Document 0387
 DOCN  M9590387
 TI    Novel method for quantifying phagocytosis of Mycobacterium avium complex
       by monocytes in whole blood.
 DT    9509
 AU    Hewish M; Meikle A; Hunter S; Crowe S; Macfarlane Burnet Centre for
       Medical Research, Fairfield, Vic.
 SO    Annu Conf Australas Soc HIV Med. 1994 Nov 3-6;6:101 (unnumbered
       abstract). Unique Identifier : AIDSLINE ASHM6/95291712
 AB    Mycobacterium avium complex (MAC) is the most common cause of
       opportunistic bacterial infection in AIDS patients. We have developed a
       rapid assay for phagocytosis of MAC, with a view to detecting impairment
       of immune function in monocytes from HIV-infected donors. In this assay,
       fluorescein (FITC)-labelled MAC was incubated with whole blood from
       healthy donors at 37 degrees C for 10 min. (controls at 0 degree C),
       monocytes were labelled with anti-CD14-phycoerythrin (PE) and the red
       cells were lysed. White blood cells were analysed for PE and FITC
       fluorescence by flow cytometry, and the percentage phagocytosis (%
       FITC-positive cells in the PE-positive population) was calculated.
       Phagocytosis of MAC by monocytes in whole blood could be assayed by this
       method, and the results were reproducible in duplicate tests. In control
       experiments (0 degree C), phagocytosis was less than 10%. Phagocytosis
       increased with increasing concentrations of MAC, in the range 0-2 x
       10(7) bacteria added to 100 microliters blood. At higher levels of MAC,
       phagocytic efficiency was high (> 90%) for some donors, but there was
       wide variation between individuals. The assay has also been adapted to
       detect phagocytosis of latex beads (Latex fluospheres, 625/645), with
       monocytes labelled with anti-CD14-FITC. These assays are currently being
       used in clinical trials in AIDS patients with disseminated MAC
       infection.
 DE    AIDS-Related Opportunistic Infections/DIAGNOSIS/*IMMUNOLOGY  Flow
       Cytometry  Fluorescein-5-isothiocyanate  Human  Monocytes/*IMMUNOLOGY
       Mycobacterium avium Complex/*IMMUNOLOGY  Mycobacterium
       avium-intracellulare Infection/DIAGNOSIS/  *IMMUNOLOGY
       Phagocytosis/*IMMUNOLOGY  MEETING ABSTRACT

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