Cutaneous sensitivity induced by immunization with irradiated Schistosoma mansoni cercariae. I. Induction, elicitation, and adoptive transfer analysis of cell-mediated cutaneous sensitivity.

Exposure of C57BL/6 mice to highly irradiated (50 kR) cercariae of Schistosoma mansoni leads to the development of partial resistance against subsequent challenge with unattenuated cercariae. We have analyzed the cellular immune responses that occur during the afferent and efferent phases of this protective sensitization. Mice were immunized by exposure to irradiated S. mansoni cercariae. After challenge with irradiated cercariae, delayed-type (18-72 hr) cutaneous sensitivity reaction sites were rich in mononuclear cells and eosinophils. This reactivity was established by 4 days after sensitization, reached its maximum between 7 and 14 days after sensitization, and was maintained for over 20 weeks. These challenge reactions could be abrogated by treatment with either 200 mg/kg cyclophosphamide or 5 mg of hydrocortisone. Syngeneic adoptive transfer of cutaneous sensitivity was accomplished with lymphoid cells from the draining lymph nodes or spleens of mice sensitized 7-14 days previously. Negative selection studies of nylon-wool non-adherent cells from sensitized donors demonstrated that the cells responsible for transferring this eosinophil-rich, delayed-type cutaneous sensitivity to S. mansoni irradiated cercariae were Thy-1+, Lyt1+, Lyt2-, surface Ig- lymphocytes.