740 |
| an enzymatic function associated with transformation of fibroblasts by oncogenic viruses. i. chick embryo fibroblast cultures transformed by avian rna tumor viruses. | chick embryo fibroblast cultures develop fibrinolytic activity after transformation by rous sarcoma virus (rsv). this fibrinolytic activity is not present in normal cultures, and it does not appear after infection with either nontransforming strains of avian leukosis viruses or cytocidal rna and dna viruses. in cultures infected with a temperature sensitive mutant of rsv the onset of fibrinolysis appears after exposure to permissive temperatures and precedes by a short interval the appearance of ... | 1973 | 4347290 |
| rna species obtained from clonal lines of avian sarcoma and from avian leukosis virus. | | 1973 | 4351610 |
| isolation of defective mutant of avian sarcoma virus. | a colony of transformed cells was isolated from chick-embryo cells infected with a stock of nondefective schmidt-ruppin strain of rous sarcoma virus. the virus recovered from this colony was a stable defective mutant very similar to the bryan strain of rous sarcoma virus in the following characteristics: (i) noninfectiousness of virus particles released from transformed cells that lack helper factor; (ii) formation of infectious pseudotypes by coinfection with avian leukosis virus or by interact ... | 1973 | 4357873 |
| presence of avian leukosis virus genes, in dna form in normal chickens. | | 1973 | 4360180 |
| antibodies in chickens against avian leukosis virus group specific antigen. | | 1973 | 4360193 |
| biological and biochemical evidence for an interaction between marek's disease herpesvirus and avian leukosis virus in vivo. | the dna-containing epstein-barr herpesvirus has been implicated in the etiology of burkitt's lymphoma, a malignant tumor of children in africa. recently, however, particles possessing four biochemical characteristics of rna tumor viruses have also been identified in these tumors. the fact that both types of viruses are found suggests that an interaction between them may be playing a role in the etiology of burkitt's lymphoma. to explore this possibility with a defined animal model, experiments w ... | 1973 | 4361680 |
| isolation of a transplantable cell line induced by the mc29 avian leukosis virus. | | 1974 | 4363662 |
| responses of isolator-derived and conventional chickens to marek's disease herpesvirus and avian leukosis virus. | | 1974 | 4364733 |
| avian tumor virus rna: a comparison of three sarcoma viruses and their transformation-defective derivatives by oligonucleotide fingerprinting and dna-rna hybridization. | earlier electrophoretic analyses have shown that the 60-70s rna of avian sarcoma viruses contains a characteristic subunit, termed class a subunit, which has a lower electrophoretic mobility than class b subunit found in transformation-defective derivatives of sarcoma viruses and in avian leukosis viruses. we have compared the rnas of three nondefective avian sarcoma viruses, b77 and prague and schmidt-ruppin strains of rous sarcoma virus, with those of their transformation-defective (td) deriva ... | 1973 | 4365699 |
| status of the endogenous avian leukosis virus in resistant cells from a producing line. | | 1974 | 4371742 |
| avian leukosis virus induced tumours in mammals. | | 1970 | 4376355 |
| minor rna and other components of host origin intrinsic to avian leukosis virus particles. | | 1970 | 4376356 |
| evidence for the vertical transmission of 'non-infectious' avian leukosis virus in 'leukosis-free' chickens. | | 1970 | 4376360 |
| the non-producer cell activation test in avian leukosis virus assay. | | 1970 | 4376362 |
| occurrence, transmission and oncogenic spectrum of the avian leukosis viruses. | | 1970 | 4376395 |
| strain mc29, an avian leukosis virus of unique properties. | | 1970 | 4376396 |
| an avian leukosis virus related to rsv(o): properties and evidence for helper activity. | | 1971 | 5101017 |
| virus particles and viral antigens in chicken tissues free of infectious avian leukosis virus. | | 1967 | 5233847 |
| [on the use of infectious viruses for demonstrating infection of chick embryos with avian leukosis virus]. | | 1968 | 5724793 |
| case report: mixed infections with subgroups a and b avian leukosis viruses in commercial white leghorn chickens. | | 1968 | 5749020 |
| detection of avian leukosis virus: comparison of five techniques. | five techniques were compared for their ability to detect decreasing dilutions of rav-i, an avian leukosis sarcoma virus, in serially passaged chick embryo fibroblast cell cultures. the indirect fluorescent antibody test, sandwich enzyme-linked immunosorbent assay (elisa) and reverse transcriptase assay were equally sensitive in detecting the virus. the indirect immunoperoxidase and complement fixation avian leukosis tests were less sensitive. it is recommended that the sandwich elisa be used fo ... | 1984 | 6084274 |
| nucleotide sequence 5' of the chicken c-myc coding region: localization of a noncoding exon that is absent from myc transcripts in most avian leukosis virus-induced lymphomas. | we have determined the nucleotide sequence of the 2.2-kilobase-pair region upstream of the chicken c-myc coding exons. using rna blot analysis, we have localized a noncoding exon to a region that is separated from the c-myc coding sequences by an intron of 700-800 base pairs. in most avian leukosis virus-induced lymphomas proviral integration has occurred within, or downstream of, the first exon, thus presumably displacing the regulatory sequences that normally control c-myc expression. more tha ... | 1984 | 6087343 |
| morphological transformation, autonomous proliferation and colony formation by chicken heart mesenchymal cells infected with avian sarcoma, erythroblastosis and myelocytomatosis viruses. | normal chicken heart mesenchymal cells at low density in monolayer culture in plasma-containing medium have a polygonal shape and are proliferatively quiescent. the combination of epidermal growth factor and insulin at hyperphysiological concentration, an insulin-like growth factor surrogate, causes these cells to assume a fusiform shape and to increase 40-fold in number during four days of incubation. these mitogenic hormones do not, however, induce normal chicken heart mesenchymal cells to for ... | 1984 | 6088924 |
