Innate Immunity -Pathogen Recognition by Innate … Immunity Acquired Immunity Cells involved...
Transcript of Innate Immunity -Pathogen Recognition by Innate … Immunity Acquired Immunity Cells involved...
© 2015 Osaka University. All rights reserved.
Laboratory of Host Defense,WPI Immunology Frontier Research Center (IFReC)
Osaka University
Shizuo AKIRA
Innate Immunity
- Pathogen Recognition by Innate Immunity-
Innate and adaptive immunity
Engulfment and digestionof pathogens,Inflammation(formerly called non-specific immunity)
Antibody(Humoral immunity)
Killer T cell(Cellular immunity)
Innate immunity
Immunity
Adaptive immunity
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Cells involved in adaptive immunity
T cell
Cellular immunity
B cell
Antibody production
Adaptive immunity can respond to millions of different foreign antigens in a highly specific manner. Each cell makes one particular antigen-specific receptor protein.
Cells involved in innate immunity
Macrophage Dendritic cell (DC)
Antigen presentation to T cells
Engulfment and digestion of pathogensCytokine production
Neutrophil
Phagocytes
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NK cell
Pathogen
Innate and adaptive immunity
Neutrophil
Dendritic cell(Antigen presenting cell)
Detection of pathogens and initial attack
Macrophage
Innate Immunity
Moving to lymph node
Specific attack against pathogens
Antigenic peptide
Adaptive Immunity
T cell
B cell
T-B interaction
Plasma cell
T cell
Antibody
Toll-like receptors (TLRs) are adjuvant receptors
Adjuvants are oily substances which, when mixed and injected with antigen, nonspecifically enhance the immune response.
Complete Freund’s Adjuvant (CFA): a water-in-oil emulsion containing killed mycobacteria
used for the potentiation of antibody production in experimental animals.
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Innate immunity specifically recognizes pathogens
pathogen
Macrophages, Dendritic Cells
Non-specific engulfment
and digestion
Old idea
Macrophages, Dendritic Cells
Specific recognition by TLRs
pathogen
New idea
DC
PathogensT cell
Regionallymph node
Infectedtissue
Draining lymphatics
Efferentlymphatics
T cell activationAntigen presentation by DC
Phagocytosis of pathogens(Non-specific)
Old Model
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Pathogen Recognition by Innate Immunity
DC
Pathogen T cell
Regional lymph node
Infected tissue
DC activation andantigen presentation
T cell activation
Efferent lymphatics
New Model
Draining lymphatics
Antigenpresentation
TLRs
Dendritic cell NaïveT cell
IFN-
Th2 cell
Th1 cell
IL-4
Co-stimulatorymolecules
(CD40, CD80, CD86)
Pro-inflammatory cytokines(IL-12, TNF-)
Pathogens
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Cancer Immunotherapy
Dr. William B. Coley (1862-1936), New York City surgeon and Sloan-Kettering researcher, examined the records of all bone cancer patients at New York Hospital. Most cases ended in death. However, he discovered one patient who had conquered cancer. This patient had suffered two attacks of bacterial infection.
Dr. Coley started to treat advanced cancer patients with live or killed bacteria, or bacterial components (Coley’s toxin).
By 1953, however, all the production of the toxins in the United States stopped.
(the cell wall skeleton from Bacille
Calmette-Guerin) : TLR2, TLR4
(lyophilized prep of a low virulence strain
of Streptococcus pyogenes) : TLR4, TLR9
BCG-CWS
OK432
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Naïve CD8+
T cellDC
CytolyticT cell
Phagocytosis
Tumor cell
No activation of cytolytic T cells in cancer patients
Tumor cell
IL-12
Inactive DC
TLRs
Activation and proliferation of cytolytic T cells
Active DC
Activation via TLRs
Induction of antitumor action
Tumor Cell
Phagocytosis
Tumor cell
Naïve CD8+
T cell
Bacterial components
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Innate Immunity Acquired Immunity
Cellsinvolved
Receptors
Recognition
MacrophagesDendritic cells T and B cells
Not rearranged(Toll-like receptors)
Pathogen-associatedMolecular patterns
(PAMPs)(ex. LPS, PGN)
Rearranged
Fine structures
(ex. Peptides)
PAMP and PRR
Pathogens have unique and conserved molecular patterns (pathogen-associated molecular patterns; PAMP)Innate immune system detect pathogen invasion by recognizing PAMPs via pattern recognition receptors (PRRs)
Most microbes, not only pathogens, express PAMPs.
