Type 1 diabetes Anti-insulin: health • No cure; therapy is insulin for life; physiologic glycaemic control never achieved Anti-insulin: disease •Excess morbidity and mortality •Incidence increasing by.
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Transcript Type 1 diabetes Anti-insulin: health • No cure; therapy is insulin for life; physiologic glycaemic control never achieved Anti-insulin: disease •Excess morbidity and mortality •Incidence increasing by.
Type 1 diabetes
Anti-insulin: health
• No cure; therapy is insulin for life;
physiologic glycaemic control never
achieved
Anti-insulin: disease
•Excess morbidity and mortality
•Incidence increasing by ~5% every 5
years; costs ~£1 billion of UK NHS budget
Peakman
Type 1 diabetes is T cell mediated
•Infiltrating CD4+, CD8+ T cells
•Anti-T cell therapies are effective
•Islet cell autoantibodies disease
CD4
T-cell
CD8
T-cell
CD4
Treg
TCR
Epitope
HLA II
HLA I
APC
Peakman
Islet
autoantigen
The Immune System
Acquired (Adaptive)
Innate
• Rapid Microbial Defense • Long-lived Microbial
Defense
• Adaptive Immune
•
Neoplasm
surveillance
System Activation
• Autoimmunity,
Transplantation
Rejection & Atopy
BDC
The Innate Immune System
• Antimicrobial Peptides (e.g., Defensins,
Cathelicidins)
• Phagocytes (Macrophages, Neutrophils, Monocytes,
Dendritic Cells)
• Pattern Recognition Receptors
• Alternative Complement System
• NK Cells
• B1B Cells*
* Aspects of both the innate and adaptive immune system
BDC
Selected Pattern Recognition
Receptors: Toll-like Receptors
TLR:
Selected
Ligands:
TLR1
PGN, Zymosan, Antifungal &
Lipoproteins
Antibacterial
TLR2
Role in Immunity:
TLR6
TLR4
LPS
Antibacterial
TLR5
Flagellin
TLR11
?
TLR9
CpG
Antibacterial &
Antiviral
TLR3
dsRNA
Antiviral
TLR7
ssRNA
TLR8
ssRNA
TLR10
?
?
Localization:
Dendritic Cells,
Macrophages,
T Cells,
B Cells,
Epithelium
Selected Pattern Recognition
Receptors: Other Families
Re ceptor
NOD Protei ns
NOD1
NOD2
C D14
C-type Lecti ns
Macrophage
Mannose Receptor
(MMR), DC-SIGN,
DEC-205
Surfact ant A, D
(Collect in Family)
MBP /MBL
Scavenge r
Re ceptors
SR-A,
CD36
Sele cted Ligands
Role in Im mun i ty
Locali zation
PGN (Gm-)
PGN (Gm + & -)
LBP :LP S, PGN
Ant ibacterial
Ant ibacterial
Ant ibacterial (with TLR4)
Cytoplasmic
Cytoplasmic
Serum &
Phagocyte Cell
Surface
Glycoproteins or
Glycolipids
Ant ibacterial, Ant iviral,
Ant ifungal
Macrophage,
DCs
LPS,
Lipoproteins,
Oligosaccharides
Opsonizat ion of Bacteria,
Virus & Fungi; Cytokine
Stimulation; Apoptot ic Cell
Clearance
Complement Act ivat ion
(Ant ibacterial & Antiviral)
Soluble in the
Lungs
Ant ibacterial; Apoptot ic
Cell Clearance
Macrophages,
Endothelium
Mannose groups
on bacterial
carbohydrates
LPS, LT A, PGN
Serum
Sys te m aticM ous e ligandHum an ligand Re ce ptor
Re fe re nce s
nam e
(alias )
(alias )
CCL1
