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Chapter 8 B/T cell development B T. Adaptive immunity B/T cells Innate immunity BCR/TCR: epitope recognition Gene rearrangement of AgR Pattern recognition.

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Presentation on theme: "Chapter 8 B/T cell development B T. Adaptive immunity B/T cells Innate immunity BCR/TCR: epitope recognition Gene rearrangement of AgR Pattern recognition."— Presentation transcript:

1 Chapter 8 B/T cell development B T

2 Adaptive immunity B/T cells Innate immunity BCR/TCR: epitope recognition Gene rearrangement of AgR Pattern recognition

3 BCR/TCR: Ag recognition MHC-restriction Extracellular Ag Intracellular Ag Structure Gene rearranged receptors Epitope

4 One cell one Ag-specific receptor Clone Fate 細胞差異 T/B: Rearranged AgR T: MHC restriction Techniques

5 Adaptive immunity 1. Antigen specificity 2. Diversity 3. Immunological memory 4. Self tolerance Four characteristics Foreign (non-self) Ag Self Ag (encoded by the host’s genome)

6 MHC-restricted? Self Ag? Aim of development 1.Productive rearranged AgR 2. Functional Ag recognition Production of AgR 3.Self tolerance

7 Hematopoiesis Central lymphoid organs Microenvironment Cell survival & death Commitment Productive rearrangement? 2

8 B-cell development T-cell development Positive & negative selection Fate Self antigen Before or after gene rearrangement of AgR ?

9 Development of B cells Stromal cells Adhesion molecules Chemokines & R Cytokines & R Microenvironment

10 The dependence on bone marrow stromal cells Early stages SDF-1 Constitutive production B cell commitment Cell-cell interaction Migration

11 Gene rearrangement

12 Loop

13 Ig gene rearrangement & B cell stages Proliferation

14 Antibody structure

15 Protein-regulated gene rearrangement

16

17 Cell survival or death Allelic exclusion One cell one Ag-specific receptor

18

19 Self-reactivity Fate The presence of autoreactive lymphocytes in periphery

20 Low frequency of Ag-specific B cells

21 Stromal cell-dependent (Spatial regulation) Temporal regulation of protein expression Proteins: receptors, cytokines, TS factors, recombinase,.. B-cell development B cell commitment BCR rearrangement Cell survival & death (BCR, self tolerance) T Protein-regulated gene rearrangement Cell survival & death One cell one AgR

22 T cell development Self MHC restriction Self tolerance Cells Microenvironment

23 T cell development

24 Epithelial cell network: thymic stroma Thymus

25

26  TCR

27  TCR genes

28  TCR  TCR or ? 

29 Developmental control of  T cells Ordered sequence

30 Repeated rearrangements can rescue nonproductive V  J  joins

31  gene rearrangement induces  gene deletion

32 T cell commitment R: Notch 1

33 Cortex T cell development Gene rearrangement 33 Positive selection : MHC restriction Negative selection : Self tolerance Medulla

34 Self MHC restriction

35 T cell development Positive selection : MHC restriction Negative selection : Self tolerance MHC

36 Gene locus

37 37 H-2 k

38 38 基因 親代來源

39 Analyze all the possible types of MHC class I and II restriction for CD4 T and CD8 T cells developed in an MHC bxk F1 hybrid mouse. 39

40 MHC: co-dominant d/k 40 Ch6 section 6-12

41 ? 41

42 MHC polymorphism 個體獨特性 TCR: MHC restriction MHC haplotype Ch6 section 6-12

43 Formula: 100(DP  ) X 100(DP  ) X 100(DQ  ) X 100(DQ  ) X 100(DR  ) X 100(DR  ) X 100(A) X 100(B) X 100(C) =10 18 Alleles / locus MHC polymorphism

44 Variability of MHC alleles

45 MHC I MHC II Peptide presented on MHC I/II

46 MHC-binding ability of peptides Multiple epitopes 46

47 MHC-restricted presentation of antigenic peptides d/k 47

48 H-2 k 48 Self MHC restriction 3 2 Positive selection : MHC restriction

49 d/k 49 Self MHC restriction

50 MHC and immune responsiveness

51 Flow cytometry: immunostaining 51

52 T cell subsets in central and peripheral organs Flow cytometry: immunostaining Normal 52

53 Hybridoma TCR transgene TCR transgenic mice Low frequency of Ag-specific T cells High frequency T cell clone 53

54 54 Flow

55 Positive selection : MHC restriction MHCI-CD8 T Cortex MHCII-CD4 T

56 Knock-out mice Techniques 基因剔除鼠 56

57 Knock-out mice 57

58 Knock-in mice 黑 白 Knock-out mice 58

59 Positive selection MHC II restriction: Interaction of CD4 with MHCII Host Application of Tg & KO mice system KO KI ? 59

60 Cre/lox system Enzyme (recombinase) Inducible knock-out mice Tissue specificity in other tissues KO Lethal effect 60

61 Immunodeficient mice Genetic defect of a gene coding for transcription factor Wnt required for terminal differentiation of cortical epithelial cells Defective gene repairing system What do SCID & nude mice lack (T/B cells) ? Severe combined immunodeficiency 61

62 Cells & microenvironment Flow cytometry Adoptive transfer 62

63 T cells : thymus MHC restriction Positive selection 63

64 Hematopoiesis MHC a MHC b MHC axb APC 64

65 Bone marrow-derived APC Thymic non-lymphoid stroma Bone marrow chimera 65 ?

66 66 Positive selection : MHC restriction

67 Cortex T cell development Gene rearrangement 67 Positive selection : MHC restriction Negative selection : Self tolerance Medulla

68 Negative selection: self tolerance AIRE (Autoimmune regulator) Transcription factor AIRE regulates the expression of ubiquitous self antigens & a wide variety of tissue-restricted self Ag (e.g. pancreas, brain) at low levels in the thymus

69 DC CD8T APC 69

70 Natural regulatory T cells (Treg)

71 Negative selection ?

72 Negative selection: self tolerance Bone marrow-derived

73 Negative selection : clonal deletion & Treg Ann Rev Immunol 30: 531, 2012

74 T cell development AIRE medulary cells The presence of autoreactive lymphocytes in periphery Natural Treg

75 CD4T  TCR  TCR T cells CD8T MHCII MHCI T cell subpopulations T cell development 1. Antigen specificity 2. Diversity 3. Immunological memory 4. Self tolerance

76 Germline-encoded receptors Gene rearranged receptors: TCR/BCR Innate immunity Adaptive immunity B/T cells Pattern recognition Epitope recognition AgR


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