The research progress of

CD4+CD25+regulatory T cell

The mechanism it participates The mechanism it participates in tumor immunityin tumor immunity

• Team members: 李彩娥 林冰钦• 金自慧 侯 毅• 陈成玉 程 卫

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History• This kind of cells was first fou

nd by Mukherji in 1986.

The cells were first named by Sakaguchi in 1995

A special CD4+ T cell

• Treg is a special CD4+ T cell

• Most CD4+ T cells belong to Th1 or Th2

• But 5%--10% of CD4+T cells belong to neither one which is called CD4+ CD25+ regulator T cells

TTregreg: Suppress the outgrowth of : Suppress the outgrowth of potentially pathogenic self-reactive T potentially pathogenic self-reactive T

cells (conventional T cells)cells (conventional T cells)

MHC II

TCR

Adapted from: Wood, K.J. and Sakaguchi, S. (2003) Nat Rev Immunol 3, 199-210

Conventional T cell

Increased Treg’s Increase in Solid TumorsTumor Treg Site N Ref

NSCLC CD4+CD25+ TIL 11 Woo

Ovarian CD4+CD25+ Ascites 9 Woo

Breast CD4+CD25+ TIL, LN 35 Liyanage

Pancreas CD4+CD25+ TIL, LN 30 Liyanage

Melanoma CD4+CD25+ Met LN 12 Viguier JI 2004

GI (gastric, colon, pancreas, esoph, liver)

CD4+CD25hi PBMC 149 Sasada

GI (gastric, esoph) CD4+CD25+ PBMC, TIL 30 Ichihara

GI (gastric, esoph) CD4+CD25+ PBMC 114 Kono K

Ovarian CD4+CD25+ Ascites 104 Curiel

Head and Neck CD4+CD25hi % PBMC 24 Schaefer

Hepatocellular CD4+CD25hi PBMC 84 Ormandy

Ovarian FoxP3 mRNA Tumor Bx 99 Wolf

•In most cases Treg suppressive function is confirmed in a subset of pts.•Correlations between stage, prognosis, Tx in some studies – e.g. gastric

Source of normal TregSource of normal Treg

Source of normal Treg

1. As a function-specific T cell subpopulation, Treg developed from thymus directly.

CD3‾CD4+ CD8‾ TCR‾ CD3‾CD4‾CD8+ TCR‾

CD3LOWCD4‾CD8+ TCRLOW

CD3+ CD4+ CD8+ TCR+

CD3+ CD4+ CD8‾ TCR+ CD3+ CD4‾ CD8+ TCR+

CD3+ CD4+ TCR+ CD3+ CD8+ TCR+

CD3+ CD4+ CD25+T cell

CD3+CD4+CD25+Tcell

CD3+ CD4‾ CD25+ T

CD3+ CD4‾ CD25+ T

CD3+ CD4‾ CD25+ T

CD3+ CD25++T

CD3‾CD4‾/LOW CD8‾ TCR‾

CD3‾CD4‾/LOW CD8‾ TCR‾

被膜

被膜下区

皮质

骨髓

髓质

胸腺小叶

Source of normal Treg

2. Treg developed from peripheral lymph organ.

Induced Treg Induced Treg

Character

.

CD25+ is symbol of activation.

FOXP3 is the specific mark.

Molecular MarkerMolecular Marker FunctionFunction

CD4+ -Binds MHC class II

-Expressed on Th cells

CD25+ -Expressed on most Treg cells

CD3+ -Ensures expression of TCR

GITR -Negative signaling

-Required for survival

CTLA-4 -Binds CD80/CD86

-Antagonizes effects of CD28 to CD80/86

CCR7 -Mediates migration of Treg cells back to lymph nodes

Foxp3 -Required for differentiation and function of Treg cells

NOTE!There are no known cell surface molecules that

uniquely distinguish the CD4+ Treg cells from conventional activated CD4+ T cells!

CD25

CTLA-4GITR CD4+CD25+

RegulatoryT cell

CD4+CD25+Tregs

In vivo Maintain immune tolerance Inhibit autoimmunity prevent transplant rejection Interfere with anti-cancer immunity Potential in immune deficiency

40

30

20

10

0

3H

up

take

(x1

0-3)

CD25– CD25+ CD25–

+CD25+

•In vitro• 5-10% of CD4+ T cells•Anergic to TCR stimulation•Suppress T cell proliferation

100 101 102 103 104

FL1-Spl/PBS/CD4

L090905.005

R2

100 101 102 103 104

FL4-Spl/PBSCD25

L090905.005

CD4

CD

25

Fo

xp3

FACS

CD25

CD25 Foxp3

Microscopy Co-culture

10% >90%

Treg

CD4 CD25

CTLA-4GITR

The Treg cell phenotype CD4

Co-receptor for TCR recognition of MHC II/Ag

CD25 IL-2R

IL-2R component, confers high affinity binding to IL-2R

Key TR growth factor

CTLA-4 cytotoxic T lymphocyte Ag-4

Binds to B7s (CD80/86) on APC, acts as co-stimulatory molecule for TR (blocking CTLA-4 inhibits TR)

GITR glucocorticoid induced TNF related protein

Ligation inhibits TR function (agonist inhibit TR, blocking augments TR)

