overview of immunology organs and tissues cells molecules components of is functions of is pathology...
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Overview of Immunology
Organs and tissues
Cells
Molecules
Components of IS
Functions of IS
Pathology of IR
* IS: Immune system IR: Immune response
Applications
Prevention
Diagnosis
Therapy
Antigen (Ag)
Immune Responses
Control mechanisms
Hypersensitivity
Autoimmune disease
Immunodeficiency
Tumor
Transplantation
rejection
Cells of Immune System
— Mononuclear phagocyte system
— Granulocytes
— Lymphocytes
MonocyteMonocyte
MacrophageMacrophage
Dendritic Cells Dendritic Cells
NeutrophilsNeutrophils
BasophilsBasophils
EosinophilsEosinophils
T lymphocyteT lymphocyte
B lymphocyteB lymphocyte
NK (Natural killer cells)NK (Natural killer cells)
Cells of the innate immune system
Mononuclear phagocytes
Granulocytes
NK cells
Cells of the adaptive immune systemT lymphocytes
B lymphocytes
Cells of Immune System
Cell surface molecules expressed on various cell types in the immune system as markers:
• Lineage marker (e.g. CD3 on T cells)
• Maturation marker (e.g. CD4 / CD8 on T cells)
• Activation marker (e.g. CD25 on T cells)
Numbers of CD: CD1 – CD247
Cluster Differentiation(CD) System
One cell can express more than one different
CDs:
e.g. T cells: CD2, CD3, CD4 or CD8, CD28……
B cells: CD19, CD20, CD21, CD79……
Different cells can express same CD:
e.g. CD69 could be expressed on activated leukocytes:
T cells, B cells, NK cells, nuetrophils, basophils
Cluster Differentiation(CD) Molecules
AgAg DCs
Th1 Tc
B Ab
PMNPMN
NK
Th2
ComplementComplement
Functions in Immune Response (IR)
TargetTargetcellscells
MHCMHCCKCK
MHCMHCCKCK
CKsCKs
CKsCKs
— Phagocytosis
— Antigen presentation
— Cytokine secretion
Mononuclear Phagocyte SystemMononuclear Phagocyte System
AgAg DCs
Th1 Tc
B Ab
PMNPMN
NK
Th2
ComplementComplement
Functions in Immune Response (IR)
TargetTargetcellscells
MHCMHCCKCK
MHCMHCCKCK
CKsCKs
CKsCKs
Recognition and killing of phagocytes
By pattern recognition receptors(PRR)
Mannose receptors: mannose
CD14 : LPS
Scavenger receptors : carbohydrates /lipids
Toll like receptors (TLRs): PAMP
(lipid-
protein 、 LPS、 RNA、 DNA)
AgAg DCs
Th1 Tc
B Ab
PMNPMN
NK
Th2
ComplementComplement
Immune Response (IR)
TargetTargetcellscells
MHCMHCCKCK
MHCMHCCKCK
CKsCKs
CKsCKs
AgAg DCs
Th1 Tc
B Ab
PMNPMN
NK
Th2
ComplementComplement
Immune Response (IR)
TargetTargetcellscells
MHCMHCCKCK
MHCMHCCKCK
CKsCKs
CKsCKs
— Pattern recognition receptors(PRR): Recognition
— Fc receptor (FcR, CD16): Opsonisation
— Complement receptor (CR): Opsonisation
PhagocytosisPhagocytosis
— Phagocytosis
— Antigen presentation
— Cytokine secretion
Mononuclear Phagocyte SystemMononuclear Phagocyte System
AgAg DCs
Th1 Tc
B Ab
PMNPMN
NK
Th2
ComplementComplement
Immune Response (IR)
TargetTargetcellscells
MHCMHCCKCK
MHCMHCCKCK
CKsCKs
CKsCKs
Antigen that is presented on the APC could be recognized by T cell
Antigen Presentation Recognized by T cellsAntigen Presentation
See:8-2
AgAg DCs
Th1 Tc
B Ab
PMNPMN
NK
Th2
ComplementComplement
Functions in Immune Response (IR)
TargetTargetcellscells
MHCMHCCKCK
MHCMHCCKCK
CKsCKs
CKsCKs
— Majority of white blood cells
— Contain: lysozyme, antibiotic peptides
—Main function: phagocytosis
— Chemotaxis: C5a
— Opsonization: Ab and C3b
Neutrophils (Polymorphonuclear cells PMNs)Neutrophils (Polymorphonuclear cells PMNs)
— Localization:• Basophils - circulation
• Mast cells - tissues
— Granule contents: Mediators
• Histamine
• Leukotrienes
— Functions:• Attract: Leukocytes - acute inflammatory
response
• Allergy
Basophils and Mast cells
Mediators: allergyMediators: allergy
– Vasodilatation,
– Vascular permeability increase,
– Smooth muscle contraction,
– Mucous secretion.
