Maedi-Visna in Sheep: Host-Virus Interactions and Utilization as a Model

Pétursson, Gudmundur; Pálsson, Páll A.; Georgsson, Guðmundur

doi:10.1159/000150122

Cited by 24 publications

(16 citation statements)

References 35 publications

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“…This suggests that similar pathogenic mechanisms may be operating during early infection [7,320,321]. A basic question that arises in both infections is why the host cannot easily clear the virus.…”

Section: Pathogenesismentioning

confidence: 99%

Small Ruminant Lentiviruses and Human Immunodeficiency Virus: Cousins that Take a Long View

Blacklaws

Harkiss²

2010

CHR

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Small ruminant lentiviruses (SRLV) and human immunodeficiency viruses (HIV) are related retroviruses that cause multisystem disease usually over a long period of time. The viruses show similarities and differences in biological and pathogenic features. The basic retroviral genomic organization is complicated by the presence of a variable number of accessory genes in both viruses, though the structure is more complex in HIV. Both are mucosal pathogens, and infect cells of the monocyte-macrophage lineage. The main difference in cell tropism is that, unlike HIV, SRLV do not infect lymphocytes. A major feature of both pathogens is restricted replication and virus latency, which are partly responsible for the establishment of chronic infection usually lasting for life. The pathologies observed are similar in the early stages of both infections, and possibly following highly active anti-retroviral therapy (HAART). While the pathogenesis of HIV-induced disease during symptomatic stages is mainly due to secondary infections and neoplastic conditions, the early and post-HAART stages are associated with chronic inflammatory changes that resemble those found in SRLV diseases which are thought to be mediated by anti-virus immune responses.

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Section: Pathogenesismentioning

confidence: 99%

Small Ruminant Lentiviruses and Human Immunodeficiency Virus: Cousins that Take a Long View

Blacklaws

Harkiss²

2010

CHR

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“…The virus is related to the human immunodeficiency virus type‐1 (HIV‐1) [ 34] and causes a systemic infection in sheep [ 27]. The host–virus interactions in visna show several features similar to those observed in early stages of infection with HIV‐1 [ 11, 28]. The main target cells in infection with visna virus are as in HIV‐1 infection, monocytes/macrophages [ 23] but lymphocytes are in contrast to infection with HIV‐1 apparently not permissive for visna virus and the infection does not cause an overt immunodeficiency.…”

Section: Introductionmentioning

confidence: 99%

Constitutive and visna virus induced expression of class I and II major histocompatibility complex antigens in the central nervous system of sheep and their role in the pathogenesis of visna lesions

Bergsteinsdóttir

Árnadóttir

Torsteinsdóttir

et al. 1998

Neuropathology Appl Neurobio

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Expression of major histocompatibility complex (MHC) antigens was studied in the brains of 10 healthy sheep 2 months to 5 years old and 13 sheep infected with visna virus by intracerebral inoculation and killed one and 6 months post infection (p.i.). In healthy sheep there was prominent expression of class I, mainly on endothelial cells but also detected on ependyma, choroid plexus and in the leptomeninges. Class II expression was sparse. It was observed on perivascular cells, in choroid plexus, leptomeninges and on microglial cells in the white matter. No definite increase with age in the constitutive expression of class I and II was observed, confirming that we are dealing with a true constitutive expression. In visna-infected sheep a considerable induction of MHC antigens on microglia was observed, which correlated with severity of lesions and was mainly found in or adjacent to inflammatory infiltrates of the white matter. Increase in class II antigen expression was detected in all sheep but class I only in sheep with the most severe lesions 6 months p.i., an indication of a higher threshold for induction of class I than class II antigens on microglia. Few cells expressed viral antigens, indicating that direct immune-mediated destruction of infected cells plays a minor role in evolution of lesions. Since the preferential induction of MHC antigens on microglia in the white matter correlated with the lesion pattern, activated microglia may play a considerable role in the pathogenesis of lesions.

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“…It is closely related biologically to lentiviruses that infect other species, including those producing immunosuppressive disease [2][3][4][5][6][7]. It differs from most of the lentiviruses in that the MVV is considered to infect solely the cells of the monocyte-macrophage series [8], contrasting with the usual concurrent lymphocyte and monocytemacrophage lentivirus infection.…”

Section: Introductionmentioning

confidence: 99%

Immunohistological study of the depressed cutaneous DTH response in sheep naturally infected with an ovine lentivirus (Maedi-Visna virus)

Pyrah

Watt

1996

Clinical and Experimental Immunology

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SUMMARYThe gross and immunohistological characteristics of the purified protein derivative (PPD)-induced cutaneous DTH reaction were studied in a group of sheep naturally infected with Maedi-Visna virus (MVV), and compared with reactions obtained in a matched control group. There was a marked, but variable, depression in the DTH lesion in the MVV group associated with a decreased density of polymorphonuclear neutrophils (PMN) and CD4 cells in the early reaction. There were no significant differences in the densities of CD8 ,°/± T cells, macrophages, B cells and MHC class II-expressing cells. This work indicates that there is a significant alteration in the initial trafficking of PMN and CD4 cells into a DTH response area in sheep infected with MVV.

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Maedi-Visna in Sheep: Host-Virus Interactions and Utilization as a Model

Cited by 24 publications

References 35 publications

Small Ruminant Lentiviruses and Human Immunodeficiency Virus: Cousins that Take a Long View

Small Ruminant Lentiviruses and Human Immunodeficiency Virus: Cousins that Take a Long View

Constitutive and visna virus induced expression of class I and II major histocompatibility complex antigens in the central nervous system of sheep and their role in the pathogenesis of visna lesions

Immunohistological study of the depressed cutaneous DTH response in sheep naturally infected with an ovine lentivirus (Maedi-Visna virus)

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