3. Immune organs
Immune cells
Immune molecules
Primary lymphoid organs
Secondary lymphoid organs
Lymphocytes: T, B, NK cells
Neutrophils
Monocytes/Macrophages
Antigen-presenting cells
Antibody , Complement,
Cytokines, MHC, CD.
The immune system protects us from attack
by infectious agents.
Immune system
4. ∗ primary lymphoid organs
thymus–T cell maturation
bone marrow – B cell
maturation
Bursa of Fabricius
∗ secondary lymphoid organs
lymph nodes
spleen
mucosal-associated
lymphoid tissue (MALT)
Poultry/Birds
Major lymphoid organs and tissue
5. The body has two types of immunity:
the innate immunity
the adaptive immunity
6.
7. Innate immunity refers to any inborn
resistance that is already present the first time
a pathogen is encountered; it doesn’t require
prior exposure and is not modified significantly
by repeated exposures to the pathogen over
the life of an individual.
the first defense line of against infection.
is the initial response by the body to
eliminate microbes and prevent infection.
Innate Immunity
8. CharacteristicsCharacteristics
Present from birthPresent from birth
HereditableHereditable
The first line of defenseThe first line of defense
Non-specificNon-specific
No immune memoryNo immune memory
Be the basisBe the basis
of specific immunityof specific immunity
Composing of
Innate immunity:
Immune barriers
Intrinsic cells
Immune
molecules
11. fatty acids in sweat
skin
movement of mucus by cilia
mucous membrane
12. BloodBlood--brain barrier (BBB)brain barrier (BBB)
◆BBB is a barrier that
separates the circulating
blood from the brain
extracellular fluid in
the CNS. ◆BBB is formed
by brain endothelial cells,
and astrocytes contribute tostrocytes contribute to
the differentiation of BBB.the differentiation of BBB.
◆Tight junctions restrictTight junctions restrict
paracellular movement ofparacellular movement of
substances across the BBB.substances across the BBB.
◆ BBB prevents the invasionBBB prevents the invasion
of pathogens into the brainof pathogens into the brain
13. BloodBlood--placentaplacenta
barrier(BPB)barrier(BPB)
◆ In the placenta, the fetalIn the placenta, the fetal
blood is separated from theblood is separated from the
mother’s blood by BPB.mother’s blood by BPB.
◆ BPB is consist of deciduaBPB is consist of decidua
basalis and trophoblast cellsbasalis and trophoblast cells
◆BPB allows slow passage ofBPB allows slow passage of
gases, ions and smallgases, ions and small
molecules but restrictsmolecules but restricts
movement of largermovement of larger
molecules.molecules.
◆BPB prevents the invasion ofBPB prevents the invasion of
pathogens into the fetuspathogens into the fetus
基蜕膜
14. Lactic acid and fatty acid in sweat:
inhibit the growth of bacteria.
Lysozyme, phospholypase A in secretions
(saliva, tears, milk)
break down the cell wall of bacteria.
Low pH (gastric acid) and pepsin in stomach:
prevents growth of bacteria.
2.Chemical barrier
15. The normal flora on the skin and in the
gastrointestinal tract
prevent the colonization of pathogens
–by secreting toxic substances
–by competing nutrition with pathogens
–by blocking the attachment of pathogens.
3.Biological barrier
16. Antimicrobial factors
in saliva (lysozyme)
Normal flora
Mucus,cilia
removal of inhaled
bacteria
Acid in stomach
(low pH)
Normal flora
Lysozyme in tears,
other secretions
Skin-physical
barrier, fatty
acids, sweat,
normal flora
22. ⅢⅢ Intrinsic cells
﹡Immune cells: All kinds of cell associated
with immune response, including phagocytes,
lymphocytes, mast cells, antigen presenting
cells (APC) as well as their precusor cells.
Immune cells derive mainly from undiffe-﹡
rentiated ‘self-renewing’ hemopoietic
stem cells (HSCs) through a process of
differentiation.
23.
24. 1. Mo /MΦ
2. Granulocytes:
neutrophils 、 basophils 、 eosinophils
3. Dendritic cells
4. NK and NKT cells
5. B1 、 T cell 、 mast cell
* Innate immunocytes
29. 1. Derived from bone
marrow
2. 3-8% of leukocytes
3. Monocytes stay in
periphel blood for 12-
24 h and then leave the
circulation and reside
within almost all of the
organs----Macrophages
Monocyte/Macrophage
30. Cells of the mononuclear phagocyte system
Location Cells
Blood Monocytes
Skin Langerhans’ cells
Liver Kupffer cells
Lung Alveolar macrophages
Spleen, lymph nodes Sinus macrophages
Brain Microglia
Bone Osteoclasts
31. 1. PRRs (pattern-recognition receptors)
1) MR (mannose receptors)
2) SR (scavenger receptors)
3) TLR (Toll like receptors)
PAMP: The ligand of PRRs
(pathogen associated molecular patterns)
2. IgG FcR (FcγR) 、 C3bR
3. MHC I/MHC II molecules; B7
4. CKR: IFN-rR, M-CSFR,GM-CSFR, MCP-1R
MCP-1(monocyte chemotactic protein 1)
1. The main surface receptors
32. Monocyte/Macrophage
2. Biological Functions
(1)(1) Kill and eliminate the microorganisms: *Kill and eliminate the microorganisms: *
* phagocytosis * opsonization* phagocytosis * opsonization
(2)(2) Kill tumor and virus-infected cell;Kill tumor and virus-infected cell;
(3)(3) Process and present Ag; *Process and present Ag; *
(4)(4) Mediate/promote inflammatory response; *Mediate/promote inflammatory response; *
IL-1, IL-6, TNF-a; IL-8, MCP-1IL-1, IL-6, TNF-a; IL-8, MCP-1
(5)(5) Modulate immune response.Modulate immune response.
