1. Challenge Problem

2. Body Defenses: The Immune System
12c

3. Let’s Review Pathogens- 8min
Something that makes us sick, causes disease
-Use your phone to find 5 pathogens, quick description and an example of a disease they cause. If you know one from memory you can write that down.
1- pathogen example ex- disease example
ex-
ex-
ex-
ex-

4. Third Line of Defense: Immune System

5. Specific Defense: The Immune System
Important Aspects
Antigen specific
recognizes and acts against particular foreign substances
Systemic
not restricted to the initial infection site
Has memory
recognizes and mounts a stronger attack on previously encountered pathogens

6. Types of Immunity Humoral immunity Cellular immunity
Antibody-mediated immunity
Cells produce chemicals for defense
Cellular immunity
Cell-mediated immunity
Cells target virus infected cells
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7. So, how does the immune system know which cells to attack?

8. Antigens Antigen Surface Proteins that identify the cell
Self: found on cells that belong to the organism
Non-Self: found on cells that do not belong to the organism
invaders

9. Antigens (Nonself)
Any substance capable of exciting the immune system and provoking an immune response
Examples of common antigens
Foreign proteins
Nucleic acids
Large carbohydrates
Some lipids
Pollen grains
Microorganisms
Slide 12.26
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

10. Self-Antigens Human cells have many surface proteins
Our immune cells do not attack our own proteins. They only attack “foreign” proteins.
Our cells in another person’s body can trigger an immune response because they are foreign
Restricts donors for transplants
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Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

11. Quick Quiz What is an antigen? (in your own words)
Why are antigens so important in the immune response?

12. Let’s review the cells involved in the immune system

13. Cells of the Immune System
Lymphocytes
Originate from hemocytoblasts in the red bone marrow
B lymphocytes become immunocompetent in the bone marrow
T lymphocytes become immunocompetent in the thymus
Macrophages
Arise from monocytes
Become widely distributed in lymphoid organs
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Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

14. Activation of Lymphocytes
Figure 12.9
Slide 12.30
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15. Immune Response: Humoral Immunity
Involves Antibodies!!

16. Humoral Immunity 1) B-Cells recognize and attach to a foreign antigen
2) B-Cells reproduce
Plasma Cells: produce Antibodies specific to attack this antigen
Memory Cells: for quick attacks on future encounters with this antigen.

17. Humoral Immunity
3) Antibodies bind to foreign antigens on cells and disable them
4) Macrophages engulf and destroy cells that have antibodies attached.

18. Humoral Immune Response
Figure 12.10
Slide 12.32
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19. Secondary Response Memory cells are long-lived
A second exposure causes a rapid response
The secondary response is stronger and longer lasting
Figure 12.11
Slide 12.33
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

20. Quick Quiz
Why is humoral immunity also called “Antibody-mediated Immunity”?
What type of lymphocyte is involved in Humoral immunity?

21. Active Immunity: Permanent
Your B cells encounter antigens and produce antibodies
Active immunity can be naturally or artificially acquired
Get Sick
Get an immunization shot
Figure 12.12
Slide 12.34
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

22. Passive Immunity: Temporary
Antibodies are obtained from someone else
Conferred naturally from a mother to her fetus
Conferred artificially from immune serum or gamma globulin
Immunological memory does not occur
Protection provided by “borrowed antibodies”
Slide 12.35

23. Antibody Structure (draw it)
Four amino acid chains linked by disulfide bonds
Two identical amino acid chains are linked to form a heavy chain
Slide 12.38a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 12.13b

24. Antibody Classes
Antibodies of each class have slightly different roles
Five major immunoglobulin classes
IgM – can fix complement
IgA – found mainly in mucus
IgD – important in activation of B cell
IgG – can cross the placental barrier
IgE – involved in allergies
Slide 12.39
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

25. Antibody Function Antibodies inactivate antigens in a number of ways
Complement fixation
Neutralization
Agglutination
Precipitation
Slide 12.40
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

26. Quick Quiz Name two ways to get “Active Immunity”
How can you get “Passive Immunity”?
What is the primary difference between active and passive immunity?

27. Antibody Act-ivity
Read the ½ sheet of paper and be prepared to get a part
After a demo, you will be moving around the room like bacteria, antibodies, B-cells, and macrophages!!

28. Assignment
Create a 6-frame comic strip that outlines the humoral immune response steps.
Must have colored pictures
Must clearly explain each step of the response.
Be creative!!