Vaccine for atherosclerosis – a review on the role of immunity in

atherosclerosis

Jan Nilsson, Lund UniversityGöran K Hansson, Karolinska

Institutet, Sweden

Atherosclerosis – an inflammatory response to lipid retention

LDL entry

LDL retentionLDL retention& modification& modification

Adhesion moleculesChemokines

Proinflammatory lipidsactivate EC and Mø

LDL uptakeLDL uptakeand presentationand presentation

T cell activation

ProinflammatoryProinflammatory cytokinescytokines

InflammationDestruction & remodeling

Lesion growth & activation

Foam cell formation

G K Hansson & J NilssonIn: Crawford & DiMarco,

Cardiology

Innate immunity in plaque inflammation

InflammatorycytokinesProteases

ProcoagulantPro-apoptotic

TLR

LPS, HSP60, oxLDL(?)

TLR

Natural antibodies

G K Hansson

Atherosclerosis in the absence of adaptive immunity?

(G K Hansson & J Nilsson, in: Crawford & DiMarco, Cardiology)

Lack of adaptive immunity leads to dramatic reduction in atherosclerosis –

without affecting cholesterol levels

*

ApoE-SCID

ApoE-

T and B cells No Yes

Aortic lesion size

Zhou, Nicoletti,Elhage & HanssonCirc 102:29192000

Similar - but not as striking - effects in immunodeficientRAG1 x apoE KODansky, PNAS 97Daugherty, JCI 97

Atherosclerosis in the absence of adaptive immunity?

(G K Hansson & J Nilsson, in: Crawford & DiMarco, Cardiology)

Splenectomy leads to accelerated atherosclerosis in apoE -/- mice

020406080

100120140160

Sham Splenectomy

*Le

sion

siz

e x

103 µ

m

Sx at 6 weeks, analysis at 18 weeks ageCaligiuri et al, JCI 109:745, 2002

B cells of atherosclerotic mice carry atheroprotective immunity

0

50

100

150

200

250

Sham Sx Sx SxTransfer - - T B

*

*

‡

‡Lesi

on s

ize

Caligiuri et al, JCI 109:745, 2002

Do T cells recognize antigens in atherosclerosis?

0

1

2

3

4

5

oxLDL - - + + + +MC + - - + + + MAb - - - - anti-DR Ctrl ab

T cells of human plaques recognize oxLDL as antigen

Stemme et alPNAS 1995

G Cooper, The Cell

CD4+ T cells recognize oligopeptide epitopes

What aboutthe lipids?

NKT cells are specialised T cells that recognize glycolipid antigens

NKTNKT cells use TCR to recognize glycolipids

CD1 binds glycolipid antigens forpresentation to NKT cells

NKT APC

G K Hansson

A role for NKT cellsin atherosclerosis?

Experimental strategies:• Cross apoE0 with CD1d0

• Activate NKT cells in apoE0 with ”artificial” lipid antigen,

Galactosyl Ceramide

E Tupin et al, J Exp Med 2004; 199:417-422

E Tupin et al, J Exp Med 2004; 199:417-422

NKT cells increase atherosclerosis

GalCer activates NKTand increases atheroscl

No effect of GalCerin CD1d-/- apoE-/-

Reduced atherosclerosisin CD1d-/- apoE-/- mice

Lesions at 15 wk

TGF- inhibits T cell activation- role in atherosclerosis? -

TNFIL-4IL-10

IFN

Non-functionalreceptors

TGF

APC

T cell

No effect ofdampening signal!

Mouse carrying a dominant-negative TGFR in T cells(Gorelik & Flavell 2000)

Cross w/ apoE-/- mouse

Dramatically increased atherosclerosis in mice lacking TGF- regulation of T cells

Dominant-negative TGFR under CD4 promoter x apoE-/-

Robertson et al, J Clin Invest 2003; 112:1342-50

Adhesion

Chemotaxis

Recruitment of immune cells to forming atherosclerotic lesions

G K Hansson

APC

CD4+T

NKT

Antigens activate T cells in lesions

oxLDL, HSP60,

others?

Activation & Th1 differentiation

IL-12

IL-18, IL-15G K Hansson

Activation of macrophages, endothelial and smooth muscle cells

IFN-

IFN-

TNF-

CD40L/RTh1

MEC

SMC

AdhesionPermeability

Prothrombotic stateProteases

↓ proliferation↓ collagen

↓ actinIL-6

Inflammatorymediators

G K Hansson

Regulation of immune activity

IL-10

TGF-

TGF-

TregTh2

Th1

M

SMC

EC

Antigen-specificTreg activation

Atheroprotective immune mechanisms

• Regulatory T cells– Produce antiinflammatory/immunosuppressive cytokines– TGF-

• Robertson JCI 03; Mallat Blood 03; – IL-10

• Mallat Circ Res 99; Pinderski ATVB 99; Caligiuri Mol Med 02

• B cells– Spleen B cells; B1 cells – Stimulated by IL-5– Possibly due to production of ”natural” antibodies

• Caligiuri JCI 02; Binder Nat Med 02, JCI 04

Can we use protective immunity to protect against

atherosclerosis?

Protective immunization

Model: Mutant rabbits, mice

Antigen: OxLDL, MDA-LDL, HSP60, beta 2-glycoprotein

Administration: Th2 adjuvant sc or mucosal Significant protection after 3 months!

Palinski PNAS 95; Ameli ATVB 96;George Athero 99; Zhou ATVB 00Harats JACC 02; Maron Circ 02

Vaccination against atherosclerosis?

• Antigen-specific protective immunity• Mediated by B cells and regulatory T cells (?)• Protective immunization works in models

– MDA-LDL; Phosphorylcholine; HSP65/60

• Many remaining questions and challenges:– Precise epitopes, pure antigens– Administration routes, adjuvants

InflammationRepair

Innate immunity Adaptive Th1 immunity

IFN-IL-18

TNF-IL-1

Antiinflammatory immunityHumoral immunity

IL-10TGF-

Anti-oxLDL

M activationEndothelial activation

RadicalsProteinases

Prothrombotic state

AntiinflammationFibrosis

SMC proliferationPlaque stability

Antibody clearance

Immune regulation of plaque activity

G K Hansson

Nilsson, Hansson, Shah, ATVB, in press