Production of a rabbit antimouse eosinophil serum with no cross-reactivity to neutrophils.

Antieosinophil serum (AES), obtained by immunizing rabbits with a highly purified suspension of mouse eosinophils, contains high titers of specific agglutinating and cytotoxic antibodies to eosinophils. Absorption with macrophages, lymphocytes, and neutrophils does not affect the antieosinophilic activity while it is markedly lowered by absorption with eosinophils. One dose of AES (0.1 ml) injected into mice with schistosomiasis mansoni caused a mean decrease in circulating eosinophils of 90% within 1 h which was maintained for 5 days, followed by gradual recovery. No other changes in the total or differential white cell counts were noted. In normal mice AES markedly depressed exudation of eosinophils in the peritoneal cavity after repeated saline stimulation. Some of the immunological and clinical implications of a monospecific AES are discussed.