Description:
After injection of living tetrahymena into the hemocoels of male cockroaches, recovered hemolymph immobilizes washed ciliates. The immobilizing material is sensitive to heat and acid, and can be separated with ammonium sulfate. Hemolymph from immune animals confers protection in another animal into which it is injected. Immobilizing activity of the hemolymph from immune animals is associated with a nonreactive, normal protein component present in hemolymph from nonimmunized insects.