Publications
| Title | Abstract | Year(sorted descending) Filter | PMID Filter |
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| tvb receptors for cytopathic and noncytopathic subgroups of avian leukosis viruses are functional death receptors. | the identification of tvb(s3), a cellular receptor for the cytopathic subgroups b and d of avian leukosis virus (alv-b and alv-d), as a tumor necrosis factor receptor-related death receptor with a cytoplasmic death domain, provides a compelling argument that viral env-receptor interactions are linked to cell death (4). however, other tvb proteins have been described that appear to have similar death domains but are cellular receptors for the noncytopathic subgroup e of alv (alv-e): tvb(t), a tur ... | 2000 | 11090145 |
| multiple infection of chickens and turkeys with avian oncogenic viruses: prevalence and molecular analysis. | the avian herpesvirus, marek's disease virus (mdv) and several retroviruses, reticuloendotheliosis virus (rev), avian leukosis virus (alv) (chickens) and lymphoproliferative disease virus (turkeys) are oncogenic and immunosuppressive agents. these viruses were detected either alone, or in various combinations in blood and tumor dnas of commercial birds using pcr. we present a 5-year retrospective study that included 207 chicken and 52 turkey flocks. of these, 32 chicken and 18 turkey flocks were ... | 1999 | 10696434 |
| resistance to avian leukosis virus lymphomagenesis occurs subsequent to proviral c-myc integration. | most chicken strains are highly susceptible to avian leukosis virus (alv) induction of bursal lymphoma, involving proviral integration within the c-myc proto-oncogene, while certain strains are genetically resistant to lymphomagenesis. a nested pcr assay was developed to analyse the appearance of proviral c-myc integrations after alv infection of lymphoma-susceptible birds, and to determine whether these integrations arise in lymphoma-resistant birds. proviral c-myc integrations are detected in ... | 1999 | 9926935 |
| novel endogenous retroviral sequences in the chicken genome closely related to hprs-103 (subgroup j) avian leukosis virus. | hprs-103, the prototype of avian leukosis virus (alv) subgroup j, is a recently identified retrovirus associated with myeloid leukosis in meat-type chickens. although this virus shows high sequence identity to other alv subgroups within the gag and pol genes, its env gene is highly diverged (with only about 40% sequence identity) from other alv subgroups. on the other hand, the sequence of the env gene of hprs-103 was 75% identical to that of e51, a member of the eav family of endogenous avian r ... | 1999 | 9934710 |
| detection of avian leukosis virus in albumen of chicken eggs using reverse transcription polymerase chain reaction. | a reverse transcriptase polymerase chain (rt-pcr) assay was developed to detect avian leukosis retrovirus (alv) in egg albumen. eggs of single comb white leghorns were from a commercial breeder (stock f) and from a pathogen-free flock (stock n). rt-pcr was undertaken on isolated rna from 20 unfertilized egg samples using seven sets of primers that correspond to the alv gp85 envelope glycoprotein which determines the alv subgroup classification. an elisa assay for alv gs antigen of egg albumen wa ... | 1999 | 10204692 |
| genome structure and expression of the ev/j family of avian endogenous viruses. | we recently reported the identification of sequences in the chicken genome that show over 95% identity to the novel envelope gene of the subgroup j avian leukosis virus (s. j. benson, b. l. ruis, a. m. fadly, and k. f. conklin, j. virol. 72:10157-10164, 1998). based on the fact that the endogenous subgroup j-related env genes were associated with long terminal repeats (ltrs), we concluded that these ltr-env sequences defined a new family of avian endogenous viruses that we designated the ev/j fa ... | 1999 | 10364281 |
| evidence of avian leukosis virus subgroup e and endogenous avian virus in measles and mumps vaccines derived from chicken cells: investigation of transmission to vaccine recipients. | reverse transcriptase (rt) activity has been detected recently in all chicken cell-derived measles and mumps vaccines. a study of a vaccine manufactured in europe indicated that the rt is associated with particles containing endogenous avian retrovirus (eav-0) rna and originates from the chicken embryonic fibroblasts (cef) used as a substrate for propagation of the vaccine. we investigated the origin of rt in measles and mumps vaccines from a u.s. manufacturer and confirm the presence of rt and ... | 1999 | 10364336 |
| dynamics of protein 27 of avian leukosis virus and transforming growth factor beta2 in lymphoid leukosis susceptible and resistant broiler chicken breeding stock. | the dynamics of the serum concentration of protein 27 (p27) of avian leukosis virus and transforming growth factor beta2 (tgf-beta2) were compared during the period between 29 and 59 weeks of age in two flocks of broiler chicken breeding stock undergoing outbreaks of severe lymphoid leukosis (ll) associated with persistent high mortality (susceptible) and in another two flocks of breeding stock with the presence of avian leukosis virus in association with low mortality due to ll (resistant). the ... | 1999 | 10401723 |
| [avian leukosis: an old problem in a new coat: diagnostic possibilities and limitations]. | current problems in parent broiler chickens caused by the new avian leukosis virus subgroup j are described. the possibilities and limitations of diagnosing avian leukosis, and in particular that caused by the j subgroup virus, are reviewed and the eradication of the disease is discussed. | 1999 | 10488520 |
| isolation and some characteristics of a subgroup j-like avian leukosis virus associated with myeloid leukosis in meat-type chickens in the united states. | several subgroup j-like avian leukosis viruses (alv-js) were isolated from broiler breeder (bb) and commercial broiler flocks experiencing myeloid leukosis (ml) at 4 wk of age or older. in all cases, diagnosis of ml was based on the presence of typical gross and microscopic lesions in affected tissues. the isolates were classified as alv-j by 1) their ability to propagate in chicken embryo fibroblasts (cef) that are resistant to avian leukosis virus (alv) subgroups a and e (c/ae) and 2) positive ... | 1999 | 10494407 |
| avian leukosis virus subgroup j: a rapidly evolving group of oncogenic retroviruses. | a strain of avian leukosis virus (alv) belonging to a new envelope subgroup j was isolated in the uk in 1988 from meat-type chickens. the disease caused by the members of this subgroup has since spread very rapidly worldwide and has become one of the major problems facing the broiler meat industry. molecular characterisation of hprs -103, the prototype of subgroup j, has shown that it has a structure of a typical alv with gag, pol and env genes. however the env gene was distinct from that of oth ... | 1999 | 10502478 |
| soluble forms of the subgroup a avian leukosis virus [alv(a)] receptor tva significantly inhibit alv(a) infection in vitro and in vivo. | the interactions between the subgroup a avian leukosis virus [alv(a)] envelope glycoproteins and soluble forms of the alv(a) receptor tva were analyzed both in vitro and in vivo by quantitating the ability of the soluble tva proteins to inhibit alv(a) entry into susceptible cells. two soluble tva proteins were tested: the 83-amino-acid tva extracellular region fused to two epitope tags (stva) or fused to the constant region of the mouse immunoglobulin g heavy chain (stva-migg). replication-compe ... | 1999 | 10559319 |
