title: Essential role of endogenous heat shock protein 90 of dendritic cells in antigen cross-presentation.
abstract: Extracellular HSP90 associated with Ag peptides have been demonstrated to efficiently cross-prime T cells, following internalization by dendritic cells (DCs). In addition, the nature of cell-associated Ags required for cross-priming is implicated as peptides and proteins chaperoned by heat shock protein (HSP). However, the role of endogenous HSP in DCs during cross-presentation remains elusive. In this paper, we show that endogenous HSP90 is essential for cross-presentation of both soluble and cell-associated Ags in DCs. Cross-presentation of soluble OVA and OVA-loaded transporter associated with Ag processing-1-deficient cells by bone marrow-derived DCs and DC-like cell line DC2.4 was profoundly blocked by HSP90 inhibitors, whereas presentation of endogenously expressed OVA was only partially suppressed. Assays using small interfering RNA and heat shock factor-1-deficient DCs (with defective expression of HSP90alpha) revealed the pivotal role of HSP90alpha in cross-presentation. The results suggest that in addition to HSP90 in Ag donor cells, endogenous HSP90 in DCs plays an essential role during Ag cross-presentation and, moreover, points to a link between heat shock factor-1-dependent induction of HSP90alpha within DC and cytotoxic T cell immunity.
authors.affiliation: Laboratory for Immunochaperones, Research Center for Allergy and Immunology, RIKEN, Yokohama Institute, Tsurumi-Ku, Yokohama, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Ichiyanagi
authors.forename: Takashi
authors.initials: T
authors.lastname: Imai
authors.forename: Chiaki
authors.initials: C
authors.lastname: Kajiwara
authors.forename: Shusaku
authors.initials: S
authors.lastname: Mizukami
authors.forename: Akira
authors.initials: A
authors.lastname: Nakai
authors.forename: Toshinori
authors.initials: T
authors.lastname: Nakayama
authors.forename: Heiichiro
authors.initials: H
authors.lastname: Udono
mesh_terms: D000818:Animals; D017951:Antigen Presentation / Q000235:genetics / Q000276:immunology*; D001854:Bone Marrow Cells / Q000276:immunology / Q000378:metabolism; D002460:Cell Line; D002478:Cells, Cultured; D018920:Coculture Techniques; D045142:Cross-Priming / Q000235:genetics / Q000276:immunology*; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism*; D018841:HSP90 Heat-Shock Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D010047:Ovalbumin / Q000276:immunology / Q000378:metabolism; D010446:Peptide Fragments / Q000276:immunology / Q000378:metabolism; D015398:Signal Transduction / Q000276:immunology; D012995:Solubility
chemical_list: D018841:HSP90 Heat-Shock Proteins; C110366:OVA-8; D010446:Peptide Fragments; D010047:Ovalbumin