title: Ex vivo culture with interleukin (IL)-12 improves CD8(+) T-cell adoptive immunotherapy for murine leukemia independent of IL-18 or IFN-gamma but requires perforin.
abstract: In animal models and clinical trials, adoptive transfer of activated, antigen-specific CD8(+) T cells mediates tumor regression in a cell dose-dependent manner. The cytokine interleukin (IL)-12 promotes CD8(+) T-cell cytotoxicity and, with IL-18, synergistically up-regulates IFN-gamma release. We have shown that culturing CD8(+) T cells ex vivo with IL-12 and IL-18 enhanced antitumor responses in vivo and in vitro using a model of C1498/ovalbumin, a murine acute myeloid leukemia cell line expressing the antigen ovalbumin. Activated ovalbumin-specific CD8(+) T cells cultured with IL-12, IL-18, both, or neither were assayed for antigen-specific cytokine production and cytolytic activity and adoptively transferred to C57BL/6 mice with established tumors. Maximal IFN-gamma release occurred after T-cell culture with IL-12 and IL-18. Tumor-specific in vitro cytotoxicity was enhanced by IL-12, unaffected by addition of IL-18, and abrogated in perforin-deficient T cells irrespective of cytokine exposure. T cells cultured with IL-12 more effectively eliminated tumors, and addition of IL-18 did not further augment responses. IFN-gamma-deficient CD8(+) T cells showed effective antitumor activity that was enhanced by IL-12 with or without IL-18. Perforin-deficient CD8(+) T cells were poor mediators of antitumor activity, though, and showed no improvement after culture with IL-12 and/or IL-18. Thus, ex vivo culture with IL-12 was sufficient to augment antigen-specific in vitro cytotoxicity and antitumor activity in vivo in an IFN-gamma-independent but perforin-dependent manner. Ex vivo culture with IL-12 may improve CD8(+) T-cell immunotherapy of cancer in the absence of donor cell-derived IFN-gamma via perforin-mediated cytolysis.
authors.affiliation: Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA. jmacgreg@umich.edu
authors.forename: Jennifer N
authors.initials: JN
authors.lastname: Macgregor
authors.forename: Qiao
authors.initials: Q
authors.lastname: Li
authors.forename: Alfred E
authors.initials: AE
authors.lastname: Chang
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Braun
authors.forename: Dennis P M
authors.initials: DP
authors.lastname: Hughes
authors.forename: Kevin T
authors.initials: KT
authors.lastname: McDonagh
mesh_terms: D000208:Acute Disease; D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D045744:Cell Line, Tumor; D003602:Cytotoxicity, Immunologic; D004357:Drug Synergism; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D005260:Female; D016219:Immunotherapy, Adoptive / Q000379:methods*; D007371:Interferon-gamma / Q000172:deficiency / Q000276:immunology; D018664:Interleukin-12 / Q000276:immunology* / Q000494:pharmacology; D020382:Interleukin-18 / Q000276:immunology* / Q000494:pharmacology; D007951:Leukemia, Myeloid / Q000276:immunology* / Q000628:therapy; D008213:Lymphocyte Activation; D008297:Male; D008562:Membrane Glycoproteins / Q000172:deficiency / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D054353:Perforin; D052899:Pore Forming Cytotoxic Proteins
chemical_list: D018984:Epitopes, T-Lymphocyte; D020382:Interleukin-18; D008562:Membrane Glycoproteins; D052899:Pore Forming Cytotoxic Proteins; D054353:Perforin; D018664:Interleukin-12; D007371:Interferon-gamma