TCA-3/I-309 I-309
CCR8
CCL2
JE/M CP-1
MCP-1
CCR2
Bertuzzi et al., 2004; Bradley et al., 1999; Cardozo et al., 2001; Cardozo et al., 2003;
Chen et al., 2001; Frigerio et al., 2002; Giarratana et al., 2004; Grew al et al., 1997;
Kutlu et al., 2003; Nomura et al., 2000; Schroppel et al., 2005; Yang et al., 2004
CCL3
M IP-1
MIP-1
CCR1 & 5
Bradley et al., 1999; Cameron et al., 2000; Giarratana et al., 2004; Lohmann et al., 2002
CCL4
M IP-1
MIP-1
CCR5
Bradley et al., 1999; Cameron et al., 2000; Lohmann et al., 2002)
CCL5
RANTES
RANTES
CCR1, 3 & 5 Bradley et al., 1999; Carvalho-Pinto et al., 2004; Frigerio et al., 2002; Weber et al., 2006
CCL6
C10
unknow n
CCR1
CCL7
M ARC/M CP-3MCP-3
CCR1, 2 & 3 Bradley et al., 1999; Matos et al., 2004
CCL8
M CP-2
MCP-2
CCR3 & 5
CCL9/10
M IP-1
unknow n
CCR1
CCL11
Eotaxin-1
Eotaxin-1
CCR3
CCL12
M CP-5
unknow n
CCR2
Bradley et al., 1999
CCL13
unknown
MCP-4
CCR2 & 3
CCL14
unknown
HCC-1
CCR1 & 5
CCL15
unknown
HCC-2/MIP-1d CCR1 & 3
CCL16
unknown
HCC-4
CCR1 & 2
CCL17
TARC
TARC
CCR4
Giarratana et al., 2004; Kim et al., 2002
CCL18
unknown
PARC
unknown
CCL19
ELC
MIP-3b/ELC
CCR7
Bouma et al., 2005a; Bouma et al., 2005b
CCL20
M IP-3/LARC MIP-3a/LARC CCR6
Cardozo et al., 2003
CCL21
SLC/6Ck ine SLC/6Ckine
CCR7
Bouma et al., 2005b; Giarratana et al., 2004
CCL22
M DC
MDC
CCR4
Giarratana et al., 2004; Kim et al., 2002
CCL23
unknown
MIPIF-1/MIP-3 CCR1
CCL24
Eotaxin-2
Eotaxin-2
CCR3
CCL25
TECK
TECK
CCR9
CCL26
unknown
Eotaxin-3
CCR3
CCL27
CTACK
CTACK
CCR10
CCL28
M EC
MEC
CCR3 & 10
CXCL1
KC
GRO
CXCR2
Cardozo et al., 2001; Matos et al., 2004
CXCL2
M IP-2
GRO
CXCR2
CXCL3
unknown
GRO
CXCR2
CXCL4
PF4
PF4
CXCR3B
CXCL5
LIX
ENA-78
CXCR2
Matos et al., 2004
CXCL6
unknown
GCP-2
CXCR1 & 2
CXCL7
TCK-1
NAP-2
CXCR2
CXC8
unknown
IL-8
CXCR1 & 2
CXCL9
M IG
MIG
CXCR3
Christen et al., 2003; Frigerio et al., 2002; Matos et al., 2004
CXCL10
IP-10
IP-10
CXCR3
Baker et al., 2003a; Baker et al., 2003b; Bradley et al., 1999; Cardozo et al., 2001;
Cardozo et al., 2003; Christen et al., 2004; Christen et al., 2003; Ejrnaes et al., 2005;
Frigerio et al., 2002; Giarratana et al., 2004; Morimoto et al., 2004; Nicoletti et al., 2002;
Rhode et al., 2005; Shimada et al., 2001
CXCL11
I-TAC
I-TAC
CXCR3
Cardozo et al., 2003
CXCL12
SDF-1/PBSF SDF-1/
CXCR4
Dubois-Laf orgue et al., 2001; Kaw asaki et al., 2004; Kayali et al., 2003
CXCL13
BLC
BLC/BCA-1
CXCR5
CXCL14
BRAK
BRAK
unknow n
CXCL15
Lungk ine
unknow n
unknow n
CXCL16
SR-PSOX
SR-PSOX
CXCR6
XCL1
lym photactinSCM-1/ATAC XCR1
Bradley et al., 1999; Weber et al., 2006
XCL2
unknown
SCM-1b
XCR1
fractalk ine f ractalkine
Cardozo et al., 2001
CX3CL1
CX 3CR1
Table 1. T1D, che m ok ine s and the ir re ce ptors
(modif ied after Lut et al., 2006).
Chemokines w ith a putative role in T1D pathogenesis are identif ied by gray background shading.
