who gets the autoimmune disease type 1 diabetes, and why?
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Who gets the autoimmune disease Type 1 diabetes, and why?. Mark Peakman King’s College London. 35 years of Type 1 diabetes immunology research – an autoimmune disease model emerges How genes and environment may come together in the “perfect storm” - PowerPoint PPT PresentationTRANSCRIPT
Who gets the autoimmune disease Type 1 diabetes, and
why?
•35 years of Type 1 diabetes immunology research – an autoimmune disease model emerges
•How genes and environment may come together in the “perfect storm”
•Devising new immunological approaches for translation into therapies
Mark Peakman
King’s College London
•Type 1 diabetes 1921; universally fatal; discovery of insulin
•Diabetic complications (renal failure, blindness, early cardiovascular disease) due to chronic hyperglycaemia
•Diabetes costs NHS ~£8-10 billion (Type 1 diabetes £2-5b)
“Western Europe: • 15,000 new cases in 2005 • 24,400 in 2020 • Incidence to double in children <5 years…”
•No known cure or spontaneous remission
Type 1 diabetes
1922
Banting
Marjorie
Best
Insulin T lymphocytes (CD3)
Background I: pathology
At diagnosis >80% of islets destroyed
John Todd and Linda Wicker, Cambridge
Background II: Large genome-wide studies
•Pinpoint variants of normal genes that are more frequent in diabetes
DC
α THelper
β cells
DC
1. Islet
2. Pancreatic lymph node
DC
3. Via blood
HLA II
Type 1 diabetes: immune pathogenesis
HLA I
Pro-inflammatory
cytokines
CTLTCytotoxic
THelper
TCytotoxic
Epitope discovery
Insulin
DC
α THelper
β cells
DC
1. Islet
2. Pancreatic lymph node
DC
3. Via blood
HLA II
Type 1 diabetes: immune pathogenesis
HLA I
Pro-inflammatory
cytokines
CTLTCytotoxic
THelper
TCytotoxic
Epitope discovery
GENE SET 1: Ag presentation to T cells
Insulin
DC
α THelper
β cells
DC
1. Islet
2. Pancreatic lymph node
DC
3. Via blood
HLA II
Type 1 diabetes: immune pathogenesis
HLA I
CTLTCytotoxic
TH
IL-10TRegulatory
TCytotoxic GENE SET 2: Immune regulation
Anti-inflammatory
cytokines
Insulin
DC
α THelper
β cells
DC
1. Islet
2. Pancreatic lymph node
DC
3. Via blood
HLA II
Type 1 diabetes: immune pathogenesis
HLA I
CTLTCytotoxic
TH
IL-10TRegulatory
TCytotoxic
GENE SET 3: Pathogen susceptibility
Insulin
DC
α THelper
β cells
DC
1. Islet
2. Pancreatic lymph node
DC
3. Via blood
HLA II
Type 1 diabetes: immune pathogenesis
HLA I
CTLTCytotoxic
TH
IL-10
TR
TCytotoxic
GENE SET 3: Pathogen susceptibility
GENE SET 1: Ag presentation to T cells
GENE SET 2: Immune regulation
Insulin
GENE SET 1: Ag presentation to T cells
TCytotoxic
DC
β cell
0
10
20
30
Number of Effectors per Target
12631 25
% S
peci
fic ly
sis
HLA-A2+ human islets with 1E6 clone
A2+ islets/control clone
A2- islets/1E6 clone
Tcytotoxic cells targeting insulin kill human β-cells.
Are these cells in the islets where β-cells are killed?
Epitope discovery
HLA
Coppieters et al, JEM, 2012
Insulin- specific T cells
In situ staining for antigen-specific T cells
GENE SET 1: Ag presentation to T cells
TCytotoxic
DC
β cell
0
10
20
30
Number of Effectors per Target
12631 25
% S
peci
fic ly
sis
A2+ human islets with 1E6 clone
A2+ islets/control clone
A2- islets/1E6 clone
Tcytotoxic cells targeting insulin kill human β-cells.
