The major group-specific antigen (gs-a) of avian leukoviruses was detected by radioimmunoassay in extracellular medium of all embryonic cultures prepared from infected chickens. Embryos of birds not carrying an avian ]eukosis virus infection and of chickens from a leukosis-free flock could thus clearly be distinguished from infected ones. Release of group-specific antigen into the extracellular...

The small RNAs contained in virions of avian leukosis and sarcoma viruses are a virus-specific subset of the total small RNA population of the host cell. The reverse transcriptase protein must be present in the budding virion for this selection to take place. Virions of the alpha form of the Bryan strain of Rous sarcoma virus, which lack detectable reverse transcriptase, incorporated an unselec...

Antibodies against a large and a small DNA polymerase isolated from chicken embryos and against avian myeloblastosis virus DNA polymerase were used to study the serological relationships of the DNA polymerase activities of three avian systems with RNA and a DNA polymerase-avian leukosis-sarcoma viruses, reticuloendotheliosis viruses, and a fraction from uninfected chicken cells. The DNA polymer...

Avian leukosis is a neoplastic disease caused in part by subgroup J avian leukosis virus J (ALV-J). Micro ribonucleic acids (miRNAs) play pivotal oncogenic and tumour-suppressor roles in tumour development and progression. However, little is known about the potential role of miRNAs in avian leukosis tumours. We have found a novel tumour-suppressor miRNA, gga-miR-375, associated with avian leuko...

rence of avian leukosis virus subgroup J in commercial layer fl ocks in China. Z. Emerging of avian leukosis virus subgroup J in a fl ock of Chinese local breed [in Chinese].opment and application of polymerase chain reaction (PCR) tests for the detection of subgroup J avian leukosis virus. (exogenous avian leukosis virus, subgroup J) has an env gene related to those of en-dogenous elements EAV...

Multiple group-specific (gs) components of the avian leukosis-sarcoma viruses were detected by immunodiffusion (Ouchterlony) tests with sera from hamsters bearing tumors induced by sarcoma viruses and with sera from adult chickens immunized with avian sarcoma or leukosis viruses. Immune hamster sera detected up to four components, whereas chicken sera detected at least one. The hamster and chic...

an adult native cock (gallus gallus domesticus) referred to the aviary clinic with multiple different sizes of round dermal nodules. the bird died few days later, and was then submitted for further evaluation. macroscopic and microscopic examinations as well as a pcr test were done to identify type and cause of the tumor. in histopathological assessment of biopsy specimen, it consisted of inter...

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 line...

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-inducin...

Chicks of distinct genotypes at the tumor virus B locus (TVB) in combination with presence or absence of endogenous avian leukosis virus ev21 gene in their genomes were examined for survival day patterns after challenge with very virulent plus Marek’s disease virus (vv+MDV) in three consecutive trials under controlled conditions. The distinct genotypic groups of the challenged birds were TVB*S1...