Studies on the sporadic and enzootic forms of bovine leukosis

Onuma, Misao; Honma, Toshio; Mikami, Takeshi; Ichijo, Shigeru; Konishi, Tatsuo

doi:10.1016/0021-9975(79)90055-0

Cited by 26 publications

(14 citation statements)

References 7 publications

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“…When BLV cDNA rep was used as a blot hybridization probe, DNAs from SBL tumors and a normal bovine lymph node shared hybridization bands of 26.3 kb (Xba I) and 8.1 kb (Eco RI), which are probably derived from ribosomal DNA (3). However, since no hybridizable bands above these backgrounds occurred with any of the DNAs from SBL tumors, BL V itself is not likely to be implicated in SBL, agreeing with the immunological and epidemiological results obtained previously (7). Eco RI-and Xba I-digested SBL DNAs were also hybridized to cDNA3'-enriched' Interestingly, we could detect, above the background (8.9 kb and 4.5 kb fragments in normal bovine DNA), several faint hybridization bands with different sizes depending on the SBL tumors used.…”

Section: Discussionsupporting

confidence: 91%

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Integration of Bovine Leukemia Virus DNA in the Genomes of Bovine Lymphosarcoma Cells

Onuma

Sagata

Okada

et al. 1982

Microbiology and Immunology

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Integration of bovine leukemia virus (BLV) in the genomes of infected cells was investigated in cattle with enzootic bovine leukosis (EBL) and sporadic bovine leukosis (SBL). Southern blot hybridization of BLV cDNA to Eco RI and Xba I restriction fragments of EBL tumor DNAs revealed that: I) one to four or more copies of proviral DNA were integrated per genome; 2) the restriction pattern of the integrated proviral DNA was the same in two or three different tumors from the same animals; and 3) different patterns were observed among tumors from four different animals. These findings suggest the monoclonal origin of different tumors in an individual animal and the existence of multiple chromosomal integration sites of BLV provirus. DNAs from several SBL tumors were also analyzed with the same restriction enzymes, but with both representative and cDNA3'-enriched's of BLV RNA. No hybridization bands reactive with representative BLV cDNA could be detected, while several bands appeared to hybridize with cDNA3'_enriched.

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Section: Discussionsupporting

confidence: 91%

“…Three forms of SBL are recognized: calf (CLS), thymic (TLS), and skin (SLS) forms. Recent immunological and molecular biological studies have revealed that BLV per se is not implicated in SBL (7). However, there still remains the possibility that this disease is caused by an unknown viral agent which may be, in some forms, related to BLV.…”

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confidence: 99%

Integration of Bovine Leukemia Virus DNA in the Genomes of Bovine Lymphosarcoma Cells

Onuma

Sagata

Okada

et al. 1982

Microbiology and Immunology

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“…However, 30-70% develop a persistent lymphocytosis (PL) characterized by a polyclonal expansion of B-lymphocytes and a much smaller percent, 0.1-10%, eventually develop lymphoid tumors. 3,6,11,12 A previous survey published in 1985 suggested up to 30% of dairy cows in the United States were infected with BLV. 12 Due to the relatively short life of production cattle in the United States, the greatest economic impact of BLV infection would appear to be that associated with interference in the international movement of cattle and their germ plasm rather than clinical disease.…”

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confidence: 99%

Absence of Bovine Leukosis Virus in Semen of Seropositive Bulls

2002

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Abstract.A polymerase chain reaction (PCR)-based detection system was established to identify the presence of bovine leukosis virus (BLV) DNA in bovine semen. Seventy-nine bulls were included in the study. Serum, peripheral blood leukocytes, and semen were collected from each of the 79 bulls. The BLV-specific antibody was detected in serum by agar gel immunodiffusion and viral DNA in blood and semen by PCR. Serologically, 29 of the 79 bulls were BLV positive. Twenty-seven of the 29 seropositive bulls and 1 of the seronegative bulls had BLV DNA in peripheral blood leukocytes. All 79 bulls tested PCR negative for the presence of BLV in semen. This data is strong evidence that properly collected semen from BLV seropositive bulls will not contribute to dissemination of this viral infection.Bovine leukosis virus (BLV) is an exogenous oncogenic retrovirus associated with enzootic bovine leukosis. The infection can result in 3 different clinical states, with many animals remaining asymptomatic in an aleukemic state (AL). However, 30-70% develop a persistent lymphocytosis (PL) characterized by a polyclonal expansion of B-lymphocytes and a much smaller percent, 0.1-10%, eventually develop lymphoid tumors. 3,6,11,12 A previous survey published in 1985 suggested up to 30% of dairy cows in the United States were infected with BLV. 12 Due to the relatively short life of production cattle in the United States, the greatest economic impact of BLV infection would appear to be that associated with interference in the international movement of cattle and their germ plasm rather than clinical disease. Thus, application of molecular biology techniques, such as polymerase chain reaction (PCR), to identify the presence of BLV in semen should facilitate certification of germ plasm as being free of contaminating virus.Previous studies by numerous investigators suggested that semen from BLV-infected bulls was noninfectious for recipient cows. 4,8,9 Sheep inoculated with entire ejaculates from BLV-infected bulls remained seronegative. Cows inseminated with ejaculates from seropositive bulls have also not seroconverted nor have their progeny. In addition, a 5-year study demonstrated that use of semen derived from both BLV seropositive and seronegative donor bulls in a BLV-free closed dairy did not result in any seroconversion. Donor bulls were from multiple artificial insemination (AI) centers, with 48% being seropositive. 9 Despite the above-mentioned studies that argued strongly against the possibility of recipient cows becoming infected by using semen from BLV-positive bulls, international movement of germ plasm from BLV-infected animals is still problematic. The most common method of testing for BLV in animals is the detection of antibodies to gp51 by agar gel immunodiffusion (AGID). However, the application of PCR for identification of viral DNA has provided a sensitive test for detecting BLV in tissues such as blood. 1,2,10 This report describes the application of PCR to the detection of BLV DNA in peripheral blood leukocytes and se...

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“…Infection of cattle with bovine leukosis virus (BLV) is associated with persistent lymphocytosis (PL) or lymphosarcoma, both of which develop after extended latency periods of between 1 and 8 years (Onuma et al, 1979;Ghysdael et al, 1984;Burny et al, 1985). Animals develop a strong humoral response to BLV structural proteins at the time of infection that persists throughout the lifetime of the animal and appears to be ineffective in preventing disease progression.…”

Section: Introductionmentioning

confidence: 99%

“…Animals develop a strong humoral response to BLV structural proteins at the time of infection that persists throughout the lifetime of the animal and appears to be ineffective in preventing disease progression. Between 30 and 70% of infected cattle develop PL that is characterized by an increase in circulating B lymphocytes; a much smaller number, 0.1 to 10%, eventually develop lymphoid tumours (Kumar et al, 1978;Onuma et al, 1979;Burny et al, 1985;Thurmond et al, 1985). The mechanism by which BLV remains latent and causes lymphocyte proliferation, and the parameters that define progression to the PL or tumour disease states, are as yet undefined.…”

Section: Introductionmentioning

confidence: 99%