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Author Craig, Le ♦ Sheffer, D. ♦ Meyer, Al ♦ Hauer, D. ♦ Lechner, F. ♦ Peterhans, E. ♦ Adams, Rj ♦ Clements, Je ♦ Narayan, O. ♦ Zink, Mc
Source CiteSeerX
Content type Text
File Format PDF
Subject Domain (in DDC) Computer science, information & general works ♦ Data processing & computer science
Subject Keyword Ovine Lentiviral Encephalitis ♦ Vivo Passage ♦ Neurovirulent Strain ♦ High Titer ♦ Neuroadapted Virus ♦ Cd4 Cell ♦ Natural Infection ♦ Joint Macrophage ♦ Persistent Infection ♦ Cell-associated Viremia ♦ Neuroadapted Strain ♦ Cause Encephalitis ♦ Nonneurovirulent Eld Strain ♦ Separate Pathogenic Determinant ♦ Severe Encephalitis ♦ Ovine Lentivirus ♦ Tnf-a Expression ♦ Mhc Class Ii Antigen Expression ♦ Ammatory Cell ♦ Eld Isolate ♦ Cultured Microglia ♦ Intracerebral Inoculation ♦ Chronic Interstitial Pneumonia ♦ Perivascular Macrophage ♦ Joint Uid ♦ Ammatory Response ♦ Sheep Replicate
Abstract The lentiviruses of sheep replicate almost exclusively in macrophages and cause chronic interstitial pneumonia, arthritis, and mastitis, but only rarely encephalitis. This study was undertaken to determine whether a nonneurovirulent ®eld strain of ovine lentivirus isolated from joint ¯uid that replicated productively in lung and joint macrophages could be adapted to enter and replicate in the brain and cause encephalitis. The ®eld isolate was passed seven times sequentially by intracerebral inoculation of sheep. The neuroadapted strain of virus caused severe encephalitis typical of visna in four of four sheep inoculated intracerebrally. The virus replicated to high titers in the brains of these animals and in cultured microglia. The in¯ammatory response in the brain was characterized by intense in®ltrates of macrophages and CD8 + and CD4 + T cells. Many of the perivascular macrophages demonstrated TNF-a expression and there was upregulation of MHC Class II antigen expression on both in¯ammatory cells and endothelium. Inoculation of this neuroadapted virus into the bone marrow of three animals resulted in persistent infection and cell-associated viremia, but not encephalitis. Virus was not detected in brains from these animals, indicating that the virus was not neuroinvasive. These data suggest that neuroinvasiveness and neurovirulence are separate pathogenic determinants, both of which are required for the development of encephalitis during natural infection.
Educational Role Student ♦ Teacher
Age Range above 22 year
Educational Use Research
Education Level UG and PG ♦ Career/Technical Study