Eosinophils and Immune Mechanisms

Exposure of eosinophil-rich peritoneal cell populations obtained from Schistosoma mansoni-infected mice to a soluble schistosomal egg antigen stimulates eosinophil migration. Supernatant fluids from serum-free lymph node cell cultures stimulated with antigens to which the donor mice had been specifically sensitized, or stimulated with phytohemagglutinin, also stimulate eosinophil migration. The active principle in such culture supernatant fluids is soluble, nondialyzable and heat-stable (56°C/30 min). It is tentatively classed as a lymphokine and designated eosinophil stimulation promoter.