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Interferon-gamma increases CD62L expression on human eosinophils
1First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Japan.
Insights
Interferon-gamma (IFN-gamma) uniquely increases L-selectin (CD62L) expression on eosinophils, unlike other cytokines. This suggests protein synthesis and cAMP are involved in IFN-gamma
Area of Science:
- Immunology
- Cell Biology
- Hematology
Background:
- L-selectin (CD62L) and Mac-1 (CD11b/CD18) are critical for eosinophil infiltration.
- Cytokine-induced changes in eosinophil CD62L and CD11b expression require further investigation.
Purpose of the Study:
- To investigate the effects of key cytokines (IL-5, GM-CSF, IFN-gamma) on CD62L and CD11b expression in human eosinophils.
- To examine the impact of dexamethasone, cycloheximide, and theophylline on IFN-gamma-induced CD62L expression.
Main Methods:
- Human peripheral blood eosinophils were isolated and cultured with IL-5, GM-CSF, or IFN-gamma.
- Flow cytometry was used to analyze CD62L and CD11b expression after incubation.
- The modulatory effects of dexamethasone, cycloheximide, and theophylline on CD62L were assessed.
Main Results:
- IL-5 and GM-CSF downregulated CD62L and upregulated CD11b expression.
- IFN-gamma time- and dose-dependently upregulated CD62L expression, with no effect on CD11b.
- Dexamethasone, cycloheximide, and theophylline reduced CD62L expression on IFN-gamma-stimulated eosinophils.
Conclusions:
- IFN-gamma uniquely enhances CD62L expression on human eosinophils.
- Protein synthesis and intracellular cAMP levels are implicated in the IFN-gamma-mediated increase of L-selectin expression.
Background:
L-selectin (CD62L) and Mac-1 (CD11b/CD18) play a crucial role in the infiltration of eosinophils. However, changes in CD62L and CD11b expression on eosinophils after stimulation with cytokines were little studied.
Methods:
Eosinophils in peripheral blood of healthy volunteers were purified and cultured with interleukin-5 (IL-5), granulocyte/macrophage colony-stimulating factor (GM-CSF) or interferon-gamma (IFN-gamma). After up to 24 h incubation, CD62L and CD11b expression were examined using flow cytometry. The effects of dexamethasone (Dex), cycloheximide (CHX) or theophylline on CD62L expression on IFN-gamma-stimulated eosinophils were also studied.
Results:
IL-5 or GM-CSF downregulated CD62L and upregulated CD11b expression on eosinophils after 30 min stimulation. Conversely, IFN-gamma upregulated CD62L after 12 h stimulation in a time- and dose-dependent manner, and had no effect on CD11b expression. Dex, CHX or theophylline dose-dependently decreased CD62L expression on IFN-gamma-stimulated eosinophils.
Conclusions:
IFN-gamma is a particular cytokine which can increase CD62L expression on circulating or infiltrated human eosinophils. It is suggested that protein synthesis and intracellular cAMP participate in the increase in L-selectin expression on IFN-gamma-stimulated eosinophils.