| mutagenic effects of dna-containing oncogenic viruses and malignant transformation of mammalian cells. | it was discovered in the 1970s that oncogenic viruses could induce gene mutations in mammalian cells. the phenomenon seems to be widespread: it was observed with all groups of dna-containing viruses and some retroviruses. the mutagenic effects of the tested viruses at gene level are not locus specific. the viruses induce point mutations, including base substitutions, as well as deletions and insertions. the mutagenic effect of sv40 is controlled by the activity of the early a gene, which encodes ... | 1984 | 6090006 |
| increased transcription of the c-myc oncogene in two methylcholanthrene-induced quail fibroblastic cell lines. | the expression of three c-onc genes (c-erb, c-myc, c-myb) was investigated in five cell lines established from fibrosarcomas induced with 20-methylcholanthrene (mca) of japanese quails. these cell lines showed low levels of the three c-onc genes, with the exception of two cell lines that accumulated moderate (mcaq 1-4) and large amounts (mcaq3-5) of c-myc rna. molecular cloning and restriction endonuclease analyses indicated that expression of c-myc in these two cell lines were not associated wi ... | 1984 | 6094223 |
| metabolism and expression of rna polymerase ii transcripts in influenza virus-infected cells. | influenza virus infection has adverse effects on the metabolism of two representative rna polymerase ii transcripts in chicken embryo fibroblasts, those coding for beta-actin and for avian leukosis virus (alv) proteins. proviral alv dna was integrated into host cell dna by prior infection with alv. within 1 h after influenza virus infection, the rate of transcription of beta-actin and alv sequences decreased 40 to 60%, as determined by labeling the cells for 5 min with [3h]uridine and by in vitr ... | 1984 | 6095046 |
| influence of endogenous viral (ev) gene expression and strain of exogenous avian leukosis virus (alv) on mortality and alv infection and shedding in chickens. | two experiments were conducted to determine the influence of endogenous viral (ev) gene expression on the response of chicken to day-old inoculation with two laboratory and two field strains of avian leukosis virus (alv). the ev2- and ev3-negative semi-congenic chickens had much higher mortality from a unique non-neoplastic syndrome (nns) than ev2- and ev3-positive semi-congenic chickens after inoculation with alv strain rav-1. the three other alv strains induced little nns. all four strains of ... | 1984 | 6098248 |
| a comparison of test materials for differentiating avian leukosis virus group-specific antigens of exogenous and endogenous origin. | three groups of pullets--those lacking endogenous viral (ev) genes, those carrying ev3, which codes for avian leukosis virus (alv) group-specific (gs) antigen but not complete virus, and those carrying ev2, which codes for complete endogenous virus--were reared to maturity free of exogenous alv infection or reared separately after inoculation at 1 day with alv. the enzyme-linked immunosorbent assay (elisa) was used to detect gs antigen in feather pulp, cloacal swabs, sera, white blood cells, and ... | 1984 | 6098249 |
| radioimmunological comparison of the dna polymerases of avian retroviruses. | 125i-labeled dna polymerases of avian myeloblastosis virus and spleen necrosis virus were used in a radioimmunological characterization of avian retrovirus dna polymerases. it was shown that avian leukosis virus and reticuloendotheliosis virus dna polymerases do not cross-react in radioimmunoassays. within the avian leukosis virus species, species-specific and type-specific antigenic determinants of the dna polymerase were defined. the previous finding of genus-specific antigenic determinants in ... | 1980 | 6154153 |
| specific antigenic relationships between the rna-dependent dna polymerases of avian reticuloendotheliosis viruses and mammalian type c retroviruses. | immunoglobulin g directed against the dna polymerase of rauscher murine leukemia virus (r-mulv) could bind to 125i-labeled dna polymerase of spleen necrosis virus (snv), a member of the reticuloendotheliosis virus (rev) species. competition radioimmunoassays showed the specificity of this cross-reaction. the antigenic determinants common to snv and r-mulv dna polymerases were shared completely by the dna polymerases of gross mulv, moloney mulv, rd 114 virus, rev-t, and duck infectious anemia vir ... | 1980 | 6154804 |
| generation of transforming viruses in cultures of chicken fibroblasts infected with an avian leukosis virus. | during serial passages of an avian leukosis virus (the transformation-defective, src deletion mutant of bratislava 77 avian sarcoma virus, designated tdb77) in chicken embryo fibroblasts, viruses which transformed chicken embryo fibroblasts in vitro emerged. chicken embryo fibroblasts infected with these viruses (sk770 and sk780) had a distinctive morphology, formed foci in monolayer cultures, and grew independent of anchorage in semisolid agar. bone marrow cells were not transformed by these vi ... | 1981 | 6169846 |
| reverse transcriptase associated with avian sarcoma-leukosis viruses. ii. comparison of subunit structure and catalytic properties. | the three enzyme forms (alpha, alpha beta-, and beta-form) of the rna-dependent dna polymerase (the reverse transcriptase) from three strains of avian sarcoma virus (asv b77, asv tsla334, and asv qv2) and one exogenous (avian myeloblastosis virus (amv)) and one endogenous avian leukosis virus (rous-associated virus type-0 (rav-0) were compared with each other in subunit structure and catalytic properties. despite the gross similarity in the subunit molecular weight (mr(alpha) = 65,000 and mr(bet ... | 1982 | 6175624 |
