Phagolysosomal pH of human neutrophils.
Human neutrophils sequester yeast cells or zymosan particles in two classes of phagocytic vacuoles: sealed and unsealed. The pH of sealed vacuoles was measured by a newly devised fluorometric procedure that used fluoresceinated zymosan particles, derived from Saccharomyces cerevisiae, as a pH probe. Five minutes after initiation of phagocytosis, sealed vacuoles were alkaline, exhibiting a pH of 7.80 +/- 0.19 (mean +/- SEM). Their acidity subsequently increased, so that the pH fell to 7.38 +/- 0.25 after 15 min. 6.35 +/- 0.35 after 30 min, and 5.68 +/- 0.26 after 60 min. The implications of these findings for neutrophil microbicidal mechanisms are discussed.
D001770:Blood Bactericidal Activity; D002021:Buffers; D016650:Fluorescein-5-isothiocyanate; D005452:Fluoresceins; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009504:Neutrophils / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D009940:Organoids / Q000032:analysis*; D010101:Oxygen Consumption; D013050:Spectrometry, Fluorescence; D013861:Thiocyanates; D014617:Vacuoles / Q000032:analysis* / Q000502:physiology; D015054:Zymosan
D002021:Buffers; D005452:Fluoresceins; D013861:Thiocyanates; D015054:Zymosan; D016650:Fluorescein-5-isothiocyanate