title: The role of the p38 mitogen-activated protein kinase, extracellular signal-regulated kinase, and phosphoinositide-3-OH kinase signal transduction pathways in CD40 ligand-induced dendritic cell activation and expansion of virus-specific CD8+ T cell memory responses.
abstract: Mature dendritic cells (DCs) are central to the development of optimal T cell immune responses. CD40 ligand (CD40L, CD154) is one of the most potent maturation stimuli for immature DCs. We studied the role of three signaling pathways, p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase (ERK), and phosphoinositide-3-OH kinase (PI3K), in CD40L-induced monocyte-derived DC activation, survival, and expansion of virus-specific CD8(+) T cell responses. p38 MAPK pathway was critical for CD40L-mediated up-regulation of CD83, a marker of DC maturation. CD40L-induced monocyte-derived DC IL-12 production was mediated by both the p38 MAPK and PI3K pathways. CD40L-mediated DC survival was mostly mediated by the PI3K pathway, with smaller contributions by p38 MAPK and ERK pathways. Finally, the p38 MAPK pathway was most important in mediating CD40L-stimulated DCs to induce strong allogeneic responses as well as expanding virus-specific memory CD8(+) T cell responses. Thus, although the p38 MAPK, PI3K, and ERK pathways independently affect various parameters of DC maturation induced by CD40L, the p38 MAPK pathway within CD40L-conditioned DCs is the most important pathway to maximally elicit T cell immune responses. This pathway should be exploited in vivo to either completely suppress or enhance CD8(+) T cell immune responses.
authors.affiliation: Clinical Sciences Division and. St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Qigui
authors.initials: Q
authors.lastname: Yu
authors.forename: Colin
authors.initials: C
authors.lastname: Kovacs
authors.forename: Feng Yun
authors.initials: FY
authors.lastname: Yue
authors.forename: Mario A
authors.initials: MA
authors.lastname: Ostrowski
mesh_terms: D023201:CD40 Ligand / Q000494:pharmacology*; D002454:Cell Differentiation / Q000276:immunology; D002470:Cell Survival / Q000276:immunology; D018920:Coculture Techniques; D003713:Dendritic Cells / Q000166:cytology / Q000201:enzymology / Q000276:immunology*; D015536:Down-Regulation / Q000276:immunology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D007156:Immunologic Memory; D018664:Interleukin-12 / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D008213:Lymphocyte Activation / Q000276:immunology; D007959:Lymphocyte Culture Test, Mixed; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism / Q000502:physiology*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D015398:Signal Transduction / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D023201:CD40 Ligand; D004791:Enzyme Inhibitors; D018984:Epitopes, T-Lymphocyte; D018664:Interleukin-12; D020928:Mitogen-Activated Protein Kinases; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D048051:p38 Mitogen-Activated Protein Kinases