Induction of adaptive immunity

Differentiation of Th

Cytokines

Cell-mediated immunity

Humoral immunity

Immunological memory

Immune effector

function

Gene rearranged receptors: TCR/BCR

Foreign Ags……….

對外

Adaptive immunity

1. Antigen specificity

2. Diversity

3. Immunological memory

4. Self tolerance

Four characteristics

Clonal selection Immune diversity

Antigenspecificity Diversity Memory

Central tolerance Peripheral tolerance

Sites ofeffector function

Primary (Central): Bone marrow 骨髓 Thymus 胸腺 Secondary (Pheripheral): Lymph nodes 淋巴結 Spleen 脾臟 Peyer’s patches

Lymph node distribution in the body

Ag Innate Adaptive

Extracellular Phagocytes B cells

Intracellular NK CD8 Tc cells(Altered self)

Immunity & Ag location

Cytotoxicity

CD4 Th

Humoral response

Cell-mediated immunity (CMI)

1

2

Phagocytes

Antigen-Presenting Cells (APC)

B/T cells

Lymphocyte activationClonal selectionHumoral Imm/CMIMemory

Inflammatory site

Inflammation

Inflammatorysite

Lymph node

Induction of adaptive immunity

Dendritic cells (DC)

Lymph node

DC

T

HEV

T cell activation

Induction of adaptive immunity

Differentiation of CD4 Th

Cytokines

Cell-mediated immunity

Humoral immunity

Immunological memory

Immune effector

function

Naïve, activated, effector

Humoral immunityCell-mediated immunity (CMI)

Act

ivat

ion

Eff

ecto

r

Three signals in naïve T cell activation

PrimingThe activation and differentiation of naïve T cells

Costimulation

Professional APC

Ag & MHC presentation pathways

DC/Macrophages/B cells

Foreignor

Self Ag

Signal 1

Signal 2

Signal 2 alone

CD4 T cell activation

IL2 production

Clonal expansion

Signal 1+2

IL2R

Professional APC

Lack of signal 2 upon T cell activation

Peripheral tolerance

Negativeregulation of signal 2

upon T cell activation

Peripheral tolerance

Inhibition of activated T cells

CD4 T cell differentiation

CMI: CD8 T Humoral response

Th17

Promote local inflammation

Signal 3: cytokine

Induction of adaptive immunity

Differentiation of Th

Cytokines

Cell-mediated immunity

Humoral immunity

Immunological memory

Immune effector

function

Effector response

Innate immunity

Activation

Effectorphase

IL6Chemokines

Amplifier of acute Inflammation

(local site, BM)

Recruitment of neutrophils

Activation of macrophages

Expression of antimicrobial peptides

IL17

Ubiquitous expression of IL17R: fibroblasts, epithelial cells, keratinocytes, etc.

Rapid T cell response to infection: Th17

G-CSFGM-CSF

CD4 T cell differentiation

CD8 T

CMI

Humoralimmunity

CMI: Macrophages activated by Th1

APC activation

Cytotoxic granules

CMI:

CD8Tcytotoxic response

Membrane effector molecule

Effector T cells

Induction of adaptive immunity

Differentiation of Th

Cytokines

Cell-mediated immunity

Humoral immunity

Immunological memory

Immune effector

function

Effector response

Effector Th2 cells

Humoral immunity:B cell response

B cells as APC

Affinity maturation

2. Somatic hypermutation

1. Isotype switching

3. Memory

CD4T-dependent:

Effector responseCD4 Th17, Th1/ Th2CD8 TcB cells

Induction of adaptive immunity

Differentiation of Th

Cytokines

Cell-mediated immunity

Humoral immunity

Immunological memory

Immune effector

function

Adaptiveimmunity

Protective immunity & time

Apoptosis of effectors

Memory cells:long-lived