title: Signal 3 availability limits the CD8 T cell response to a solid tumor.
abstract: CD8 T cells need a third signal, along with Ag and costimulation, for effective survival and development of effector functions, and this can be provided by IL-12 or type I IFN. Adoptively transferred OT-I T cells, specific for H-2K(b) and OVA, encounter Ag in the draining lymph nodes of mice with the OVA-expressing E.G7 tumor growing at a s.c. site. The OT-I cells respond by undergoing limited clonal expansion and development of effector functions (granzyme B expression and IFN-gamma production), and they migrate to the tumor where they persist but fail to control tumor growth. In contrast, OT-I T cells deficient for both the IL-12 and type I IFN receptors expand only transiently and rapidly disappear. These results suggested that some signal 3 cytokine is available, but that it is insufficient to support a CTL response that can control tumor growth. Consistent with this, administration of IL-12 at day 10 of tumor growth resulted in a large and sustained expansion of wild-type OT-I cells with enhanced effector functions, and tumor growth was controlled. This did not occur when the OT-I cells lacked the IL-12 and type I IFN receptors, demonstrating that the therapeutic effect of IL-12 results from direct delivery of signal 3 to the CD8 T cells responding to tumor Ag in the signal 3-deficient environment of the tumor.
authors.affiliation: Department of Laboratory Medicine and Pathology, Center for Immunology, University of Minnesota, Minneapolis, MN 55455, USA.
authors.forename: Julie M
authors.initials: JM
authors.lastname: Curtsinger
authors.forename: Michael Y
authors.initials: MY
authors.lastname: Gerner
authors.forename: Debra C
authors.initials: DC
authors.lastname: Lins
authors.forename: Matthew F
authors.initials: MF
authors.lastname: Mescher
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D017951:Antigen Presentation / Q000235:genetics; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000235:genetics / Q000276:immunology; D049109:Cell Proliferation; D016207:Cytokines / Q000096:biosynthesis / Q000502:physiology*; D016130:Immunophenotyping; D007370:Interferon Type I / Q000502:physiology; D018664:Interleukin-12 / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D010534:Peritoneal Neoplasms / Q000276:immunology / Q000473:pathology; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000637:transplantation; D013945:Thymoma / Q000276:immunology* / Q000473:pathology
chemical_list: D016207:Cytokines; D007370:Interferon Type I; D018664:Interleukin-12