The correlation between the direct and indirect detection of bovine leukemia virus infection in cattle

Cockerell, Gary L.; Rovnak, Joel

doi:10.1016/0145-2126(88)90112-9

Cited by 30 publications

(15 citation statements)

References 10 publications

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“…This result indicates that it is difficult to detect BLV infection by using the serological test alone. BLV infections without the detection of BLV antibodies by serological tests have been observed previously [32-36]. Thus, this result showed that, when viral gene expression is very low in BLV-infected cells, the infected cells can escape the immune response and survive, without evoking an immune response by viral protein production.…”

Section: Discussionsupporting

confidence: 65%

BLV-CoCoMo-qPCR: a useful tool for evaluating bovine leukemia virus infection status

et al. 2012

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BackgroundBovine 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 proviral load of known and novel BLV variants in BLV-infected animals. Indeed, the assay was highly effective in detecting BLV in cattle from a range of international locations. This assay enabled us to demonstrate that proviral load correlates not only with BLV infection capacity as assessed by syncytium formation, but also with BLV disease progression. In this study, we compared the sensitivity of our BLV-CoCoMo-qPCR method for detecting BLV proviruses with the sensitivities of two real-time PCR systems, and also determined the differences of proviral load with serotests.ResultsBLV-CoCoMo-qPCR was found to be highly sensitive when compared with the real-time PCR-based TaqMan MGB assay developed by Lew et al. and the commercial TaKaRa cycleave PCR system. The BLV copy number determined by BLV-CoCoMo-qPCR was only partially correlated with the positive rate for anti-BLV antibody as determined by the enzyme-linked immunosorbent assay, passive hemagglutination reaction, or agar gel immunodiffusion. This result indicates that, although serotests are widely used for the diagnosis of BLV infection, it is difficult to detect BLV infection with confidence by using serological tests alone. Two cattle were experimentally infected with BLV. The kinetics of the provirus did not precisely correlate with the change in anti-BLV antibody production. Moreover, both reactions were different in cattle that carried different bovine leukocyte antigen (BoLA)-DRB3 genotypes.ConclusionsOur results suggest that the quantitative measurement of proviral load by BLV-CoCoMo-qPCR is useful tool for evaluating the progression of BLV-induced disease. BLV-CoCoMo-qPCR allows us to monitor the spread of BLV infection in different viewpoint compared with classical serotest.

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Section: Discussionsupporting

confidence: 65%

BLV-CoCoMo-qPCR: a useful tool for evaluating bovine leukemia virus infection status

et al. 2012

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“…21 Second, circulating lymphocytes from seropositive, hematologically normal, and asymptomatic cattle contain 1-3 proviral copies, and the percentage of BLV-infected cells has been found to be less than 10%. 5,24 These levels can be below the detection level of PCR but still might elicit a detectable immune response. This is consistent with the findings of this study (results not shown) that herds with higher seroprevalence tend to have a larger proportion of individuals yielding positive results in all serological assays but negative by PCR.…”

Section: Discussionmentioning

confidence: 99%

“…In a number of studies, PCR failed to detect BLV provirus in cattle that tested positive in serum. 1,5,7 The nested PCR was included because several studies indicated that it performed better than AGID, 3,9,16 which is used as reference in many other studies. The superior performance of PCR stems from its ability for earlier detection of infected animals 2,7 and detection of as few as 4-10 copies of proviral BLV.…”

Section: Proviral Detection By Nested Pcrmentioning

confidence: 99%

Evaluation of a New Antibody-Based Enzyme-Linked Immunosorbent Assay for the Detection of Bovine Leukemia Virus Infection in Dairy Cattle

et al. 2005

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Abstract. The objective of this study was to validate a new blocking enzyme-linked immunosorbent assay (ELISA) (designated M108 for milk and S108 for serum samples) for detecting bovine leukemia virus (BLV) infection in dairy cattle. Milk, serum, and ethylenediaminetetraacetic acid-blood samples were collected from 524 adult Holstein cows originating from 6 dairy herds in Central Argentina. The M108 and S108 were compared with agar gel immunodiffusion (AGID), polymerase chain reaction and a commercial ELISA. Because there is currently no reference test capable of serving as a gold standard, the test sensitivity (SE) and specificity (SP) were evaluated by the use of a latent class model. Statistical inference was performed by classical maximum likelihood and by Bayesian techniques. The maximum-likelihood analysis was performed assuming conditional independence of tests, whereas the Bayesian approach allowed for conditional dependence. No clear conclusion could be drawn about conditional dependence of tests. Results with maximum likelihood (under conditional independence) and posterior Bayes (under conditional dependence) were practically the same. Conservative estimates of SE and SP (with 95% confidence intervals) for M108 were 98.6 (96.7; 99.6) and 96.7 (92.9; 98.8) and for S108 99.5 (98.2; 99.9) and 95.4 (90.9; 98.1), respectively. The ELISA 108 using either milk or serum to detect BLV-infected animals had comparable SE and SP with the official AGID and a commercial ELISA test, which are currently the most widely accepted tests for the serological diagnosis of BLV infection. Therefore, ELISA 108 can be used as an alternative test in monitoring and control programs.

