title: Interleukin-10 promotes the maintenance of antitumor CD8(+) T-cell effector function in situ.
abstract: Interleukin-10 (IL-10) is a multifunctional cytokine that can exert suppressive and stimulatory effects on T cells. It was investigated whether IL-10 could serve as an immunostimulant for specific CD8(+) cytotoxic T cell (CTL) in vivo after vaccination and, if so, under what conditions. In tumor prevention models, administration of IL-10 before, or soon after, peptide-pulsed primary dendritic cell immunization resulted in immune suppression and enhanced tumor progression. Injection of IL-10, however, just after a booster vaccine significantly enhanced antitumor immunity and vaccine efficacy. Analysis of spleen cells derived from these latter animals 3 weeks after IL-10 treatment revealed that the number of CD8(+) CD44(hi) CD122(+) T cells had increased and that antigen-specific proliferation in vitro was enhanced. Although cytotoxicity assays did not support differences between the various treatment groups, 2 more sensitive assays measuring antigen-specific interferon-gamma production at the single-cell level demonstrated increases in the number of antigen-specific responder T cells in animals in the vaccine/IL-10 treatment group. Thus, IL-10 may maintain the number of antitumor CD8(+) T cells. In adoptive transfer studies, the ability of IL-10 to maintain CTL function could be enhanced by the depletion of CD4(+) T cells. This suggests that IL-10 mediates contrasting effects on both CD4(+) and CD8(+) T cells that result in either immune dampening or immune potentiation in situ, respectively. Appreciation of this dichotomy in IL-10 immunobiology may allow for the design of more effective cancer vaccines designed to activate and maintain specific CD8(+) T-cell effector function in situ.
authors.affiliation: Department of Surgery, University of Pittsburgh School of Medicine, PA, USA. fujiis@mail.rockefeller.edu
authors.forename: S
authors.initials: S
authors.lastname: Fujii
authors.forename: K
authors.initials: K
authors.lastname: Shimizu
authors.forename: T
authors.initials: T
authors.lastname: Shimizu
authors.forename: M T
authors.initials: MT
authors.lastname: Lotze
mesh_terms: D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000502:physiology*; D019496:Cancer Vaccines / Q000008:administration & dosage / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology; D005260:Female; D016130:Immunophenotyping; D016219:Immunotherapy, Adoptive / Q000379:methods; D007371:Interferon-gamma / Q000096:biosynthesis / Q000276:immunology; D016753:Interleukin-10 / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D051379:Mice; D008810:Mice, Inbred C57BL; D009374:Neoplasms, Experimental / Q000188:drug therapy / Q000517:prevention & control; D010047:Ovalbumin / Q000276:immunology; D013154:Spleen / Q000166:cytology / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000187:drug effects / Q000276:immunology* / Q000637:transplantation; D013997:Time Factors; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000637:transplantation
chemical_list: D019496:Cancer Vaccines; D016753:Interleukin-10; D007371:Interferon-gamma; D010047:Ovalbumin