Background

Amphiregulin (AREG) plays critical roles in mammary gland development, immune responses against nematode infection, and mucous production in the lung. Since remarkable eosinophil infiltration has been shown at all of these tissue sites, we examined AREG production by human eosinophils in vitro.

Methods

Using Ficoll and antibody-coated immunomagnetic beads, eosinophils and other blood cells were purified from peripheral blood samples obtained from normal or mild allergic patients. Eosinophils were cultured in the presence of 10 ng/ml of granulocyte-macrophage colony-stimulating factor (GM-CSF), 10 ng/ml of IL-5, 100 ng/ml of IFN-gamma or immobilized secretory IgA. Total mRNA was extracted after 6 h of culture, and mRNA expression was measured using a microarray and RT-PCR. The AREG concentration in the supernatant and cell lysate after 48 h of culture was measured using ELISA.

Results

AREG mRNA was constitutively expressed in fresh eosinophils, and the expression level in the eosinophils was higher than that in other types of blood cells. AREG mRNA increased significantly upon stimulation with GM-CSF and IL-5 but not with IFN-gamma. AREG mRNA expression in GM-CSF-stimulated eosinophils was enhanced by dexamethasone. Fresh eosinophils did not contain AREG protein. AREG was significantly released into the supernatant when the eosinophils were stimulated with GM-CSF, but not with IFN-gamma or immobilized secretory IgA.

Conclusion

Our data suggested that eosinophils produce and release AREG, and participate in some physiological and pathological conditions in vivo.