FoxP3 Forkhead/winged-helix TF critical fo

r TR activity and development

Unlike surface markers / receptors, T

E do not express FoxP3

Foxp3

Molecular mechanism of Molecular mechanism of CD4+CD25+ inhibiting tumor CD4+CD25+ inhibiting tumor

immunityimmunity• Two classes on its effect wayTwo classes on its effect way

Ⅱ.Inhibition through cell-cell contact

Ⅰ.Inhibition dependents on cytokines

Act on effector T cells

DC is an important cell in CD4+CD25+Foxp3+regulatary

inhibition

DC is an important cell in CD4+CD25+Foxp3+regulatary

inhibition

The former The former include include inhibition inhibition induced by induced by TGF-β and IL-TGF-β and IL-10 signal 10 signal pathwaypathway

The former The former include include inhibition inhibition induced by induced by TGF-β and IL-TGF-β and IL-10 signal 10 signal pathwaypathway

the latter is the latter is mainlyredumainlyreduced by CTced by CTLA-4LA-4..

the latter is the latter is mainlyredumainlyreduced by CTced by CTLA-4LA-4..

＊ CD25 and IL-2 signal pathway

＊ TGFβand IL-10 signal path ＊

Cell adhesion inhibition associated with CTLA-4

＊ Inhibit expression of DC

TUMOR

TUMORAPC

CD4+ CD8+IL-2, IFN-γ

‘Conventional’ T cells

APC

CD4+ CD8+IL-2, IFN-γ

‘Conventional’ T cells

APC

CD4+ CD8+IL-2, IFN-γ

‘Conventional’ T cells

CD4+ Treg CD8+ Treg

APC

CD4+ CD8+IL-2, IFN-γ

‘Conventional’ T cells

CD4+ Treg CD8+ Treg

APC

CD4+ CD8+IL-2, IFN-γ

‘Conventional’ T cells

CD4+ Treg CD8+ Treg

TUMOR

APC

CD4+ CD8+IL-2, IFN-γ

‘Conventional’ T cells

CD8+ Treg

TUMOR

CCL22migration

CD4+ Treg

CCR4

APC

CD4+ CD8+IL-2, IFN-γ

‘Conventional’ T cells

CD8+ Treg

TUMOR

CCL22migration

CD4+ Treg

CCR4

That is all. Thank you!

CD25 and IL-2 signal pathwayCD25 and IL-2 signal pathway

• CD25 , main antigen on surface of Treg CD25 , main antigen on surface of Treg cell, α-chain of IL-2R.cell, α-chain of IL-2R.

• IL -2 is mainly secreted by effector T cell.IL -2 is mainly secreted by effector T cell.Its competition is the main mechanism oIts competition is the main mechanism of inhibition IL-2f inhibition IL-2R on effector T cell:dimer on Treg:trimR on effector T cell:dimer on Treg:trimer er

Secretion of IL-2 can increase expression of IL-2R on Treg cells while decrease it on effector Tcells.

Secretion of IL-2 can increase expression of IL-2R on Treg cells while decrease it on effector Tcells.

TGFβand IL-10 signal pathwayTGFβand IL-10 signal pathway

• TGF-βacts to inhibit reaction and proliferTGF-βacts to inhibit reaction and proliferation of lymphocyts, and inhibit the activation of lymphocyts, and inhibit the activation of Mφ.ation of Mφ.

Effcctor:CD8+T cellEffcctor:CD8+T cell ＆＆ NK cellNK cell

phosphorate

TGF-βR +

TGF-β

initiate

segment kinase domain

activate

SMAD

gene expresson

•Inhibition of Treg cell on NK cell are performed by NKG-2D to reduce its toxic activity directly.

IL-10 participates in Treg cell inhibition by regulating co-stimulatory molecules on APC.

IL-10 participates in Treg cell inhibition by regulating co-stimulatory molecules on APC.

Antigen cytokine

CD40

CD80/CD86

IL-10

Cell adhesion inhibition Cell adhesion inhibition associated by CTLA-4associated by CTLA-4

• Activation of naïve T cells :Activation of naïve T cells :

Peptide-MHC + TCRPeptide-MHC + TCR

B7 + CD28B7 + CD28

B7 B7

CD28

CD28 CTLA-4

CTLA-4

stimulatestimulate inhibit inhibit

APCAPC

• CTLA-4 has a much higher avidity for binding B7 family members than that does CD28 and are expressed more widely in the body.

• Binding of CTLA-4 to B7 on DC expression of IDO(indoleamine 2,3-dioxygenase ) on DC, Tregs activated by IDO markedly upregulated programmed cell death 1 ligand 1 (PD-L1) and PD-L2 expression on target DCs, and the ability of Tregs to suppress target T cell proliferation can be abrogated by antibodies against the programmed cell death 1/PD-L (PD-1/PD-L) pathway.

Inhibit expression of DCInhibit expression of DC

• NF-KbNF-Kb

(CD40,CD80\CD86,IL-12,TNF-a,CCL5) (CD40,CD80\CD86,IL-12,TNF-a,CCL5)

• Cell-cell contact Cell-cell contact

• cytokine: TGF-β, IL -10cytokine: TGF-β, IL -10

DCs may induce T cell tolerance to tumors.

Tumor cells

Tolerogenic DC

Lack of inflammation

Tumor-induced Treg

infection

inflammation

effector T cells

IL-10, VEGF

IL-10R

IL-10

Tumor cells

STAT3

Down regulation of co-stimulation