Use of a radioimmunoassay to quantify thrombospondin

Abstract

Results of radioimmunoassay procedures applied to samples containing thrombospondin indicated that reliable values are obtained either in saline or in plasma. Plasma levels in apparently normal individuals ranged from approximately 20 to 300 ng/ml. The mean for 20 individuals was 175 ng/ml. Plasma specimens stored either refrigerated at 4 degrees C or frozen at -80 degrees C showed significantly diminished thrombospondin levels over a period of 90 days. Serum levels of thrombospondin were found to range from 10,000 to 30,000 ng/ml.

Thrombospondin in Clinical Disease States

“…Radioimmunoassay has been the method of choice in the quantitation of these plate let α-granule proteins. [66][67][68] A wide range of mean values has been obtained for TSP in normal plasma (Table 1), all of which fall within the normal range of 20 to 300 ng/ml reported by Saglio and Slayter. 66 This variability may simply reflect the different preparations of TSP and anti-TSP used in these assays.…”

“…[66][67][68] A wide range of mean values has been obtained for TSP in normal plasma (Table 1), all of which fall within the normal range of 20 to 300 ng/ml reported by Saglio and Slayter. 66 This variability may simply reflect the different preparations of TSP and anti-TSP used in these assays. 64 No ageor sex-related differences in plasma TSP were evi dent.…”

Noncovalent and Covalent Interactions of Thrombospondin with Polymerizing Fibrin

“…The concentration of TSP in platelets has been calculated to be 59 mg/ ml, 7 whereas the plasma concentration is 20-300 ng/ml. [8][9][10] When activated by thrombin, platelets secrete the contents of their alpha-granules and aggregate, thus creating a pool of TSP around the platelet plug having a large concentration gradient in TSP. Upon secretion, TSP becomes partially bound to the platelet surface.…”

Mechanisms for Expression of Thrombospondin on the Platelet Cell Surface

“…31 The dissociation constant of TSP for resting plate lets was estimated to be 50 nM. At the normal plasma concentration of TSP, which has been esti mated to be as high as 20 to 165 ng/ml, [32][33][34][35][36] it is predicted that there should be 30 to 225 molecules of TSP on the surface of the resting platelet. These values are in close agreement with the measured level of TSP reported with the monoclonal antibody reagent.…”