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Lemaitre et al. Cell 86, 973-83 (1996)
Innate Immune Response in Drosophila
Spatzle
Toll
Tube
Cactus
Dorsal
Fungi
Pelle
Anti-fungal peptide genes
Mammalian Toll-like receptors (TLRs)
TIR domainLeucine Rich Repeats Ig-like domain
IL-1R family
dTo
ll
TL
R1
TL
R2
TL
R3
TL
R4
TL
R5
TL
R6
TL
R7
TL
R8
TL
R9
TL
R10
TL
R11
TL
R12
TL
R13
IL-1
RI
IL-1
R A
cp
T1/
ST
2
IL-1
8R
IL-1
8R A
cp
TIG
IRR
-1
SIG
IRR
IL-1
R A
pl
TLR
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Structure of the Leucine-rich repeats
motif: xLxxLxLxxNxLxxLxxxxxxxLx-sheet -helix
Structures of the cell surfaces of bacteria
Teichoic acid
Gram-positive bacteria
Gram-negative bacteria
Mycoplasma
Lipoteichoic acid (LTA) Lipopolysaccharide (LPS)
LipoproteinsPorin
Peptidoglycan (PGN)
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Structure of LPS
O-antigen
Core
Lipid A
LPS recognition via CD14
TNF-IL-1IL-6IFN-NO
.
.
.
Liver
LBP
LPS
CD14
solubleCD14
Endothelial cell
Macrophage
Gram negative
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TLR4
MD-2
CD14
LPSLBP
Signal transduction
LPS recognition and signaling
Bacterial lipopeptide (Pam3CSK4)
OO
OOSCH2CH
N CO
SerLysLysLysLysH
O
Mycoplasma lipopeptide (MALP-2)O
O
OOSCH2CH
N CO
HH GlyAsnAsnAspGlu-
TLR6TLR1
Pam3CSK4 MALP-2
TLR2 recognizes lipoproteins together with TLR1 or TLR6
TLR2 TLR2
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Flagellated bacteria
pilus
nucleoidflagellum
DNA
Cell wall
capsule
1. Unmethylated CpG motifs are much more common inbacterial DNA than in vertebrate DNA.
2. CpG motifs are often methylated in vertebrate DNA.
3. DNA containing unmethylated CpG motifs activatemacrophages, dendritic cells, NK cells and B cells.
4. CpG DNA stimulates a Th1 immune responsedominated by the release of IL-12 and IFN-g.
5. CpG DNA is now promising for immunotherapy ofcancer, allergy and infectious diseases.
CpG DNA
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TLR9 recognizes bacterial and viral DNA
Unmethylated CpG-DNA
TLR9
Inflammation
CpG
Th1 differentiation
Activation of adaptive immunitycytokineinterferonschemokines
bacteria virus
Bacterial flagella and flagellin
Bacteria with Flagella Flagellium
Flagellin
monotrichous
lophotrichous
peritrichous
amphitrichous
Hook
Basal Body
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Flagellin recognition by intestinal epithelial cells and dendritic cells
Intestinal lumenEpithelial cells Apical surface
Basolateral surface
M cell
Flagellin
TLR5 TLR5
Accumulation of leukocytes
macrophagesDendritic cells
Attack
Infected sites
Cytokines and chemokines
IL-8
The imidazoquinolines
The imidazoquinolines are synthetic compounds that have a capacity to induce IFN-a and other cytokine synthesis in a variety of cell types.
