Mechanisms of pathogenesis induced by bovine leukemia virus as a model for human T-cell leukemia virus

Abstract

Bovine leukemia virus (BLV) and human T-cell leukemia virus type 1 (HTLV-1) make up a unique retrovirus family. Both viruses induce chronic lymphoproliferative diseases with BLV affecting the B-cell lineage and HTLV-1 affecting the T-cell lineage. The pathologies of BLV- and HTLV-induced infections are notably similar, with an absence of chronic viraemia and a long latency period. These viruses encode at least two regulatory proteins, namely, Tax and Rex, in the pX region located between the env gene and the 3′ long terminal repeat. The Tax protein is a key contributor to the oncogenic potential of the virus, and is also the key protein involved in viral replication. However, BLV infection is not sufficient for leukemogenesis, and additional events such as gene mutations must take place. In this review, we first summarize the similarities between the two viruses in terms of genomic organization, virology, and pathology. We then describe the current knowledge of the BLV model, which may also be relevant for the understanding of leukemogenesis caused by HTLV-1. In addition, we address our improved understanding of Tax functions through the newly identified BLV Tax mutants, which have a substitution between amino acids 240 and 265.

Dinámica de la Leucosis Bovina en el ganado criollo Hartón del Valle en infección natural

“…El VLB se ha convertido en una herramienta muy importante para el estudio del HTLV 1 ya que la infección que ambos producen es similar afectando las células T y las células B en el caso de VLB, no producen viremia crónica y su organización genética es igual (Aida et al, 2013).…”

CHANGES IN LEUKOCYTE AND ERYTHROCYTE BLOOD PROFILE AND PARAMETERS UNDER A COMBINED Anaplasma marginale AND BOVINE LEUKEMIA VIRUS INFECTION IN CATTLE

“…A large amount of data has been accumulated on the pronounced effect of expression of BLV proviral DNA, in particular tax gene, on stress reactivity in cells, apoptosis, cell renewal rates, and immune system of infected animals [7,43,44]. We have previously shown that it is in animals with high leukocytosis that expression of BLV RNA can be detected by RT-PCR [4].…”

Genetic diversity of bovine leukemia virus worldwide

“…In 1871, bovine leukosis was first reported as yellowish nodules in the enlarged spleen of cattle (Leisering 1871;Aida et al 2013). Bovine leukosis is a neoplastic disease of cattle and is classified as two types: sporadic bovine leukosis (SBL; also known as T cell leukosis), and enzootic bovine leukosis (EBL) (also known as B cell leukosis).…”