Bovine Leukemia Virus
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The bovine leukemia virus or bovine leukemia virus or bovine leukemia virus ( BLV for short ) is a lymphotropic retrovirus whose main host is cattle . It causes in a proportion of infected cattle, the enzootic bovine leukosis , a B cell - leukemia , and can be transmitted through milk and blood. Transmission by blood-sucking insects is also being discussed for tropical countries .
Properties, systematics
The bovine leukemia virus BLV belongs taxonomically to the delta retroviruses, which also include the human pathogenic viruses HTLV-1 and HTLV-2 , as well as the closely related monkey viruses STLV-1, -2 and -3. The virus particles shown using an electron microscope are between 60 and 125 nm in size and the approximately 9 kb RNA genome with (+) polarity codes for the gene regions gag , pol and env common to all retroviruses . It also contains a so-called 'X region' between env and the 3'LTR, which is common to all delta retroviruses and which codes for the regulatory proteins tax and rex.
It is transmitted through direct contact with infected cells, through (unpasteurized) milk and possibly (especially in tropical countries) through insect bites. Veterinary measures such as B. dehorning , ear marking , multiple use of hypodermic needles contribute or contributed to a significant part of the spread. The main reservoir is domesticated cattle. The extent to which there are other game reserves is controversial, but there is evidence that FSVO persists in water buffalo .
BLV mainly infects B-lymphocytes , sometimes also monocytes and macrophages . The infected B-lymphocytes often express the CD5 and CD11b antigen.
Occurrence
Since the bovine leukosis caused by the virus damages the dairy herd, attempts are being made or have been made in Europe and other countries to eradicate this virus . Germany and most of the countries of the European Community have been bovine leukosis-free for many years. The virus still occurs in livestock in non-European countries ( South America , North America , Africa ).
In North America, no efforts have been made to eradicate the virus either, since the effect on milk yield is small and leukemia, which leads to the loss of the animal, rarely occurs.
Infections of other mammals
An attempt to infect primates was only successful in a highly immunocompromised monkey. According to current knowledge, the virus particles are not infectious for human cells. Like other RNA tumor viruses, BLV needs a specific receptor to enter a cell. The BLV receptor on bovine cells is known and its homologous protein on human cells does not function as a virus receptor for BLV. Individual researchers postulate that BLV is involved in human diseases, but so far there is no convincing experimental evidence for this.
Few of the infected cattle develop leukemia. An experimental transfer was successful in sheep, goats, rabbits, pigs, cats, dogs, rats, guinea pigs and monkeys. They at least react with the formation of antibodies. Sheep developed tumors after experimental infections, and more rarely goats and chickens.
literature
- N. Gillet, A. Florins, M. Boxus, C. Burteau, A. Nigro, F. Vandermeers, H. Balon, AB Bouzar, J. Defoiche, A. Burny, M. Reichert, R. Kettmann, L. Willems : Mechanisms of leukemogenesis induced by bovine leukemia virus: prospects for novel anti-retroviral therapies in human. In: Retrovirology. 4, 2007, p. 18. free full text
Individual evidence
- ↑ a b c d ICTV: ICTV Taxonomy history: Commelina yellow mottle virus , EC 51, Berlin, Germany, July 2019; Email ratification March 2020 (MSL # 35)
- ↑ a b c N. Gillet, A. Florins, M. Boxus, C. Burteau, A. Nigro, F. Vandermeers, H. Balon, AB Bouzar, J. Defoiche, A. Burny, M. Reichert, R. Kettmann , L. Willems: Mechanisms of leukemogenesis induced by bovine leukemia virus: prospects for novel anti-retroviral therapies in human. In: Retrovirology. 4, 2007 Mar 16, p. 18. doi: 10.1186 / 1742-4690-4-18
- ↑ F. Schödel, B. Hahn, R. Hübner, V. Hochstein-Mintzel: Transmission of bovine leukemia virus (BLV) to immunocompromised monkeys: evidence for persistent infection. In: Microbiologica. Volume 9, Number 2, April 1986, pp. 163-172, ISSN 0391-5352 . PMID 3012289 .
- ↑ J. Ban, J. Hlavaty, O. Orlik, GA Splitter, C. Altaner: The human homologue of the bovine leukemia virus receptor BLVRcp1 is the delta-subunit of adapter-related AP-3 protein that does not bind the BVLgp51. In: Arch Virol. 144 (10), 1999, pp. 2013-2022. PMID 10550673
- ↑ Bovine Leukemia Virus Infection and Human Breast Cancer Risk. ( Memento of December 29, 2010 in the Internet Archive ) at: cbcrp.org
- ↑ breast-cancer-research.com
- ↑ Jana Elwert: Genome analysis of various isolates of the bovine leukosis virus with special consideration of the serological status and the geographic origin of the cattle . Diss. FU Berlin, 1997. (full text)