Characterization of the human platelet Fc sub. gamma. receptor
Thrombocytopenia is often associated with immune complex disease and may in part be due to the interaction of circulating (IgG) immune complexes with an Fc{sub {gamma}} receptor on the platelet surface. Characterization of the immune complex-platelet interaction should provide for a better understanding of the pathophysiology of immune thrombocytpenia. To this end, a ligand binding assay, employing {sup 125}I-IgG trimer, was established. Receptor expression was determined by measuring the saturable binding of radiolabeled trimer to platelets at equilibrium. Normal human platelets were observed to express 8559 {plus minus} 852 binding sites for IgG trimer with a Kd of 12.5 {plus minus} 1.7 {times} 10{sup {minus}8} M. Binding of IgG trimer to human platelets was blocked following preincubation of the cells with an anti-Fc{sub {gamma}}RII monoclonal antibody. Furthermore, this binding was ionic-strength dependent but was unaffected by the presence of Mg{sup ++} or cytochalasin B. Platelet Fc{sub {gamma}} receptor modulation was examined by assessing the effects of various physiologic and pharmacologic on the ability of platelets to bind IgG trimer. Platelet Fc{sub {gamma}} receptor expression was not affected by thrombin, ADP, or {gamma}-interferon. However, in 7/12 normal donors, treatment of platelets with dexamethasone resulted in a decrease in the number of Fc{sub {gamma}} receptors expressed.
- Research Organization:
- Pennsylvania Univ., Philadelphia, PA (USA)
- OSTI ID:
- 5481817
- Country of Publication:
- United States
- Language:
- English
Similar Records
Human Fc. gamma. RIII: Cloning, expression, and identification of the chromosomal locus of two Fc receptors for IgG
Evidence for immunoglobulin Fc receptor-mediated prostaglandin2 and platelet-activating factor formation by cultured rat mesangial cells
Related Subjects
550901 -- Pathology-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ADP
ADRENAL HORMONES
ANIMALS
ANTIBODIES
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BLOOD PLATELETS
BODY FLUIDS
CHEMICAL COMPOSITION
COAGULANTS
CORTICOSTEROIDS
DAYS LIVING RADIOISOTOPES
DEXAMETHASONE
DISEASES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ENZYMES
GLOBULINS
GLUCOCORTICOIDS
GROWTH FACTORS
HEMATOLOGIC AGENTS
HEMOSTATICS
HYDROLASES
HYDROXY COMPOUNDS
IMMUNE SYSTEM DISEASES
IMMUNOGLOBULINS
INTERFERON
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KETONES
KINETICS
LYMPHOKINES
MAMMALS
MAN
MATERIALS
MEMBRANE PROTEINS
MITOGENS
MONOCLONAL ANTIBODIES
NUCLEI
NUCLEOTIDES
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PATHOGENESIS
PEPTIDE HYDROLASES
PREGNANES
PRIMATES
PROTEINS
RADIOASSAY
RADIOISOTOPES
REACTION KINETICS
RECEPTORS
SERINE PROTEINASES
STEROIDS
THROMBIN
TRACER TECHNIQUES
VERTEBRATES