Imiquimod is now approved for treatment for external genital warts caused by human papillomavirus infection.
The imidazoquinolines have potent anti-viral and anti-tumor properties in animals.
R-848 is more potent derivative of imiquimod and anticipated to be used for clinical treatment.
Imiquimod’s activity was discovered while screening for anti-herpes virus activity.
Imiquimod
N
NN
NH2
O
OH
N
NN
NH2
R-848
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TLR7 and TLR3 recognize single-stranded and double-stranded RNA respectively
Imidazoquinoline derivatives
TLR3
Viral single-stranded
RNA
interferons
TLR7
Viral double-stranded
RNA
Imiquimod
N
NN
NH2
O
OH
N
NN
NH2
R-848
LipidLipoprotein
Nucleic acids
TLR ligands
TLR2/6TLR1/2
TLR4
TLR3TLR7
TLR8TLR9
TLR13
Protein
DNARNA
LipoproteinLPS
Flagellin
TLR5 TLR11
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TLR ligands
Bacteria Fungus Virus ParasiteTLR
Triacyl lipopeptide - - -TLR1/2
TLR2
TLR2/6
TLR3
TLR4
TLR5
TLR7
TLR8
TLR9
TLR11
TLR13
PGN, LTA
Diacyl lipopeptide
-LPS
Flagellin
RNA
DNA
Flagellin
RNA
-
--
Zymosan
β-glucan Glycoinositolphospholipids
DNA
--
-
-
--
Structural protein
RNA
Structural protein
RNA
RNA
DNA
-
-
DNA, Hemozoin
-
-
tGPI-mutin
-
--
-
Profilin-like molecule
Song DH, Lee JO.Immunol Rev. 250:216-29 (2012)
TLR shows horseshoe-like structureForms a hetero- or homo-dimer (M-shaped
structure) to bind to PAMPs
Structure of TLR and ligand complex
TLR4
Triacyl lipopeptide Diacyl lipopeptide dsRNA
TLR3TLR6TLR2TLR1TLR2
TLR5TLR4
FlagellinLPS
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In addition to responding to PAMPs, TLRs respond to endogenoushost molecules and trigger inflammatory responses.
Most of these are produced as a result of cell death and injury or by tumor cells. These include degradation products of the extracellular matrix (ECM), heat-shock proteins and high-mobility group box 1 (HMGB1) proteins, which act as stimulators for cell surface TLRs.
In addition, chromatin-DNA and ribonucleoprotein complexes released by dying cells and immune complex–containing self antigens can stimulate TLR7 and TLR9 and lead to the development of systemic autoimmune disease.
In atherosclerosis and Alzheimer’s disease, oxidized low-densitylipoprotein and amyloid-β, respectively, trigger sterile inflammation and are recognized by TLR4 and TLR6.
Endogenous ligands for TLRs
Autoimmunity, Immune regulation
RAGE?FgRIIA
Immune complex
ECM
HSP
HMGB1β-amyloid
Ox-LDL
Inflammation, Repair
Dying cells
Ox-phospholipid
TLR2TLR4TLR6
β-defensin2
TLR9TLR7
Co-receptors
Mitochondria DNA
Peroxiredoxin
TLR3
U1 RNA
Endogenous ligands for TLRs
HMGB1& DNA
LL37& DNA or RNA
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TLR4
MyD88
NF-B IRF
TLR3
TRIF
TIRAP
TRIF
TRAM
IKKiTBK1
TIRAP
IRAK
MyD88
Inflammatory cytokines IFN/
Selective usage of adaptors in TLR signalingTLR2TLR5TLR7TLR9
TLR7 TLR9
IFNα
RNA DNA
endosome
IRF7
MyD88IRAK1
IRF7
virusesType1 IFN production by TLR7 and TLR9
TLR7/9 induces type1
interferons through the
formation of MyD88-IRAK1-
IRF7. This pathway occurs in
plasmacytoid dendritic cells
which produce a huge amount
of IFNα during viral infection.
