Induction bykilled Listeria monocytogenesofeffector T cells mediating delayed-type hypersensitivity butnotprotection inmice

SUMMARY Using a local passive transfer system, we foundthateffector T cells mediating delayed-type hypersensitivity (DTH)butnotacquired cellular resistance (ACR)toListeria monocytogenes (strain EGD)weregenerated inmiceimmunized withkilled Listeria, although immunized micedidnot expressDTH orACR.Whennon-adherent cells ofperitoneal, lymphnode, orspleen cells frommice immunized withkilled Listeria weretransferred into thefootpad ofnaive recipient micealong with eliciting antigen, positive delayed footpad reaction (DFR)was elicited. However, there was no evident protection against challenge atthesite ofthelocal transfer. Cells frommiceimmunized with viable Listeria conferred significant degrees ofDFR andACR ontherecipients. DFR transferred by cells immunized withkilled Listeria was mediated byL3T4+T cells inan antigen-specific manner. Theantigen-specific proliferative responseofTcells frommiceimmunized withkilled Listeria was muchlowerthanthatofT cells frommiceimmunized withviable Listeria. Theproduction of macrophage chemotactic factor (MCF)bycells fromkilled Listeria-immune mice wasmuchthesame asthatbycells fromviable Listeria-immune mice. Incontrast, theproduction ofinterleukin-2 (IL-2) andmacrophage activating factor (MAF)was muchlower incells fromkilled Listeria-immune mice. Theelimination ofL.monocytogenes(strain L461), astrain oflowvirulence, wasenhanced atthesite ofDFR transferred withcells fromkilled Listeria-immune mice.Theseresults suggestthat stimulation withkilled bacteria iseffective forthegeneration ofDTH-mediating effector Tcells, and that different effector Tcells mediating DTH orACR areinvolved incell-mediated immunity toL. monocytogenes.