An improved fluorochrome microassay for the detection of living and non-living intracellular bacteria in human neutrophils.
Acridine orange fluorescence may be used to distinguish living from non-living intracellular bacteria in individual glass-adherent neutrophil granulocytes (PMN). An improvement of the original assay (Smith and Rommel, 1977; Pantazis and Kniker, 1979) is described which allows differentiation between ingested and cell-adherent bacteria. It is shown that this differentiation is impossible with the original method using wet-mounted preparations. With the improved method, however, using dry-mounted preparations, cell-adherent as well as extracellular bacteria lose their fluorescence. Moreover, the fluorescence of cell nuclei and granula is reduced to a minimum. Phagocytosis kinetics and selective inhibition of the myeloperoxidase of PMN show that living intracellular bacteria fluoresce green and non-living bacteria red in such dry-mounted preparations. The preparations can be stored and interpreted for at least 2 months. Application of this method requires 0.1 ml blood or cell-rich body fluid per preparation and is fast and inexpensive.
W
W
Horn
C
C
Hansmann
K
K
Federlin
D000165:Acridine Orange; D001386:Azides / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006801:Humans; D009504:Neutrophils / Q000382:microbiology*; D010587:Phagocytosis; D011190:Potassium Cyanide / Q000494:pharmacology; D013050:Spectrometry, Fluorescence; D013194:Staining and Labeling; D013211:Staphylococcus aureus
D001386:Azides; D000165:Acridine Orange; D011190:Potassium Cyanide