Eosinophil-adhesion-inducing activity produced by antigen-stimulated mononuclear cells involves GM-CSF

Area of Science:

• Immunology
• Allergic Inflammation Research
• Respiratory Medicine

Background:

• Eosinophil accumulation in allergic inflammation begins with their adhesion to endothelial cells (EC).
• Antigen exposure upregulates eosinophil adhesive properties, likely mediated by cytokines from stimulated mononuclear cells.

Purpose of the Study:

• To identify factors from antigen-stimulated mononuclear cells that induce eosinophil adhesion and migration in atopic asthmatics.
• To investigate the role of specific cytokines and chemokines in these processes.

Main Methods:

• Peripheral blood mononuclear cells (PBMC) from asthmatics were cultured with Dermatophagoides farinae (Df) antigen.
• Eosinophil adhesion to human pulmonary microvascular endothelial cells (HPMEC) and eosinophil migration were assessed using culture supernatants.
• The effects of anti-cytokine/chemokine antibodies (anti-GM-CSF, anti-IL-5, anti-RANTES) were evaluated.

Main Results:

• Supernatants from Df-stimulated PBMC significantly increased eosinophil adhesion to HPMEC.
• This adhesion was significantly inhibited by anti-GM-CSF but not by anti-IL-5 or anti-RANTES.
• Eosinophil migration was inhibited by anti-GM-CSF and partly by anti-RANTES.

Conclusions:

• Granulocyte-macrophage colony-stimulating factor (GM-CSF) is involved in both eosinophil adhesion and migration induced by antigen-stimulated PBMC.
• RANTES plays a role specifically in eosinophil migration.
• GM-CSF and RANTES are implicated in eosinophil accumulation at allergic inflammation sites.