Eosinophils Act as Antigen-Presenting Cells to Induce Immunity to Strongyloides stercoralis in Mice

The objective of the present study was to explore the ability of eosinophils to present Strongyloides stercoralis antigen in naive and immunized mice. Antigen-pulsed eosinophils were injected intraperitoneally into naive or immunized mice, and then mice were examined for antigen-specific immune responses. A single inoculation of antigen-pulsed eosinophilswas sufficient to primenaivemice and toboost immunizedmice for antigen-specificT helper cell type2 (Th2) immuneresponseswith increased interleukin (IL)–4andIL-5production.Mice inoculated 3 times with live eosinophils pulsed with antigen showed significant increases in parasite antigen–specific immu-noglobulin (Ig)Mand IgG levels in their serum.Antigen-pulsed eosinophils deficient inmajor histocompatibility complex class II molecules or antigen-pulsed dead eosinophils failed to induce immune responses, thereby dem-onstrating the requirement fordirect interactionbetweeneosinophils andTcells.These experimentsdemonstrate that eosinophils function as antigen-presenting cells for the induction of the primary and the expansion of the secondary Th2 immune responses to S. stercoralis in mice. Eosinophils aremultifunctional cells that possess potent cytotoxic and proinflammatory capabilities [1, 2]. In ad-dition, eosinophils have been shown to function as antigen-presenting cells (APCs) in experimental allerg