| stability of avian leukosis virus type-specific antigen in the cell after fixation in periodate-lysine-paraformaldehyde. | stability of avian leukosis virus type-specific antigen in chicken embryo fibroblasts after fixation in periodate-lysine-paraformaldehyde was tested by the indirect immunoperoxidase method. antigen that had been steeped in 0.015m tris-hcl saline buffer solution containing 20% bovine serum and 30% glycerin was preserved at -20 degrees c, 4 degrees c and room temperature without loss of its antigenicity as long as 16 weeks. it was also stable against heat treatment at 56 degrees c, acid treatment ... | 1982 | 6176884 |
| monoclonal antibodies with specificity for three different serotypes of marek's disease viruses in chickens. | a total of 50 antibody-secreting hybridoma cells against marek's disease virus (mdv) and turkey herpesvirus (hvt) have been produced. eleven hybridomas were used for serotyping a panel of 15 pathogenic and nonpathogenic strains of mdv and hvt, representing three serotypes. the antibodies from the culture medium have fluorescence antibody (fa) titers of up to 100 and those from mouse ascitic fluid have titers ranging from 10(4) to 10(6). monoclonal antibody t81 is type-common, i.e., it reacts at ... | 1983 | 6184394 |
| expression of c-myc rna in bursal lymphoma cell lines: identification of c-myc-encoded proteins by hybrid-selected translation. | we examined expression of the c-myc locus in four cell lines established from bursal lymphomas induced by avian leukosis virus. in all four lines the level of myc-related rna was elevated. in three lines a majority of the myc-containing rnas lacked viral-ltr-related sequences, in contrast to results obtained with primary tumors. this suggests that ltr sequences are not required for maintenance of high level c-myc expression. one line, rp9, has a complex pattern of myc rnas containing ltr sequenc ... | 1983 | 6190569 |
| characterization of a replication-defective temperature-sensitive mutant of rous sarcoma virus. | a temperature-sensitive mutant (la83) of rous sarcoma virus defective both in the transformation and replication function has been isolated and partially characterized. temperature-shift experiments showed that the defects in both the focus-forming and replication functions were late and continuous. the mutant la83 was complemented by avian leukosis viruses. complementation of la83 replication was also observed with the glycoprotein-deletion mutant, brian high-titer rsv(-) suggesting that the en ... | 1984 | 6204447 |
| immunohistochemical identification of group specific antigen in avian leukosis virus infected chickens. | an indirect immunoperoxidase method was employed in the detection of the group specific antigen of avian leukosis virus in the oviduct, spleen, myocardium and bursae of fabricius of chickens. in the magnum of the oviduct the group specific antigen was detected at the base and in the lumina of glands. in the spleen the group specific antigen was found in and around the arterioles, sheathed capillaries, and in the capsular tissue. in the myocardium the group specific antigen was present in the int ... | 1984 | 6206933 |
| mechanisms of oncogenesis by subgroup f avian leukosis viruses. | subgroup f avian leukosis viruses, such as rav-61 and ring-necked pheasant virus, are recombinants between exogenous chicken retroviruses and endogenous pheasant viruses and contain new envelope (env) genes. chickens infected as 10-day-old embryos with subgroup f viruses develop fibrosarcomas, nephroblastomas, osteopetrosis, b-cell lymphomas, and a high incidence of a proliferative disorder involving the lung. fibrosarcomas, nephroblastomas, and lymphomas appear after long latent periods (3 to 1 ... | 1984 | 6207306 |
| correlation between cell killing and massive second-round superinfection by members of some subgroups of avian leukosis virus. | avian leukosis viruses of subgroups b, d, and f are cytopathic for chicken cells, whereas viruses of subgroups a, c, and e are not. the amounts of unintegrated linear viral dna in cells at different times after infection with cytopathic or noncytopathic viruses were determined by hybridization and transfection assays. shortly after infection, there is a transient accumulation of unintegrated linear viral dna in cells infected with cytopathic avian leukosis viruses. by 10 days after infection, th ... | 1980 | 6245246 |
| viral dna in bursal lymphomas induced by avian leukosis viruses. | avian leukosis viruses (alv) induce malignant lymphoma of the bursa of fabricius. viral dna in tumors and normal tissues from infected birds were analyzed by using restriction endonucleases. viral dna fragments diagnostic of the exogenous alv were easily detected in tumors, uninvolved bursal tissue, kidney, and erythrocyte nuclei. exogenous viral dna was more difficult to detect in liver. using a restriction endonuclease (saci) which cleaves linear unintegrated alv dna in a single site to define ... | 1980 | 6246253 |
| pathogenesis of virus-induced osteopetrosis in the chicken. | infection of chicken embryos with a nondefective avian leukosis virus mav-2(0) induced bone hyperplasia and profound suppression of bursal and thymic lymphoid cell development within 2- to 3 weeks after hatching. a time-course study of infectivity during embryonal life showed a gradual loss of susceptibility between the 10th day of incubation and hatching. this finding suggests that an embryonal stem cell either before or early after seeding into the bone and primary lymphoid organs is a virus-s ... | 1980 | 6248593 |
| detection of viral markers and incomplete viral genome rescue from asv transformed rodent cells. | two non-virogenic rat cell lines twerc and fr transformed with pr-rsv and fsv, respectively, were analyzed. both these cell lines contained vrna, but only in twerc cells was the major viral polypeptide p27 synthetized. transforming virus can be rescued from both cell lines only after fusing them with chicken fibroblasts preinfected with avian leukosis viruses of subgroup a, c, d, f and both td mutants of pr-rsv-c and b77-c. similarly, virus was rescued in experiments in which qef infected with r ... | 1980 | 6250919 |