| detection of exogenous and endogenous avian leukosis virus in commercial chicken eggs using reverse transcription and polymerase chain reaction assay. | avian leukosis retroviruses (alv) cause lymphomas and other cancers in chickens. previous studies have used enzyme-linked immunosorbent assays (elisa) and indirect immunofluorescence assays (ifa) to detect alv p27 group-specific antigens (gsa) in commercial chicken eggs. in the poultry industry eradication programme against exogenous alv, elisa assays are used to identify chickens infected with the virus. the inability of elisa and ifa assays to discriminate between alv gsa of endogenous or exog ... | 1999 | 26905496 |
| tropism of subgroup j avian leukosis virus as detected by in situ hybridization. | the hprs-103 strain of avian retrovirus is the prototype of subgroup j avian leukosis virus (alv-j) and causes myeloid leukosis in meat-type chickens. using immunohistochemical detection of the viral groupspecific antigen (gag) we have previously demonstrated that the induction of myeloid leukosis by alv-j is associated with viral tropism for myelomonocytic cells. in this paper we describe an in situ hybridization (ish) technique using digoxigenin (dig)-labelled probes for detecting rna transcri ... | 1999 | 26911502 |
| isolation of serotype 2 marek's disease virus from a cell line of avian lymphoid leukosis. | to determine a serotype of marek's disease virus (mdv) persistently infected in a lymphoid leukosis (ll)-cell line, lscc-bk3, clone a (bk3a), and to examine the pathogenicity of the virus, an attempt was made to isolate mdv from culture fluid of the ll-cell line, using chick embryo fibroblast cultures resistant to infection with subgroup a avian leukosis virus (alv) to eliminate subgroup a alv. the mdv isolate, serologically identified as serotype 2 mdv and designated as the 2h strain, was free ... | 1998 | 9524935 |
| molecular characterization of endogenous viral genes of the avian leukosis virus family in an experimental population of brown-egg layers. | retroviral dna sequences similar to the exogenous avian leukosis virus can be found in the genome of many chicken breeds and have been identified as the alve family of endogenous viral (ev) genes. most of them have been described by a restriction fragment length polymorphism (rflp) procedure with two restriction enzymes and a full length viral probe. in order to facilitate the comparison of alve genes between strains, the nomenclature workshop held at the xxiv international society for animal ge ... | 1998 | 9565246 |
| antigenic variants of j subgroup avian leukosis virus: sequence analysis reveals multiple changes in the env gene. | hprs-103, the prototype of avian leukosis virus (alv) subgroup j, was isolated in 1989 from meat-type chickens from commercial flocks where it induces myelocytic myeloid leukosis (ml). the hprs-103 env gene differs considerably from other alv subgroups but shows high identity (75-97%) to env-like sequences of the different members of the eav family of endogenous avian retroviruses. recently, we have isolated several viruses related to hprs-103 from cases of ml. although these isolates showed pro ... | 1998 | 9568971 |
| differential selection of cells with proviral c-myc and c-erbb integrations after avian leukosis virus infection. | avian leukosis virus (alv) infection induces bursal lymphomas in chickens after proviral integration within the c-myc proto-oncogene and induces erythroblastosis after integration within the c-erbb proto-oncogene. a nested pcr assay was used to analyze the appearance of these integrations at an early stage of tumor induction after infection of embryos. five to eight distinct proviral c-myc integration events were amplified from bursas of infected 35-day-old birds, in good agreement with the numb ... | 1998 | 9621008 |
| detection of avian leukosis virus subgroup j using the polymerase chain reaction. | a polymerase chain reaction (pcr) assay was developed for the detection of avian leukosis virus strain j (alv-j) in chickens. primers were based in the e element and the 3' terminus of the long terminal repeat of proviral alv-j. pcr products were amplified from genomic dna extracted from chicken embryo fibroblasts (cef) infected with either strain hprs-103, the prototype of alv-j, or field isolates of alv-j obtained from broiler breeder flocks in the united states that exhibited myeloid leukosis ... | 1998 | 9645329 |
| development and application of polymerase chain reaction (pcr) tests for the detection of subgroup j avian leukosis virus. | subgroup j avian leukosis virus (alv) is a recently identified avian retrovirus associated with myeloid leukosis in meat-type chickens. the env gene of the hprs-103 strain of alv, the prototype of this subgroup, differs considerably from that of other subgroups, but shows close homology to the env-like sequences of members of the eav family of endogenous retroviruses. polymerase chain reaction (pcr) tests using two sets of primers were developed for the specific detection of the members of this ... | 1998 | 9660074 |
| examination of antisense rna and oligodeoxynucleotides as potential inhibitors of avian leukosis virus replication in rp30 cells. | avian leukosis virus (alv) is an economically important pathogen of chickens. both antisense rna and antisense oligodeoxynucleotides (odn) have been used to diminish the replication and spread of other retroviruses. the use of antisense rna and odn to inhibit alv replication has been examined in cultured rp30 cells. using an expression system that constitutively transcribes antisense alv rna, one transfected cell clone showed a significant reduction in virus growth. however, this effect was not ... | 1998 | 9733130 |
| response of chickens carrying germline insert alva11 to challenge with a field strain of subgroup a avian leukosis virus. | the alva11 germline insert in chickens is a defective subgroup a avian leukosis virus (alv) proviral insert that expresses a low-to-moderate level of subgroup a alv envelope glycoprotein. chicks carrying or lacking alva11 were evaluated for response to challenge by rpl-42, a pathogenic field strain of subgroup a alv, by either exposure to chicks shedding rpl-42 or direct injection with various doses of rpl-42. chicks carrying alva11 were significantly more resistant, as measured by infectious vi ... | 1998 | 9876848 |
| bic, a novel gene activated by proviral insertions in avian leukosis virus-induced lymphomas, is likely to function through its noncoding rna. | the bic locus is a common retroviral integration site in avian leukosis virus (alv)-induced b-cell lymphomas originally identified by infection of chickens with alvs of two different subgroups (clurman and hayward, mol. cell. biol. 9:2657-2664, 1989). based on its frequent association with c-myc activation and its preferential activation in metastatic tumors, the bic locus is thought to harbor a gene that can collaborate with c-myc in lymphomagenesis and presumably plays a role in late stages of ... | 1997 | 9032277 |
| tissue tropism of the hprs-103 strain of j subgroup avian leukosis virus and of a derivative acutely transforming virus. | the tissue tropism was studied for the hprs-103 strain of avian leukosis virus, which belongs to a new envelope subgroup, designated j. studies were conducted in blood monocyte and bone marrow cell cultures and in chickens from six lines that had been shown previously to differ in susceptibility to induction by this virus of myeloid leukosis and other tumors. using an immunohistochemical technique to detect expression of viral group-specific antigen (gag) in various tissues, we detected no major ... | 1997 | 9066079 |
| avian retroviruses. | avian leukosis virus (alv) and reticuloendotheliosis virus (rev) are the most common naturally occurring avian retroviruses associated with neoplastic disease conditions in domesticated poultry. avian leukosis virus infects primarily chickens, whereas rev infects chickens, turkeys, and other avian species. in addition to causing tumors, both alv and rev can reduce productivity and induce immunosuppression and other production problems in affected flocks. | 1997 | 9071747 |