The Adaptive Immune System
• Cell-mediated Immunity (Cytotoxicity)
• T cells
• CD4+ (Th1 & Th2)
• CD8+ (Tc1 & Tc2)
• Humoral Immunity (Antibody production)
• B Cells
BDC
Th1 and Th2 CD4+ T Cells
Th1
Th2
• IL-12 induces differentiation •
• Cytokine Production:
•
Interferon-
Interleukin-2
• Intracellular Pathogens
•
• Macrophage Activation
•
• Delayed Type
Hypersensitivity
•
•
IL-4 induces differentiation
Cytokine Production:
Interleukin-4
Interleukin-5
Interleukin-13
Extracellular Pathogens
B Cell activation & IgE
Eosinophil responses
Immediate Type
Hypersensitivity
BDC
T cell signaling molecules and autoimmunity
Human T1D loci (Ref1)
MHC : λs ≈ 3
Insulin : odds 1.9
CTLA4 : odds 1.2
PTPN22 odds 1.7
Cblb : Komeda rat
(Yokoi N, Nat Genet, 2002)
Pten: Cre-loxP knock-out
(Suzuki A, Immunity, 2001)
Zap70: Sakaguchi mice
(Sakaguchi N, Nature, 2003)
(Mustelin T, et al. Mol Immunol. 2004)
Concannon P et al. Diabetes. 2005 Oct;54(10):2995-3001.
H. Ueda
B and T Lymphocyte Antigen Receptors
VH
VH
V
CH1 CH1
VL
CH2
CH2
Ig/Ig CH3
CH3
e
VL
CL
CL
V
z z
e
C C
Ig/Ig
fyn
lck
Zap 70
Blk, Fyn or Lyn
2 light chains ( or )
2 heavy chains (5 isotypes: IgG, M, A, D, E)
2 Binding sites (Divalent)
Secreted into circulation
Binds Soluble Antigen
2 Chains / (95%) or / (5%)
1 Binding site (Monovalent)
Membrane Bound, Not Secreted
Binds Antigen Complexed with MHC
BDC
J. Noble
HLA
Human Leukocyte Antigen
human MHC
cell-surface proteins
important in self vs. nonself
distinction
present peptide antigens to T cells
CLASS I: A,B,C
CLASS II: DR,DQ,DP
DQB1*0402
-chain
Leu56
-chain
Asp57
BDC
BDC
Hahn, Wucherpfenning et al. Nature Immunology 6:490-496, 2005
Topology of Self-peptide/MHC Binding by Ob.1A12 TCR
Autoimmune (MBP Peptide+DR2)
Ob.1A12
Anti-viral (HA Peptide+DR1)
HA1.7
Red:
TCR
Yellow: TCR
Hahn, Wucherpfenning et al. Nature Immunology 6:490-496, 2005
Ob.1A12
HA1.7
Anti-viral
(HA
Peptide+D
R1)
Autoimmune
(MBP
Peptide+DR2)
Red:
TCR
Yellow: TCR
The Human Leukocyte Antigen Complex (6p21.31)
Class II (1.1 Mb)
DP
DQ
Class III
(0.7Mb)
DR
Class I (2.2Mb)
B C
A
Telomere
Centromere
Frequent
Recombination
Recombination
is Rare
Complement
and Cytokines
Class I-like genes
and pseudogenes
Recombination
is Rare
BDC
HLA Class I and II Molecules Have a Distinct Structure and Function
•Binds 8-10mers
•Expressed on most
Nucleated cells
•Presents Cytosolic
Proteins to CD8+ T cells
•Binds 13-25mers
•Expressed on APCs,
Macs, B cells, activated
T cells
•Presents Vesicular
Proteins to CD4+ T cells
1 2
1 1
2 3
2 2
Class I
Class II
BDC
Cis and Trans- Class II Dimerization
Maternal
DQA1
DQB1
0501
0201
cis
DQA1*0501/DQB1*0201
Paternal
0301
0302
cis
trans
DQA1*0301/DQB1*0302
DQA1*0301/DQB1*0201
DQA1*0501/DQB1*0302
BDC
HLA-Peptide: TCR
2 Helix
NH3+
1 Helix
TCR
alpha
TCR
beta
COO-
BDC
“Tetramer” for T Cell Analysis
DQ
DQ
PEPTIDE
DQ
Avidin
DQ
BDC
HLA Class II tetramer ( DR0401-hGAD555-567)
streptavidin
Leucine
zippers
MHC
spacers
peptide
W.W.Kwok & G.T.Nepom,
Benaroya Research Institute at Virginia Mason
