Genetic analysis of Rous sarcoma virus (subgroup A) induced tumourigenesis and performance of synthetic broiler stocks in relation to group-specific antigen shedding (original) (raw)
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Veterinary Pathology, 2009
The role of subgroup J avian leukosis virus (ALV J) infection profile in the development of histiocytic sarcomatosis (HS) in chickens was evaluated using retrospective analysis of 2 experiments involving in ovo and at-hatch inoculation of commercial meat-type and ADOL line 0 chickens with 100 or 10,000 TCID 50 of various strains ALV J. HS was observed only in persistently viremic, meat-type chickens that were inoculated at hatch, but not in immunotolerized (persistently viremic, with no antibodies), in ovo inoculated chickens. However, the immunotolerized, in ovo inoculated chickens developed a high incidence of myeloid tumors. HS appeared to arise from the splenic ellipsoids and red pulp, and metastasized to liver, kidney, and other organs. The neoplastic cells were diffusely positive for ChL5, CD45, and MHC class II with multifocal infiltration of T and B lymphocytes. Expression of viral antigen gp85 within HS was very low compared with that noted in ALV J-induced myelocytomas. The above observations suggest that the mechanisms of oncogenesis of HS might be different from that of other ALV J-induced tumors.
Turkish Journal of Veterinary and Animal Sciences, 2006
The aim of this study was to investigate the presence of antibodies to ALV-J in broilers and broiler breeders. For this, 5 broiler units and 1 broiler breeding unit in the Marmara region were visited. Seventy 4-6-week-old chicks from the broiler units, consisting of 14 chicks from each broiler unit, were selected. Seventeen chickens from the broiler breeding unit were also selected. The chicks from the broiler units were necropsied and all internal organs were checked for the presence of tumors. Blood sera collected from all animals were analyzed for the presence of antibodies to avian leukosis virus subgroup-J (ALV-J) by a commercial ELISA (IDEXX). Growth retardation, depression, diarrhea and respiratory disorders were seen in chicks from the broiler units. No tumors were observed in the internal organs. However, pseudomembranes on the liver of 3 chicks and Gumboro-like lesions in the bursa of Fabricius in 5 chicks were seen. No antibodies to ALV-J were detected in any of the broiler chicks' sera. However, antibodies to ALV-J were detected in 13 (76%) of the17 broiler breeders, which indicates the necessity to apply eradication programs for ALV-J in breeding flocks in Turkey.
Journal of virology, 1991
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 infected cells, selected with G418 (CEF/NEA and QT6/NEA, respectively) were found to be resistant to superinfections with subgroup A retroviruses. The CEF/NEA preparations were used as a cell-associated antigen to inoculate adult chickens by the intravenous route compared with direct inoculations of NEA recombinant helper-free virus used as a cell-free antigen. Chickens injected with the cell-associated antigen (CEF/NEA) exhibited an immune response demonstrated by induction of high titers of...
Genetics Selection Evolution, 1994
DNA sequences related to avian leukosis virus (ev genes) were identified in the genome of chickens from 6 experimental strains including 3 randombred lines (Wyandotte, Fayoumi and White Leghorn), 2 divergently selected Rhode Island Red lines and a synthetic broiler line. Digestion of genomic DNA with Sad and BamHI enzymes and hybridization with either RAV-2 sequences or an LTR-gag probe revealed 66 different SacI bands, 53 of which could be associated with particular BamHI bands such that the ev loci could be defined at the molecular level. The distribution patterns were very strain-specific. Average band frequency and heterozygosity level could be correlated with the genetic history of the lines and their inbreeding level which varied from 0.04 to 0.28. Withinfamily segregation did not show any allelic relationship between retroviral insertions that were considered to be 2 genes. The Fayoumi line showed the largest variation in ev number per bird and contained a few birds free of any endogenous viral sequences, designated ev0. The broiler line showed the highest ev number. Very few ev loci were shared by different lines; only ev6 was found in all strains. Comparison with the established classification in White Leghorns was not straightforward and further analysis of DNA polymorphism and viral expression is needed. chicken / DNA polymorphism / genetic variability / endogenous retrovirus Résumé -Analyse comparative des gènes viraux endogènes apparentés aux virus leucosiques aviaires dans des lignées expérimentales de poule domestique. Les gènes viraux endogènes (ev) apparentés aux virus des leucoses et sarcomes aviaires ont été identifiés sur un échantillon de reproducteurs et de leurs descendants issus de 6 populations expérimentales de poule qui différaient par leur origine génétique (Leghorn blanche, Wyandotte, Fayoumi, 2 lignées de Rhode Island Red, une lignée synthétique de poule de chair notée Yll), leur niveau moyen de consanguinité (estimations de 0,04 à 0,28) et la sélection subie. La digestion de l'ADN génomique par les enzymes SacI ou BamHI suivie de l'hybridation avec les sondes RAV ou LTR-gag dérivées du virus du sarcome de Rous a révélé 66 fragments avec Sac7 dont 53 ont pu être associés avec un fragment BamHI afin de caractériser les gènes ev au niveau moléculaire. Chaque population a présenté une distribution qui lui est propre. Les différences de fréquences géniques et d'hétérozygotie sont assez bien reliées aux taua de consanguinité des populations. L'étude de la ségrégation familiale n'a montré aucune relation d'allélisme entre ce que nous avions considéré comme 2 gènes ev. Le nombre de gènes ev par animal était particulièrement variable dans la souche Fayoumi qui présentait quelques animaux sans copies virales endogènes (notés ev0). La souche Y11 a montré le plus grand nombre d'insertions virales. Les populations d'origine génétique différente ont très peu de gènes ev en commun ce qui n'a pas permis le calcul d'une distance génétique; seul le gène ev6 est partagé par toutes, fait remarquable dont la signification est discutée. Parmi les 53 loci identifiés avec 2 enzymes de restriction, la majorité apparaît différente des gènes ev déjà décrits dans la souche Leghorn blanche actuellement utilisée comme référence pour la nomenclature internationale. poulet / polymorphisme d'ADN / variabilité génétique / rétrovirus endogène INTRODUCTION
Avian Diseases, 2008
Primary chicken embryo fibroblasts (CEF) from special specific pathogen-free chicken lines are used for detection of contamination of adult or embryonic tissues, meconium, or tissue culture fluids with avian leukosis viruses (ALV). The suitability and efficiency of such tests depend on the susceptibility of CEF to the various subgroups of exogenous as well as endogenous ALV. The ideal CEF for such tests should be not only susceptible to all retroviruses, but also free of endogenous viruses so that such tests are immune to any interference that may occur between the endogenous and the tested (exogenous) viruses. CEF and/or chickens free of endogenous viruses are also desirable for gene transfer studies using retroviral vectors, such as RNA interference (RNAi) experiments and transgenic work. The absence of ev genes in CEF or chickens can empower clean detection of successful RNAi construct delivery or gene transfer. CEF free of ev genes are also essential reagents routinely used in growing and detecting unknown retroviruses in varied viral assays. This report documents the development of a new line of chickens, 0.TVB*S1, that is free of endogenous viruses and susceptible to all subgroups of ALV identified in chickens.