| role of contact and genetic transmission of endogenous virus-21 in the susceptibility of chickens to avian leukosis virus infection and tumors. | the role of contact and genetic transmission of endogenous virus-21 (ev21) on response of chickens to avian leukosis virus (alv) infection and tumors was studied. f1 progeny of a cross between rprl late-feathering (lf) line ev21+ males and rprl early feathering (ef) line 15b1 females harboring or lacking ev21 were used. the ef chicks lacking ev21 were inoculated with a field strain of subgroup a alv at hatch and contact exposed to lf, ev21+ hatchmates for various time intervals. in a second expe ... | 1997 | 9200232 |
| use of reverse transcriptase polymerase chain reaction for detection of vaccine contamination by avian leukosis virus. | a reverse transcriptase polymerase chain reaction (rt-pcr) for avian leukosis virus (alv) was developed for the detection of contamination of vaccines produced in embryonated eggs and cell cultures derived from chicken. alv is highly pathogenic and induces a wide spectrum of disease in infected animals. alv can be divided into five subgroups (a-e). the envelope glycoprotein (env gp85) is the main antigen determinant and responsible for subgroup classification. viral rna of all subgroups (a-e) wa ... | 1997 | 9220392 |
| vbp and rela regulate avian leukosis virus long terminal repeat-enhanced transcription in b cells. | the avian leukosis virus (alv) long terminal repeat (ltr) contains a compact transcription enhancer that is active in many cell types. a major feature of the enhancer is multiple ccaat/enhancer element motifs that could be important for the strong transcriptional activity of this unit. the contributions of the three ccaat/enhancer elements to ltr function were examined in b cells, as this cell type is targeted for alv tumor induction following integration of ltr sequences next to the c-myc proto ... | 1997 | 9223487 |
| minimal truncation of the c-myb gene product in rapid-onset b-cell lymphoma. | oncogenic activation of c-myb by insertional mutagenesis has been implicated in rapid-onset b-cell lymphomas induced by the nonacute avian leukosis virus eu-8. in these tumors, proviruses are integrated either upstream of the c-myb coding region or within the first intron of c-myb. tumors with either type of integration contained identical chimeric mrnas in which the viral 5' splice site was juxtaposed to the 3' splice site of c-myb exon 2 and myb exon 1 was eliminated. both classes of integrati ... | 1997 | 9261372 |
| genetic determinant of rapid-onset b-cell lymphoma by avian leukosis virus. | infection of 10 day-old chicken embryos with the recombinant avian leukosis virus (alv) eu-8 induces a high incidence of rapid-onset b-cell lymphoma by insertional activation of the c-myb gene. lr-9, a related alv with differences from eu-8 in the gag and pol genes, induces rapid-onset lymphoma at only a low incidence. to localize the viral determinant(s) responsible for this biologic difference, we constructed and tested a series of reciprocal chimeras between eu-8 and lr-9 alvs. the ability to ... | 1997 | 9261373 |
| viral diseases of the immune system and strategies to control infectious bursal disease by vaccination. | viral infections which are immunosuppressive can affect the economics of poultry production, often as a result of the chicken's increased susceptibility to secondary infections and sub-optimal response to vaccinations. the mechanism of this immunosuppression has been studied in detail for certain chicken viruses. the replicating virus can have both direct and indirect effects on the cells of the immune system. the special role of the bursa of fabricius, as a lympho-epithelial organ, will be ment ... | 1997 | 9276986 |
| avian tumor viruses: persistent and evolving pathogens. | most neoplasias of lymphoid and other hematopoietic cells in commercial poultry are caused by viruses which belong to one of four distinct groups. marek's disease virus (mdv) is an oncogenic herpesvirus. avian leukosis virus (alv), reticuloendotheliosis virus (rev) and lymphoproliferative disease virus (lpdv) are oncogenic retroviruses. each group is distinguished by nucleic acid type, molecular structure, antigenicity, epidemiology, host range and other characteristics. however, most of these v ... | 1997 | 9276987 |
| selection of an avian retrovirus mutant with extended receptor usage. | receptor recognition by avian retroviruses is thought to involve the interaction of two regions of the su protein, hr1 and hr2, with the host cell surface receptor. these regions exhibit considerable variation, concordant with differences in receptor usage among the many avian leukosis virus subgroups. we hypothesize that some retroviruses have altered receptor usage in response to selective pressures imposed by receptor polymorphisms in their hosts. to test this hypothesis, we passaged td-pr-rs ... | 1997 | 9311868 |
| identification of a cellular receptor for subgroup e avian leukosis virus. | genetic studies in chickens and receptor interference experiments have indicated that avian leukosis virus (alv)-e may utilize a cellular receptor related to the receptor for alv-b and alv-d. recently, we cloned car1, a tumor necrosis factor receptor (tnfr)-related protein, that serves as a cellular receptor for alv-b and alv-d. to determine whether the cellular receptor for alv-e is a car1-like protein, a cdna library was made from turkey embryo fibroblasts (tefs), which are susceptible to alv- ... | 1997 | 9326659 |
| some chickens which are viraemic with subgroup j avian leukosis virus have antibody-forming cells but no circulating antibody. | new immunoperoxidase-based assays for splenic igg -antibody-forming cells (afc) and serum igg-antibody were used to look for antibody to hprs-103 in meat-type birds. meat type birds are known to be less likely to produce neutralising antibody and to be less likely to clear virus from their serum than layer-type birds after infection at hatch. in this work all 12 of the brown leghorn layer-type birds and 5/12 of the line 21 meat-type birds had produced afc and serum antibody and had cleared serum ... | 1997 | 9368962 |
| a low incidence of histiocytic sarcomatosis associated with infection of chickens with the hprs-103 strain of subgroup j avian leukosis virus. | ten cases of histiocytic proliferative lesions in meat-type chickens associated in low incidence with infection by subgroup j avian leukosis virus (alv) are described. six were field cases in adult chickens from naturally infected flocks and four were from younger birds from transmission experiments with hprs-103 alv or the related acutely transforming alv strains 17 and 879. the lesions were observed mostly in the spleen and in some cases in other organs. microscopically, the lesions were compr ... | 1997 | 9454931 |
| homologous modification of human chromosomal genes in chicken b-cell x human microcell hybrids | chicken cell lines derived from avian leukosis virus-induced b-cell tumors are highly recombination-proficient. in these cells, homologous recombination between transfected dna sequences and the corresponding chromosomal alleles occurs at high frequency, and targeting efficiencies of 10-90% can be obtained. we previously described a chromosome shuttle approach in which these cells can be used to modify human chromosomal alleles at high efficiency. in this method, marked human chromosomes are tra ... | 1996 | 9245343 |
| expression of transduced genes in mice generated by infecting blastocysts with avian leukosis virus-based retroviral vectors. | transgenic mouse lines have been developed that express the tv-a receptor under the control of the chicken beta-actin promoter. these mice express the tv-a receptor in most or all tissues and in the early embryo. an avian leukosis virus (alv)-based retroviral vector system was used for the efficient delivery of genes into preimplantation mouse embryos from these transgenic lines. experimental animals could be generated quickly and easily by infecting susceptible blastocysts with alv-based retrov ... | 1996 | 8643506 |
