4 . Innate Immunity II.pdf

7/28/2019 4 . Innate Immunity II.pdf

http://slidepdf.com/reader/full/4-innate-immunity-iipdf 1/35

Innate Immunity (II)



Hematopoiesis

I. Innate Immunity Cells



IIS cells

Phagocytes:

anti-bacterian + anti-viral

Extracellular R

-TLR (Toll-like R)

-non-TLR

Cytosolic R

- Nod-like R

-RIG-like R

NK:

anti-viral

typeKAR/KIR



1. TLR →dimers

2. adaptor proteins

(MyD88)/ TRIF)3. Activation of

transcriptin factors

(NfKB, IRFs)

4. +Genes CC, CK,

CAMs/IFN→

Acute inflammation

Antiviral state

Adptoris I: MyD88=Myeloid differentiation factor 88); TRIF (TIR domain containing adaptor

inducing IFN β)IRF (interferon response factor)

Phagocytic cells:Extracellular TLRs Signallization



Signalling functions on TLRs

Abas, Lichtman, Pilai; Cell Mol Imm, 7th ed; 2012



Phagocytic cells:

receptors

Toll-like Receptors (TLR)

Extracellular RTLR1,TLR2,TLR4, TLR5,TLR6

Cytosolic R:TLR3,7,8,9NOD, RIG

Non-Toll-Like R

C-typeR,

Scavenger

N-FML

Others: FcR, C’R



localizare Exemple Liganzi: PAMs/DAMPs

Endosomalmembranesof phgocytes

(DC*, altele)

TLR3, 7-9* Microbial Molecules:CpG* (DNA prokariotes)Viral Nucleic Acides:

dsRNA, ssRNACytoplasm ofphagocytes

NOD1,2

NALP faminflammasome

Peptydoglicans (bacterialwall)Flagellin, muramyldipeptide, LPS;

DAMPs: urate crystals;Cytoplasm ofDC, Mφ;Other cells:fibroblast

RIG-1MDA-5

Viral RNA

Types of Cytosolic Receptors




Phagocytic cells:extracellular receptors

Toll-like Receptors (TLR)

Extracellular R

TLR1,TLR2,TLR4, TLR5,TLR6

Cytosolic R:

TLR3, TLR7,TLR8, TLR9

Non-Toll-Like R

C-typeR,

Scavenger

N-FML

Altii: FcR, C’R



localization Example Ligands: PAMs/DAMPs

Plasma/Endosomalmembranes of

phagocytes(DC, B, EC, others)

TLR1-9 Microbial Molecules:LPS, peptdoglycans

Viral Nucleic Acids

Plasma membranesof phagocytes

MannoseReceptors

Dectin

Carbohydrates withterminal Man/Fru

Glucans→fungal cellwall


CD36 MicrobialDiacylglycerides


FPR & FPRL-1

peptides→ N-formyl-Met

residues

Non-TLRReceptors




Signalling functions on TLRs




The Effector Mechanisms ofPhagocytes

• Secretion: –

CKs, CAMs, CCs:→ Inflammation (acute) – CK: IFNs → Antiviral defense

• Killing the pathogen: –

Phagocytosis → (part of) inflammation



Induction of

Inflammationfollowing

recognition of

pathogens

TNF

© New Science Press Ltd. 2000

or mast cell

Inflammatory mediators:

Cytokines, chemokinesand lipids



Leukocyte recruitment to sites of inflammation




Inflammation

• Pro-inflammatory cytokines (TNF, IL-1) signal toendothelial cells to make them:

– Leaky to fluid (influx of plasma; containingantibodies, complement components, etc.)

– Sticky for leukocytes, leading to influx ofneutrophils first, then monocytes, lymphocytes

– Systemic effects: fever, acute phase response

•

Inflammation may also be triggered by complementactivation or by activation of the coagulationsystem



Phagocytosis


1. Ingestion/ engulfment (mediated by receptors/opsosnins,2. digestion, and3. subsequent processing of microorganisms by macrophages and

neutrophils



Phagocytosis –first step

1) Chemotaxis & attachment:

a- Attraction by chemotacticsubstances

(microbes, damaged tissues)

b- Attachment by receptors onsurfaces of phagocytes



Opsonins• Complement

components (C3b)

• Collectins: MBL

• Antibodies

Phagocyticreceptors

• Receptors for opsonins

(complement R, Fc R)

• PRR (C-type lectin R)

MBL,mannose-binding lectin

Ingestionmediators



Phagocytosis

Primary granules:

Antimicrobial peptides

Lysozyme(degrades peptidoglycan)

Proteases (elastase,etc.)

Secondary granules:

phagocyte oxidase

Lysosomes:

Digestive enzymes


Fusion with phagocyte granules and releasedigestive, toxic contents



Phagocytosis

3- Killing (two microbicidal routes)a- Oxygen depended system (powerful microbicidal

agents)Oxygen converted to superoxide, anion,

hydrogen peroxide, activated oxygen andhydroxyl radicals.

b- Oxygen-independent system (anaerobic

conditions)Digestion and killing by lysozyme. Lactoferrin,low pH, cationic proteins and hydrolytic andproteolytic enzymes



Antiviral activityIIS cells

Phagocytes:anti-bacterian + anti-viral

Extracellular R

-TLR (Toll-like R)

-non-TLR

Cytosolic R

-TLR3, 7-9

- Nod-like R

-RIG-like R

NK:anti-viral

R typeKAR/KIR



The Effector Mechanisms ofPhagocytes

• Secretion: –

CKs, CAMs, CCs:→ Inflammation (acute) – CK: IFNs → Antiviral defense

• Killing the pathogen: –

Phagocytosis → (part of) inflammation



Viral Immunity

• Viruses evolve extremely rapidly→ great challenge for II• Anti-viral immunity has 2 roles

