Platelet modulation of human neutrophil functions
The combined presence of platelets (PLTS) and neutrophils (PMN) at inflammatory sites has led to examination of the hypothesis that interaction of these cells modulates their responses to stimuli. Gel-filtered human PLTS (GFP) were found to inhibit N-formyl-met-leu-phe (FMLP) and phorbol myristate acetate (PMA) stimulated PMN O/sub 2//sup -/ generation in a concentration-dependent fashion. The heat-stable inhibitory activity was present in the supernatants of GFP after incubation with FMLP (10/sup -7/M), thrombin (0.5 U/ml) or ADP (20 ..mu..M), suggesting a role for PLT release products. PLT lysates added to PMN produced up to 80% inhibition of O/sub 2//sup -/ generation for PMA and 40% for FMLP. Like GFP, lysates failed to scavenge O/sub 2/..pi.. produced by xanthine oxidase-hypoxanthine. The inhibitory activity could not be ascribed to serotonin or adenosine. PLT lysates failed to compete with /sup 3/H-FMLP for binding to PMN. Sephadex G-200 fractionation of PLT lysates releaved two peaks of inhibitory activity with apparent Mr > 200,000 and < 14,000 Daltons. Pretreatment of PMN with PLT lysates also results in a concentration-dependent inhibition of degranulation provoked by FMLP (2 x 10/sup -7/M) or PMA (2 ng/ml) and PMN chemotaxis to FMLP (10/sup -8/M). These studies indicate that preformed PLT mediator(s) released in response to physiological stimuli may limit tissue damage by PMN at sites of inflammation.
- Research Organization:
- St. Louis Univ. School of Medicine, MO
- OSTI ID:
- 5499248
- Report Number(s):
- CONF-8604222-; TRN: 86-026807
- 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
59 BASIC BIOLOGICAL SCIENCES
BLOOD PLATELETS
BIOLOGICAL EFFECTS
INFLAMMATION
INHIBITION
NEUTROPHILS
BIOLOGICAL FUNCTIONS
ADP
MAN
PHORBOL ESTERS
SUPEROXIDE RADICALS
THROMBIN
ANIMALS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CARCINOGENS
COAGULANTS
DRUGS
ENZYMES
ESTERS
FUNCTIONS
HEMATOLOGIC AGENTS
HEMOSTATICS
HYDROLASES
LEUKOCYTES
MAMMALS
MATERIALS
NUCLEOTIDES
ORGANIC COMPOUNDS
PATHOLOGICAL CHANGES
PEPTIDE HYDROLASES
PRIMATES
RADICALS
SERINE PROTEINASES
SYMPTOMS
VERTEBRATES
560301* - Chemicals Metabolism & Toxicology- Cells- (-1987)
550201 - Biochemistry- Tracer Techniques