Download Chapter 13 Immunoregulation

Chapter 17
Immunoregulation
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Chapter 17 Immunoregulation
The ability of the immune
system
to
control
and
regulate its own responses is
called immunoregulation.
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• To keep the individual homeostasis by
regulating
the
balance
between
immunocyte and immunocyte, between
immunocyte and immune molecule, and
between immune system and nerve
system /endocrine system.
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Contents
 PartⅠ Immunoregulation on genetic level
 PartⅡ Immunoregulation on molecular level
 PartⅢ
Immunoregulation on cellular level
 PartⅣ Immunoregulation on individual and
mass level
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PartⅠ Regulation on genetic level
Immune response of individual controled
by hereditary background:
• Genes encode TCR and BCR
• Genes encode molecules regulating
immune response: MHC ?
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PartⅡ Regulation on molecular level
•
•
•
•
Regulation of Ag
Regulation of Ab
Regulation of Complement
Regulation of co-stimulator and
receptor
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1. Regulation of antigen
Origination stage of immune response:
• Route of Ag entrance a individual
• Dosage of Ag
• Structural characteristic: antigen
competition
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2. Regulation of antibody
• Regulation of immune complex: IgM,
IgG
• Regulation of idotype-anti-idiotype
network
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2. Regulation of
antibody
• Regulation of Ag-Ab complex to
immune
response-----Antibody
feedback regulation
• IgM ---- positive feedback regulation
• IgG ---- negative feedback regulation
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g
B cell
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FcRⅡB
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2. Regulation of idiotypic networks
Idiotypic determinant or idiotype: a unique
determinant on an antibody ,usually
formed by one or more of the
hypervariable regions.
Idiotypic determinant may be recognized as
“foreign” in an individual, but they are
usually present in quantities too low to
induce self-tolerance.
Anti-idiotypic antibody: antibodies against
idiotype of antibodies -------- internal
image of Ag
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B
Ab2β
Ab2α
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3. Regulation of
complements
• Promote APC capture antigens:
CR1 receptor on APC capture C3b-Ag-Ab
complex
• Promote the activation of B cell:
CR1, CR2 on B cell
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4. Regulation of co-stimulator and receptor
• T cell: B7 ------ CD28, CTLA-4
• B cell: CD40L ------ CD40, FcRⅡB
5. Regulation of cytokines
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PartⅢ Regulation on cellular
level
• Regulation of T cells:
Natural regulatory T cells(Treg): CD4+CD25+foxp3+
Th cell subset
• Regulation of B cells
• AICD (activation induced cell death)
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The immunoregulation of T cell subsets

Th1 cells promote
immunity suppressing
immunity.
the cellular
the humoral

Th2 cells promote the humoral
immunity suppressing the cellular
immunity.
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Interaction of Th1 and Th2
Th0
+IL-12
+IL-4
Th1
IL-2
IFN-
Cell mediated
immunity
Th2
inhibit
IL-4
IL-10
Humoral
immunity
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Regulation of T cell subset by different
cytokines
• T cell subset
cytokine
• CD4+Th1
• CD4+Th2
• CD4+Th3
• CD4+Th17
Representative
IL-2, IFN-γ
IL-4, IL-10
TGF-β
IL-17
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Activation-induced cell death（AICD）
AICD: activated T or B cell apoptosis
elicited by Fas(CD95)
• Apoptosis of target cell :
FasL on Tc binds to Fas on target cells----induce the apoptosis of target cell.
• Apoptosis of activated T cells:
Fas is also expressed on activated Tc or B cell,
so FasL on activated T cell binds to Fas on
activated T cell or B cell, then induces
activated T cells or B cell apoptosis.
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(FasL)
(Fas)
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Part IV Regulation on systemic level
• Regulation of nerve-endocrine-immune
system networks:
Nerve
and
endocrine
regulate
immune system.
Immune system regulate nerve and
endocrine system.
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Interaction of neuroendocrine system
and immune system
精神因素
中枢神经系统
内分泌激素
内分泌系统 免疫介质 免疫系统
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Keep a good humor
everyday !!!
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