Low molecular weight eosinophil chemotactic factor (ECF) production by rat peritoneal mononuclear phagocytes.

A low molecular weight eosinophil chemotactic factor (ECF) which has previously been found within mast cells and polymorphonuclear cells is shown to be released from highly purified rat peritoneal macrophages on exposure to the calcium ionophore A 23187 or after phagocytosis of zymosan coated with complement (Z x). The ECF is not performed, its release does not correlate with that of the lysosomal enzyme beta-glucuronidase, and its molecular weight is similar to that of ECF in mast cells and neutrophils. Thus, the macrophage has to be added to the list of cells able to regulate eosinophil accumulation at tissue sites.