Lipopolysaccharide (LPS)-mediated macrophage activation: the role of calcium in the generation of tumoricidal activity
As the authors reported, calcium ionophore, A23187, activates macrophages (M theta) for tumor cell killing and the activated M theta produce a soluble cytotoxic factor (M theta-CF) that is similar if not identical to tumor necrosis factor. Based on these observations they have investigated whether calcium is involved in the activation mediated by another potent M theta activator, LPS. The authors have shown that A23187 caused uptake of extracellular /sup 45/Ca/sup + +/ but LPS did not. They have examined the effect of depleting extracellular calcium by using medium containing no added calcium containing 1.0 mM EGTA. In no case did depletion result in decreased M theta-CF production by the M theta activated with LPS. Measurements using the fluorescent, intracellular calcium indicator, Quin 2 have also been performed. While ionomycin, caused a rapid change in the Quin-2 signal, LPS at a concentration even in excess of that required to activate the M theta caused no change in the signal. When high doses of Quin 2 or another intracellular chelator, 8-(diethylaminol-octyl-3,4,5-trimethoxybenzoate, were used to treat M theta, M theta-CF production decreased and cytotoxic activity was impaired. These data indicate that one or more of the processes involved in M theta-CF production does require calcium, but that activation mediated by LPS occurs without the influx of extracellular calcium or redistribution of intracellular calcium.
- Research Organization:
- Johns Hopkins Univ., Baltimore, MD
- OSTI ID:
- 5459292
- Report Number(s):
- CONF-8604222-; TRN: 86-028534
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:3; Conference: 70. annual meeting of the Federation of American Society for Experimental Biology, St. Louis, MO, USA, 13 Apr 1986
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CALCIUM
MEMBRANE TRANSPORT
LIPOPOLYSACCHARIDES
BIOLOGICAL EFFECTS
TUMOR CELLS
CELL KILLING
CALCIUM 45
MACROPHAGES
NEOPLASMS
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METALS
ANIMAL CELLS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CALCIUM ISOTOPES
CARBOHYDRATES
CONNECTIVE TISSUE CELLS
DAYS LIVING RADIOISOTOPES
DISEASES
ELEMENTS
EVEN-ODD NUCLEI
INTERMEDIATE MASS NUCLEI
ISOTOPES
LIPIDS
METALS
NUCLEI
ORGANIC COMPOUNDS
PHAGOCYTES
POLYSACCHARIDES
RADIOISOTOPES
SACCHARIDES
SOMATIC CELLS
550901* - Pathology- Tracer Techniques