Document 0312
 DOCN  M9590312
 TI    CD4 expression is not related to HIV-1 in vitro infection of alveolar
       macrophages.
 DT    9509
 AU    Lewin SR; Sonza S; Irving L; McDonald CF; Mills J; Crowe SM; National
       Centre for HIV Virology Research, Macfarlane Burnet; Centre for Medical
       Research, Fairfield, Victoria.
 SO    Annu Conf Australas Soc HIV Med. 1994 Nov 3-6;6:191 (unnumbered
       abstract). Unique Identifier : AIDSLINE ASHM6/95291787
 AB    The CD4 glycoprotein is the major cellular receptor for HIV. It has been
       reported by us and other groups that CD4 surface expression of monocytes
       decreases with time in culture while their susceptibility to HIV-1
       increases. Our aim was to investigate whether this phenomenon occurs in
       macrophages that have differentiated in vivo by investigating CD4
       expression and HIV-1 infection of alveolar macrophages (AM). Using
       fluorescent activated cell scanner (FACS) analysis of Leu-3a labelled
       directly or indirectly with FITC or allophycocyanin (APC), we found that
       CD4 was expressed at low but detectable levels, despite high background
       autofluorescence well described in AM. The sensitivity of detection was
       greatest using APC indirectly conjugated to anti-Leu 3a. This finding
       was confirmed by the detection of CD4 mRNA using RT-PCR. Despite this
       low level of surface CD4, AM can be infected with the macrophage tropic
       HIV-1 strain, Ba-L. Infection of AM was documented by rising reverse
       transcriptase concentrations in culture fluid over time and de novo
       appearance of HIV cDNA (gag sequences detected after PCR amplification)
       On the other hand, monocytes, on the day of isolation, although
       expressing high levels of CD4 can not be productively infected with
       Ba-L. We conclude that differentiation of monocytes into macrophages in
       vivo appears to be necessary for successful HIV-1 in vitro infection of
       cells of the monocyte/macrophage lineage. The exact role of CD4 in the
       infection of mature macrophages requires further evaluation with
       functional experiments involving blocking with soluble CD4.
 DE    Antigens, CD4/*IMMUNOLOGY  Cells, Cultured  Human  HIV-1/*IMMUNOLOGY
       Macrophages, Alveolar/*IMMUNOLOGY/VIROLOGY
       Monocytes/IMMUNOLOGY/VIROLOGY  Support, Non-U.S. Gov't  Virus
       Integration/IMMUNOLOGY  MEETING ABSTRACT

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