T cell Recognition of Antigen on an APC
Antigen
Endocytosis
CD4+
T cell
T Cell
Receptor
APC
Peptide
MHC II
T cell Activation by an Activated APC
IL-1
IL-6
IL-12
IL-12 Receptor
CD28
“Signal 3”
B7
CD4+
T cell
LPS
T Cell
Receptor
“Signal 2”
TLR4
“Signal 1”
Peptide
MHC II
Signal 1: Specificity
Signal 2: Activation
Signal 3: Differentiation
Antigen Presenting Cell (APC)
The 2-Signal Model of Lymphocyte Activation
Absence of Signal 2
T Cell
APC
TCR
MHC
Tolerance
Clonal Anergy or Deletion
Signal 1 + Signal 2
CD28
T Cell
B7
APC
TCR
MHC
cytokines
Activation
BDC
APC and T cell Interactions
CTLA-4
B7 (CD80/86)
B7 (CD80/86)
CD28
Activation
Recognition
TCR
MHC II
Activation
APC
CD58 (LFA-3)
Activation
CD40
CD2
Adhesion
CD40L
CD4+
T Cell
Molecular Interactions of Helper T Cells and APC
CD4+ T Cell
CTLA-4
CD28
p56 lck
CD3
e
CD40L
C C
V
CD2
z zh h
TCR
V
CD45
LFA-1
VLA-1
peptide
B7
B7
CD80/CD86
CD4
CD40
MHC II
LFA-3
ICAM-1
Collagen
APC/ B cell
L. Chess 2002
T cell activation is regulated by signals derived from the TCR
/CD3/CD4 complex and the CD40L and CD28/CTLA-4 co-stimulatory
molecules
CD4+ T Cell
Antigen specific TCR signals
Co-stimulatory signals
(- ) / [+]
lck
e
CD3
z z hh
C C
CD28/
CTLA4
V
CD40L
[+]
, TCR
Peptide antigen
CD40
CD80 (B7.1)/
CD86 (B7.2)
V
CD4
MHC class II
signal
Antigen Presenting Cell (APC)
L. Chess 2002
TCR
CD4
TCR signaling
CD45
CD28
PLC1
Zap70 Lck
Fyn
Tec
Lck
Shc
PTK
Grb2
PIP2
(ION)
SOS
(PMA)
Ras
IP3 + DAG
Ca++
PKC
MAPK
calcineurin
NFB
NFAT activation
Fathman
T cell activation induces expression
of functional T cell surface molecules
Activated
CD4+ T cell
MHC/peptid
e
Induction and
activation of B cells
APCs
CD40L
TCR
APC
TCR
Resting
CD4+ T cell
Late Activated
CD4+ T cell
TCR
CD25
(+)
Qa-1/V
(-)
VLA-1
Collagen
TCR
(anti-Qa-1/V)
Activated
CD8+ T cell
Regulatory
CD8+ T cell
Down-regulation of
Activated CD4+ T Cells
Migration of
sites of
inflammation
L. Chess 2002
Immunological tolerance
• Definition:
– specific immune unresponsiveness to an antigen that
is induced by exposure of lymphocytes to that antigen
(tolerogen vs immunogen)
• Significance:
– All individuals should be tolerant of their own
antigens (self-tolerance); breakdown -->autoimmunity
– The induction of tolerance could be exploited to treat
autoimmune diseases
– Mechanisms of tolerance must first be understood
Fathman
Mechanisms of unresponsiveness to self antigens
• Central tolerance
– Immature self-reactive T lymphocytes that recognize self antigens
in the thymus undergo negative selection (deletion)
• Peripheral tolerance
– Mature self-reactive T lymphocytes that escape central tolerance
and recognize self antigens in peripheral tissues can be inactivated
(anergy), killed (deletion) or regulated (suppressed)
• “Clonal ignorance”
– Mature self-reactive lymphocytes do not respond to self antigens
in non-inflamed settings
Fathman
The Control of Activated CD4+ T Cells by Regulatory T cells
NKT cells/
CD4+CD25+ cells
CD4+CD25- cells
Apoptosis
peptide/APC
(- )
TH1 CD4+ cells
IL-12/
IFN-
