Document 0870
 DOCN  M9540870
 TI    The proteins of lymphocyte- and macrophage-tropic strains of simian
       immunodeficiency virus are processed differently in macrophages.
 DT    9504
 AU    Stephens EB; McClure HM; Narayan O; Department of Microbiology,
       Immunology, and Molecular Genetics,; University of Kansas Medical
       Center, Kansas City 66160-7424.
 SO    Virology. 1995 Jan 10;206(1):535-44. Unique Identifier : AIDSLINE
       MED/95133190
 AB    Since the pathogenesis of SIVmac disease complex is thought to be
       explained by the tropism of the infecting virus for either CD4+
       T-lymphocytes or macrophages or both types of cells, we compared the
       infection in primary macaque macrophages with molecularly cloned,
       lymphocyte-tropic SIVmac239 and a cloned, macrophage-tropic chimeric
       virus (SIVmac239/17E) whose env gene was derived from brain of a macaque
       (17E) dying from SIV-induced encephalopathy. SIVmac239/17E caused a
       productive, syncytial cytopathic infection accompanied by accumulation
       of virus particles within cytoplasmic vesicles of the macrophages.
       Pulse-chase and immune precipitation studies showed that both the viral
       glycoprotein precursor (gp160) and the gag precursor (p57) were cleaved
       into gp120 and p27, respectively, and both were released into the
       culture medium of infected cells, although most of the p27 remained cell
       associated. SIVmac239 also infected macrophages, but in comparison to
       SIVmac239/17E, minimal virus replication occurred. Immunocytostaining
       revealed that while occasional syncytia were observed in cultures, the
       majority of the infected cells were not associated with syncytium
       formation. Ultrastructural studies did not reveal the accumulation of
       virions within infected macrophages. Pulse-chase studies showed that
       both gp160 and p57 were produced but were cleaved inefficiently and only
       minimal amounts of gp120 and p27 were released into the culture medium,
       even after prolonged incubation times. The processing of proteins of the
       two viruses was indistinguishable in lymphocytes. Since these two
       viruses are identical except for changes within the env gene, these
       results indicate that efficient assembly and release of SIV from
       blood-derived macrophages is mediated by changes in the envelope
       glycoprotein.
 DE    Animal  Biological Transport  Cell Line  Cell Membrane/METABOLISM
       Electrophoresis, Gel, Pulsed-Field  Glycoproteins/METABOLISM
       Lymphocytes/*METABOLISM/VIROLOGY  Macaca mulatta
       Macrophages/*METABOLISM/ULTRASTRUCTURE/VIROLOGY  Microscopy, Electron
       *Protein Processing, Post-Translational  Support, U.S. Gov't, P.H.S.
       SIV/*METABOLISM/PATHOGENICITY  Viral Proteins/*METABOLISM  JOURNAL
       ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).