Veterinary Research Communications - VET RES COMMUN, 1999
The dynamics of the serum concentration of protein 27 (P27) of avian leukosis virus and transforming growth factor ß2 (TGF-ß2) 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 average mean concentration of serum P27 in the LL-susceptible flocks was significantly higher (2 (1282 pg/ml) among all flocks and at all sampling times. The significance of TGF-ß2 in inhibition of lymphoid tumour development is discussed.
Veterinary research communications, 1999
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 average mean concentration of serum P27 in the LL-susceptible flocks was significantly higher (p<0.05) than that in the LL-resistant flocks in six out of seven samplings performed at 5-week intervals, between 29 and 59 weeks of age. The peak in the average rise of serum P27 in the LL-resistant flocks (309 pg/ml) was associated with the highest level of TGF-beta2 (1282 pg/ml) among all flocks and at all sampling times. The significance of TGF-beta2 in inhibition of lymphoid tumour developm...
Avian Diseases, 2006
Chickens from seven different parental lines of commercial White Leghorn layer flocks from three independent breeders were inoculated with a naturally occurring avian leukosis virus (ALV) containing an ALV-B envelope and an ALV-J long terminal repeat (LTR) termed ALV-B/J. Additional groups of chickens from the same seven parental lines were inoculated with ALV-B. Chickens were tested for ALV viremia and antibody at 0, 4, 8, 16, and 32 wk postinfection. Chickens from all parental lines studied were susceptible to infection with ALV-B with 40%-100% of inoculated chickens positive for ALV at hatch following embryo infection. Similarly, infection of egg layer flocks with the ALV-B/J recombinant virus at 8 days of embryonation induced tolerance to ALV with 86%-100% of the chickens viremic, 40%-75% of the chickens shedding virus, and only 2/125 (2%) of the chickens producing serum-neutralizing antibodies against homologous ALV-B/J recombinant virus at 32 wk postinfection. In contrast, when infected with the ALV-B/J recombinant virus at hatch, 33%-82% of the chickens were viremic, 28%-47% shed virus, and 0%-56% produced serum-neutralizing antibodies against homologous ALV-B/J recombinant virus at 32 wk postinfection. Infection with the ALV-B/J recombinant virus at embryonation and at hatch induced predominately lymphoid leukosis (LL), along with other common ALV neoplasms, including erythroblastosis, osteopetrosis, nephroblastomas, and rhabdosarcomas. No incidence of myeloid leukosis (ML) was observed in any of the commercial White Leghorn egg layer flocks infected with ALV-B/J in the present study. Data suggest that the parental line of commercial layers may influence development of ALV-B/J-induced viremia and antibody, but not tumor type. Differences in type of tumors noted in the present study and those noted in the field case where the ALV-B/J was first isolated may be attributed to differences in the genetics of the commercial layer flock in which ML was first diagnosed and the present commercial layer flocks tested in the present study.
Genetics Selection Evolution, 2004
Selection for disease resistance related traits is a tool of choice for evidencing and exploring genetic variability and studying underlying resistance mechanisms. In this framework, chickens originating from a base population, homozygote for the B 19 major histocompatibility complex (MHC) were divergently selected for either progression or regression of tumors induced at 4 weeks of age by a SR-D strain of Rous sarcoma virus (RSV). The first generation of selection was based on a progeny test and subsequent selections were performed on full-sibs. Data of 18 generations including a total of 2010 birds measured were analyzed for the tumor profile index (TPI), a synthetic criterion of resistance derived from recording the volume of the tumors and mortality. Response to selection and heritability of TPI were estimated using a restricted maximum likelihood method with an animal model. Significant progress was shown in both directions: the lines differing significantly for TPI and mortality becoming null in the "regressor" line. Heritability of TPI was estimated as 0.49 ± 0.05 and 0.53 ± 0.06 within the progressor and regressor lines respectively, and 0.46 ± 0.03 when estimated over lines. Preliminary results showed within the progressor line a possible association between one Rfp-Y type and the growth of tumors.