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Náttúrufræðingurinn - 2015, Side 44

Náttúrufræðingurinn - 2015, Side 44
Náttúrufræðingurinn 44 Lokaorð Þegar veirur sem ræktuðust frá al- næmissjúklingum laust eftir 1980 voru skoðaðar í rafeindasmásjá komu í ljós veiruagnir sem líktust RNA-æxlisveirum og mynduðust á sama hátt við knappskot frá frumu- himnu sýktra frumna. Þetta benti til að alnæmisveiran væri retroveira. Það var staðfest þegar öfugumriti fannst í veiruögnunum.1 Raðgrein- ing á erfðaefni sýndi meiri skyld- leika við mæði-visnuveiru en við æxlisveirur. Alnæmisveirunni HIV var því skipað í undirflokk lenti- veira,49,50 enda olli hún ekki æxlis- vexti í sýktum einstaklingum. Áður en rannsóknir á alnæmisveirunni hófust voru það einkum dýra- læknar og lítill hópur áhugasamra veirufræðinga sem lögðu stund á rannsóknir á lentiveirum. Þær þóttu nokkuð sérstakar, ekki síst vegna þeirra sérkennilegu hæggengu sjúkdóma sem þær ollu í dýrum. Eftir að alnæmisveiran fannst varð hún fljótlega best þekkt af öllum veirum og sú sem flestar rannsóknir beindust að, og varð hún ímynd lentiveira. Áður höfðu sjúkdómar sem lentiveirur ollu einkum valdið sauðfjárbændum áhyggjum vegna fjárfellis og annars tjóns. Hliðstæður hæggengur og banvænn smitsjúk- dómur af völdum lentiveiru ógn- aði nú sjálfu mannkyninu. Það er athyglisvert að þær rannsóknir sem leiddu til þess að alnæmisveiran var greind sem lentiveira eru hliðstæðar fyrstu rannsóknum á visnuveiru, eins og lýst er í þessari grein. Summary Maedi and visna and the origin of lentivirus research Maedi, a slowly progressing pneumonia of sheep, and a central nervous system disease called visna were brought to Iceland in 1933 by imported sheep of Karakul breed. They were transmissible in sheep with an incubation time of 2–3 years. Based on his studies of visna and maedi, Björn Sigurðsson formulated the concept of slow infections in 1954. Visna virus was isolated in tissue culture from sheep brain in 1957 and maedi virus was isolated the following year from sheep lungs. Both viruses caused similar cyto- pathic effect and electron microscope studies showed identical spherical parti- cles, which were formed by budding from the cell membrane. Further studies confirmed that maedi and visna are caused by the same virus, named maedi- visna virus (MVV). Electron microscope studies suggested that MVV was related to RNA tumor viruses of animals, oncor- naviruses.This was later supported by the finding that MVV is an RNA virus and confirmed when reverse tran- scriptase was found in MVV, which was therefore classified as a retrovirus to- gether with the oncornaviruses. In 1975 MVV was placed in a subgroup of retro- viruses named lentiviruses, which cause cytopathic effect in vitro and slowly pro- gressing inflammatory disease in ani- mals, but are non-oncogenic. In the early 1980s, the causative agent of AIDS was found to be a non-oncogenic retrovirus and was classified as a lentivirus. Thus, human immunodeficiency virus HIV became the first lentivirus causing a slow infection in humans. Þakkir Höfundur þakkar Tilraunastöð Háskóla Íslands í Meinafræði á Keldum fyrir leyfi til að birta gamlar myndir frá Keldum. Greinin er tileinkuð íslensku sauðkindinni. Heimildir 1. Barré-Sinoussi, F., Chermann, J.C., Rey, F., Nugeyre, M.T., Chamaret, S., Gruest, J., Dauguet, C., Axler-Blin, C., Vézinet-Brun, F., Rouzioux, C., Rozenbaum, W. & Montagnier, L. 1983. Isolation of a T-lymphotropic retrovirus from a patient at risk for acquired immune deficiency syndrome (AIDS). Science 220. 868–871. 2. Wain-Hobson, S., Alizon, M. & Montagnier, L. 1985. Relationship of AIDS to other retroviruses [Letter]. Nature 313. 743. 3. Case, K. 1986. Nomenclature: Human immunodeficiency virus. Annals of Internal Medicine 105. 