– Blocking infection (antibodies, complement, etc.) – Blocking viral replication (interferon, killing infected cells)

• Viruses have evolved many mechanisms of evading immunity

Virus-infected

cell

Interferon-a

Infected cell makes

interferon, uninfected

cells respond to interferonand become refractory to

viral growth



localizare Exemple Liganzi: PAMs/DAMPs

Endosomalmembranesof phgocytes

(DC*, altele)

TLR3, 7-9* Microbial Molecules:CpG* (DNAprokariotes)

Viral Nucleic Acides:dsRNA, ssRNA

Cytoplasm ofphagocytes

NOD1,2

NALP faminflammasomes

Peptydoglicans(bacterial wall)Flagellin, muramyldipeptide, LPS;Cristale urat; DAMP

Cytoplasm ofDC, Mφ;Other cells:fibroblast

RIG-1MDA-5

Viral RNA

Cytosolic Receptors ofPhagocytes




RIG-like R (RLR)

• Receptors for –

ds RNA: recognize RNA viruses – ss RNA: recognize DNA viruses (transcription)

Structure:Recognizing Domain: RNA-helicasesEffector Domain: 2x caspases recruting domain-like(CARD-like)

MDA-5: melanoma diffrentiation-associated gene 5;

RIG-I: retinoic acid-inducible gene I



RLR functions

– RIG-I – MDA-5

Functions:• Recognize cytosolic molecules of

viral origin• Signalization →→

Activation of IRFs (3,7)→ IFN tip I

Activation of NFkβ → pro-inflammatory CK

TRAF3: TNF receptor-associated factor 3 ,

IPS-1: IFN-β promoter stimulator proteinIRF= Interferon Response Factor



Antiviral activity IIS

cellsPhagocytes:

Extracellular R

-TLR (Toll-likeR)

-non-TLR

Cytosolic R

-TLR3, 7-9

- Nod-like R

-RIG-like R

NK:

anti-viral

R type KAR/KIR



NK Cells

• First line of defenseagainst: – Tumor cells

–

Virally-infected cells – Other intracellular

pathogens

•

Implicated in: – Transplant rejection

– Autoimmunity

– Spontaneous abortions

Christina Trambas, Cancer Council of Tasmania,

http://www.ciml.univ-mrs.fr/fr/science/lab-eric-vivier/pour-specialistes

NK Cell

Tumor Cell



Characteristics

• Nonspecific, cytotoxic• Express activating and inhibiting receptors• 5-15% of circulating lymphocyte population•

3 Subsets – Majority: CD3negCD56dimCD16pos • Contain perforin and granzymes• Moderate cytokine secretion

– Minor: CD3negCD56brightCD16neg •

Secrete high levels of cytokines (IFNγ, TNFα, IL-10)• Weakly cytolytic

– Rare: CD3negCD56negCD16pos

• Poorly cytolytic• Secrete only small amounts of cytokinesCD3: involved in TCR expression

CD56: cell adhesion moleculeCD16: FcγRIIIA

What NK cells recognize?



What NK cells recognize?Which are the NK ligands?

• presence & absence of Self : MHC I: HLA-A, -Bw, -Cw, -G• induced/ modified self: proteines that signalls cellular stress: HSP,

MIC-A, MIC-B, (MHC I chain-related proteins type A, B)

Fam Receptori NK Molecular Nature Ligands Coresp.mouse

KIR Ig-superfamily HLA-A, -Bw, -Cw, -G gp49

ILT/LIR Ig-superfamily HLA Cls Ia (-G) LRC

CD94/NKG2 (KLR) C-type lectin-like HLA Cls Ib (-E) NKC / Ly49

KAR (NKG2D, KLRK1) C-type lectin-like MIC-A,B & MHC I-like NKG2D

NCR Ig-superfamily Viral Hemmaglutinine, NCR

MIC-A, B protein = MHC class I polypeptide-related sequence A,B protein



NK Cell Receptors

Vivier, E. et al. Innate or adaptive immunity? The example of natural killer cells. Science. 331, 44-49 (2011).



Lysis Methods

Smyth, M. J. et al . Activation of NK cell cytotoxicity. Mol. Immunol. 42, 501 –510 (2005).



The end



Phagocytosis and killing

•Phagocyte oxidase (=NADPH oxidase):

makes reactive oxygen intermediates (superoxide anion, hydrogen peroxide)•Inducible Nitric oxide synthase (iNOS):

makes reactive nitrogen intermediates (NO)

Chronic granulomatous

disease: genetic defect in

phagocyte oxidase is X-linked(most commonly gp91)

phagolysosome

cytoplasm



NOD1 and NOD2 are intracellular molecules and resemble some plant disease

resistance proteins; Mutations in the NOD2 gene increase susceptibility to

Crohn’s disease (a form of inflammatory bowel disease)

NOD1 & NOD2 recognize peptidoglycansubstructures and promote innate immune responses



NOD-like receptor (NLR)

• Nucleotide Oligomerization Domain receptors,

• ~ 20 different cytosolic proteins

• Function:

– recognize endogenous or microbial molecule

– form oligomers that activate inflammatory caspases

– causing cleavage and activation of IL-1

– activate the NF-κB signaling pathway

• Family members:

– NLRCs (previously called NODs: C → a caspase recruitmentdomain (CARD) at their N-terminus

– NLRPs (previously called NALPs: P a pyrin domain at their N-terminus

– Other NLRs: MHC Class II transactivator (CIITA) and NAIP.

4 . Innate Immunity II.pdf

Documents

Transcript of 4 . Innate Immunity II.pdf