Taormina Sicily site of Toll 2004 Creation of a Toll chimera to regulate activation CD4 CD4 Chimera CD4 Wild Type Toll Antibody ligation of CD4 domain Toll chimeras signal constitutively Medzhitov et al 1997 Nature 388 394 7 Toll chimeras activate NFkB Medzhitov et al 1997 Nature 388 394 7 Gram positive and Gram negative bacteria Gram positive Gram negative outer membrane Peptidoglycan LPS Lipopolysaccharide LPS structure O Antigen R6 Outer core O Antigen Gal 4 R R 5 R3 Inner core Man R 2 Kdo PO4 GLN Abe Glc Rha Gal n 1 40 GLN PO4 Lipid A Does Tlr2 really bind to LPS Yang et al 1998 Nature 395 284 9 Yang et al 1998 Nature 395 284 9 Mapping of the LPS mutation identified Tlr4 as a player in LPS signaling LPS resistant LPS sensitive In the mouse Tlr4 mutations cause a dominant loss of response to LPS transcript not expressed in C57BL 10ScCr mice either Poltorak et al 1998 Science 282 2085 88 Transfer of LPS m u i r e t c Ba LBP MD2 CD14 Toll LOS is processed from aggregates and passed to MD2 via CD14 Gioannini et al 2004 PNAS101 4186 4191 Crystal structure of Der P 2 Derewenda et al 2002 JMB 318 189 197 Tolls are activated by a range of elicitors Lipopeptide 1 2 Zymosan glycolipid peptidoglycan 6 2 LPS HSP70 Monomeric flagellin 4 5 10 Uropathogenic E coli 11 dsRNA ssRNA 3 7 CpG 9 Activated Tlr5 induces NFkB Hayashi et al 2001 Nature 410 1099 1103 Purification of the PAMP signaling through TLR5 Hayashi et al 2001 Nature 410 1099 1103 Testing the role of flagellin in Tlr5 induction Induce non flagellated E coli to express Listeria flagellin Mutate Salmonella such that it no longer produces flagellin Flagellin signaling Hayashi et al 2001 Nature 410 10991103 A common allele of Tlr5 encodes a stop codon Wild type Tlr5 Tlr5 392STOP Hawn et al 2003 J Exp Med 198 1563 1572 Tlr2 mutations predispose a patient towards lepromatous rather than tubercular leprosy Arg677 Trp mutation The location of the Tlr affects its function Nat Immunol 2006 Jan 7 1 49 56 A role for Tlr9 in Lupus Chromatin antibody complex anti iGg2a antibodies Tlr9 Leadbetter et al 2002 Nature 416 603 607 Drugs and adjuvants based on toll signaling Company Product 3M imiquimod Coley synthetic CpG oligo Dynavax 1018 SS Idera IMOxine Eisai E5564 Anadys isatoribine Use genital warts lymphoma Mechanism Tlr7 agonist Tlr9 agonist Hep B vaccine carcinoma Sepsis Chronic HepC Tlr9 agonist Tlr9 agonist Tlr4 antagonist Tlr7 agonist Nature Biotechnology Published online 6 March 2006 doi 10 1038 nbt0306 230 A natural ligand of Tlr7 8 is ssRNA Heil et al 2004 Science 303 1526 1529 Imiquimod sold as Aldara Tlr 7 8 agonist with potent antiviral activity Treatment of basal cell carcinoma with imiquimod Before During After Corixa has studied a Tlr4 antagonist Lipid A Analog Fort et al The Journal of Immunology 2005 174 6416 6423 Toll ligands might make good vaccine adjuvants Tlrs signal in different manners Tlr4 Tram Trif IRAK 1 IRF7 IFN A Tlr9 Mal MyD88 MyD88 TBK 1 IKK NFkB 4 F IRF3 IFN B Tlr signaling can skew the Th1 Th2 balance Developmental History Stimulus Th1 response Cell mediated immunity Good for fighting intracellular infections Delayed type hypersensitivity Th2 response Antibody mediated immunity Good for fighting extracellular parasites Allergy Microbes have evolved methods of inhibiting Toll signaling Pseudomonas strain PA14 kills better than strain D12 Toll signaling is induced to a lesser degree with PA14 than D12 Proc Natl Acad Sci U S A 2005 Feb 15 102 7 2573 8 Blocking Toll signaling by viruses and bacteria TLR4 TLR3 TRIF NS3 4A Hepatitis C Virus protein Yersinia virulence protein YOPJ IKK complex IFN IRF3 TNF NFKB Hepatitis C virus interferes with Toll Signaling Protease insensitive Trif maintains the Tlr3 response to poly IC PNAS February 22 2005 vol 102 no 8 2992 2997 Clearly activation of dendritic cells is important at a whole cell level Different types of phagocytosis follow Toll activation Nature 2006 Apr 6 440 7085 808 12 Complement can be activated through three pathways Classical pathway Mannan binding lectin Alternative pathway Antigen antibody complexes Mannose on pathogens Foreign surfaces C1q C1r C1s C4 C2 MBL MASP1 2 C4 C2 C3 B D C3 convertase Inflammation Mediators Opsonization Membrane attack Complex C3a C5a C3b C5b C6 C7 C8 C9 From Immunobiology by Janeway et al The alternative pathway C3a C3b C3 D B B C3b C3b C3b Factor B binding D cleaves B C3 convertase Bb Activation of complement proteases Proteolytic removal of pre peptide leads to protease activation Paul Vth edition The thioester bond forms an unstable intermediate Initial thioester S C Internal activation C S O C S O N Intermediate O N N N N N Surface binding C SH O O C SH O O N R H N N N C S O O R Gadjeva et al 1998 J Immunology165 985 990 R N N Convertase is deactivated by factors H and I Bb I H Bb H C3b Factor H binds and replaces Bb C3b C3b is now a substrate for Factor I iC3b iC3b left bound to cell surface C3 cleavage produces several active peptides S C O C3 activation SH R Further processing C3a anaphylotoxin R C3b Ligand for complement receptor 1 C3d Ligand for Complement Receptor 2 Inhibition of a thioester protein aTEP 1 in mosquito cells blocks phagocytosis Levashina et al 2001 Cell 104 709 718