133 bls. 4. Montagnier, L. 1985. Lymphadenopathy-associated virus: From molecul- ar biology to pathogenicity. Annals of Internal Medicine 103. 689–693. 5. Björn Sigurðsson 1954. Rida: a chronic encephalitis of sheep. With general remarks on infections which develop slowly and some of their special characteristics. British Veterinary Journal 110. 341–354. 6. Haase, A. 1986. The pathogenesis of slow virus infections: molecular analyses. Journal of Infectious Diseases153. 441–447. 7. Guðmundur Pétursson, Valgerður Andrésdóttir, Ólafur Andrésson, Sig- urbjörg Þorsteinsdóttir, Guðmundur Georgsson & Páll Pálsson 1991. Review. Human and ovine lentivirus infections compared. Comparative Immunology, Microbiology & Infectious Diseases 14. 277–287. 8. Halldór Þormar 2005. Maedi-visna virus and its relationship to human immunodeficiency virus. AIDS Review 7. 233–245. 9. Níels Dungal 1946. Experiments with Jaagsiekte. American Journal of Pathology 22. 737–759. 10. Rosadio, R.H., Lairmore, M.D., Russell, H.I. & DeMartini, J.C. 1988, Retrovirus-associated ovine pulmonary carcinoma (sheep pulmonary adenomatosis) and lymphoid interstitial pneumonia. I. Lesion develop- ment and age susceptibility. Veterinary Pathology 25. 475–483. 11. Palmarini, M., Sharp, J.M., de las Heras, M. & Fan, H. 1999. Jaagsiekte sheep retrovirus is necessary and sufficient to induce a contagious lung cancer in sheep, Journal of Virology 73. 6964–6972. 12. Leroux, C., Girard, N., Cottin, V., Greenland, T., Mornex, J.F. & Archer, F. 2007. Jaagsiekte Sheep Retrovirus (JSRV): from virus to lung cancer in sheep. Veterinary Research 38. 211–228. 13. Guðmundur Gíslason 1947. XII. þáttur um rannsóknir á vegum sauðfjár- sjúkdómanefndar. Í: Þættir um innflutning búfjár og karakúlsjúkdóma. Rit Landbúnaðarráðuneytisins, Ríkisprentsmiðjan Gutenberg, Reykjavik. 235–254. 14. Marsh, H. 1923. Progressive pneumonia in sheep. Journal of the American Veterinary Medical Association 62. 458–473. 15. Páll Pálsson 1976. Maedi and visna in sheep. Í: Slow virus diseases of animals and man (ritstj. Kimberlin, R.H.) North Holland Publishing Company, Amsterdam. 17–43. 16. Björn Sigurðsson, Páll Pálsson & Halldór Grímsson 1957. Visna, a demyel- inating transmissible disease of sheep. Journal of Neuropathology & Experimental Neurology 16. 389–403. 17. Ressang, A., de Boer, G. & Wijn, G. 1968. The lung in zwoegerziekte. Vet- erinary Pathology 5. 353–369. 18. Ressang, A., Stam F. & de Boer, G. 1966. A meningo-leukoencephalo- myelitis resembling visna in Dutch Zwoeger sheep. Veterinary Pathology 3. 401–411. 19. Brodie, S., Bickle, H. & DeMartini, J. 1995. Virological markers in cerebro- spinal fluid are predictive of ovine lentivirus-associated subclinical encephalomyelitis. Clinical Immunology and Immunopathology 77. 14–18. 20. Björn Sigurðsson, Halldór Grímsson & Páll Pálsson 1952. Maedi, a chron- ic progressive infection of sheep’s lungs. Journal of Infectious Diseases 90. 233–241. 21. Björn Sigurðsson, Páll Pálsson & Anna Tryggvadóttir 1953. Transmission experiments with maedi. Journal of Infectious Diseases 93. 166–175. 22. Björn Sigurðsson & Páll Pálsson 1958. Visna of sheep. A slow, demyel- inating infection. British Journal of Experimental Pathology 39. 519–528. 23. Björn Sigurðsson, Halldór Þormar & Páll Pálsson 1960. Cultivation of visna virus in tissue culture. Archiv für die gesamte Virusforschung 10:3. 368–381. 24. Halldór Þormar 1960. Stability of visna virus in infectious tissue culture fluid. Archiv für die gesamte Virusforschung 10:4. 501–509. 25. Björn Sigurðsson, Páll Agnar Pálsson & van Bogaert, L. 1962. Pathology of visna. Transmissible demyelinating disease in sheep in Iceland. Acta

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