A novel protein capable of activating eosinophile cells; a DNA or oligonucleotides encoding this protein; a recombinant vector containing this DNA; a transformant containing this recombinant vector; a process for producing the above protein by using this transformant; a cell reacting specifically with the above protein; a cell membrane or a receptor binding specifically to the above protein; an agonist or an antagonist to the protein; an antibody binding specifically to the protein; and remedies or diagnostic methods with the use of the same for allergic inflammation, eosinophilic pneumonia, sudden eosinophilia, autoimmune disease, malignant tumor, or vermination.