Studies on the regulation of eosinophils in bronchial asthma Part 1. Characterization of eosinophil chemotactic factor (ECF) derived from peripheral blood mononuclear cells stimulated with Candida antigen

Eosinophilic infiltration in bronchial tissue is characteristic in the pathogenesis of bronchial asthma. The eosinophil chemotactic factor (ECF) derived from mononuclear cells has been reported to have some effect on the cell infiltration, and interleukin-5 (IL-5), a lymphokine derived from T lymphocytes, to be a factor related to growth, chemotaxis and activation for eosinophils. Lymphocytes accumulated in the bronchoalveolar lavage fluids of non-atopic and severe asthmatics have been shown to be highly responsive to Candida antigen, and high ECF production was observed in non-atopic and severe asthmatics by measurement of ECF activity in the supernatant of peripheral blood mononuclear cells cultured with Candida antigen. In this report, the molecular weight by gel filtration and inhibition test using anti-murine IL-5 antibody were studied to characterize the lymphocyte-derived ECF. Gel filtration analysis of the ECF indicated a molecular weight of 20,000 to 65,000 Da with a peak of activity around 40,000 to 50,000 Da. The ECF activity was reduced by incubation with anti-murine IL-5 antibody, which suggests that the supernatant contains IL-5. ECF from mononuclear cells, containing IL-5, may play an important role in the pathogenesis of eosinophil infiltration in non-atopic and severe asthmatics