The research progress of CD4+CD25+regulatory T cell

1. The research progress of CD4+CD25+regulatory T cell and The mechanism it participates in tumor immunity

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

3. History • This kind of cells was first found by Mukherji in 1986.

4. The cells were first named by Sakaguchi in 1995 history

5. 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

6. Conventional T cell TCR MHC II Adapted from: Wood, K.J. and Sakaguchi, S. (2003) Nat RevImmunol3, 199-210 Treg: Suppress the outgrowth of potentially pathogenic self-reactive T cells (conventional T cells)

7. Increased Treg’s Increase in Solid Tumors • In most cases Treg suppressive function is confirmed in a subset of pts. • Correlations between stage, prognosis, Tx in some studies – e.g. gastric

8. Source of normal Treg

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

10. 骨髓 CD3‾CD4‾/LOW CD8‾ TCR‾ 胸腺小叶 被膜 CD3‾CD4‾/LOW CD8‾ TCR‾ 被膜下区 CD3+ CD4+ CD25+T cell CD3‾CD4+ CD8‾ TCR‾ CD3‾CD4‾CD8+ TCR‾ CD3+CD4+CD25+Tcell CD3LOWCD4‾CD8+ TCRabLOW 皮质 CD3+ CD4‾ CD25+ T CD3+ CD4+ CD8+ TCRab+ CD3+ CD4‾ CD25+ T CD3+ CD4‾ CD25+ T CD3+ CD4+ CD8‾ TCRab+ CD3+ CD4‾ CD8+ TCRab+ 髓质 CD3+ CD25++T CD3+ CD4+ TCRab+ CD3+ CD8+ TCRab+

11. Source of normal Treg 2. Treg developed from peripheral lymph organ.

12. Induced Treg

13. . CD25+ is symbol of activation. FOXP3 is the specific mark. Character

14. Molecular Features of Treg cells

15. CD25 GITR CTLA-4 CD4+CD25+ Regulatory T cell NOTE! There are no known cell surface molecules that uniquely distinguish the CD4+ Treg cells from conventional activated CD4+ T cells!

16. 40 30 3H uptake (x10-3) 20 10 0 CD25– CD25+ CD25– + CD25+ CD4+CD25+Tregs FACS Microscopy Co-culture 10% >90% Foxp3 CD25 CD25 Foxp3 CD4 CD25 • In vivo • Maintainimmune tolerance • Inhibit autoimmunity • prevent transplant rejection • Interfere with anti-cancer immunity • Potential in immune deficiency • In vitro • 5-10% of CD4+ T cells • Anergic to TCR stimulation • Suppress T cell proliferation

17. CD4 Co-receptor for TCR recognition of MHC II/Ag CD25IL-2Ra IL-2R component, confers high affinity binding to IL-2Rbg Key TR growth factor CTLA-4cytotoxic T lymphocyte Ag-4 Binds to B7s (CD80/86) on APC, acts as co-stimulatory molecule for TR (blocking CTLA-4 inhibits TR) GITRglucocorticoid induced TNF related protein Ligation inhibits TR function (agonist inhibit TR, blocking augments TR) FoxP3 Forkhead/winged-helix TF critical for TR activity and development Unlike surface markers / receptors, TE do not express FoxP3 CD4 CD25 GITR CTLA-4 Treg The Treg cell phenotype Foxp3

18. Molecular mechanism of CD4+CD25+ inhibiting tumor immunity • Two classes on its effect way Ⅰ.Inhibition dependents on cytokines Ⅱ.Inhibition through cell-cell contact Act on effector T cells

19. The former include inhibition induced by TGF-β and IL-10 signal pathway the latter is mainlyreduced by CTLA-4. DC is an important cell in CD4+CD25+Foxp3+regulatary inhibition

23. ＊CD25 and IL-2 signal pathway ＊TGFβand IL-10 signal path ＊Cell adhesion inhibition associated with CTLA-4 ＊Inhibit expression of DC

24. TUMOR

25. IL-2, IFN-γ ‘Conventional’ T cells TUMOR APC CD4+ CD8+

26. IL-2, IFN-γ ‘Conventional’ T cells APC CD4+ CD8+

27. IL-2, IFN-γ ‘Conventional’ T cells CD4+ Treg CD8+ Treg APC CD4+ CD8+

28. IL-2, IFN-γ ‘Conventional’ T cells CD4+ Treg CD8+ Treg APC CD4+ CD8+

29. IL-2, IFN-γ ‘Conventional’ T cells CD4+ Treg CD8+ Treg Advantage! TUMOR APC CD4+ CD8+

30. CD4+ Treg CCR4 migration IL-2, IFN-γ ‘Conventional’ T cells CD8+ Treg CCL22 TUMOR APC CD4+ CD8+

31. CD4+ Treg CCR4 migration IL-2, IFN-γ ‘Conventional’ T cells CD8+ Treg Advantage! CCL22 TUMOR APC CD4+ CD8+

32. That is all. Thank you!

33. CD25 and IL-2 signal pathway • CD25 , main antigen on surface of Treg cell, α-chain of IL-2R. • IL -2 is mainly secreted by effector T cell.Its competition is the main mechanism of inhibition IL-2R on effector T cell:dimer on Treg:trimer

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

35. TGFβand IL-10 signal pathway • TGF-βacts to inhibit reaction and proliferation of lymphocyts, and inhibit the activation of Mφ. Effcctor:CD8+T cell＆NK cell

36. TGF-βR + TGF-β segment kinase domain phosphorate activate gene expresson SMAD initiate

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

38. CD40 CD80/CD86 IL-10 participates in Treg cell inhibition by regulating co-stimulatory molecules on APC. IL-10 Antigen cytokine

39. Cell adhesion inhibition associated by CTLA-4 • Activation of naïve T cells : Peptide-MHC + TCR B7 + CD28

40. B7 CTLA-4 CD28 stimulate inhibit APC

41. 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.

43. Inhibit expression of DC • NF-Kb (CD40,CD80\CD86,IL-12,TNF-a,CCL5) • Cell-cell contact • cytokine: TGF-β, IL -10

44. DCs may induce T cell tolerance to tumors. Tumor cells infection Tumor cells IL-10 IL-10, VEGF inflammation Lack of inflammation IL-10R Tolerogenic DC STAT3 Down regulation of co-stimulation Tumor-induced Treg effector T cells