How does this interaction look at the molecular level?
Crystal
CTL
β cell Dissociation constant Kd ~250μM
(ie ultra-low vs tumour antigens (~50 μM) or virus (~5 μM))
In press
HLA-A2 (*0201)
TcR
β-chainα-chain
•Bulek et al, Nat Imm 2012
Unique features of insulin-specific TCR:
• Weakest binding affinity to a natural agonist antigen ever described
• highly peptide-centric binding dominated by hotspots focused on just two amino acids in the peptide
β-cell
Killer T cell
insulin peptide
•Major opportunities for cross-reactivity
•The antigenic peptide that primed killer T cells may not be from insulin originally
GENE SET 2: Immune regulation
No IL-10 response
IL-10 response
7.5y Balance of islet-specific TH cells in peripheral blood in Type 1 diabetes is abnormal
•Candidate genes: CD25, CTLA4, IL-10
GENE SET 2: Immune regulation
GENE SET 3: Pathogen susceptibility
α THelper
β cells
DC
1. Islet
2. Pancreatic lymph node
DC
3. Via blood
HLA II
HLA I
CTLTCytotoxic
Insulin
TCytotoxic
GENE SET 3: Pathogen susceptibility
Candidate genes: IFIH1 EBI2TLR7/TLR8BACH2FUT2
Sense pathogens:Set “response rheostat”
DC
α THelper
β cells
DC
1. Islet
2. Pancreatic lymph node
DC
3. Via blood
HLA II
Type 1 diabetes: the model
HLA I
CTLTCytotoxic
TH
IL-10
TR
TCytotoxic
GENE SET 3: Pathogen susceptibility
GENE SET 1: Ag presentation to T cells
GENE SET 2: Immune regulation
Insulin
B
Islet cell AAbs
• Anti-CD3, transient depletion of T cells• Rituximab, anti-CD20, depletes B cells • Abatacept, CTLA4-Ig, co-stimulation blockade
Therapeutic options in T1D: “immune suppression”
Emergence of the concept of Antigen Specific Immunotherapy (ASI) for autoimmune disease
“The administration of auto-antigen in a form or by a route designed to induce or re-establish tolerance to the same antigen or to the target tissues of the autoimmune response”
Lead disease setting: clinical allergy (multiple sclerosis)
Inject whole proteins or peptides from allergens
Good, sustained clinical efficacy
24/11/11
Figure 1
Benefit
IL-10
TR
Proinsulin peptide immunotherapy
•Monthly i.d. injections of proinsulin peptide x 3;•10, 100 and 1000μg per dose
0
1
2
3
4
5
IL-1
0 (S
I) **
10g placebo
0 3 6 0 3 6month of study
*5µM10µM
•Induction of IL-10 response to proinsulin peptide C19-A3 after low dose i.d administration in T1D patients
•No autoantibody increase or induction; no anti-peptide antibodies
•No pro-inflammatory cytokine induction
•Improved glycaemic control
0 3 6
Peptide administration
Month of study
Phase Ib (New T1D) Monthly
Bi-weekly
Developmental programme
(Phase I in 2014)
•Multiple peptides from >1 β-cell antigen
Who gets the autoimmune disease Type 1 diabetes, and
why?
•35 years of Type 1 diabetes immunology research – an autoimmune disease model emerges
•Genes and environment come together in the “perfect storm”
•New immunological approaches for translation into therapies are emerging: an exciting decade ahead
Funders and collaborators•Department of Immunobiology at KCL
•Clinical collaborators, Guy’s and St Thomas’ NHS Foundation Trust & King’s College Hospital
•Cardiff University (Colin Dayan); Cambridge University (Catherine Guy, David Dunger, Linda Wicker, John Todd); University of Bristol (Polly Bingley)
•Funding agencies:
Naimit