| identification of efiv, a stable factor present in many avian cell types that transactivates sequences in the 5' portion of the rous sarcoma virus long terminal repeat enhancer. | we define a protein complex present in avian nuclear extracts that interacts with the schmidt-ruppin strain of the rous sarcoma virus (rsv) long terminal repeat (ltr) between positions -197 and -168 relative to the transcriptional start site. we call this complex efiv and demonstrate that the efiv protein(s) is present in several avian cell types examined, including b cells (s13 and dt40), t cells (msb), and chicken embryo fibroblasts. we also report that the efiv binding site activates transcri ... | 1996 | 8523553 |
| infectious agents and environmental factors in lymphoid malignancies. | a strong association was found to exist between patterns of lymphoid malignancies and socioeconomic status. b-cell lymphomas and t-acute lymphoblastic leukemia are much more prevalent in developing countries where the chances of acquiring infections especially at a younger age are high. b-cell precursor acute lymphatic leukemia, however, are much more prevalent in the western world. many infectious agents are associated with lymphatic malignancies. epstein-barr virus is involved in african burki ... | 1996 | 8813340 |
| intratesticular inoculation of avian leukosis virus (alv) in chickens--production of neutralizing antibodies and lack of virus shedding into semen. | in order to investigate the possibility of producing transgenic chickens by injection of avian leukosis virus-based vectors into testis, we have analyzed the infection rate of testicular cells following inoculation of rous-associated virus type 1 (rav-1) into the gonads of adult and 1-wk-old brown leghorn males. viroproduction, neutralizing antibody production, and vital dna presence in testis, blood, muscle, and semen were analyzed at various times after infection. inoculation of rav-1 into the ... | 1996 | 8980816 |
| an outbreak of lymphomas in commercial broiler breeder chickens vaccinated with a fowlpox vaccine contaminated with reticuloendotheliosis virus. | gross and microscopic examinations of affected tissues from chickens of two commercial broiler breeder flocks aged 27 and 31 weeks revealed lesions of visceral lymphomas with bursal involvement in some chickens. reticuloendotheliosis virus (rev), but not avian leukosis virus (alv), was isolated from blood of affected chickens. furthermore, dna extracted from tumours tested positive for rev, but not for alv or marek's disease virus by polymerase chain reaction (pcr) test. attempts to determine th ... | 1996 | 18645835 |
| development of an alloantiserum (r2) that detects susceptibility of chickens to subgroup e endogenous avian leukosis virus. | an alloantiserum, termed r2, specifically agglutinates red blood cells (rbc) from line 100b chickens that are susceptible to avian leukosis viruses (alv) belonging to subgroups b and e, but does not agglutinate rbc from congenic inbred line 7(2) chickens that are resistant to alv b and e. the r2 antigen was also detected on lymphocytes and thrombocytes. using chickens from a special cross, it was found that r2 reactivity requires that the chickens must: (1) be susceptible to infection by alv-e; ... | 1996 | 18645878 |
| endogenous viral genes influence infection with avian leukosis virus. | the influence of endogenous viral (ev) genes on avian leukosis virus (alv) infection was studied in alv-free white leghorn chickens exposed to chicks from alv shedding dams. the study included four lines, each segregating for one ev gene, one line free of ev genes, and four commercial stocks segregating for a number of ev genes. genes ev12 and ev21 that produce the complete endogenous virus were associated with significant reductions in antibody response to alv. in commercial stocks with ev21 in ... | 1995 | 18645822 |
| production of avian leukosis virus particles in mammalian cells can be mediated by the interaction of the human immunodeficiency virus protein rev and the rev-responsive element. | in human immunodeficiency virus type 1-infected cells, the efficient expression of viral proteins from unspliced and singly spliced rnas is dependent on two factors: the presence in the cell of the viral protein rev and the presence in the viral rna of the rev-responsive element (rre). we show here that the hiv-1 rev/rre system can increase the expression of avian leukosis virus (alv) structural proteins in mammalian cells (d-17 canine osteosarcoma) and promote the release of mature alv virions ... | 1995 | 8524879 |
| a recombinant fowlpox virus expressing the envelope antigen of subgroup a avian leukosis/sarcoma virus. | a recombinant fowlpox virus (fpv) was constructed by inserting cloned sequences from schmidt-ruppin subgroup a avian sarcoma virus coding for the viral envelope (env) antigen into a nonessential region of fpv dna downstream from a synthetic promoter. sera from chickens hyperimmunized with the recombinant fpv neutralized the infectivity of the homologous subgroup a virus (rcasbp/ap) but only weakly neutralized the infectivity of rous sarcoma virus, another subgroup a avian leukosis virus. similar ... | 1995 | 8561735 |
| genomic analysis of collagen and endogenous virus loci in the ucd-200 and 206 lines of chickens, animal models for scleroderma. | university of california at davis (ucd) lines 200 and 206 chickens develop a hereditary systemic scleroderma-like connective tissue disease characterized by severe lymphocytic infiltration and excessive accumulation of collagen in skin and internal organs. the immune system seems to play an important role in the development and/or perpetuation of this condition. the main goal of our work with this strain is the investigation of interactions between endothelial cells, lymphocytes, macrophages and ... | 1995 | 8579730 |
| amino acid investigations of tumor-associated antigen of mc31 transformed cells. | there are numerous evidences (mainly indirect) for the presence of tumor-associated surface antigens (tasa) in cells transformed by avian oncornaviruses. hayami, et al. (1977) and ignjatovic et al. (1978) established that such antigens on avian leukosis virus (alv) cells have neither virus, nor oncofetal origin. on leukosis virus strain mc31-transformed turkey cells, filchev and ivanov (1986) and wesselinova (1989, 1991) also describe a tasa. but there are only a few studies on the nature and pr ... | 1995 | 8590434 |
| germline transmission of exogenous genes in chickens using helper-free ecotropic avian leukosis virus-based vectors. | we have used vectors derived from avian leukosis viruses to transduce exogenous genes into early somatic stem cells of chicken embryos. the ecotropic helper cell line, isolde, was used to generate stocks of nl-b vector carrying the neo(r) selectable marker and the escherichia coli lacz gene. microinjection of the nl-b vector directly beneath unincubated chicken embryo blastoderms resulted in infection of germline stem cells. one of the 16 male birds hatched (6.25%) from the injected embryos cont ... | 1995 | 7581517 |
| influence of the alv6 recombinant avian leukosis virus transgene on production traits and infection with avian tumor viruses in chickens. | the biological costs of the alv6 recombinant transgene that in chickens induces dominant resistance to the subgroup a avian leukosis virus (alv), in terms of effects on production traits, were studied. four generations of white leghorn chickens of line tr, segregating for alv6 but free of endogenous viral genes, as well as two generations of crosses between tr and ottawa line wg (wgtr) were tested under a specific-pathogen-free environment. in the birds studied, the transgene appeared unchanged ... | 1995 | 7603962 |