| ten genetic loci in the chicken that contain structural genes for endogenous avian leukosis viruses. | our interpretation of the results presented here may be summarized as follows: (1) endogenous viral genes can be located at any of a large number of sites in the chicken chromsome. (2) different phenotypes of viral gene expression are observed, depending on the nature of the viral sequences at a given site and depending on whether the necessary sequence elements for expression are present. (3) endogenous viral genes perform no essential function in the chicken. | 1980 | 6253185 |
| subgroup-e avian-leukosis-virus-associated disease in chickens. | | 1980 | 6253188 |
| performance of 3 successive generations of specified-pathogenfree chickens maintained as a closed flock. | no antibodies against salmonella pullorum, mycoplasma gallisepticum, mycoplasma synoviae, haemophilus gallinarum, fowl pox virus, marek's disease virus, herpes virus of turkey, infectious laryngotracheitis virus, avian adenovirus, avian reovirus, infectious bursal disease virus, reticuloendotheliosis virus, avian leukosis virus, avian encephalomyelitis virus and newcastle disease virus were detectable in the sera obtained from these chickens in 3 generations at various ages. antibodies against i ... | 1980 | 6253742 |
| characterization of y73, an avian sarcoma virus: a unique transforming gene and its product, a phosphopolyprotein with protein kinase activity. | the y73 strain of avian sarcoma virus recently isolated in japan is defective in replication and is associated with subgroup a leukosis virus (yav). the virus caused sarcoma but not acute leukosis when inoculated into chickens. studies on the viral rna showed that a 26s rna, etimated to be 4.8 kilobases long, was y73 viral rna carrying a transforming gene. the 26s rna has sequences in common with the rna of an avian leukosis virus but no homology with the src gene sequence of avian sarcoma virus ... | 1980 | 6255480 |
| analysis of avian leukosis virus dna and rna in bursal tumours: viral gene expression is not required for maintenance of the tumor state. | each of twelve tumors induced by either rous-associated virus-1 or -2 (rav-1 or rav-2) contained a predominant population of cells with alv proviruses integrated at common sites, consistent with a clonal origin. seven of nine rav-2-induced bursal tumors contained single proviruses, and all seven solitary proviruses had suffered deletions. the detailed structures of four of these proviruses show that major deletions had occurred near or at the 5' ends, spanning sequences potentially important in ... | 1981 | 6258797 |
| avian leukosis virus-induced tumors have common proviral integration sites and synthesize discrete new rnas: oncogenesis by promoter insertion. | unlike other rna tumor viruses, avian leukosis viruses (which cause lymphomas and occasionally other neoplasms) lack discrete "transforming genes". we have analyzed the virus-related dna and rna of avian leukosis virus (alv)-induced tumors in an attempt to gain insight into the mechanism of alv oncogenesis. our results show that viral gene products are not required for maintenance of neoplastic transformation. primary and metastatic tumors are clonal and thus presumably derived from a single inf ... | 1981 | 6258798 |
| activation of a cellular onc gene by promoter insertion in alv-induced lymphoid leukosis. | analyses of dna and rna from avian leukosis virus (alv)-induced lymphomas have provided strong evidence that, in most tumours, alv induces neoplastic disease by activating the c-myc gene, the cellular counterpart of the transforming gene of mc29 virus. the data indicate that, as a rare event, the alv provirus integrates adjacent to the c-myc gene and that transcription, initiating from a viral promoter, causes enhanced expression of c-myc, leading to neoplastic transformation. | 1981 | 6261142 |
| the origin and structure of endogenous retroviral dna. | dna related to the genomes of avian leukosis viruses (alv) and mouse mammary tumor viruses (mmtv) is widely distributed among normal chickens and mice. we have used restriction mapping techniques to compare individuals from inbred and outbred populations with respect to genetically-transmitted proviral dna, in efforts to understand its origins and functions. we have found that outbred animals have variable numbers of alv and mmtv proviruses located at various sites in their host genomes, with so ... | 1980 | 6261653 |
| independent recombination between avian leukosis virus terminal sequences and host dna in virus-induced proliferative disease. | a cdna transcript of rous sarcoma virus, which contained the long terminal repeat (ltr) and some additional 3'-terminal sequences, was inserted into the plasmid pbr322. this recombinant plasmid, p53, was then used as a hybridization probe to detect viral terminal sequences in dna from a number of tissues of birds with a variety of avian leukosis virus (alv)-induced proliferative diseases. using restriction endonuclease digestion and blot hybridization analysis, we detected, in addition to standa ... | 1981 | 6262828 |
| histone h5 in the immature blood cells of chickens with leukosis induced by avian leukosis virus strain e26. | whole histone was isolated from the immature cells of the peripheral blood of white leghorn chickens, line 151, with leukosis experimentally induced by avian leukosis virus, strain e26 (alv-e26). histone h5 was demonstrated in all samples of these cells and was characterized by electrophoresis in polyacrylamide gel, extraction with perchloric acid, amino acid analysis, and immunodiffusion in agarose gel. histone h5 was not detected in the myeloblasts of chickens with myeloblastosis caused by the ... | 1981 | 6264195 |
| segregation of chicken endogenous viral loci ev 7 and ev 12 with the expression of infectious subgroup e avian leukosis viruses. | | 1981 | 6264692 |