— Present in circulation:
— Granule contents:• Peroxides/toxin
• Histaminase et al
— Functions:• Parasites killing
• Anti-inflammatory and allergy regulation
Eosinophils
AgAg DCs
Th1 Tc
B Ab
PMNPMN
NK
Th2
ComplementComplement
Immune Response (IR)
TargetTargetcellscells
MHCMHCCKCK
MHCMHCCKCK
CKsCKs
CKsCKs
1. KAR : (Killer activating receptors):
Induce killing of the infected cells.
2. KIR: (Killer inhibitory receptor):
Prevent NK from killing the normal cells.
3. CD16: Mediate ADCC (see:Ab)
4. IL-2R: Bind to IL-2 and become lymphokine activated killer cells ( LAK) (see:CK)
Markers and functions of NK cells
Cells of the innate immune system
Mononuclear phagocytes
Granulocytes
NK (Natural killer cells)
Cells of the adaptive immune systemT lymphocyte
B lymphocyte
Cells of Immune System
AgAg DCs
Th1 Tc
B Ab
PMNPMN
NK
Th2
ComplementComplement
Immune Response (IR)
TargetTargetcellscells
MHCMHCCKCK
MHCMHCCKCK
CKsCKs
CKsCKs
AgAg DCs
Th1 Tc
B Ab
PMNPMN
NK
Th2
ComplementComplement
TargetTargetcellscells
MHCMHCCKCK
MHCMHCCKCK
CKsCKs
CKsCKs
Functions of T cells ?
• Composed of or chains ( 5-10% ) • Recognize Ag peptide /MHC complex
specifically;
• Mediates T cell activation.
TCR
• Composed of γ 、 δ 、 ε and ζ chains;
• Mediates T cell activation signal into cells;
• Specific marker of T cells.
CD3
— CD4• On T helper cells• Ligand to MHC class Ⅱ molecules
— CD8
• On T cytoxic cells• Ligand to MHC class Ⅰ molecules
AgAg DCs
Th1 Tc
B Ab
PMNPMN
NK
Th2
ComplementComplement
TargetTargetcellscells
MHCMHCCKCK
MHCMHCCKCK
CKsCKs
CKsCKs
Functions of T cells ?
TH (CD4+CD3+) TH1: Help Tc and macrophages by secration of
IFNγ/IL-2.
TH2 : Help B cells by secretion of IL-4, IL-5,IL-6.
TC (CD8+CD3+) Killing of target cells by releasing perforin and
granzymes
Functions of T cells
Release of lytic granules containing perforin and granzymes
which enter the target cells
Mechanisms of cytotoxicity
Death of target cells
See: 8-1
BCR ( B cell receptor):1) Cell surface of Ig ( IgM and IgD)
2) Specific binding with antigen
CD79
Mediate B cell activation
CD19/CD201 ) Co-receptors for B cell activation2 ) Specific marker of B cells
Markers of B cells
AgAg APCs
Th1 Tc
B Ab
PMNPMN
NK
Th2
ComplementComplement
Immune Response (IR)
TargetTargetcellscells
MHCMHCCKCK
MHCMHCCKCK
CKsCKs
CKsCKs
• Site of maturation:
• MHC requirement for recognition:
• Markers:
• Functions
Characteristics of B and T cells
Innate immunity Adaptive immunity
Components chemical barrier
PhagocytesNK cells
T and B cells
Cytokines
Complement
Antibodies
Characteristics Receptors: Limited diversity Broad specificity Recognize many related molecules
Receptors: Very large diversity Very narrow specificity Recognize a particular epitopes
Immediate response Slow response
No memory Memory
Occurs in all metazoans Occurs in vertebrates only
AgAg DCs
Th1 Tc
B Ab
PMNPMN
NK
Th2
ComplementComplement
TargetTargetcellscells
MHCMHCCKCK
MHCMHCCKCK
CKsCKs
CKsCKs
Crosstalk between Innate and Adaptive Immunity
Questions:
1. Which cells belong to the immune system?
2. The functions of mononuclear phagocytes are….?
3. Try to explain the classification and function of
lymphocytes.
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