| functional analysis of avian class i (bfiv) glycoproteins by epitope tagging and mutagenesis in vitro. | similarities between the physical structures of avian and mammalian major histocompatibility complex (mhc) class i glycoproteins have been proposed based on comparative alignment of their amino acid sequences. to investigate the physical structure of the chicken class i glycoprotein, we cloned the cdna representing the bfiv locus of the b21 haplotype. a unique, chimeric class i glycoprotein was constructed by incorporating an epitope tag (flag) at the n terminus. monoclonal antibodies to the fla ... | 1995 | 7621880 |
| virofection: a one-step procedure for using replication-defective retrovirus vectors. | virofection is a simple new way to use replication-defective vectors. it consists of the cotransfection of two plasmids: one plasmid bearing the genome of the replication-defective retrovirus vector and a second "helper" plasmid expressing the gag, pol, and env retrovirus sequences. it provides stable integration into the chromosome and long-term expression of only vector-borne sequences. we present here several helper plasmids derived from avian leukosis viruses, which we have used for the viro ... | 1995 | 7645216 |
| in vitro analysis of a primary, major histocompatibility complex (mhc)-restricted, cytotoxic t-lymphocyte response to avian leukosis virus (alv), using target cells expressing mhc class i cdna inserted into a recombinant alv vector. | the interaction between the major histocompatibility complex (mhc) and cytotoxic t lymphocytes (ctls) is an important component of the host's resistance to viral infections and tumor formation. in this study, an avian leukosis virus (alv) vector system, rcasbp, expressing mhc chicken class i (b-f) cdna was used to develop target cells expressing the chicken class i glycoproteins complexed with alv antigens on the cell surface. peripheral blood from chickens inoculated with alv was shown to conta ... | 1995 | 7666545 |
| hprs-103 (exogenous avian leukosis virus, subgroup j) has an env gene related to those of endogenous elements eav-0 and e51 and an e element found previously only in sarcoma viruses. | the avian leukosis and sarcoma virus (alsv) group comprises eight subgroups based on envelope properties. hprs-103, an exogenous retrovirus recently isolated from meat-type chicken lines, is similar to the viruses of these subgroups in group antigen but differs from them in envelope properties and has been assigned to a new subgroup, j. hprs-103 has a wide host range in birds, and unlike other nontransforming alsvs which cause late-onset b-cell lymphomas, hprs-103 causes late-onset myelocytomas. ... | 1995 | 7815543 |
| structure and expression of endogenous retroviral sequences in the permanent lmh chicken cell line. | from dna mapping data, four endogenous proviral loci have been observed in the chicken permanent cell line lmh. the locus corresponding to endogenous virus (ev) ev1 is present in duplicate whereas the locus corresponding to ev3 is present in one copy. the other loci are probably ev6 and a solitary long terminal repeat. a rna northern blot analysis revealed both ev3 and ev6 transcripts but no ev1 transcript was detected. using avian leukosis virus (alv)-based vectors, transcomplementing assays we ... | 1995 | 7899200 |
| effect of serotype 2 and 3 marek's disease vaccines on the development of avian leukosis virus-induced pre-neoplastic bursal follicles. | the effect of serotype 2 and 3 marek's disease virus (mdv) vaccines on the development of pre-neoplastic bursal lesions induced by two strains of subgroup a avian leukosis virus (alv) was studied. chickens of line 15i5 x 7(1) susceptible to alv-induced lymphoma were inoculated at hatch with rous-associated virus-1 (rav-1) or strain rpl-40 of subgroup a alv. all chickens, except for negative controls, were also inoculated at hatch with strain 301b/1 of serotype 2 mdv or strain fc126 of turkey her ... | 1995 | 8719208 |
| sequence of host-range determinants in the env gene of a full-length, infectious proviral clone of exogenous avian leukosis virus hprs-103 confirms that it represents a new subgroup (designated j). | a genomic dna library was constructed, in a bacteriophage lambda vector, from line 0 chick embryo fibroblasts (cefs) infected with hprs-103, an exogenous avian leukosis virus (alv; envelope subgroup j) recently isolated from meat-type chickens. the library was screened at high stringency using a full length rav-1 (subgroup a) proviral probe. from 10(6) plaques, two clones which hybridized strongly to the rav-1 probe were isolated; one contained a full-length copy of the proviral genome of hprs-1 ... | 1995 | 7844530 |
| reflections on the pathogenesis of diseases caused by the acute avian leukosis/sarcoma viruses with special reference to avian erythroblastosis. | the various diseases that follow experimental infection with the acute and non-acute avian oncoviruses are discussed with special reference to the pathogenesis of avian erythroblastosis. one view, based on in vitro studies, sees erythroblastosis as the product of a failure in the differentiation of virus-infected stem cells to mature erythrocytes, as a result of cell 'transformation'. the results of some in vivo studies, however, point to a resemblance of the disease to a haemolytic anaemia, whe ... | 1994 | 7863611 |
| art-ch: a vl30 in chickens? | the complete sequence of art-ch, a recently found chicken retrotransposon (a. v. gudkov, e. a. komarova, m. a. nikiforov, and t. e. zaitsevskaya, j. virol. 66:1726-1736, 1992), was characterized. art-ch has the structure of a 3,300-bp-long provirus, including two 388-bp long terminal repeats (ltrs) (u3, 245 bp; r region, 17 bp; and u5, 126 bp), a trna(trp)-binding site, and a polypurine tract, similar to avian leukosis viruses. at least some of the approximately 50 genomic copies of art-ch are t ... | 1994 | 7904657 |
| a system for tissue-specific gene targeting: transgenic mice susceptible to subgroup a avian leukosis virus-based retroviral vectors. | avian leukosis viruses (alvs) have been used extensively as genetic vectors in avian systems, but their utility in mammals or mammalian cell lines is compromised by inefficient viral entry. we have overcome this limitation by generating transgenic mice that express the receptor for the subgroup a alv under the control of the chicken alpha sk-actin promoter. the skeletal muscles of these transgenic animals are susceptible to efficient infection by subgroup a alv. because infection is restricted t ... | 1994 | 7972042 |
| replication of an osteopetrosis-inducing avian leukosis virus in fibroblasts, osteoblasts, and osteopetrotic bone. | avian leukosis virus (alv)-induced osteopetrosis is caused by the abnormal growth and differentiation of osteoblasts. to evaluate the role of infection in osteopetrosis induction, the replication of an osteopetrosis-inducing virus (br21) has been compared in osteopetrotic bone, calvarial-derived osteoblasts, and chick embryo fibroblasts. much higher levels of infection occurred in diseased bone than in the cultures. severe cases of osteopetrosis contained 10 times more viral dna, 30 times more m ... | 1994 | 7975214 |
| integration of multiple chicken retroviruses into multiple chicken herpesviruses: herpesviral gd as a common target of integration. | integration of two different avian retroviruses, reticuloendotheliosis virus (rev) and avian leukosis virus (alv), into the genome of two different avian herpesviruses, the herpesvirus of turkeys (hvt) and marek's disease virus (mdv), was investigated. integration events occurred by the fourth and sixth in vitro passage of cells coinfected with rev/hvt and alv/mdv, respectively. in order to further characterize the integration events, integrated proviruses and surrounding herpesviral genetic mat ... | 1994 | 8030268 |