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TLRs bridging between innate and adaptive immunity
Cytokines and chemokines Local inflammation(leukocytes migration etc) Antibacterial peptides Antibacterial responseInterferons Antiviral response
Innate immune response
PAMPS (Cell wall components, flagellin, nucleic acids etc)
Toll-like receptors
: receptors for pathogen specific peptide(T cell receptors and antibodies)
(Vaccine)
Innate immune cells
Antigen presentation by DC
Activation of adaptive Immunity
(Pathogen sensors)
Escape from recognition by TLRs
• A certain adenovirus decreases CpG motifs in the genome: Escape from TLR9 recognition.
• Poxvirus protein A52R blocks TLR signaling pathways.
• LPS of Prophyromonas gingivalis and of Leprospira are less toxic due to deviation from the typical TLR4-activating lipid A.
• Flagellin of Helicobacter pylori is poorly recognized by TLR5.
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Single nucleotide polymorphism of TLRsTwo cosegregating polymorphisms of the human TLR4 gene-Asp299Gly
and Thr399Ile, present in approximately 10% of white individuals
hyporesponsive to inhaled LPS
susceptibility to Gram-negative bacterial infection
premature birth, which is frequently the result of infections
severe respiratory syncytial virus bronchiolitis in infants
less frequently in atherosclerosis
SNP within the C-terminal region of human TLR2 (Arg753Gln)
associated with Staphylococcal infection, tuberculosis and
acute rheumatic fever caused by Streptococcus pyogenes
A stop codon within the human TLR5 gene
association with pneumonia caused by Legionella pneumophila
TLR4
TLR2
TLR5
T cell
Th2
Th1 IFN-
IL-4
Tumor immunityResistance to bacterial
and viral infection Anti-allergy
Allergy
Resisitance to helminth
antigen
Th1 and Th2 responses in acquired immunityTLR ligands predominantly induce Th1 response.
Autoimmune disease
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Clinical Trial using TLR ligands
Infection:Preventive vaccines, Therapeutic vaccines, General enhancement of resistance to infectious diseases Cancer:Tumor vaccine, Cellular immunotherapy
using dendritic cells, Recovery of immune function after anti-cancer drug treatment Allergy: Pollen allergy and asthma
Gram positivebacteria
Spatzle
Pro-Spatzle
Proteasecascade
dsRNALPS
flagellinCpG DNAlipoprotein
Drosophila Mammals
Pathogen Recognition in flies and mammals
Fungi
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10
12
12
222
9
Deuterostomia
Protostomia
TLRs in various species
Human
Mouse
Fugu
Sea urchin
Mollusca
PlatyzoaNematoda
Echinoderm
UrochordataCephalochordata
HemichordataPriapulida
AnnelidaLophophorata
Sponge
Drosophila
Phylogenetic tree of insect and mammalian TLRs
Mammalian TLRs
Insect Tolls AgToll11AgToll10
AgToll7DmToll7DmToll2
AgToll8
AgToll6DmToll8
DmToll6
DmToll4DmToll3AgToll5B
AgTollBAgToll5A
AgTollDmToll5
DmToll1mTLR5
hTLR5 mTLR9
hTLR9
mTLR8hTLR8mTLR7
hTLR7
mTLR3hTLR3
mTLR4hTLR4
hTLR2mTLR2mTLR6mTLR1
hTLR1hTLR6
hTLR10AgToll9 DmToll9
mIL-1RAcPL
hIL-1RmIL-1R
hIL-18RmIL-18R
hIL-1RAcPmIL-1RAcP
