E. Fernandezsegura et al., SURFACE EXPRESSION AND DISTRIBUTION OF FC RECEPTOR-III (CD16 MOLECULE) ON HUMAN NATURAL-KILLER-CELLS AND POLYMORPHONUCLEAR NEUTROPHILS, Microscopy research and technique, 28(4), 1994, pp. 277-285
Human natural killer cells and polymorphonuclear neutrophils constitut
ively express the low-affinity IgG Fc receptor (Fc gamma RIII, CD16 mo
lecule). To investigate cell surface morphology, antigenic receptor de
nsity, and topographical distribution of Fc gamma RIII on the plasma m
embrane of natural killer cells and polymorphonuclear neutrophils, con
ventional scanning electron microscopy (SEM), flow cytometry, and immu
noscanning electron microscopy were used. Fc gamma RIII was detected w
ith an indirect immunogold labeling procedure, and receptors were visu
alized in the backscattered and secondary electron imaging mode of SEM
. Natural killer cells showed a cell surface morphology compatible wit
h lymphocytic differentiation characterized by microvilli and microrid
ges. Polymorphonuclear neutrophils showed surface features characteriz
ed by ridges with folds and scattered short microvilli. Natural killer
cells displayed a lower cell labeling density, whereas polymorphonucl
ear neutrophils showed a high level of expression of Fc gamma RIII on
the plasma membrane by quantitative analysis with SEM in the backscatt
ered electron imaging mode. Flow cytometry analysis confirmed these fi
ndings. Analysis of the topographical distribution of Fc gamma RIII an
tigenic receptor sites by SEM in the backscattered and secondary elect
ron imaging modes showed that Fc gamma RIII on natural killer cells ar
e randomly distributed, whereas Fc gamma RIII are located on ridges an
d folds of the plasma membrane of polymorphonuclear neutrophils. These
observations suggest that natural killer cells and polymorphonuclear
neutrophils differ in their levels of expression and topographic distr
ibution of Fc gamma RIII on the plasma membrane. This different spatia
l distribution of Fc gamma RIII would provide morphological evidence o
f certain cellular functions mediated by natural killer cells and poly
morphonuclear neutrophils. (C) 1994 Wiley-Liss, Inc.