Download Immune system

Aims
• Lymphatic organs
Immune system
• Inflammation
• Natural immune system
• Adaptive immune system
• Major histocompatibility complex (MHC)
• Disorders of the immune system
2
1
Immune system
What is the immune system?
Lymphoid organs
The immune system is a complex of organs, cells,
and circulating protein
Immune cells
Lymphoid organs
thymus
Immune proteins
spleen
Lymph node
3
Immune cells
Eosinophil
4
Lymphocyte
Leukocytes or White blood cells
Neutrophil
mucosa-associated
lymphoid organ (MALT)
B cells: antibody
Lymphocyte
T cells: phagocytosis
Cytotoxic T cells
Basophil
Helper T cells
Suppressor T cells
NK cells
Monocyte
5
6
Inflammation
Immune proteins
Body’s local response to infection or injury
Antibodies
1. Injury or bacteria entry into tissue
2. Vasodilatation of the surrounding vessels
Complements
blood flow (hot and redness)
7
8
9
10
3. Filtration of protein and fluid into interstitial fluid
(swelling)
4. Neutrophils and monocyte from capillaries into
infected area
5. Destruction of bacteria in the tissue (pus)
6. Tissue repair
Natural
Natural immune
immune system
system
Immune system
•
Natural
Natural immune
immune system
system
(nonspecific)
(nonspecific)
Innate defense mechanism
Non specific to any antigen
Adaptive
Adaptive immune
immune system
system
(specific)
(specific)
genetic
Surface barrier and mucosal immunity
- Humoral immunity
• skin
- Cell mediated immunity
• coughing, sneezing, ciliary action: lung
11
• sticky mucous
12
phagocytes
phagocytes
• skin secretion: acid pH
• neutrophil
• saliva, tear, nasal secretion: lysozyme
• stomach: hydrochloric acid and protein digesting
enzyme
• macrophages:
spleen
Cells
Cells of
of natural
natural immune
immune are:
are:
• phagocytes
• mast cells
• natural killer cells
(NK cells)
• eosinophil
monocytes
medullary sinus of lymph node
Liver: kuffer’s cell
13
Natural killer
14
Natural killer
• Large granule lymphocyte
• precise mechanism by which they recognized
their target cells is not clear
• Target cells: tumor cell or virus-infected body
cells
• kill on contact
• can be stimulated by interferon
15
Eosinophil
16
Eosinophil
• cell can release killing enzyme called peroxidase and
• The least numerous of WBC in blood
Phospholipase D
• granule contain a protein rich in arginine residues
called major basic protein
• Important in killing helminth (worm) infections
• Cell can secrete membrane penetrating protein
• Involve in hypersensitive reaction
called perforins
17
18
Complement
Complement
• A major trigger enzyme plasma system
• Important in killing bacteria and fungi
Phagocytosis
Making pore in bacterial cell membrane
Help to get rid of AgAg-Ab complex
• Important in initiaion of the inflammatory response
19
Adaptive
Adaptive immune
immune system
system
How antigen meet T& B lymphocyte
Humoral immunity
Cell mediated immunity
B lymphocytes
and antibodies
T lymphocytes
•
acquired immunity
•
Specific and memory
20
21
22
Adaptive
Adaptive immune
immune system
system
Pathogens
Humoral immunity
Humoral immunity
Antibodies
B cell
B lymphocytes
• produce from bone marrow and thymus
Cellular immunity
• can transform to plasma cell by antigens
B cell
T cell
Plasma cell
23
Antibodies
24
Antibodies
• There are 5 main classes: IgG,
IgG, IgA,
IgA, IgM,
IgM, IgD,
IgD, IgE
• Immnunoglobulin
• IgG
• Y shape: heavy and light polypeptide chains
ƒ Most abundant
ƒ cross from mother to baby and protect baby
for 22-3 months
• IgA
ƒ common in secretion eg saliva, gastric juice
ƒ found in milk
25
26
27
28
• IgM
ƒ primary immune response
ƒ activate complement
• IgD
ƒ act as surface receptor on B cells
• IgE
ƒ bound to mast cells
ƒ involve in pathogenesis of allergic and helminth
disease
Clonal selection
Antibody diversity
• human makes 10,000,000 different kinds of antibodies
too much for genome to encode
• Each antibody composed of identical light and identical
heavy chains
• Each B cell makes 1 kind of antibody
• Clonal selection
29
30
Self
Self and
and non-self
non-self
Cell mediated immunity
How immune system recognize body cell?
T cell
Originate in thymus of infants
Produced in bone marrow of adults
T cell function
Do not secrete antibodies
Some attack other cells (T cytotoxic; TC)
Specific recognition molecules: Major
Some produce lymphokines -- molecules that
regulate other white blood cell responses
histocompatibilty complex (MHC)
31
MHC (HLA)
•
Set of molecule making up tissue type
•
There are three types of MHC
32
-
MHC I : present endogenously synthesized
antigen
- MHC II : present exogenously derived
protein eg bacterial products
- MHC III : complement
33
34
How immunity is not destroy themselves
Thymus
MHC
mechanism
T & B lymphocyte that react to body cells
Will be destroyed
35
36
Disorders of the immune system
Graft Rejection
-
Donor APC
Recipient APC
MHC on the graft cell differ from MHC of
recipient.
-
Cytotoxic T cells are mainly responsible for
Recipient T cell
graft rejection.
-
Recipient T cell
Immunosuppressive drug prevent graft
rejection.
37
Acquired immune deficiency syndrome (AIDS)
Transfusion reaction
-
38
-
ABO is the most important for transfusion
Human immunodeficiency virus (HIV) is a
retrovirus.
reactions.
-
Integrated the
virus RNA into
Host DNA.
-
ABO blood group mismatch results in
hemolysis.
39
40
Allergy
-
HIV enter and live in helper T cell.
-
infected T cells are destroyed by normal T
cells, therefore T cell reduce in amount.
-
Immune defense of host can not function
properly.
-
AIDS patient dies from infections or
cancers.
41
42
Autoimmune disease
-
Immune attack the body’s own cells and
tissues which results is being damage
and/or alteration function of organs
For examples
Multiple sclerosis – myelin
Myasthenia gravis – acetylcholine receptor on
skeletal muscle
Grave’s disease – Thyroid stimulating hormone
43
Autoantibody to
receptor
45
receptor
44