title: Toll-like receptor expression in murine DC subsets: lack of TLR7 expression by CD8 alpha+ DC correlates with unresponsiveness to imidazoquinolines.
abstract: Toll-like receptors (TLR) recognize microbial and viral patterns and activate dendritic cells (DC). TLR distribution among human DC subsets is heterogeneous: plasmacytoid DC (PDC) express TLR1, 7 and 9, while other DC types do not express TLR9 but express other TLR. Here, we report that mRNA for most TLR is expressed at similar levels by murine splenic DC sub-types, including PDC, but that TLR3 is preferentially expressed by CD8 alpha(+) DC while TLR5 and TLR7 are selectively absent from the same subset. Consistent with the latter, TLR7 ligand activates CD8 alpha(-) DC and PDC, but not CD8 alpha(+) DC as measured by survival ex vivo, up-regulation of surface markers and production of IL-12p40. These data suggest that the dichotomy in TLR expression between plasmacytoid and non-plasmacytoid DC is not conserved between species. However, lack of TLR7 expression could restrict the involvement of CD8 alpha(+) DC in recognition of certain mouse pathogens.
authors.affiliation: Immunobiology Laboratory, Cancer Research UK, London Research Institute, London, GB.
authors.forename: Alexander D
authors.initials: AD
authors.lastname: Edwards
authors.forename: Sandra S
authors.initials: SS
authors.lastname: Diebold
authors.forename: Emma M C
authors.initials: EM
authors.lastname: Slack
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Tomizawa
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Hemmi
authors.forename: Tsuneyasu
authors.initials: T
authors.lastname: Kaisho
authors.forename: Shizuo
authors.initials: S
authors.lastname: Akira
authors.forename: Caetano
authors.initials: C
authors.lastname: Reis e Sousa
mesh_terms: D000818:Animals; D016827:CD8 Antigens / Q000032:analysis*; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000145:classification* / Q000187:drug effects / Q000276:immunology*; D029721:Drosophila Proteins; D005260:Female; D007093:Imidazoles / Q000494:pharmacology; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D012333:RNA, Messenger / Q000096:biosynthesis; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D013045:Species Specificity; D013154:Spleen / Q000276:immunology; D051194:Toll-Like Receptor 1; D051196:Toll-Like Receptor 3; D051198:Toll-Like Receptor 5; D051199:Toll-Like Receptor 7; D051193:Toll-Like Receptors; D014158:Transcription, Genetic
chemical_list: D016827:CD8 Antigens; C431698:CD8alpha antigen; D029721:Drosophila Proteins; D007093:Imidazoles; D008562:Membrane Glycoproteins; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D051194:Toll-Like Receptor 1; D051196:Toll-Like Receptor 3; D051198:Toll-Like Receptor 5; D051199:Toll-Like Receptor 7; D051193:Toll-Like Receptors; C402365:resiquimod