Comparative Analysis of Dibutyric cAMP and Butyric Acid on the Differentiation of Human Eosinophilic Leukemia EoL-1 Cells

Purification of enough numbers of circulating eosinophils is difficult because eosinophils account for less than 5% peripheral blood leukocytes. Human eosinophilic leukemia EoL-1 cells have been considered an in vitro source of eosinophils as they can differentiate into mature eosinophil-like cells when incubated with dibutyryl cAMP (dbcAMP) or butyric acid. In this study, the viability and phenotypic maturation of EoL-1 cells stimulated by either dbcAMP or butyric acid were comparatively analyzed. After treatment with 100 microM dbcAMP or 0.5 microM butyric acid, EoL-1 cells showed morphological signs of differentiation, although the number of nonviable EoL-1 cells was significantly increased following butyric acid treatment. Stimulation of EoL-1 cells with 0.5 microM butyric acid more effectively induced the expression of mature eosinophil markers than stimulation with dbcAMP. These results suggest that treatment of EoL-1 cells with 0.5 microM butyric acid for limited duration could be an effective strategy for inducing their differentiation. Considering that expression of CCR3 was not sufficient in EoL-1 cells stimulated with 0.5 microM butyric acid, treatment of the chemically stimulated EoL-1 cells with cytokines, which primarily support eosinophil maturation, would help to obtain differentiated EoL-1 cells with greater functional maturity.

Effects of Mycoplasma Pneumoniae on Activation of Human Eosinophilic Leukaemia EoL-1 Cells / 소아알레르기및호흡기학회지

PURPOSE: Mycoplasma pneumoniae is a common cause of lower respiratory disease, especially in children and young adults. Several studies have suggested that respiratory infection by M. pneumoniae is associated with reactive airway disease and asthma. Though eosinophilia in peripheral blood are revealed in patients with mycoplasmal pneumonia, what is not known is the functional capacity of M. pneumoniae to activate human eosinophils. We investigated whether M. pneumoniae lysate (MPL) can activate human eosinophils to release inflammatory mediators. METHODS: Human eosinophilic leukemic cell lines, EoL-1 cells were incubated with MPL. Activation of EoL-1 cells was monitored by IL-8 production, superoxide production and surface expression of CD69, ICAM-1, CD11b, and CD49d. In addition, we examined the effect of MPL and the role of mitogen-activated protein kinases (MAPKs) on IL-8 expression in EoL- 1 cells. RESULTS: MPL induced IL-8 release in a time- and dose- dependent manner. However MPL did not induce superoxide anion production and CD69, ICAM-1, CD11b, and CD49d surface expression in EoL-1 cells. Pretreatment with mitogen-activated protein/extracellular signal- regulated kinase (ERK) [MEK] inhibitor PD98059, c-Jun N-terminal kinase (JNK) inhibitor II SP600125, and selective p38 MAPK inhibitor SB202190 inhibited MPL-induced IL-8 production, but the MPL stimulation had no effect on the activities of nuclear factor (NF)-kappaB. CONCLUSION: These observations suggest that MPL causes activation of EoL-1 cells, and activation of MAPKs by MPL may be one of the mechanisms that result in an increase of the production of IL-8.

House Dust Mite Induces Expression of Intercellular Adhesion Molecule-1 in EoL-1 Human Eosinophilic Leukemic Cells

The house dust mite (HDM) is considered to be the most common indoor allergen associated with bronchial asthma. In this study, we investigated whether crude extract of the HDM Dermatophagoides farinae could activate human eosinophilic leukemic cells (EoL-1) to induce upregulation of cell-surface adhesion molecules. When EoL-1 cells were incubated with D. farinae extract, expression of intercellular adhesion molecule-1 (ICAM-1) significantly increased on the cell surfaces compared to cells incubated with medium alone. In contrast, surface expression of CD11b and CD49d in EoL-1 cells was not affected by D. farinae extract. In addition, pretreatment of cells with NF- kappaB inhibitor (MG-132) or JNK inhibitor (SP600125) significantly inhibited ICAM-1 expression promoted by HDM extract. However, neither p38 MAP kinase inhibitor nor MEK inhibitor prevented HDM-induced ICAM-1 expression in EoL-1 cells. These results suggest that crude extract of D. farinae induces ICAM-1 expression in EoL-1 cells through signaling pathways involving both NF- kappaB and JNK.

Effects of Hyperosmolar Stimuli on Activation of Human Eosinophilic Leukaemia EoL-1 Cells / 소아과

PURPOSE: Airway dehydration and subsequent hyperosmolarity of periciliary fluid are considered critical events in exercise-induced bronchoconstriction. The aim of this study was to establish if a hyperosmolar challenge could induce activation of eosinophils. METHODS: Human eosinophilic leukaemic cell lines, EoL-1 cells were incubated with hyperosmolar solutions for 15 minutes. Activation of EoL-1 cells was monitored by degranulation and superoxide anion production. In addition, we examined surface expression of CD69 and ICAM-1. RESULTS: Hyperosmolar stimuli didn't induce superoxide anion production and degranulation. In addition, EoL-1 cells cultured with hyperosmolar medium at 930 mOsm/kg H2O resulted in no significant increment in fluorescent intensity of CD69 and ICAM-1 expression compared with results for cells incubated with isomolar medium. CONCLUSION: We found that hyperosmolar stimuli don't cause activation of EoL-1 cells, but further studies are required to determine the role of eosinophil in the mechanism of exercise-induced asthma.