hIL-1RAcPLDmMyD88
hMyD88mMyD88AgMyD88At1g52900(TX)At4g36140(TNL)
At4g36140(TNL)At1g72850(TN)
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Innate and Adaptive Immunity
Innateimmunity
Adaptive immunity
Innate immunity is not a remnant system but activeas advanced system collaborating with adaptive immunity
Old idea New idea
Innateimmunity
Innateimmunity
Adaptive immunity
Cytoplasmic Pathogen Sensors
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Signaling pathways mediated by RIG-I and Mda5
Mitochondria
IKK/
Nucleus
Cytoplasm
NF- B
Type I IFN
Inflammatory cytokines
TBK1IKKi
IBs
MDA5
CARDRNA helicaseRIG-I
IPS-1/MAVS
P
P
IRF3
P
P
CARD
dsRNA
RNA helicase CARD CARD
CARD
IKK
Viral Recognition in the cytoplasm
RIG-I Mda5
IBs
IKK
IKKIRFkinase(TBK1, IKKi)
IRF3
longdsRNA(>3kb)
Type I IFNInflammatory cytokines
IPS-1
dsDNA
DNA virus
DNA sensors
TBK1
IKKi
IRF3
Type I IFNInflammatory cytokines
a variety of RNA viruses Picornaviruses
Mitochondria
STINGCARD
NF-B
CARD
CARD
CARD
CARD
IKK
IKK
IBs
NF-B
Triphosphateshort ssRNA,dsRNA
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Cytosolic DNA sensor: cGAS-cGAMP-STING axis
cGAS(cGAMP synthase)
dsDNA
cGAMP(cyclicGMP-AMP)
Type 1 IFNs
+ATP+GTP
cGAMP
STING
O
NH2
3’
5’
3’
5’ OH
O O-
P
GNH
N N
N
A
O
NH4+
OO
O O NH4+
OP
OOH
O
HN
O
N
NNH2N
TLR-dependent and -independent recognition of bacterial components
MyD88
PGN
NOD1
NOD2
CARD NOD LRR
CARD NOD LRRCARD
NF-B
TLR2
MDP
iE-DAP
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Nod-like receptor and HIN-200 protein family
Gene name
NOD1NOD2
NLRC4NAIP5
NLRP1NLRP3NLRP6
AIM2
Core domain
NOD domain
HIN-200 domain
Functional domain
CARD, LRRs2CARD, LRRs
CARD, LRRs3BIR, LRRs
PYRIN, CARD, LRRsPYRIN, LRRsPYRIN, LRRs
PYRIN
NF-BMAPK
Inflammasome
IL-1 gene IL-18 gene
Pro-IL-1 Pro-IL-18
Caspase-1
Mature-IL-1 Mature-IL-18
Inflammatory Stimuli
IL-1, IL-18 activation pathways
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Inflammasomes
Flagellin, etc.dsDNA ?
LRRs
NLRC4NLRP3
Caspase-1
ASC
NODPYRIN
PYRIN CARD
CaspaseCARD
LRRs
AIM2
NODCARDPYRIN HIN-200
Pro-IL-1b/IL-18
Processing
Mature IL-1b/IL-18
P. aeruginosaS. typhimurium
Influenza A virusC. albicans
Vaccinia virusF. tularensis L. monocytogenes
Lysosomal membrane disrupting agentsactivate NLRP3-inflammasome
Cholesterolcrystals
Uric acidcrystals
Human islet amyloidpolypeptides
Asbestos
Accumulation by hyper-nutrition Pulmonaryaspiration
Atherosclerosis Gout Type IIdiabetes
Lunginflammation
Inflammatory diseases caused by persistent activation of NLRP3-inflammasome
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Syk
cytosol
Inflammatory cytokines
NF-kB
Syk
-Glucan
Pathogen recognition by C-type lectin receptors (CLRs)
P
P
P
P SykP
PFcR FcR
CCCARD CARD9CARDPYD BCL10
MALT1
MAPK
Dectin-1 Dectin-2 Mincle
-Mannan
MycobacteriaTrehalose dimycolate(TDM)
Candida albicansPneumocystis carinii Malassezia
Casp-L
Regulation of adaptive immunity by innate immunity
TLR RLR NLR
Pathogens
Adaptive immunity
antibody
Cytotoxic T cellHelper T cell
NK cell
Regulatory T cell
CLRInnate
immunity