title: Priming in the presence of IL-10 results in direct enhancement of CD8+ T cell primary responses and inhibition of secondary responses.
abstract: Although IL-10 acts as an inhibitory cytokine for APC and CD4(+) T cell function, its effects on CD8(+) T cells are unclear. Additionally, little is known about whether initial priming in the presence of IL-10 can have long-lasting effects and influence subsequent CD8(+) T cell responses that occur in the absence of the cytokine. In the present study, we clarified the role of IL-10 during primary responses and examined whether exposure to IL-10 during initial priming of CD8(+) T cells impacted secondary responses. To determine the effect of IL-10 on Ag-specific T cell responses, peptide-pulsed IL-10R2(-/-) splenic dendritic cells were used to prime T cells from OT-I CD8(+) TCR transgenic mice. During the primary response, the presence of IL-10 resulted in enhancement of CD8(+) T cell numbers without detectable alterations in the kinetics or percentage of cells that underwent proliferation. A modest increase in survival, not attributable to Bcl-2 or Bcl-x(L), was also observed with IL-10 treatment. Other parameters of CD8(+) T cell function, including IL-2, IFN-gamma, TNF-alpha, and granzyme production, were unaltered. In contrast, initial exposure to IL-10 during the primary response resulted in decreased OT-I expansion during secondary stimulation. This was accompanied by lowered IL-2 levels and reduced percentages of proliferating BrdU(+) cells and OT-I cells that were CD25(high). IFN-gamma, TNF-alpha, and granzyme production were unaltered. These data suggest that initial exposure of CD8(+) T cells to IL-10 may be temporarily stimulatory; however, programming of the cells may be altered, resulting in diminished overall responses.
authors.affiliation: Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: Silvia S
authors.initials: SS
authors.lastname: Kang
authors.forename: Paul M
authors.initials: PM
authors.lastname: Allen
mesh_terms: D000276:Adjuvants, Immunologic / Q000502:physiology*; D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000201:enzymology / Q000276:immunology* / Q000378:metabolism*; D049109:Cell Proliferation; D002470:Cell Survival / Q000276:immunology; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism; D003713:Dendritic Cells / Q000276:immunology*; D015536:Down-Regulation / Q000276:immunology*; D005260:Female; D007117:Immunization, Secondary / Q000379:methods; D016130:Immunophenotyping; D016753:Interleukin-10 / Q000494:pharmacology*; D007376:Interleukin-2 / Q000037:antagonists & inhibitors / Q000378:metabolism; D007424:Intracellular Fluid / Q000276:immunology / Q000378:metabolism; D008213:Lymphocyte Activation / Q000276:immunology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D015375:Receptors, Interleukin-2 / Q000096:biosynthesis; D012697:Serine Endopeptidases / Q000378:metabolism; D051020:bcl-X Protein
chemical_list: D000276:Adjuvants, Immunologic; C494812:Bcl2l1 protein, mouse; D016207:Cytokines; D007376:Interleukin-2; D019253:Proto-Oncogene Proteins c-bcl-2; D015375:Receptors, Interleukin-2; D051020:bcl-X Protein; D016753:Interleukin-10; D012697:Serine Endopeptidases