Inactivation of Polymorphonuclear-Neutrophil Derived Eosinophil Chemotactic Factor by Human Serum

Abstract

A low-molecular-weight eosinophil chemotactic factor (ECF) can be released from human neutrophils on stimulation with the calcium ionophore (A 23187) and during phagocytosis. The presence of human serum suppresses the chemotaxis of eosinophils by ECF significantly. The inhibition is not cell-directed but affects the ECF either by binding or enzymatic cleavage. The inactivators belong to a heterogeneous class of serum components in the 19s, 7s and 4s molecular weight range. Highly purified human IgM and IgA, but neither IgG nor human serum albumin inhibit eosinophil chemotaxis.