This week: Protection from Pathogens

1
This week Protection from Pathogens
2
Taking in food and oxygen exposes us to pathogens
esophagus
stomach
3
Pathogen a disease causing agent
4
E. coli
Phage virus
Ebola
Fungus from soil
various pathogens
5
The Immune System

• Specific
• B-cells -gt antibodies
• T-cells

• Non-specific
• barriers

Fig 43.2
6
Non-Specific Immune System Barriers
Skin- Dry Inhospitable Competition Secret
ions (lysozyme) Hairs and Mucus (protect
openings) Traps particles, swallowed Stomach
acid kills pathogens
Fig 43.2
7
Skin protects us from most pathogens
8
Fig 43.2
9
Stomach acid kills pathogens
Hairs and Mucus (protect openings) Traps
particles
esophagus
stomach
10
Non-Specific Immune System Barriers
Skin- Dry Inhospitable Competition Secret
ions (lysozyme) Hairs and Mucus (protect
openings) Traps particles, swallowed Stomach
acid kills pathogens
Fig 43.2
11
The Immune System

• Specific
• B-cells -gt antibodies
• T-cells

• Non-specific
• barriers

Fig 43.2
12
The Specific Immune System
13
B-cells and T-cells move through the circulatory
system scanning for pathogens
14
B-cells develop in bone marrow T-cells in the
thymus
15
B-cells make and secrete antibodies
Fig 43.14
16
Variable region
An Antibody
Constant region
Fig 43.10
17
Antibodies recognize and bind to antigens
Fig 43.10
18
B-cells make antibodies that bind to antigens
marking them for destruction
Marked for destruction by WBC
Fig 43.19
19
Each B-cell/antibody recognizes a specific antigen
Fig43.14
20
B-cell DNA rearranges to make a unique and random
gene
Fig43.13
21
Each B-cell/antibody recognizes a specific antigen
Fig43.14
22
B-cells make antibodies that bind to antigens
marking them for destruction
Marked for destruction by WBC
Fig 43.19
23
Antibody binding to antigens can lead to...
Engulf and Destroy
Neutralization
Fig43.21
24

• What about damaged or abnormal cells?
• Viral infections
• Cancer cells
• Non-functional cells

25
T-cells recognize and destroy abnormal cells
Fig 43.18
26
Helper T-cells activate B-cells and Killer T-cells
CB 43.17
27
Killer T-cells recognize and destroy abnormal
cells
Fig 43.18
28
Helper T-cells activate B-cells which produce
antibodies
CB 43.19
29
CB43.16
30
It can take 7-14 days to produce sufficient
antibodies to eliminate a pathogen
Fig 43.15
31
Memory B-cells make the response to a second
exposure more rapid
Fig 43.14
This is how vaccines work.
32
Vaccines work via memory B-cells that make the
response to a second exposure more rapid
Fig 43.15
33
Next Vaccines, when politics and science
collide...