Soluble stem cell factor in human serum

Abstract

Stem cell factor (SCF) is a recently described factor active in the early stages of hematopoiesis. It can exist in membrane-bound form and in proteolytically released soluble form. The levels and nature of SCF in human serum are described. As determined by an enzyme-linked immunosorbent assay performed for 257 samples, SCF level in serum averaged 3.3 +/- 1.1 ng/mL. The serum SCF was partially purified by immunoaffinity chromatography and analyzed by glycosidase treatments in conjunction with sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. The results show that the SCF has N- linked and O-linked carbohydrate and corresponds to the soluble form, at or about 165 amino acids in length. The findings suggest functional importance for soluble SCF in humans.

IL‐33‐activated murine mast cells control the dichotomy between RORγt+ and Helios+Tregs via the MK2/3‐mediated IL‐6 production in vitro

“…In contrast to this, MK2/3 did not regulate mast cell proliferation in presence of low SCF concentrations. Reflecting the finding that connective tissue mast cells (CTMCs) require only low levels of SCF for their homeostatic survival in vivo and in vitro , the frequencies of CTMCs in the peritoneal cavity of wt and mk2/3 −/− mice were comparable (Fig. G).…”

Serum inhibitors for human mast cell growth: possible role of retinol

“…There are two types of SCF, i.e., a membrane‐bound form and a soluble form. Soluble SCF circulates in the blood at detectable levels (1, 2). Because only limited numbers of mast cells can be obtained from human tissues, attempts have been made to establish human mast cell cultures using SCF.…”

True

“…11,27 In spite of the relatively similar effects which both factors exert, a comparison of the levels of FLT3 ligand and SCF in normal individuals and in those with hematopoietic disorders reveals some striking differences. Levels of SCF in normal human serum average several nanograms per milliliter, 28,29 while FLT3 ligand serum levels are usually below 100 pg/ml.…”