IL-1 and IFN-r promote the APC to express MHC andIL-1 and IFN-r promote the APC to express MHC and
activate T and B cells; TNF-a promotes the activation,activate T and B cells; TNF-a promotes the activation,
proliferation and differentiation of CTL; IL-10 canproliferation and differentiation of CTL; IL-10 can
inhibit the activation of Mo/Mac.inhibit the activation of Mo/Mac.
35. Human phagocytes
that arrive quickly at
the site of a bacterial
infection and whose
primary function
is to eat and kill
bacteria.
36. Opsonization is the process of making microbes easier
to phagocytose, more palatable to the phagocytes.
Opsonins, IgG antibody and complement coating on the
microbes aid attachment of the microbes to the
phagocyte and trigger activation of phagocytosis.
Ab
bacteria
Mφ
lysosome
*
42. activated NKsFcRAntibody IgG
Target cell Target cellTarget cell
ADCC (antibody dependent cell-mediated cytotoxicity)
NK cells could be activated by the Ag-Ab (IgG) complexes
through binding to its CD16 FcR, and then trigger killing
activity and induce apoptosis of target cells.
NK
apoptosis
*
45. Neutrophil
1. Derived from bone marrow
2. 60-70% of leukocytes
3. Short life: 2-3 days
4. Receptors: IgG FcR 、 C3bR
5. Biological functions:
Engulf and kill microorganisms;
Opsonization
48. Main functions of Intrinsic cellsMain functions of Intrinsic cells
Cellular responseCellular response
Phagocytes and phagocytosisPhagocytes and phagocytosis
* phagocytosis * opsonization* phagocytosis * opsonization
Natural killer (NK)Natural killer (NK)
*ADCC * natural killing target*ADCC * natural killing target
Inflammatory reactionInflammatory reaction
49. Inflammatory reaction
Mast cellsMast cells releasreleasinging histamine andhistamine and
prostaglandin cause local vessel dilationprostaglandin cause local vessel dilation,,
increased capillary permeabilityincreased capillary permeability,, resulting in:resulting in:
edemaedema (swelling) due to fluids seeping from(swelling) due to fluids seeping from
capillariescapillaries..
PPhagocytes move out of vesselshagocytes move out of vessels, release toxic, release toxic
chemicals and enzymes that destroychemicals and enzymes that destroy
everything in the area, including theeverything in the area, including the
neutrophils themselves.neutrophils themselves.
51. 1. Patterns Recognition Receptors1. Patterns Recognition Receptors
(PRR)(PRR)
PRRs: The receptors on intrinsic cells
which can recognize and bind specific
molecular structure on some pathogens,
injured or apoptotic cells.
Most of immune cells involved in
innate immunity can express PRR.
PRR recognizes microbes by PAMPs.
52. (1) Toll-like receptor (TLR)(1) Toll-like receptor (TLR)
﹡﹡name from a related protein calledname from a related protein called
Toll.Toll.
﹡﹡Intrinsic cells can detect and respond
to infection by recognizing
conserved motifs (LPS, flagellin(LPS, flagellin ，， etet
al.)al.) of microbes using TLRs and
initiate protective response.initiate protective response.
54. (2) Mannose binding lectin (MBL)(2) Mannose binding lectin (MBL)
﹡﹡liver-derivedliver-derived serum proteinserum protein
﹡﹡bind mannose on the surface ofbind mannose on the surface of
pathogenpathogen
﹡﹡the pathogens are captured andthe pathogens are captured and
destroyed by phagocytes throughdestroyed by phagocytes through
opsonization and complement.opsonization and complement.
55.
56. 2. Pathogen Associated Molecular2. Pathogen Associated Molecular
Patterns (PAMPs)Patterns (PAMPs)
PAMPsPAMPs are some high-conserved macromoleculesare some high-conserved macromolecules
uniquely expressed by pathogens, which can beuniquely expressed by pathogens, which can be
recognized by the innate immune system.recognized by the innate immune system.
Structures of microbial pathogensStructures of microbial pathogens
Peptidoglycan (G+), Teichoic acid (G+),Peptidoglycan (G+), Teichoic acid (G+),
LPS (G-), Mannose, Bacterial DNA / RNALPS (G-), Mannose, Bacterial DNA / RNA
Not present on mammalian cellsNot present on mammalian cells
So the Innate immune system can distinguishSo the Innate immune system can distinguish
self (mammalian) from non-self (pathogen).self (mammalian) from non-self (pathogen).
57. Ⅴ Featuers of Innate Immunity
1. Action phages of innate immunity
58. PRR
recognizes pathogen expressing PAMP,
and apoptotic cells
FcγR and C3bR
recognizes pathogen combined with IgG
or C3b
KAR on the surface of NK cells
recognizes tumor and virus-infected
cells
2. Features of Innate immunity
(1) Features of recognition
60. 3. Relationship of innate immunity and
adaptive immunity
Is the first line of defense against
infections
Initiate adaptive immune response
Affect the types of adaptive immune
response
Regulate adaptive immune response
