DYNAMIC REORGANIZATION OF THE ALKALINE PHOSPHATASE-CONTAINING COMPARTMENT DURING CHEMOTACTIC PEPTIDE STIMULATION OF HUMAN NEUTROPHILS IMAGED BY BACKSCATTERED ELECTRONS
E. Fernandezsegura et al., DYNAMIC REORGANIZATION OF THE ALKALINE PHOSPHATASE-CONTAINING COMPARTMENT DURING CHEMOTACTIC PEPTIDE STIMULATION OF HUMAN NEUTROPHILS IMAGED BY BACKSCATTERED ELECTRONS, HISTOCHEM C, 104(2), 1995, pp. 175-181
Scanning electron microscopy (EM) and cytochemical techniques were use
d to examine the alkaline phosphatase-containing compartment in human
neutrophils after stimulation with nanomolar concentrations of N-formy
lmethionyl-leucyl-phenylalanine (10(-8) M fMLP). Alkaline phosphatase
(AlkPase) activity was demonstrated with a lead-based metal capture cy
tochemical method. The reaction product was visualized with the backsc
attered electron imaging mode of scanning EM, and analyzed by electron
probe X-ray microanalysis. Alkaline phosphatase activity was detected
only in fMLP-stimulated neutrophils; unstimulated neutrophils display
ed no activity. Stimulation of human neutrophils with 10(-8) M fMLP in
duced a time-dependent intracellular redistribution of irregular round
or tubular granules containing alkaline phosphatase activity, as seen
by backscattering. The intracellular redistribution of alkaline phosp
hatase activity was accompanied by increased cytochemical activity on
the cell surface. The reaction product was localized preferentially on
ridges and folds of polar neutrophils. Reorganization of the AlkPase-
containing compartment correlated with changes induced by fMLP in cell
shape, ie, membrane ruffling and front-tail polarity, as as observed
with the secondary electron image mode of scanning EM. These findings
demonstrate the intracellular reorganization, increase, and asymmetric
distribution of alkaline phosphatase activity on the plasma membrane
of human neutrophils after stimulation by chemotactic peptides.