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Petersen MI, Carignano HA, Suarez Archilla G, Caffaro ME, Alvarez I, Miretti MM, Trono K. Expression-based analysis of genes related to single nucleotide polymorphism hits associated with bovine leukemia virus proviral load in Argentinean dairy cattle. J Dairy Sci 2020; 104:1993-2007. [PMID: 33246606 DOI: 10.3168/jds.2020-18924] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 08/29/2020] [Indexed: 12/29/2022]
Abstract
In dairy cattle infected with bovine leukemia virus (BLV), the proviral load (PVL) level is directly related to the viral transmission from infected animals to their healthy herdmates. Two contrasting phenotypic groups can be identified when assessing PVL in peripheral blood of infected cows. A large number of reports point to bovine genetic variants (single nucleotide polymorphisms) as one of the key determinants underlying PVL level. However, biological mechanisms driving BLV PVL profiles and infection progression in cattle have not yet been elucidated. In this study, we evaluated whether a set of candidate genes affecting BLV PVL level according to whole genome association studies are differentially expressed in peripheral blood mononuclear cells derived from phenotypically contrasting groups of BLV-infected cows. During a 10-mo-long sampling scheme, 129 Holstein cows were phenotyped measuring anti-BLV antibody levels, PVL quantification, and white blood cell subpopulation counts. Finally, the expression of 8 genes (BOLA-DRB3, PRRC2A, ABT1, TNF, BAG6, BOLA-A, LY6G5B, and IER3) located within the bovine major histocompatibility complex region harboring whole genome association SNP hits was evaluated in 2 phenotypic groups: high PVL (n = 7) and low PVL (n = 8). The log2 initial fluorescence value (N0) transformed mean expression values for the ABT1 transcription factor were statistically different in high- and low-PVL groups, showing a higher expression of the ABT1 gene in low-PVL cows. The PRRC2A and IER3 genes had a significant positive (correlation coefficient = 0.61) and negative (correlation coefficient = -0.45) correlation with the lymphocyte counts, respectively. Additionally, the relationships between gene expression values and lymphocyte counts were modeled using linear regressions. Lymphocyte levels in infected cows were better explained (coefficient of determination = 0.56) when fitted a multiple linear regression model using both PRRC2A and IER3 expression values as independent variables. The present study showed evidence of differential gene expression between contrasting BLV infection phenotypes. These genes have not been previously related to BLV pathobiology. This valuable information represents a step forward in understanding the BLV biology and the immune response of naturally infected cows under a commercial milk production system. Efforts to elucidate biological mechanisms leading to BLV infection progression in cows are valuable for BLV control programs. Further studies integrating genotypic data, global transcriptome analysis, and BLV progression phenotypes are needed to better understand the BLV-host interaction.
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Affiliation(s)
- M I Petersen
- Instituto de Virología e Innovaciones Tecnológicas, Instituto Nacional de Tecnología Agropecuaria - Consejo Nacional de Investigaciones Científicas y Técnicas, B1686 Hurlingham, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, C1033AAJ Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, C1033AAJ Ciudad Autónoma de Buenos Aires, Argentina
| | - H A Carignano
- Instituto de Virología e Innovaciones Tecnológicas, Instituto Nacional de Tecnología Agropecuaria - Consejo Nacional de Investigaciones Científicas y Técnicas, B1686 Hurlingham, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, C1033AAJ Ciudad Autónoma de Buenos Aires, Argentina; Instituto de Genética, Instituto Nacional de Tecnología Agropecuaria, B1686 Hurlingham, Argentina.
| | - G Suarez Archilla
- Estación Experimental Agropecuaria Rafaela, Instituto Nacional de Tecnología Agropecuaria, S2300 Rafaela, Argentina
| | - M E Caffaro
- Instituto de Genética, Instituto Nacional de Tecnología Agropecuaria, B1686 Hurlingham, Argentina
| | - I Alvarez
- Instituto de Virología e Innovaciones Tecnológicas, Instituto Nacional de Tecnología Agropecuaria - Consejo Nacional de Investigaciones Científicas y Técnicas, B1686 Hurlingham, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, C1033AAJ Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, C1033AAJ Ciudad Autónoma de Buenos Aires, Argentina
| | - M M Miretti
- Consejo Nacional de Investigaciones Científicas y Técnicas, C1033AAJ Ciudad Autónoma de Buenos Aires, Argentina; Grupo de Investigación en Genética Aplicada, Instituto de Biología Subtropical, FCEQyN, Universidad Nacional de Misiones, N3300 Posadas, Argentina
| | - K Trono
- Instituto de Virología e Innovaciones Tecnológicas, Instituto Nacional de Tecnología Agropecuaria - Consejo Nacional de Investigaciones Científicas y Técnicas, B1686 Hurlingham, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, C1033AAJ Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, C1033AAJ Ciudad Autónoma de Buenos Aires, Argentina
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Chen YC, Chang CC, Hsu WL, Chuang ST. Dairy cattle with bovine leukaemia virus RNA show significantly increased leukocyte counts. Vet J 2020; 257:105449. [PMID: 32546356 DOI: 10.1016/j.tvjl.2020.105449] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 03/25/2020] [Accepted: 12/31/2019] [Indexed: 12/26/2022]
Abstract
Infection with bovine leukaemia virus (BLV), a retrovirus, causes dysfunction of the immune system and can have a marked economic impact on dairy industries due to decreased milk production and reduced lifespan in affected dairy cattle. The presence of proviral DNA has been the major diagnostic indicator of BLV infection. However in the course of BLV infection, the viral genome can be dormant, without detectable gene expression, resulting in limited impact on infected animals. At present, there is limited knowledge regarding haematological indices in dairy cattle that could indicate activation of the BLV genome and suggest reactivated BLV infection. In this study, BLV infection and BLV genome reactivation were evaluated based on the presence of BLV DNA and BLV env gene transcripts, respectively. BLV RNA transcription was confirmed. Among 93 whole blood samples obtained from asymptomatic dairy cattle, the prevalence of BLV proviral DNA and transcripts was 93.5% (n = 87/93) and 83.9% (n = 78/93), respectively. Between groups with and without BLV, the mean counts of white blood cells and lymphocytes in whole blood were significantly associated with the presence of BLV RNA (P < 0.05), but not with BLV proviral DNA. These results shed light on the activation status of the BLV genome and should be taken into account when evaluating the possible impact of BLV on cattle.
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Affiliation(s)
- Y C Chen
- Graduate Institute of Veterinary Pathobiology, College of Veterinary Medicine, National Chung Hsing University, 145 Xingda Rd., South Dist., Taichung 402, Taiwan
| | - C C Chang
- Graduate Institute of Microbiology and Public Health, College of Veterinary Medicine, National Chung Hsing University, 145 Xingda Rd., South Dist., Taichung 402, Taiwan
| | - W L Hsu
- Graduate Institute of Microbiology and Public Health, College of Veterinary Medicine, National Chung Hsing University, 145 Xingda Rd., South Dist., Taichung 402, Taiwan.
| | - S T Chuang
- Department of Veterinary Medicine, College of Veterinary Medicine, National Chung Hsing University, 145 Xingda Rd., South Dist., Taichung 402, Taiwan.
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Correction: Alvarez, I., et al . Detection of Bovine Leukemia Virus RNA in Blood Samples of Naturally Infected Dairy Cattle. Vet. Sci. 2019, 6, 66. Vet Sci 2019; 6:vetsci6040084. [PMID: 31652834 PMCID: PMC6958470 DOI: 10.3390/vetsci6040084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 10/23/2019] [Indexed: 11/17/2022] Open
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