| in vivo selection of two agents differing in hepatoma-inducing activity from strain mc29 avian leukosis virus. | mc29 virus induces acute leukemia (myelocytomatosis) and primary tumors of liver (hepatomas) in turkey poults. by in vivo passages two viruses were selected; designated "liver" and "bone marrow" variants, differing in hepatoma-inducing activity. the "liver" variant induces hepatoma and acute leukemia, the "bone marrow" variant induces acute leukemia. the variants differ in leukemogenic activity. the "bone marrow" variant induces high grade leukocytosis, while the "liver" variant causes lymphocyt ... | 1981 | 6264898 |
| analysis of avian leukosis virus infections with an enzyme immunoassay. | an enzyme-linked immunosorbent assay (elisa) for avian leukosis virus group-specific antigen was used to study infections with and shedding of avian leukosis virus in a commercial flock of chickens with a known high incidence of infection. avian leukosis virus group-specific antigen was detected in serum or cloacal washings from 76% of a group of 100 61-week-old hens. with eggs collected during the next 3 weeks, antigen was detected in the albumen of 88% of the eggs from elisa-positive hens and ... | 1981 | 6265361 |
| oncogenicity of three strains of avian leukosis virus in white leghorn chicks of bk line. | | 1980 | 6265807 |
| expression of forssman antigen of avian lymphoblastoid cell lines transformed by marek's disease virus or avian leukosis virus. | the expression of forssman-type heterophile antigen on marek's disease (md) virus (mdv)-transformed cell lines, mdcc-msbi 1, -hp1, -rp1 and -bp1, and avian leukosis virus (alv)-transformed cell lines, lscc-1104b1 and -1104x5 was investigated by membrane immunofluorescence and complement-dependent antibody cytotoxicity tests. forssman antigen was detected on a high percentage of the cells in two alv-transformed cell lines and on a smaller percentage of splenic lymphocytes from normal chicken. of ... | 1981 | 6267170 |
| identification of a packaged cellular mrna in virions of rous sarcoma virus. | a novel messenger activity has been identified by in vitro translation of the 70s virion rnas of a variety of avian leukosis and avian sarcoma viruses. when the 70s virion rna complex was heat dissociated and the polyadenylated rna was fractionated on neutral sucrose gradients, a polypeptide of 34,000 daltons (34k) was observed in the translation products of 18s polyadenylic acid-containing virion rna. aside from the p60(src)-related subgenomic messenger activities, this was the only prominent m ... | 1981 | 6268836 |
| cell killing by avian leukosis viruses. | infection of chicken cells with a cytopathic avian leukosis virus resulted in the detachment of killed cells from the culture dish. the detached, dead cells contained more unintegrated viral dna than the attached cells. these results confirm the hypothesis that cell killing after infection with a cytopathic avian leukosis virus is associated with accumulation of large amounts of unintegrated viral dna. no accumulation of large amounts of integrated viral dna was found in cells infected with cyto ... | 1981 | 6270346 |
| genetics of leukemogenesis by avian leukosis viruses. | | 1981 | 6274756 |
| variety of endogenous proviruses in the genomes of chickens of different breeds. | we have compared endogenous proviruses in dna of chickens of 11 breeds by means of southern's technique. many of the endogenous virus loci found were missing from the genomes of the extensively studied white leghorn chickens, although some of the proviruses and especially ev-1 appeared to be widely spread among different chickens. most of the proviruses were similar to rous-associated virus (rav-o) as judged by the ecori digestion patterns. several genetically different proviruses were found in ... | 1981 | 6275023 |
| host susceptibility to endogenous viruses: defective, glycoprotein-expressing proviruses interfere with infections. | three defective endogenous avian leukosis viruses, ev3, ev6 and ev9, interfered with subgroup e virus infections, ev3, ev6, and ev9 expressed high levels of subgroup e envelope glycoproteins. these glycoproteins reduced the activity of cellular receptors for subgroup e viruses. ev3 and ev6 protected chickens and cultured cells from subgroup e virus infections. | 1981 | 6275116 |
| multiple arrangements of viral dna and an activated host oncogene in bursal lymphomas. | proviruses of avian leukosis virus (alv) are located in the vicinity of a putative cellular oncogene (c-myc) in alv-induced bursal lymphomas. enhanced expression of c-myc occurs in association with proviruses found in any of three configurations: (i) on the 5' side ('upstream') of c-myc in the same transcriptional orientation; (ii) on the 3' side ('downstream') of c-myc in the same orientation; (iii) upstream, in the transcriptional orientation opposite to that of c-myc. thus, activation of adja ... | 1982 | 6276760 |
| establishment of b-lymphoblastoid cell lines from marek's disease virus-induced tumors in turkeys. | four lymphoblastoid cell lines were established from tumours of turkeys inoculated with high doses of the ga strain of marek's disease virus (mdv). unlike other md lymphoblastoid cell lines of chicken origin, these mdv transformed turkey line appear to be b lymphocytes and produce immunoglobulin. growth characteristics of these cell lines are slightly different; however, they all produce low levels of mdv-specific antigen and carry the complete genome of the virus as determined by virus rescue i ... | 1982 | 6277804 |
| an igm-producing b lymphoblastoid cell line established from lymphomas induced by a non-defective reticuloendotheliosis virus. | chick syncytial virus (csv), a strain of avian reticuloendotheliosis virus (rev) causes lymphoid tumours in chickens after a prolonged incubation period. a number of csv-induced tumours were examined for cell surface antigen and were found to be of the b cell type and to produce immunoglobulin. attempts were made to grow in vitro cell lines from csv-induced tumours and a lymphoblastoid cell line was established from a liver tumour of a chicken that was inoculated with csv via the yolk sac in emb ... | 1982 | 6278061 |
