Bovine leukemia virus (BLV) expression is mostly silent in peripheral blood mononuclear cells (PBMCs) of infected animals. However, when infected cells are cultured, they are stimulated to produce virus. We studied viral transcription in PBMCs taken from BLV-infected sheep because the pattern of transcriptional activation in these cells should closely mimic activation of virus expression within...

BACKGROUND Bovine leukemia virus (BLV) is associated with enzootic bovine leukosis, which is the most common neoplastic disease of cattle. BLV infects cattle worldwide, imposing a severe economic impact on the dairy cattle industry. Recently, we developed a new quantitative real-time polymerase chain reaction (PCR) method using Coordination of Common Motifs (CoCoMo) primers to measure the provi...

Lymphocyte phenotypes were determined in sheep experimentally infected with bovine leukemia virus (BLV). BLV infection was detected by serological tests AGID and ELISA. Flow cytometry analysis with the use of specific monoclonal antibodies for CD markers and conjugates labeled with FITC or PE was performed. Proliferating cell nuclear antigen (PCNA) was estimated in lymphocytes of infected and h...

Efficient bovine leukemia virus (BLV) transcription requires the virus-encoded transactivator Tax(BLV), which acts through three Tax(BLV)-responsive elements located in the 5' long terminal repeat. It has been proposed that the binding of the CRE-binding protein (CREB) and the activating transcription factor (ATF) to the three imperfect cAMP-responsive elements (CREs) located in each Tax(BLV)-r...

It is widely accepted that the majority of cancers result from multiple cellular events leading to malignancy after a prolonged period of clinical latency, and that the immune system plays a critical role in the control of cancer progression. Bovine leukemia virus (BLV) is an oncogenic member of the Retroviridae family. Complete genomic sequences of BLV strains isolated from peripheral blood mo...

Bovine leukemia virus (BLV) and the human T-cell leukemia virus types I and II comprise a unique retrovirus subfamily which has evolved complex strategies for the regulation of gene expression. A transcriptional control circuit has been characterized in both human and bovine systems in which cis-acting promoter control elements are responsive to trans-acting factors encoded in the pX region of ...

Bovine leukemia virus (BLV) is a retrovirus responsible for lymphoproliferative disorders in cattle. Although infections of BLV in animals are well known, little is known about its capacity to infect humans. This study investigated the presence of anti-BLV antibodies and BLV proviruses in human and cattle samples. An indirect enzyme-linked immunosorbent assay (ELISA) was used to detect anti-BL...

The purpose of this study was to determine the prevalence of bovine leukemia virus (BLV) in Khorasan Razavi and Khorasan Shomali provinces which are the main provinces located in the northeast of Iran. Total number of 429 blood samples were collected from industrial dairy herds. The samples were categorized based on province, age (2-3, 4-6, and 7-10 years old), calving (≤ 2, 3-5, and > 5) and h...

Degenerate PCR primers which amplify a conserved region of the DNA polymerase genes of the herpesvirus family were used to provide sequence evidence for a new bovine herpesvirus in bovine B-lymphoma cells and peripheral blood mononuclear cells (PBMC). The sequence of the resultant amplicon was found to be distinct from those of known herpesvirus isolates. Alignment of amino acid sequences demon...

Large-animal models for leukemia have the potential to aid in the understanding of networks that contribute to oncogenesis. Infection of cattle and sheep with bovine leukemia virus (BLV), a complex retrovirus related to human T-cell leukemia virus type 1 (HTLV-1), is associated with the development of B-cell leukemia. Whereas the natural disease in cattle is characterized by a low tumor inciden...