such as bacteria fungi and viruses INNATE IMMUNITY all animals Rapid response Recognition of traits shared by broad ranges of pathogens using a small set of receptors Recognition of traits ID: 210758
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1Slide2
Pathogens
(such as bacteria,
fungi, and viruses)
INNATE IMMUNITY
(all animals)
• Rapid response
Recognition of traits shared
by broad ranges ofpathogens, using a smallset of receptors
•
Recognition of traits
specific to particularpathogens, using a vastarray of receptors
•
• Slower response
Barrier defenses:
SkinMucous membranesSecretions
Internal defenses:
Phagocytic cellsNatural killer cellsAntimicrobial proteinsInflammatory response
Humoral response:
Antibodies defend againstinfection in body fluids.
Cell-mediated response:
Cytotoxic cells defendagainst infection in body cells.
ADAPTIVE IMMUNITY(vertebrates only)
2Slide3
Pathogen
PHAGOCYTIC
CELL
Vacuole
Lysosome
containing
enzymes
3Slide4
Thymus
Peyer’s
patches
(small
intestine)
Appendix(cecum)
Adenoid
Tonsils
Lymphatic
vessels
Spleen
Lymphnodes
Lymphnode
Bloodcapillary
Interstitialfluid
Tissuecells
Lymphatic vessel
Lymphatic vessel
Masses ofdefensive cells
4Slide5
Pathogen
Splinter
Mast
cell
Macro-
phage
Capillary
Red
blood cells
Neutrophil
Signaling
molecules
Movementof fluid
Phagocytosis
5Slide6
Antigen
receptors
Mature B cell
Mature T cell
6Slide7
Cytoplasm of B cell
Antigen-
binding
site
B cell
antigen
receptor
B cell
Lightchain
Disulfide
bridgeAntigen-binding site
Variable
regions
Constant regions
Transmembraneregion
Heavy chains
Plasmamembrane
C
C
C
C
VV
V
V
7Slide8
Antibody
Antigen
receptor
B cell
Antigen
Epitope
Pathogen
(a) B cell antigen receptors and antibodies
Antibody C
Antibody B
Antibody A
Antigen
(b) Antigen receptor specificity
8Slide9
T cell
antigen
receptor
T cell
Cytoplasm of T cell
Plasma
membrane
chain
chainDisulfide
bridge
Antigen-bindingsite
Variable
regions
Constantregions
Transmembraneregion
V
V
C
C
9Slide10
Displayed
antigen
fragment
MHC
molecule
Antigenfragment
Pathogen
Host cell
T cell
T cell antigen
receptor(a) Antigen recognition by a T cell
(b) A closer look at antigen presentation
Antigen
fragmentMHC
moleculeHost cell
Top view
10Slide11
DNA of
undifferentiated
B cell
DNA of
differentiatedB cell
Recombination deletes DNA between
randomly selected V segment and
J segmentFunctional gene
Transcription
RNA processing
Translation
pre-mRNA
mRNA
Light-chain polypeptide
Antigen receptorB cell
Variableregion
Constantregion
2
3
4
1
Poly-A tail
Cap
V
39
J
5
J
5
V
39
V
37
V
38
V
39
V
37
V
38
V
39
V
40
J
5
J
5
J
4
J
3
J
2
J
1
Intron
Intron
V
C
C
C
C
C
C
C
C
C
V
V
V
V
Intron
11Slide12
Antigen
Antigen
receptor
Antibody
Plasma cells
Memory cells
B cells that
differ in
antigenspecificity
12Slide13
Antigen-
presenting
cell
Pathogen
Antigen fragment
Class II MHC molecule
Accessory protein
Antigen receptor
Helper T cell
Cytokines
Humoral
immunity
Cell-
mediatedimmunity
B cell
Cytotoxic T cell
3
2
1
13Slide14
Cytotoxic T cell
3
1
2
Accessory
protein
Class I MHC
molecule
Infected
cell
Antigen
receptor
Antigen
fragment
Perforin
Pore
Gran-
zymes
Released
cytotoxic
T cellDying
infected cell
14Slide15
Pathogen
3
1
2
Antigen-presenting
cell
Antigen
fragment
Class II
MHC
molecule
Antigen
receptor
Accessory
protein
Helper T cell
B cell
Cytokines
Activated
helper T cell
Memory B cells
Plasma cells
Secreted
antibodies
15Slide16
Opsonization
Neutralization
Antibody
Virus
Bacterium
Macrophage
Activation of complement system and pore
formation
Complement proteins
Formation of membrane
attack complex
Flow of water
and ions
Pore
Antigen
Foreign
cell
16Slide17
IgE
Allergen
Histamine
Granule
Mast cell
17