| association of 3' terminal rna sequences with avian leukosis viruses causing a high incidence of osteopetrosis. | | 1982 | 6278705 |
| induction of anemia by avian leukosis viruses of five subgroups. | | 1982 | 6278749 |
| at least two regions of the viral genome determine the oncogenic potential of avian leukosis viruses. | recombinants of oncogenic and nononcogenic avian leukosis viruses were tested for their oncogenic potential in chickens. the results indicate that at least two regions of the viral genome determine the oncogenic potential of these viruses. the first region contains sequences that control viral mrna synthesis. these sequences determine the potential of a virus to induce a low incidence of lymphomas, carcinomas, chondrosarcomas, fibrosarcomas, and osteopetrosis. the second region lies outside the ... | 1982 | 6280174 |
| [causal relationship and pathogenesis of leukosis, kidney tumors, ovarian neoplasms and osteopetrosis following infection with avian leukosis viruses]. | | 1982 | 6280953 |
| assay of avian leukosis viruses by indirect immunoperoxidase method. | chick embryo fibroblast cells (cef) infected with avian leukosis viruses were stained selectively by the indirect immunoperoxidase method. good results were obtained by the use of a successive combination of periodate-lysine-paraformaldehyde fixation and diaminobenzidine reaction mixture. viral antigens were detected type-specifically on infected cells. type-specific antisera determined by the neutralization test were absorbed by the homologous type of virus-infected cef, but not by the heterolo ... | 1981 | 6281662 |
| subgenomic mrna in ok10 defective leukemia virus-transformed cells. | ok10, a defective leukemia virus, is produced as a defective particle by so-called nonproducer transformed quail fibroblasts. ok10 defective viral particles contain an 8-kilobases (kb)-long genomic rna, lack any detectable reverse transcriptase activity, and are not infectious. we studied the genetic content of ok10 rna extracted from both virions and infected cells. as shown by rna-cdna hybridizations in stringent conditions, about 77% (6.4 kb) of the ok10 8.0kb rna was related to avian leukosi ... | 1982 | 6283157 |
| avian nephroblastoma virus mav-2(n) and avian osteopetrosis virus mav-2(o) are genetically distinct. | avian myeloblastosis virus consists of a mixture of a defective leukaemia virus and several non-defective associated avian leukosis viruses. the genomes of two of the associated avian leukosis viruses were examined in this study and were chosen because one of them, mav-2(n), induces predominantly nephroblastoma, while the other, mav-2(o), induces predominantly osteopetrosis. competitive hybridization studies employing labelled virion rna and dna from normal and malignant tissue failed to demonst ... | 1982 | 6284866 |
| effect of endogenous leukosis virus genes on response to infection with avian leukosis and reticuloendotheliosis viruses. | we examined the effect of the presence or absence of endogenous viral gene (ev) 3, which controls expression of group-specific viral and envelope antigens (gs+chf+ phenotype), and ev2, which controls the production of a complete subgroup e virus (v-e+ phenotype), on the response of chickens to rav-1, an exogenous avian leukosis virus (alv) with an antigenic relationship to endogenous virus. after inoculation at one day of age, the chickens lacking either ev gene expression had a lower frequency ... | 1982 | 6285878 |
| sequence of the long terminal repeat and adjacent segments of the endogenous avian virus rous-associated virus 0. | rous-associated virus 0 (rav-0), an endogenous chicken virus, does not cause disease when inoculated into susceptible domestic chickens. an infectious unintegrated circular rav-0 dna was molecularly cloned, and the sequence of the long terminal repeat (ltr) and adjacent segments was determined. the sequence of the ltr was found to be very similar to that of replication-defective endogenous virus ev-1. like the ev-1 ltr, the rav-0 ltr is smaller (278 base pairs instead of 330) than the ltrs of th ... | 1982 | 6286997 |
| studies of avian leukosis virus infection in chickens from a commercial breeder flock. | progeny chicks from a commercial breeder flock with a high rate of avian leukosis virus (alv) infection were classified as congenitally or contact infected with alv on the basis of virus tests on their meconia at hatching and the presence or absence of antibodies at 20 weeks of age. the alv infection profile, shedding, tumor mortality, and egg production in the congenitally-infected chickens were compared with those in the contact-infected hatchmates. results show that viremic-tolerant hens clas ... | 1982 | 6287446 |
| common proviral integration sites in c57bl mouse lymphomas induced by radiation leukemia virus and absence of novel virus-related sequences in radiogenic lymphoma dna. | three c57bl/ka mice were inoculated with radlv/vl3, a thymotropic and leukemogenic virus population released by the permanent bl/vl3 cell line, which was derived from a c57bl/ka lymphoma induced by radiation leukemia virus (radlv). the neoplastic thymus and bone marrow cells from these mice were grown until the cultures became permanently established, and their dnas were examined for the presence of virus-related sequences by restriction enzyme analysis. all six cell lines displayed identical ec ... | 1982 | 6289014 |
| isolation of 16l virus: a rapidly transforming sarcoma virus from an avian leukosis virus-induced sarcoma. | we have isolated a replication-defective rapidly transforming sarcoma virus (designated 16l virus) from a fibro-sarcoma in a chicken infected with td107a, a transformation-defective deletion mutant of subgroup a schmidt-ruppin rous sarcoma virus. 16l virus transforms fibroblasts and causes sarcomas in infected chickens within 2 wk. its genomic rna is 6.0 kilobases and contains sequences homologous to the transforming gene (fps) of fujinami sarcoma virus (fsv). rnase t1 oligonucleotide analysis s ... | 1982 | 6289331 |
