Back to Search
Start Over
Fc-receptor-mediated phagocytosis occurs in macrophages without an increase in average [Ca++]i
- Source :
- The Journal of Cell Biology
- Publication Year :
- 1986
- Publisher :
- The Rockefeller University Press, 1986.
-
Abstract
- The calcium ion has been implicated as a cytosolic signal or regulator in phagocytosis. Using the Ca++-sensitive photoprotein aequorin we have measured intracellular free Ca++ ion concentration ([Ca++]i) in thioglycolate-elicited mouse peritoneal macrophages during phagocytosis and IgG-induced spreading. Macrophages plated on glass were loaded with aequorin and [Ca++]i was then measured from cell populations, both as previously described (McNeil, P. L., and D. L. Taylor, 1985, Cell Calcium, 6:83-92). Aequorin indicated a resting [Ca++]i in adherent macrophages of 84 nM and was responsive to changes in [Ca++]i induced by the addition of Mg-ATP (0.1 mM) or serum to medium. However, during the 15 min required for phagocytosis of seven or eight IgG-coated erythrocytes per macrophage loaded with aequorin, we measured no change in [Ca++]i. Similarly, the ligation of Fc-receptors that occurs when macrophages spread on immune complex-coated coverslips did not change macrophage [Ca++]i. In contrast, a rise in [Ca++]i of macrophages was measured during phagocytosis occurring in a serum-free saline of pH 7.85, and as a consequence of incubation with quin2 A/M. We estimate that had a change in [Ca++]i occurred during phagocytosis, aequorin would have detected a rise from 0.1 to 1.0 microM taking place in as little as 2% of the macrophage's cytoplasmic volume. We therefore suggest that either Ca++ is not involved as a cytoplasmic signal for phagocytosis or that increases in [Ca++]i during phagocytosis are confined to such small regions of cytoplasm as to be below the limits of detection by our cellular averaging method. Our data emphasizes, moreover, the need for well-defined, nonperturbing conditions in such measurements of [Ca++]i.
- Subjects :
- Cytoplasm
Erythrocytes
Latex
Phagocytosis
Aequorin
Fc receptor
Photoprotein
chemistry.chemical_element
Receptors, Fc
Calcium
Microbiology
Biochemistry
Mice
Macrophage
Animals
biology
Macrophages
Cytology--Research
Cell Biology
Articles
Hydrogen-Ion Concentration
Cell biology
Culture Media
Cytosol
chemistry
FOS: Biological sciences
biology.protein
Biophysics
Aminoquinolines
Cytology
Intracellular
Calcium ions--Physiological effect
Subjects
Details
- Language :
- English
- ISSN :
- 15408140 and 00219525
- Volume :
- 102
- Issue :
- 5
- Database :
- OpenAIRE
- Journal :
- The Journal of Cell Biology
- Accession number :
- edsair.doi.dedup.....7e405f84f2e51abd4ed00a6eb0402ce7