title: Multiple dendritic cell populations activate CD4+ T cells after viral stimulation.
abstract: Dendritic cells (DC) are a heterogeneous cell population that bridge the innate and adaptive immune systems. CD8alpha DC play a prominent, and sometimes exclusive, role in driving amplification of CD8(+) T cells during a viral infection. Whether this reliance on a single subset of DC also applies for CD4(+) T cell activation is unknown. We used a direct ex vivo antigen presentation assay to probe the capacity of flow cytometrically purified DC populations to drive amplification of CD4(+) and CD8(+) T cells following infection with influenza virus by different routes. This study examined the contributions of non-CD8alpha DC populations in the amplification of CD8(+) and CD4(+) T cells in cutaneous and systemic influenza viral infections. We confirmed that in vivo, effective immune responses for CD8(+) T cells are dominated by presentation of antigen by CD8alpha DC but can involve non-CD8alpha DC. In contrast, CD4(+) T cell responses relied more heavily on the contributions of dermal DC migrating from peripheral lymphoid tissues following cutaneous infection, and CD4 DC in the spleen after systemic infection. CD4(+) T cell priming by DC subsets that is dependent upon the route of administration raises the possibility that vaccination approaches could be tailored to prime helper T cell immunity.
authors.affiliation: Division of Immunology, The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia.
authors.forename: Adele M
authors.initials: AM
authors.lastname: Mount
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Smith
authors.forename: Fiona
authors.initials: F
authors.lastname: Kupresanin
authors.forename: Kristina
authors.initials: K
authors.lastname: Stoermer
authors.forename: William R
authors.initials: WR
authors.lastname: Heath
authors.forename: Gabrielle T
authors.initials: GT
authors.lastname: Belz
mesh_terms: D000818:Animals; D017951:Antigen Presentation; D015496:CD4-Positive T-Lymphocytes / Q000821:virology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002465:Cell Movement; D003713:Dendritic Cells / Q000276:immunology*; D007109:Immunity; D008213:Lymphocyte Activation / Q000276:immunology*; D051379:Mice; D009975:Orthomyxoviridae; D012867:Skin / Q000473:pathology / Q000821:virology; D013154:Spleen / Q000473:pathology / Q000821:virology