[An anti-human eosinophil monoclonal antibody AE500 that reacts only with granulocytes from hypereosinophilic patients].

To investigate the heterogeneity of human eosinophils, we established a murine anti-human eosinophil monoclonal antibody AE500 (IgM, kappa) by immunizing blood eosinophils from patients with idiopathic eosinophilia. The reactivity of AE500 with human leukocytes was analyzed by a fluorescence-activated cell sorter. AE500 reacted with all the populations of blood eosinophils and neutrophils from patients with eosinophilia (idiopathic eosinophilia, n X 4 or asthma, n =), but not with those from asthmatic patients without eosinophilia (n = 8) or normal subjects (n = 6). AE500 did not react with granulocytes from other family members of AE500-positive individuals. These results suggest that the anti-human eosinophil antibody AE500 reacts with a cell surface antigen of blood granulocytes in a hypereosinophilic state. This anti-eosinophilic antibody would be useful in investigating the mechanism of eosinophilia in a variety of diseases.