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“…In cattle, the ability to transmit BLV varies (35,37), and expression of antigen after in vitro culture has been shown to correlate with infectivity (38). The level of BLV expression in the animal also may correlate with the probability of development of persistent lymphocytosis (18,39). If a ribozyme could inhibit viral expression enough to prevent persistent lymphocytosis, it may be that transmission within a herd would be markedly impaired.…”

Section: Discussionmentioning

confidence: 99%

Ribozyme cleaves rex/tax mRNA and inhibits bovine leukemia virus expression.

Cantor

McElwain

Birkebak

et al. 1993

Proc. Natl. Acad. Sci. U.S.A.

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Bovine leukemia virus (BLV) encodes at least two regulatory proteins, Rex and Tax. Tax, the transactivating protein, stimulates the long terminal repeat to promote viral transcription and may be involved in tumorigenesis. Rex is involved in the transition from early expression of regulatory proteins to later expression of viral structural proteins. We have targeted ribozymes against the mRNA encoding Rex and Tax. The ribozymes consist of the hammerhead catalytic motif flanked by antisense sequences that hybridize with the complementary rex/tax mRNA. To evaluate cleavage in a cell-free system, we transcribed portions of rex/tax mRNA and incubated them with synthetic RNA ribozymes. A ribozyme was identified that cleaves >80% of the target RNA. Synthetic DNA encoding this ribozyme was cloned into the expression vector pRc/RSV and transfected into BLV-infected bat lung cells. Intracellular cleavage of rex/tax mRNA was confirmed by reverse transcriptase PCR. In cells expressing the ribozyme, viral expression was markedly inhibited. Expression of the BLV core protein p24 was inhibited by 61%, and reverse transcriptase activity in supernatant was inhibited by 92%. Ribozyme inhibition of BLV expression suggests that cattle expressing these sequences may be able to control BLV replication.Bovine leukemia virus (BLV), a retrovirus structurally similar to human T-cell leukemia viruses I and II (HTLV-I and -II), causes persistent lymphocytosis and B-lymphocyte lymphoma in cattle and sheep (1). After initial infection, BLV expresses a doubly spliced transcript encoding the regulatory proteins Rex and Tax (2). Tax trans-activates the viral long terminal repeat and also cellular promoters, including c-fos and somatostatin (3). Cotransfection experiments have shown that Tax is necessary for viral expression in vitro (4). Rex regulates the transition from early expression of the doubly spliced transcript encoding regulatory proteins to the later expression of singly spliced or unspliced transcripts that express the env gene or the gag and pol genes (5). Recently, the 3' region of HTLV-I and BLV has been shown to encode RNA with alternative splice patterns that may express other regulatory proteins (6-8).Because of the critical role of regulatory proteins such as Tax and Rex in the HTLV/BLV group of viruses, we hypothesized that the rex/tax mRNA would be a rational target for ribozyme-mediated inhibition. The hammerhead motif, first identified in plant RNA pathogens (9, 10), cleaves the phosphodiester bond downstream of a GUC triplet (9,10). By flanking the hammerhead motif with antisense sequences, Haseloff and Gerlach (11) demonstrated cleavage of specific target RNAs. In this study, we demonstrate a ribozyme that cleaves rex/tax mRNA and, when transfected into BLV-infected cells, markedly inhibits viral expression.The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact...

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The correlation between the direct and indirect detection of bovine leukemia virus infection in cattle

Cited by 30 publications

References 10 publications

BLV-CoCoMo-qPCR: a useful tool for evaluating bovine leukemia virus infection status

BLV-CoCoMo-qPCR: a useful tool for evaluating bovine leukemia virus infection status

Evaluation of a New Antibody-Based Enzyme-Linked Immunosorbent Assay for the Detection of Bovine Leukemia Virus Infection in Dairy Cattle

Ribozyme cleaves rex/tax mRNA and inhibits bovine leukemia virus expression.

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