(- )
IL-10
IL-4
Resting CD4 T cells
IFN-
(- )
Activated CD4 T cells
(- )
TH2 CD4+ cells
Regulatory immunity
CD4/CD8 interactions
CD8 or CD4
CD8 or CD4 suppressor
suppressor effector
precursor
L. Chess 2002
Regulatory T Cell Subsets
Re gulatory T cell
Suppressor Cell
Murine Marke rs Proposed Me chanisms of Inhibition
CD8+
Recognition of Qa-1:peptide on activated CD4+ T
cells induction of cytotoxicity
Natural Tre g
CD4+, CD25+
Cell-contact dependent but not antigen-specific;
CTLA-4+,
Ligation of B7 on effector cells; IL-2
GITR+, Foxp3+ sequestration; CTLA-4 interaction with IDO
(intracellular)
tolerogenic DCs; IL-10 & TGF-beta production
Adaptive Tre g
CD4+, CD25-,
Cell-contact dependent but not antigen-specific
Foxp3inhibition
Tr1
CD4+, CD45Rblo Cell-contact independent; IL-10 & IL-4 secretion
Th3
CD4+, CD45Rblo Cell-contact independent; T GF-beta secretion
Invariant NKT cell Invariant TCR
CD1d:glycolipid complex recognition; IL-10
secretion
(V14-J281),
CD4+, CD8-,
NK1.1+
Regulatory T Cells in Autoimmunity
CD4+CD45RBlo TGF, IL10
Th3
TGF,+/IL10,IL4
TR1
IL10, normal
TGF,no IL4
CD4+CD25+
CTLA4
(? =TR1)
Other CD4+
IL2, IFN
CD8+
CD4-CD8-TCR Fas
Gamma/Delta
NKT
IL4,IL10,IFN,
TGF
BDC
Colitis by CD45RBhi
EAE, glomeruloneph, MG,
clone DM
IBD by CD45RBhi ,
Respond IL-15
Thymectomy autoimmune
Constituitive CTLA4
MBP EAE model
Oral tolerance intestine
Skin Allograft
Gut, Nasal Insulin
CD1 Activated
Roncarolo et al. Curr Opinion Immunol 2000
XPID: X-linked Polyendocrinopathy,
Immune dysfunction and Diarrhea
Foxp3 Gene Essential CD4-CD25 T Reg
• XLAAD: Autoimmunity Allergic Dysregulation
• Defect in scurfin protein (gene = Foxp3/JM2)
or “scurfy mouse”
• Immunopathogenesis relates to a deficiency of
T regulatory cells
-Scurfy x Nude: No Autoimmunity
-CD4+ T cells into Nude: Disease
-Bone Marrow into irradiated: No Disease
-Mixed Chimera: No Disease
BDC
Requirements for the development
of an autoimmune disease
Nature Immunology (9): 759-761 (2001)
Fathman
Immunopathophysiology of Diabetes
Dendritic cell/
APC
CD2
CD4+
Cell
(TH0 )
DR3,
DR4,,DQ8/insulin
peptide
IL-12
,, TCR
IFN-
CD40L
CD40
IL-4
CD4+ Cell
(TH2 )
Macrophage/dendritic cell
Fc R
FasL
perforin
CD40L
Activated
TH1 CD4+ T
Cell
CD8+ CTL
IL-1, TNF, LT, NO, PGE-2
IL-4
CD40L
B Cell
?anti-insulin,
GAD ab antiMog
?Antibody mediated injury
cell death
islet cells
L. Chess 2002
Induction of CD4+ TH1 mediated
autoimmunity:
A paradigm for the pathogenesis of
rheumatoid arthritis, multiple sclerosis and
type I diabetes (1) expansion of CD4+,
autoreactive TH1 cells
specific for autoantigens
MHC/self-peptide
CD4
TCR Vx
CD4
MHC/V
TCR Vx
CD4+ Vx T cell APC
Activated autoreactive CD4+
TCR Vx TH1 cell
(2) migration and
infiltration of these self
reactive CD4+ TH1 cells
into tissues and induction
of inflammation and
autoimmunity
(3) induction of regulatory
cells which control the
growth and activation of
the pathogenic
autoreactive repertoire of
CD4+ T cells
L. Chess 2002
1984:Subset Participants Immunology in Diabetes Rome