| the vbp and a1/ebp leucine zipper factors bind overlapping subsets of avian retroviral long terminal repeat ccaat/enhancer elements. | two long terminal repeat (ltr) enhancer-binding proteins which may regulate high rates of avian leukosis virus (alv) ltr-enhanced c-myc transcription during bursal lymphomagenesis have been identified (a. ruddell, m. linial, and m. groudine, mol. cell. biol. 9:5660-5668, 1989). the genes encoding the a1/ebp and a3/ebp binding factors were cloned by expression screening of a lambda gt11 cdna library from chicken bursal lymphoma cells. the a1/ebp cdna encodes a novel leucine zipper transcription f ... | 1994 | 8083963 |
| gene conversion in the chicken immunoglobulin locus: a paradigm of homologous recombination in higher eukaryotes. | gene conversion was first defined in yeast as a type of homologous recombination in which the donor sequence does not change. in chicken b cells, gene conversion builds the antigen receptor repertoire by introducing sequence diversity into the immunoglobulin genes. immunoglobulin gene conversion continues at high frequency in an avian leukosis virus induced chicken b cell line. this cell line can be modified by homologous integration of transfected dna constructs offering a model system for stud ... | 1994 | 8143801 |
| transcriptional regulation of alv bursal lymphomagenesis. | avian leukosis virus (alv) induces bursal lymphoma in chickens after rare integration of proviral long terminal repeat (ltr) sequences next to the c-myc proto-oncogene. labile ltr-binding proteins are essential for c-myc hyperexpression, since ltr-enhanced transcription, as well as the activity of the ltr-binding proteins, is specifically decreased following protein synthesis inhibition. this lability is restricted to hematopoetic cells of alv-susceptible chicken strains, suggesting that the lab ... | 1994 | 8152295 |
| diseases and management of backyard chicken flocks in chitungwiza, zimbabwe. | to gather information on backyard chicken flocks in chitungwiza, an urban center in zimbabwe, 85 flock owners were interviewed. the mean flock size was 53 birds (range 1-650), and most birds were kept for meat, for either domestic consumption or local sale. mean age at slaughter was 12.4 weeks (range 8-24). none of the owners vaccinated their birds, and reported mortality rates were high (mean 25%), most commonly being associated with diseases causing eye and respiratory problems. most owners co ... | 1994 | 7832719 |
| consistent chromosomal aberration in cell lines transformed with marek's disease herpesvirus: evidence of genomic dna amplification. | a specific chromosomal aberration was observed in 14 of 15 avian lymphoblastoid cell lines transformed with marek's disease herpesvirus. this aberration, designated dup(1p)(p22-p23), appeared as an extra g-positive band and interband on the short arm of one chromosome i homolog. using fluorescent in situ hybridization, we identified amplified genomic dna sequences in this region. this amplification involves sequences linked to an endogenous retrovirus locus and genes in the histone multigene fam ... | 1993 | 8390410 |
| recovery of acutely transforming viruses from myeloid leukosis induced by the hprs-103 strain of avian leukosis virus. | viruses rapidly able to transform cultured chicken bone marrow cells have been isolated from cases of myelocytic myeloid leukosis (mml) induced experimentally by the hprs-103 strain of avian leukosis virus, and from field cases of mml. hprs-103 virus itself did not acutely transform cultured bone-marrow cells. these findings suggest that during myeloid leukemogenesis by hprs-103 virus, recombinant viruses are generated with transduced cellular oncogenes. the transformed cell appeared to be a mac ... | 1993 | 8395801 |
| research note: a rapid method for the detection of the rous-associated endogenous solitary long terminal repeat, ev15. | a rapid method has been developed for the detection of the solitary long terminal repeat ev15, a member of the avian leukosis virus (alv) family of endogenous viral elements (ev genes) in chickens. detection is accomplished by a polymerase chain reaction (pcr) assay that can be performed on purified genomic dna samples or crude preparations of partially purified whole blood lysates. the test discriminates unambiguously between birds that are homozygous ev15-, homozygous ev15+, or heterozygous ev ... | 1993 | 8397393 |
| detection of reticuloendotheliosis virus infection using the polymerase chain reaction. | the polymerase chain reaction (pcr) was shown to be a sensitive and useful method for detection of infection by members of the group of avian reticuloendotheliosis virus (rev). genomic dna extracted from chick embryo fibroblasts (cefs), blood and tumours of chickens experimentally infected with the spleen necrosis virus (snv) strain of rev was used as the target for chain elongation. deoxyoligonucleotide primers that encompass a portion of the unique 3', repeat and unique 5' region of the long t ... | 1993 | 18671039 |
| effects of age at infection with serotype 2 marek's disease virus on enhancement of avian leukosis virus-induced lymphomas. | inoculation of susceptible, 15i5 x 7i chickens with serotype 2 marek's disease virus (mdv) at various ages had no influence on the development of avian leukosis virus (alv)-induced viraemia or antibody in chickens infected with alv and turkey herpesvirus (hvt) at hatch. however, the incidence of alv-induced lymphoma (ll) was significantly higher in chickens infected with alv and hvt at hatch and inoculated with serotype 2 mdv up to 6 weeks of age than in chickens receiving serotype 2 mdv at 8 to ... | 1993 | 18671041 |
| endogenous leukosis viral antigen in eggs from meat-type chickens on an avian leukosis virus eradication programme. | in an effort to eliminate exogenous avian leukosis virus (alv) from a susceptible population, albumen of one egg per hen from each of four generations was tested by elisa for group-specific antigen (gsa) of leukosis/sarcoma viruses. from 1510 to 2099 hens were tested in each generation. hens were not used as breeders if optical density readings for gsa were 0.4 or greater. despite this procedure, there was no appeciable change in the occurrence of gsa in eggs from one generation to the next and ... | 1992 | 18670937 |
| feather pulp as a source of antibody to avian viruses. | feather pulp from white leghorns that had been inoculated with the rav-1 strain of avian leukosis virus (alv) was tested for antibody by elisa. in an elisa on three feather pulps and serum from each of four inoculated chickens, there was a highly significant correlation between antibody levels in feather pulp (1 pulp per 800 mul of buffer) and a 1:500 dilution of serum. also based on elisa, there were highly significant correlations between levels of maternal and actively acquired antibody to ne ... | 1992 | 18670946 |
| activation of the c-myb locus is insufficient for the rapid induction of disseminated avian b-cell lymphoma. | we have previously reported that infection of 9- to 13-day-old chicken embryos with rav-1 results in rapid development of a novel b-cell lymphoma in which proviral insertion has activated expression of the c-myb gene (e. pizer and e. h. humphries, j. virol. 63:1630-1640, 1989). the biological properties of these b-cell lymphomas are distinct from those associated with the b-cell lymphomas that develop following avian leukosis virus proviral insertion within the c-myc locus. in an extension of th ... | 1992 | 1309260 |
