Activation of human eosinophil and neutrophil functions by haematopoietic growth factors: comparisons of IL‐1, IL‐3, IL‐5 and GM‐CSF

Abstract

Summary. We compared the effect of haematopoietic growth factors granulocyte‐macrophage colony‐stimulating factor (GM‐CSF), interleukin (IL)‐1, IL‐3, and IL‐5 on the functional activation of human eosinophils and neutrophils from the same donor. All four colony‐stimulating factors (CSF) enhanced the phagocytosis of Candida albicans by eosinophils and increased staphylococcal, but not Candida, killing. GM‐CSF and IL‐5 had a profound stimulating effect on eosinophil staphylocidal activity. GM‐CSF and IL‐3 enhanced the generation of leukotriene C₄ (LTC₄) induced by calcium ionophore A23187 and the release of arylsulphatase and β‐glucuronidase from specific and small granules of eosinophils. In contrast, IL‐1 and IL‐5 had no effect on degranulation. GM‐CSF and IL‐1 enhanced phagocytosis of C. albicans by neutrophils, and GM‐CSF stimulated degranulation and the release of the enzymes β‐glucuronidase and arylsulphatase from neutrophils while IL‐1 stimulated the release of arylsulphatase only. This study indicates that the eosinophilactive colony‐stimulating factors can markedly enhance the host defence function of the eosinophil and even make it the equal of the neutrophil in staphylocidal activity. The CSF‐activated eosinophil, however, may cause inappropriate inflammation and normal tissue damage.