Interleukin-6 Directly Modulates Stem Cell Factor-Dependent Development of Human Mast Cells Derived From CD34+Cord Blood Cells

Abstract

In the present study, we attempted to clarify the effects of interleukin-6 (IL-6) on the growth and properties of human mast cells using cultured mast cells selectively generated by stem cell factor (SCF) from CD34+ cord blood cells. The addition of IL-6 to cultures containing mast cells resulted in a substantial reduction of the number of progenies grown by SCF in the liquid culture. This IL-6–mediated inhibition of mast cell growth may be due in part to the suppression at the precursor level, according to the results of a clonal cell culture assay. Moreover, a flow cytometric analysis showed that the cultured mast cells grown in the presence of SCF+IL-6 had decreased c-kit expression. The exposure of cultured mast cells to SCF+IL-6 also caused substantial increases in the cell size, frequency of chymase-positive cells, and intracellular histamine level compared with the values obtained with SCF alone. The flow cytometric analysis showed low but significant levels of expression of IL-6 receptor (IL-6R) and gp130 on the cultured mast cells grown with SCF. The addition of either anti–IL-6R antibody or anti-gp130 antibody abrogated the biological functions of IL-6. Although IL-4 exerted an effect similar to that of IL-6 on the cultured mast cells under stimulation with SCF, the results of comparative experiments suggest that the two cytokines use different regulatory mechanisms. Taken together, the present findings suggest that IL-6 modulates SCF-dependent human mast cell development directly via an IL-6R-gp130 system.

IL‐6 attenuates apoptosis, while neither IL‐6 nor IL‐10 affect the numbers or protease phenotype of fetal liver‐derived human mast cells

“…Possibly, the growth enhancing effect of rhIL-6 requires serum. Another study employing serum-free media found that rhIL-6 diminished the numbers of total mast cells derived from cord blood in the presence of rhSCF, and increased the percentages of chymase-positive cells without a substantial change in their numbers [16]. This previous study utilized only 10 ng/mL (10-fold lower than the current study) of rhSCF and an atmosphere consisting of 5% CO 2 , 5% O 2 and 90% N 2 (,25% of the O 2 content used in the current study) to develop mast cells, possibly accounting for the different outcomes.…”

STI571 inhibits growth and adhesion of human mast cells in culture

“…Serum-deprived liquid cultures were carried out in 24-well culture plates (#3047; Becton Dickinson) using a modification of the technique described previously [22][23][24]. To examine the effects of STI571 on the SCF-dependent development of mast cells, we used 10-week cultured cells grown with 20 ng/mL of SCF from CD34 ϩ cord blood cells as target cells, because a large number of such cultured cells were positive for tryptase, as described previously [22,23].…”

“…Serum-deprived liquid cultures were carried out in 24-well culture plates (#3047; Becton Dickinson) using a modification of the technique described previously [22][23][24]. To examine the effects of STI571 on the SCF-dependent development of mast cells, we used 10-week cultured cells grown with 20 ng/mL of SCF from CD34 ϩ cord blood cells as target cells, because a large number of such cultured cells were positive for tryptase, as described previously [22,23]. In a doseϪresponse study, 10-week cultured cells (1ϫ10 5 ) were incubated for 2 weeks in 24-well culture plates containing 2 mL of ␣-medium supplemented with 1% bovine serum albumin (BSA), 300 g/mL fully ironsaturated human transferrin (ϳ98% pure, Sigma), 16 g/mL soybean lecithin (Sigma), 9.6 g/mL cholesterol (Nakalai Chemicals Ltd., Tokyo, Japan), 20 ng/mL of SCF with or without various concentrations of STI571.…”

“…These lines of evidence prompted us to evaluate the effects of STI571 on the growth and function of normal mast cells in humans. For this purpose, we used a serum-deprived culture system that permitted the selective growth of a large number of mast cells from CD34 ϩ human cord blood under stimulation with SCF [22].…”

A protocol for generating high numbers of mature and functional human mast cells from peripheral blood

“…To date, several methods have been described to obtain primary cultures of human MCs. These include the bone marrow [18], cord blood [27][28][29], peripheral blood [9,30], and foetal liver [10,31] as a source of MC progenitors. Depending on the source of the progenitor cells and the methodology used, the number of MCs generated, the degree of their maturity, and their phenotype and responsiveness towards various stimuli vary greatly [31][32][33].…”