| art-ch, a new chicken retroviruslike element. | a 3' region of a previously unknown retroviruslike element named art-ch (avian retrotransposon from chicken genome) was obtained in the course of polymerase chain reaction-mediated cloning of avian leukosis virus long terminal repeats (ltrs) from dnas of infected chicken cells. about 50 copies of art-ch are present in the genome of chickens of different breeds. art-ch is not found in dna of quails, ducks, turkeys, or several other birds tested. the art-ch element is about 3 kb in size, including ... | 1992 | 1310773 |
| sporadic congenital transmission of avian leukosis virus in hens discharging the virus into the oviducts. | the efficacy of the albumen test for infectious avian leukosis virus (alv) was examined in detecting congenitally transmitting hens. seventy-three white leghorn non-viremic hens with antibody to alv were used. eleven of the hens shed infectious alv into their egg albumen, whereas only 7 of the 11 alv-positive hens shed alv antigens. the egg albumen test for infectious alv was shown to be more effective in detecting the congenitally transmitting hens than that for alv antigens. then, twenty of th ... | 1992 | 1313708 |
| a transgene, alv6, that expresses the envelope of subgroup a avian leukosis virus reduces the rate of congenital transmission of a field strain of avian leukosis virus. | a major mode of transmission of avian leukosis virus (alv) is from a dam that is viremic with and immunologically tolerant to alv, through the egg to the progeny. the authors have produced a line of chickens transgenic for a defective alv provirus that expresses envelope glycoprotein, but not infectious virus, and is very resistant to infection with subgroup a alv. in the present experiment the authors sought to prevent or reduce congenital transmission by mating viremic-tolerant hens to males c ... | 1992 | 1319049 |
| association of the major histocompatibility complex with avian leukosis virus infection in chickens. | 1. association of the b blood group, the major histocompatibility complex (mhc) in chickens, with avian leukosis virus (alv) infection shown by shedding of group-specific (gs) antigen was studied in an australorp line selected for short oviposition interval to improve egg production. three haplotypes (b8a, b9a and b21) were segregating in this line at frequencies of 66.7, 15.6 and 17.8%, respectively, averaged over three generations. 2. the relative risk (odds ratio) of a hen becoming a gs-antig ... | 1992 | 1322760 |
| endogenous viral gene distribution in populations of meat-type chickens. | the present study was designed to document the complexity of endogenous viral (ev) genes and seek evidence for their association with production traits in selected and control strains of meat-type chickens. three populations were studied, each consisting of a control strain and one to three strains selected for various production traits. the ev genes were revealed by digesting genomic dna with restriction enzymes and detecting dna fragments on southern blots using radioactive probes from nucleot ... | 1992 | 1326106 |
| in situ expression of helper-free avian leukosis virus (alv)-based retrovirus vectors in early chick embryos. | defective avian leukosis-based vectors expressing the bacterial lacz gene were used as helper-free preparations to infect early stage brown-leghorn embryos. both in toto x-gal staining and dna analysis using southern blot technique were applied to detect virus integration and expression. our results demonstrate a low efficiency of in vitro infection in early stages of embryonic development. southern blot analysis reveals that only 1% of embryonic cells integrate the vector genome after infection ... | 1992 | 1326313 |
| persistence of marek's disease virus in a subpopulation of b cells that is transformed by avian leukosis virus, but not in normal bursal b cells. | previous studies have described an augmentation of avian leukosis virus (alv)-induced lymphoid leukosis in chickens that were coinfected with a serotype 2 marek's disease virus (mdv) strain, sb-1. as a first step toward understanding the mechanism of this augmentation, we have analyzed the tropism of the mdv for the alv-transformed b cell. after hatching, chickens were coinfected with alv and a nonpathogenic strain of mdv, sb-1. seventy primary and metastatic alv-induced lymphomas that developed ... | 1992 | 1326647 |
| effect of avian leukosis virus infection on productivity of layers. | 1992 | 1327184 | |
| a1/ebp: a leucine zipper protein that binds ccaat/enhancer elements in the avian leukosis virus long terminal repeat enhancer. | avian leukosis virus (alv) induces bursal lymphoma in chickens after integration of proviral long terminal repeat (ltr) enhancer sequences next to the c-myc proto-oncogene. labile ltr-binding proteins appear to be essential for c-myc hyperexpression, since both ltr-enhanced transcription and the activities of ltr-binding proteins are specifically decreased after inhibition of protein synthesis (a. ruddell, m. linial, w. schubach, and m. groudine, j. virol. 62:2728-2735, 1988). this lability is r ... | 1992 | 1328681 |
| differentiation of pathogenic and non-pathogenic serotype 1 marek's disease viruses (mdvs) by the polymerase chain reaction amplification of the tandem direct repeats within the mdv genome. | there are no simple, direct methods to reliably distinguish oncogenic serotype 1 marek's disease viruses (mdvs) from their attenuated variants. the present study was an attempt to apply polymerase chain reaction (pcr) to develop a rapid and sensitive assay for the presence of the mdv genome. pcr oligos were chosen to flank the 132-base-pair tandem direct repeats in the serotype 1 mdv genome. the pcr reaction was specific for serotype 1 mdvs, amplifying fragments corresponding to one to three cop ... | 1992 | 1329706 |
| myeloid leukaemogenicity and transmission of the hprs-103 strain of avian leukosis virus. | the hprs-103 strain of avian leukosis virus (alv) was isolated recently from meat-type chickens and represents a new envelope subgroup. its oncogenicity has been studied in three meat-type and five leghorn strains of chickens. in the meat-type strains, the virus, following embryonal inoculation, induced an overall incidence of 27% myelocytic myeloid leukosis (myelocytomatosis) and 12% renal adenomas, with long median latent periods. amongst the leghorn lines, these tumors occurred with similar i ... | 1992 | 1331625 |
| rag-2 expression is not essential for chicken immunoglobulin gene conversion. | chicken b cells diversify their immunoglobulin genes by gene conversion in the bursa of fabricius. the avian leukosis virus-induced b-cell line dt40 continues to diversify its immunoglobulin light chain locus by gene conversion during in vitro passage. since a variable(diversity)joining recombination-activating gene, rag-2, is specifically expressed in chicken b cells undergoing immunoglobulin gene conversion, it has been suggested that rag-2 may be involved in the immunoglobulin gene conversion ... | 1992 | 1570327 |
| detection of proviral dna and viral rna in various tissues early after avian leukosis virus infection. | using molecular biological techniques, a study was made of the tissue tropism of avian leukosis virus (alv) early after infection. two strains of chickens, one with and the other without endogenous viral genes, were infected with alv of subgroup a immediately after hatching; specimens of nine tissues and blood samples were analyzed at various times thereafter. a polymerase chain reaction (pcr), specific to alv subgroup a, was used to detect proviral dna and viral rna. in situ hybridization was u ... | 1992 | 1602809 |
| detection of avian leukosis virus antigens by the elisa and its use for detecting infectious virus after cultivation of samples and partial characterization of specific pathogen-free chicken lines maintained in this laboratory. | an enzyme-linked immunosorbent assay (elisa) for detecting avian leukosis virus (alv) antigens was developed with rabbit anti-alv serum. the elisa detected purified alv of subgroups a and b at a concentration of 0.4 ng/well and about 10(3) infectious units/well estimated by a resistance-inducing factor (rif) test, and antigens in culture fluids from chicken embryo fibroblasts infected with subgroups a, b or e of alv. these results showed that common antigens among the subgroups were detected by ... | 1991 | 1653036 |
