Document 0271
 DOCN  M9590271
 TI    Endocytosis and carriage of HIV-1 by human dendritic cells.
 DT    9509
 AU    Reece J; Vardaxis N; Crowe S; Cameron P; AIDS Pathogenesis Research
       Unit, Macfarlane Burnet Centre for; Medical Research, Fairfield,
       Victoria, Australia.
 SO    Annu Conf Australas Soc HIV Med. 1994 Nov 3-6;6:251 (unnumbered poster).
       Unique Identifier : AIDSLINE ASHM6/95291828
 AB    Blood dendritic cells (DCs) may play a critical role in the pathogenesis
       of HIV-1 infection by means other than their direct infection. CD4-
       blood DCs exposed to HIV-1, although uninfected, can efficiently
       transfer infection into CD4+ T cells, whereas cultured monocytes are
       less efficient. The ability of virus-pulsed DCs to transfer virus to T
       cells is trypsin resistant and short lived, and may reflect the cell's
       ability to internalize and recycle vesicles in the endocytic pathway. To
       examine the underlying mechanisms of carriage and uptake of virus by
       DCs, endocytosis and uptake of fluorescent latex beads by DCs at
       different stages of maturation was examined. Freshly isolated (immature)
       blood DCs were found to be very efficient at uptake of beads of sizes
       ranging from 14nm to 2300nm, comparable with that of fresh and cultured
       monocytes. A slight decrease in uptake, as the bead size increased, was
       also observed. In contrast, cultured (mature) DCs were much less
       efficient at bead uptake than immature DCs and monocytes. Confocal
       microscopy was used to examine the position and No. of beads within DCs
       and monocytes over a 24 hour period. Beads remaining in class II
       containing vacuolar compartments were also identified by the addition of
       HLA-DR-FITC during incubation with beads, and the movement of beads into
       acidic compartments was identified by a change in fluorescence of
       DR-FITC. Inefficient transfer of HIV-1 from cultured monocytes to T
       cells may be related to their ability to process and degrade virus in
       acidic compartments, whereas virus remains mainly in the non-acidic
       compartments of DCs, thereby enabling transfer to T cells.
 DE    Cells, Cultured  CD4-Positive T-Lymphocytes/VIROLOGY  Dendritic
       Cells/*VIROLOGY  Endocytosis/*PHYSIOLOGY  Human  HIV-1/*PATHOGENICITY
       Microscopy, Confocal  MEETING ABSTRACT

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