Eosinophil chemotactic activity in the supernatant of mononuclear cell culture stimulated with specific antigen

Peripheral blood mononuclear cells (PBMC) separated from patients with asthma who were sensitive to Dermatophagoides farinae (Df) were cultured in alpha-medium for 5 days at 37 degrees C in 5% CO2, in the presence or absence of 10 ng/ml of Df antigen. Eosinophils were purified from the peripheral blood of patients with eosinophilia who were not sensitive to Df. Eosinophil chemotactic activity (ECA) was tested using a modified Boyden chamber method. ECA in the supernatant of PBMC stimulated with Df antigen was detectable after 24 hrs, peaked at 72 hrs and continued throughout the experiment. ECA was not observed in the supernatant of PBMC culture from subjects who were not sensitive to Df, and negligible activity was also observed when PBMC were stimulated with an unrelated antigen. The activity was unchanged by heating at 56 degrees C for 30 min, but was inactivated at 100 degrees C for 10 min. CV-6209, a specific PAF antagonist, failed to inhibit this chemotactic activity. The molecular weight of this eosinophil chemotactic factor (ECF) was greater than 30,000 daltons as determined by an ultrafiltration study. In conclusion, these data suggest that in asthmatic patients sensitive to Dermatophagoides farinae mononuclear cells stimulated with a related antigen produce one of cytokine(s) which possess(es) ECA, and may play an important role in the recruitment of eosinophils in chronic asthma.