| immune response and resistance to rous sarcoma virus challenge of chickens immunized with cell-associated glycoproteins provided with a recombinant avian leukosis virus. | the rous-associated virus 1 env gene, which encodes the envelope gp85 and gp37 glycoproteins, was isolated and inserted in place of the v-erbb oncogene into an avian erythroblastosis virus-based vector, carrying the neo resistance gene substituted for the v-erba oncogene, to generate the pnea recombinant vector. a helper-free virus stock of the pnea vector was produced on an avian transcomplementing cell line and used to infect primary chicken embryo fibroblasts (cefs) or quail qt6 cells. these ... | 1991 | 1654445 |
| the influence of ev6 on the immune response to avian leukosis virus infection in rapid-feathering progeny of slow- and rapid-feathering dams. | endogenous virus (ev) locus ev6 encodes only virus envelope glycoprotein. the influence of ev6 on the immune response to contact infection with hatchmates infected with avian leukosis virus (alv) was compared in replicate hatches. the alv subgroup e-resistant, rapid-feathering (rf) female chickens produced by slow-feathering (sf) and rf dams with and without ev6 were exposed at hatch to hatchmates infected with alv subgroup a (strain rpl-40). the rpl-40 viremia, shedding, and virus neutralizing ... | 1991 | 1656418 |
| influence of maternal antibody on avian leukosis virus infection in white leghorn chickens harboring endogenous virus-21 (ev21). | slow-feathering (sf) white leghorn dams harboring the endogenous viral gene ev21, which encodes for complete endogenous virus-21 (ev21), and rapid-feathering (rf) dams lacking ev21 were immunized with a live field strain of avian leukosis virus (alv) subgroup a. one group of sf dams and one group of rf dams were not immunized and were maintained to produce chicks lacking maternal alv antibody. when the sf dams were crossed with line 15b1 males, the resulting male progeny were sf, ev21-positive, ... | 1991 | 1659362 |
| inhibition of proliferation of primary avian fibroblasts through expression of histone h5 depends on the degree of phosphorylation of the protein. | to obtain stable and constitutive expression of histone h5 at levels comparable to those observed in normal chicken erythrocytes, an avian self-inactivating retroviral vector was used to transfer the h5 gene into cells which do not express this protein. the vector, pdah5, was obtained by removing the caat and tata boxes of the 3'ltr of the avian leukosis virus rav-2 and inserting the h5 sequence. infection of qt6 quail cells with the recombinant virus (dah5) led to the stable integration of the ... | 1991 | 1849905 |
| a novel subgroup of exogenous avian leukosis virus in chickens. | an avian leukosis virus with a wide host range belonging to a new subgroup for chickens was isolated from meat-type chicken lines. the virus, of which hprs-103 strain is the prototype, was of low oncogenicity in chickens but appeared to behave like an exogenous leukosis virus. neutralizing antibodies to the virus were found in three of five meat-type chicken lines, but not in seven layer lines. the virus and its rous sarcoma virus pseudotype did not replicate in, or transform, mammalian cells. | 1991 | 1849967 |
| increased ratio of targeted to random integration after transfection of chicken b cell lines. | constructs of four different genetic loci were transfected into the avian leukosis virus-induced chicken b cell line dt40, which continues diversification of its rearranged light chain immunoglobulin gene by gene conversion. analysis of stable transfectants revealed an unexpectedly high frequency of targeted integration into the homologous gene loci of dt40. transcriptional activity of the target gene locus is not required, since a construct of the untranscribed ovalbumin gene also integrated pr ... | 1991 | 1913816 |
| response of meat-type chickens to infection with rav-1 avian leukosis virus. | meat-type and white leghorn chickens were inoculated with the rav-1 strain of avian leukosis virus at 1 day of age and the severity of infection was assessed by clinical illness, haematology and post-mortem findings. the following were examined from selected birds: histological section for chronic mononuclear myocarditis, immunohistochemically-stained sections of myocardium, spleen, bursa of fabricius and kidney for group-specific viral antigen, and ultrathin sections of these tissues for virus ... | 1991 | 18680061 |
| retroviral expressed hemagglutinin-neuraminidase protein protects chickens from newcastle disease virus induced disease. | the hemagglutinin-neuraminidase (hn) gene and the phosphoprotein (p) gene of newcastle disease virus (ndv) were inserted into a replication competent avian leukosis virus vector. the expression of the hn gene from this vector in chick embryo cells has been previously reported. the p gene is also expressed from this vector in chick embryo cells. the retroviruses were used to immunize 4-week-old chickens. birds receiving the virus containing the hn gene developed low levels of serum hi titers and ... | 1990 | 1965848 |
| ongoing diversification of the rearranged immunoglobulin light-chain gene in a bursal lymphoma cell line. | the chicken immunoglobulin light-chain gene (igl) encodes only a single variable gene segment capable of recombination. to generate an immune repertoire, chickens diversify this unique rearranged vl gene segment during b-cell development in the bursa of fabricius. sequence analysis of igl cdnas suggests that both gene conversion events derived from vl segment pseudogene templates (psi vl) and non-template-derived single-base-pair substitutions contribute to this diversity. to facilitate the stud ... | 1990 | 2111450 |
| chronic myocarditis and circulatory syndrome in a white leghorn strain induced by an avian leukosis virus: light and electron microscopic study. | specific-pathogen-free white leghorn chickens were inoculated at 1 day of age with avian leukosis virus (alv, rav-1). all chickens in expt. 1, killed 33 or 64 days postinoculation, had focal chronic lymphocytic or lymphoplasmacytic myocarditis. among those held beyond 33 days, eight of 22 developed lesions in the myocardium that resulted in a chronic circulatory syndrome (ccs) typical of right-sided heart failure. chickens in expt. 2 were held for 210 days, and 21% of 125 developed ccs. in expt. ... | 1990 | 2157391 |
| preparation of a detailed restriction map of the avian leukosis virus mav-2(o). | unintegrated mav-2(o) dna was isolated from infected chicken embryo fibroblasts and inserted into the lambda bacteriophage vector lambda gtwes lambda b. three x 10(6) bacteriophage plaques were screened, yielding a total of seven clones, six of which contained dna representing the complete mav-2(o) genome. viral dna was isolated from four of the clones and was used to transfect chicken embryo fibroblasts. all four clones produced virus as monitored by reverse transcriptase assay. when the four c ... | 1990 | 2157399 |
| infrequent involvement of c-fos in avian leukosis virus-induced nephroblastoma. | to determine whether c-fos is involved in avian leukosis virus-induced nephroblastoma, 28 tumors from chickens were analyzed for novel fos fragments. dna from 1 of 16 clonal outgrowths (in chicken 6561) contained novel fos-related ecori and kpni fragments which hybridized to both v-fos and viral probes. oncogenicity tests using filtered 6561 tumor cell homogenates did not reveal a tumor-inducing transduction of c-fos. we conclude that c-fos is only an occasional target for proviral insertions or ... | 1990 | 2161956 |