| characterization of c-lil, a chicken cellular sequence associated with a stock of b77 avian sarcoma virus. | using biochemical methods, we have shown that a new specific sequence, v-lil, is associated with a given stock of b77 avian sarcoma virus (clone 9). we prepared a dna complementary to v-lil sequences, using substractive hybridizations, and investigated the properties of this sequence. v-lil has a genetic complexity of ca. 2,000 nucleotides and is not present in various stocks of avian sarcoma virus, avian leukosis virus, or defective leukemia virus. v-lil is not associated with b77 avian sarcoma ... | 1982 | 6292471 |
| molecular analysis of the c-myc locus in normal tissue and in avian leukosis virus-induced lymphomas. | we isolated molecular clones of the provirus-host cell junctions (tumor junction fragments) from two avian leukosis virus-induced lymphomas and compared the structures of these clones with a clone of the normal c-myc gene. restriction mapping and dna sequencing demonstrated that normal proviral integration events occurred adjacent to c-myc in both tumors, without gross structural alteration of c-myc. the right long terminal repeat of an avian leukosis virus provirus is integrated upstream from t ... | 1982 | 6292482 |
| orientation and position of avian leukosis virus dna relative to the cellular oncogene c-myc in b-lymphoma tumors of highly susceptible 15i5 x 7(2) chickens. | we previously reported our characterizations of the b-lymphoma tumors induced in a highly susceptible line of chickens (15i5 x 7(2)) by the avian leukosis virus rav-1 (proc. natl. acad. sci. 78:3418-3422, 1981). we demonstrated that in greater than 90% of the tumors, the rav-1 provirus is integrated near a cellular oncogene, c-myc. in the present study, we devised a simple approach, relying on sali digestion, for further defining the locations and orientations of the proviruses with respect to t ... | 1982 | 6292531 |
| effect of intron size on splicing efficiency in retroviral transcripts. | to study the effect of intron size on splicing efficiency we have varied the size of the avian leukosis virus (alv) env mrna intron in a cloned alv genome. this was accomplished by deletion of alv sequences or insertion of phage lambda dna. the effect of these modifications on splicing was analyzed by microinjection of the modified clones into rsv(-) chicken cells. viral env mrna when transcribed and properly spliced within these cells complemented the rsv(-) env deficiency leading to the produc ... | 1982 | 6292870 |
| pathogenicity of avian leukosis viruses. | three methods were used in attempts to obtain non-oncogenic avian leukosis virus for possible use as an immunoprophylactic agent for the control of lymphoid leukosis in chickens. these were: 1) isolate a nononcogenic virus from commercial breeder flocks experiencing very little or no lymphoid leukosis; 2) obtain a non-oncogenic recombinant from mixed infection of a strain with low oncogenicity, rous-associated virus-60 (rav-60), with rav-1 or rav-2 in cell culture; and 3) attempt to attenuate su ... | 1982 | 6293446 |
| the effectiveness of selection for reduced avian leukosis virus shedding in different chicken strains. | | 1982 | 6293449 |
| comparison of the oligosaccharide moieties of the major envelope glycoproteins of the subgroup a and subgroup b avian myeloblastosis-associated viruses. | the nature of the oligosaccharide chains of the major envelope glycoprotein, gp85, from avian myeloblastosis-associated viruses has been examined for the subgroup a and subgroup b viruses replicated in fibroblasts from the same chicken embryos. pronase-digested glycopeptides from [3h]mannose- or [3h]glucosamine-labeled viruses were analyzed by the combined techniques of gel filtration, endo-beta-n-acetylglucosaminidase digestion, and concanavalin a affinity chromatography. the gp85 protein from ... | 1983 | 6296432 |
| ontogeny of yellow fever 17d vaccine: rna oligonucleotide fingerprint and monoclonal antibody analyses of vaccines produced world-wide. | yellow fever 17d vaccines are currently manufactured with approval of the world health organization (who) in 11 countries. these vaccines have proven highly efficacious and safe. nevertheless, they have not been fully characterized genetically, a problem for future standardization and modernization of vaccine manufacture now being proposed by who. vaccines in use are derived from two distinct substrains (17d-204 and 17dd) which represent independently maintained passage series from original 17d. ... | 1983 | 6298349 |
| identification and nucleotide sequence of a human locus homologous to the v-myc oncogene of avian myelocytomatosis virus mc29. | avian myelocytomatosis virus mc29 is a replication-defective acute leukaemia virus which induces a variety of tumours in chickens including sarcomas, renal and hepatic carcinomas, and myelocytomatosis. the oncogenic potential of the virus is mediated by the gene v-myc, acquired from sequences (c-myc) present in normal uninfected chicken dna. sequences closely related to chicken c-myc have been highly conserved throughout evolution, from drosophila to vertebrates. the hypothesis that c-myc may be ... | 1983 | 6298632 |
| induction of angiosarcomas by ring-necked pheasant virus. | ring-necked pheasant virus, an avian leukosis virus, when injected into 10-day old chick embryos, caused angiosarcomas in the lungs of infected chickens within a short time. angiosarcomas appeared as localized foci of proliferating cells in the lungs as early as 2 weeks posthatch, and by 6 weeks, the lungs of the infected chickens were frequently filled with tumor cells. between 3 and 10 weeks of age, 80% of infected chickens died of the angiosarcomas; the 20% which lived 8 weeks or longer had s ... | 1983 | 6299960 |
| rapid induction of hypothyroidism by an avian leukosis virus. | infection of 10-day chicken embryos with an avian leukosis virus, rav-7, resulted in hypothyroidism within 3 weeks posthatching. histological examination of the thyroids from infected chickens showed an extensive infiltration of lymphoblastoid cells by 7 days posthatching. areas resembling germinal centers were present in the thyroids of infected chickens by 3 weeks posthatching. examination of circulating thyroid and pancreas hormones showed a significant reduction in t3 and t4 levels and a tre ... | 1983 | 6302005 |
