CD34+CD31+ immature myeloid cells (IMC) as an inhibitor cell on the production of antimicrobial peptide: II. Glycyrrhizin inhibits IMC suppressor cell activities (89.27)

Abstract

Abstract In the accompanying paper I, CD34+CD31+ IMC are shown to be inhibitory on HBD-1 production by normal human epidermal keratinocytes (NHEK). CCL2 and IL-10 released from CD34+CD31+ IMC are identified as effectors in this suppressor cell activity. In this study, the suppressor cell activity of CD34+CD31+ IMC was shown to be controlled by glycyrrhizin (GL), an active component of licorice root. CD34+CD31+ IMC were isolated from peripheral blood of exercised donors, as described in the accompanying paper I. These IMC were transwell-cultured with NHEK for 48 hrs in the presence or absence of GL (Minophagen Pharmaceutical Co., Ltd., Tokyo, Japan), and cells in the bottom chamber (NHEK) were assayed for HBD-1 mRNA expression by RT-PCR. Also, the production of CCL2 and IL-10 by CD34+CD31+ IMC (1 x 106 cells/ml) treated with GL was measured by ELISA. In the results, NHEK transwell-cultured with CD34+CD31+ IMC did not express HBD-1 mRNA, while these transwell-cultures were performed with GL (10-100 μg/ml), HBD-1 mRNA was expressed by NHEK. The production of CCL2 and IL-10 was greatly reduced in CD34+CD31+ IMC cultures added with GL. These results indicate that the suppressor cell activity of CD34+CD31+ IMC on HBD-1 production by NHEK is controlled by GL. This study was supported by SHC #8610.