Th 细胞亚群和 T 记忆细胞 季明春 扬州大学医学院

2 Th 细胞亚群 Th1/Th2 cells Th17 Cells Tfh Cells Th9 Cells Treg Cells

3 Th 细胞亚群 Th1/Th2 cells Th17 Cells Tfh Cells Th9 Cells Treg Cells

4 Introduction of Th1/Th2 cells In 1986, T.R. Mosman and R.L. Coffman observed that individual clones of mouse helper T cells could be separated into two classes depending upon the specific cytokines the cells secrete in response to antigenic stimulation.

Induction of Th1 and Th2 Responses Th2 Th1 Antigens IL-4 IL-12 IFN-γ APC Na ï ve CD 4 Effector Cells Signal 2 Signal 1 IL-2 IFN-γ IL-4 IL-5 IL-10 Cellular Immune Responses Humoral Immune Responses

7 Th1 and Th2 Differentiation in vivo Infection of mice with Leishmania Major ( 利什曼原虫 ) provides a valuable model for the study of Th1 and Th2 differentiation in vivo

Leishmania major Infection in Mice Provides a Useful Model to Study Th1 and Th2 Differentiation and Memory in vivo

Leishmania major infection: Mouse Models Balb/C BL/6 Th 1 response Death Recovery Th 2 response IL-12 αIL-12/αIFN-γ

Signaling of IL-12 Receptor 11 22 TYK2TYK2 JAK2JAK2 p40 p35 STAT4STAT4 P P Y Stat4 P P Y Y IFN-  Production Expression  1: Expressed on Th1, Th2, N.K., and B cells  2: Expressed on activated Naïve T, Th1, and N.K. cells Regulation Enhanced by: activation of  -CD28, IL-2, IL-7, IL-15, IFN-  (mouse), IFN-  (human) Inhibited by: IL-4, IL-10, TGF- , PGE2, Dex

Cytokines On Th1 Cell Development Pathogen APC CD 4 + T Cell STAT4 TCR IFN-γ IFN-γ+++ IL-27 TCCR/ WSX-1 IL-12 IL-23 IL-12 IL-18 Naïve CD 4 + Th1 Th1 Effector IL-12Rβ1 β2 IL-18R IL-12Rβ1 β2 STAT1T-betIFN-γT-bet STAT4 NFKB GADD45 p3B IRAK NFKB

12 The Th1/Th2 Paradigm in Human Diseases (1) Transplantation rejection and tolerance Th1—DTH—rejection Th2—tolerance Successful pregnancy and unexplained recurrent abortion Successful pregnancy Th2/Tho Recurrent abortion—Th1 Allergic disorders Th2 cells—the involvement of the mast cell/eosinophil/IgE-producing B cell in the pathogenesis of allergy

13 The Th1/Th2 Paradigm in Human Diseases (2) Autoimmune disorders Autoimmune thyroid diseases—Th1 Multiple sclerosis (MS)—Th1 profile Th1 or insulin-dependent diabetes mellitus—Th1 profile Systemic sclerosis (SSc)—Th2 profile

14 Th 细胞亚群 Th1/Th2 cells Th17 Cells—— IL-17-producing T cells Tfh Cells Th9 Cells Treg Cells

A new subset of Th cells — Th17 Naïve CD4 + T cell TGF- β IL-4 IL-23 IL-6 Th17 Th1 Th2 Treg IL-6 IL-17A IL-17B TGF- β IL-13 IL-4 IL-5 IL-12 IFN- γ (-)

T(H)-17 differentiation: of mice and men Nat Immunol. 2007, 8(9):903-5

17 Th17 and diseases Infection Tumor Autoimmune disease Rheumatoid Arthritis(RA) SLE Multiple Sclerosis(MS)

18 Th 细胞亚群 Th1/Th2 cells Th17 Cells Tfh Cells —— Follicular B helper T cells Th9 Cells Treg Cells

19 Lose expression of CXCR5 Naïve T cells: CXCR5 - CXCR5 is transiently upregulated on CD4 + T cells following activation Retain CXCR5 expression Th1/Th2 Th17/Treg differentiation T FH cells Origin of T FH cells

Follicular helper T cells: Lineage and location Immunity 30, March 20, 2009 First contact between pMHC Ⅱ -specific effector T FH cells and antigen- primed pMHC Ⅱ + B cells occurs at the T-B borders. Pre-GC effector T FH cells

21 T FH cells and autoimmunity  Human SLE patients : an increased frequency of ICOS + CD4 + T cells in their peripheral blood.  Lupus-prone mice: an increased frequency of ICOS + CD4 + T cells in spleens.  Chronic inflammation: T FH cells may also promote chronic inflammation. Any dysregulation of T cell function or tolerance induction can have a significant effect on the selection of Ab specificities:

22 T FH cells and immunodeficiencies Ineffective T cell help to B cells appears to underlie certain humoral immunodeficiencies.  X-linked lymphoproliferative disease (XLP)  ICOS deficiency  CVID It is likely that compromised development or function of T FH cells contributes to impaired B cell differentiation and humoral immunity in conditions of immunodeficiency.

23 Th 细胞亚群 Th1/Th2 cells Th17 Cells Tfh Cells Th9 Cells —— IL-9-producing T cells Treg Cells

24 Introduction Recently, two reports described a discrete subset of interleukin-9(IL-9)-producing T cells that might be closely related to the T H 2-cell lineage. These IL-9-producing T cells seem to be a distinct population that does not show the characteristics of other described T-cell subsets “ T H 9 ” cells.