| genomes of endogenous and exogenous avian retroviruses. | the endogenous viruses of chickens are closely related to the exogenous avian leukosis viruses (alv) yet as a group differ from these viruses in their host range, growth rate, and oncogenicity. the present study was undertaken to determine the patterns of relationship among the genomes of endogenous and exogenous alvs. complete or partial t1 oligonucleotide maps were prepared from the genomes of endogenous viruses that reside at eight distinct loci in chickens. selected endogenous viruses and re ... | 1983 | 6302996 |
| studies of reticuloendotheliosis virus-induced lymphomagenesis in chickens. | seventy-three percent of chickens inoculated with the chick syncytial strain of reticuloendotheliosis virus (rev) at hatching developed lymphomas by 39 weeks of age. neonatal treatment with cyclophosphamide or surgical bursectomy at 2, 4, 8, or 12 weeks of age significantly (p less than 0.01) reduced lymphoma development. in a further experiment, surgical bursectomy of rev-infected chickens followed by intravenous inoculation of the chickens with a single cell suspension of their own bursa cells ... | 1983 | 6303293 |
| activation of the cellular oncogene c-erbb by ltr insertion: molecular basis for induction of erythroblastosis by avian leukosis virus. | avian leukosis virus (alv), a slowly oncogenic retrovirus, induces in chickens a variety of neoplasms, including lymphoid leukosis and erythroblastosis. in lymphoid leukosis, a cellular oncogene, c-myc, is activated by the insertion of alv ltr. we provide evidence that alv utilizes a similar mechanism in erythroblastosis induction by activating a different cellular oncogene, c-erbb. we report the isolation, from leukemic erythroblast dna, of a clone that represents the viral-cell junction fragme ... | 1983 | 6305505 |
| detection of antibodies against avian leukosis viruses with indirect immunoperoxidase absorbance test. | | 1983 | 6306321 |
| b5 and b15 associated with progressive marek's disease, rous sarcoma, and avian leukosis virus-induced tumors in inbred 15i4 chickens. | rprl 15i4 inbred chickens are nearly histocompatible except for the b5 and b15 haplotypes that determine the major transplantation antigens. b5b5 and b15b15 15i4 chickens were equally and highly susceptible to tumors induced by marek's disease, rous sarcoma, or avian leukosis viruses (alv), suggesting both of these haplotypes may determine a general influence leading to tumor development. the 15i4 birds were highly susceptible to erythroblastosis, and most developed immunological tolerance to th ... | 1983 | 6306630 |
| viral sequences determining the oncogenicity of avian leukosis viruses. | our analyses of the sequence of the recombinant virus ntre7 and comparison with its endogenous and exogenous alv parents indicate that a section of approximately 400 base pairs at the 3' end of the genome encodes a function which is required for oncogenicity. this section includes an exogenous virus specific region (xsr) of approximately 148 base pairs and the u3 region of the ltr. at present it seems most likely that the function required for oncogenicity is the transcription promoter contained ... | 1983 | 6306683 |
| cancer induction by insertional mutagenesis: the role of viral genes in avian leukosis virus induced cancers. | | 1983 | 6306689 |
| immunological phenotype of lymphomas induced by avian leukosis viruses. | the production of immunoglobulin by six cell lines derived from bursal tumors induced by avian leukosis virus follows two general patterns: (i) three cell lines that have been extensively passaged in culture synthesize and secrete light chains only; (ii) three cell lines that are recently isolated produce and secrete monomeric immunoglobulin m in addition to free light chains. all six cell lines synthesize and secrete both glycosylated and unglycosylated forms of light chain. we conclude that th ... | 1983 | 6308424 |
| cis-acting rna packaging locus in the 115-nucleotide direct repeat of rous sarcoma virus. | the v-src gene of schmidt-ruppin strain a of rous sarcoma virus is flanked by a 115-nucleotide direct repeat. mutants that lack either the upstream or downstream copy replicate normally. however, mutants that lack both copies do not replicate. cloned viral dna lacking both copies of the 115-nucleotide sequence is capable of directing the transcription of viral rna posttransfection. this viral rna is polyadenylated, spliced, exported from the nucleus, and translated into protein normally. however ... | 1983 | 6313966 |
| avian leukosis virus infection and congenital transmission in lines of chickens resisting selection for reduced shedding. | two lines (d and e) of three breeder lines of chickens that had resisted selection for reduced avian leukosis virus (alv) congenital transmission on the breeder's premises did not resist the same selection procedures (tests for gs-antigen in albumen) under laboratory conditions. the incidence of alv congenital transmission in the remaining third line (f) was spontaneously reduced from 13% to 0.9%. environmental alv exposure of uninfected chicks after hatching induced 7-10% of the progeny from li ... | 1983 | 6314970 |
| evidence that avian tumour virus-immune chicken sera recognize only viral structural antigens on the surface of avian tumour virus-infected cells. | the specificity of the humoral response of chickens to avian tumour viruses (atv) was investigated by reacting atv-immune sera with triton x-100 extracts of uninfected, infected and transformed chicken embryo fibroblasts. analysis of these immune reactions by polyacrylamide gel electrophoresis revealed that avian leukosis virus-challenged and rous sarcoma virus-challenged chickens recognized only two major cell surface antigens of 100000 and 29000 mol. wt. which were present on transformed and n ... | 1983 | 6315863 |