Subgroup J avian leucosis virus (ALV-J) generally causes neoplastic diseases, immunosuppression and subsequently increases susceptibility to secondary infection in birds. The spread of ALV-J mainly depends on congenital infection and horizontal contact. Although ALV-J infection causes enormous losses yearly in the poultry industry worldwide, effective measures to control ALV-J remain lacking. I...

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 ce...

Commercial Marek's disease (MD) vaccines produced by two manufacturers were tested for possible contamination with avian leukosis virus (ALV). Samples of MD vaccines manufactured by two companies (A and B) were received from a breeder company; samples were also received directly from vaccine company B. Using virus isolation tests, samples initially tested positive for subgroup E (endogenous) AL...

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...

All currently licensed yellow fever (YF) vaccines are propagated in chicken embryos. Recent studies of chick cell-derived measles and mumps vaccines show evidence of two types of retrovirus particles, the endogenous avian retrovirus (EAV) and the endogenous avian leukosis virus (ALV-E), which originate from the chicken embryonic fibroblast substrates. In this study, we investigated substrate-de...

avian leukosis viruses (alvs) cause different types of tumours in poultry and can affect the health and egg production of the birds. to investigate the presence of the virus in chicken layer flocks in shiraz, 222 egg albumen from local layer breeder (25 eggs), local layer grand parent (30 eggs), broiler breeder (60 eggs), commercial layer (46 eggs) and broiler grand parent (61 eggs) were tested...

We describe the characterization of a spontaneously transformed chicken monocytic cell line that developed as a single colony of cells in a heterophil culture that was inadvertently left in the incubator over a period of 25 days. These cells, hitherto named HTC, grow efficiently at both 37 or 41 degrees C in culture medium containing either 5% FBS or 2% chicken serum. The HTC cells are acid pho...

Avian leukosis virus (ALV) is a simple retrovirus that causes a wide range of tumors in chickens, the most common of which are B-cell lymphomas. The viral genome integrates into the host genome and uses its strong promoter and enhancer sequences to alter the expression of nearby genes, frequently inducing tumors. In this study, we compare the preferences for ALV integration sites in cultured ce...

The transcription factor Blimp-1 has emerged as a regulator of cell fate in embryonic (germ cell) and adult (B- and T-cell immune effector and epithelial) lineages. It has also been proposed to act as a tumor suppressor in B-cell malignancy. Here, we present a novel in vivo system enabling the targeted genetic manipulation of cells expressing Prdm1, the gene encoding Blimp-1. We created bacteri...