TGF-β deviates T H 2 cells to a “ T H -9 ” fate IL-9-producing T cells could be generated from T H 2 cells that were exposed to TGF-β in vitro, even when the T H 2 cells were highly polarized. × IL-4 inhibits TGF-β-induced Foxp3+ T cells IL-4 actively inhibits the induction of Foxp3 in the presence of TGF-β. The inhibition of Foxp3 expression by IL-4 is mediated through the IL-4-STAT6 pathway. The Foxp3 can directly interact with GATA-3 and this association inhibits GATA-3 mediated transactivation of IL-5, which is one of its target genes.

26 Function of IL-9 + T cells IL-9 is involved in immunity against helminths and is important for recruiting mast cells to the site of infection. Lower levels of IL-9 production correlated with decreased mast-cell recruitment and impaired immunity against the helminth Trichuris muris.

27 T H 9 cells lack suppressive function and promote tissue inflammation. ◆ T H 9 cells also produced IL-10. However, unlike IL- 10-producing Tr1 cells,T H 9 cells do not have any suppressive effects in vitro but readily proliferate and thus act like effector T cells. ◆ Adoptive transfer of IL-9 + IL-10 + T cells into recombination- activating gene 1-deficient mice induced colitis and peripheral neuritis, the severity of which was aggravated if the IL-9 + IL-10 + T cells were transferred with CD45RB hi CD4 + effector T cells. Function of IL-9 + T cells

28 Th 细胞亚群 Th1/Th2 cells Th17 Cells Tfh Cells Th9 Cells Treg Cells —— Suppressor or Regulatory T Cells

29 Introduction Regulation of immune responses to self-antigen is a complex process –Maintaining self-tolerance –Retaining the capacity to mount immune responses against invading microorganisms

30 Discovery of Suppressor T Cells In 1995, Sakaguchi et al made the seminal observation: The transfer of CD4+ T cells which had been depleted of the minor subpopulation (10%) of cells to nu/nu recipients induced organ- specific autoimmune diseases in the majority of recipients. The minor subpopulation of cells are CD4+CD25+ T cells.

31 CD4 + CD25 + Tr cells Constitutively express the IL-2R-α (CD25) Glucocorticoid induced tumor necrosis factor receptor (GITP) 5-10% of the peripheral T cell pool The regulatory effect by a mechanism dependant on cell- cell contact Expression of the inhibitory co-stimulatory molecule CTLA-4 Cell surface TGF-β or release IL-10 Foxp3, master regulatory gene

Overview of phenotypes and functions of CD4 + T cells Naïve CD4 Th1 Tr Th2 IFN-γ Cell mediated immune responses IL-4 IL-5 IL-10 IL-13 humoral immune response Tr 1 Th 3 CD4 + CD25 + High IL-10, low TGF-β TGF-β cell-cell contact Natural Tr in thymus contact-dependent Adaptive Tr in peripheral lymphoid tissue cytokines- dependant Regulatory T cells

Differentiation of Tr cells Naïve CD4 + T cells Tr1 Th3 CD4 + CD25 TGF-β IL-10 + IFN-α _

34 Primary function of Tr cells Maintaining self-tolerance and homeostasis Preventing infection-induced immunopathology Prolong pathogen persistence by suppressing protective Th1 responses

35 Generation of Tr1 cells OVA-TCR Naïve CD4 Tr1 cells IL-10 IL-5 +TGF-β OVA + IL-10 Immunosuppressive drugs Anti-IL-4 + Anti-IL-12

Phenotype and function of Tr 1 cells Expression CCR5 and TS-STL Immunosuppressive properties: - prevent the development of Th1 mediated autoimmune disease - suppress immune response to pathogens, tumors and allo antigens - suppress of proliferative responses and cytokine production The suppressive effects of Tr1 cells are reversed by neutralizing IL-10

37 Th3 cells Secrete TGF-β Suppress the induction of experiment autoimmune encephalomyelitis (EAE). Suppress the induction of protective tumor-specific cytotoxin T lymphocyte (CTL) responses

What is the target cell for CD25+ T-cell-mediated suppression?

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记忆性 T 细胞 Memory T cell Differentiation and Memory Generation

Immune response and generation of memory cells

44 Phase of memory

Generation of CD4+ effector T cells

Subsets of Th1 cells with different cytokine profiles are related to protection and memory cell generation CCR7 + ( central memory cells ) secondary stimulation IFN-γ-producing cells ● Lower in expression of CCR7, Effector memory cells ● Mediating protection against infections ● Apoptosis ● Would be more limited in mediating optimal and sustained protection ● Apoptosis ● Reservoir of long-term central memory cells ● Unlikely to the sufficient for optimal protection

Generation of CD8+ effector T cells

Characterization of na ï ve, effector and memory T cells in humans

Characterization of na ï ve and memory T cells by the expression of surface molecules

50 Differentiation model for memory T cells(1)

51 Differentiation model for memory T cells(1)

52 Differentiation model for memory T cells(1)

53 Concept of memory The ability to remember the specific antigen and generate faster, stronger response against re-infection More antigen-specific T cells Faster and greater response

54 Features of memory Shorter latency period Faster response Higher magnitude Longer persistence time Key feature of immune system Basis for vaccine design