1. The Immune System
The Basics

2. Immunity – Three Lines of Defense
First Line – keep pathogens out!
HOW? Skin, Mucus, Tears (+ Lysozyme), cilia, HCl in stomach to kill bacteria, “good” symbiotic bacteria
Second Line – oh no, something got in, start pitchin’ a general defense
HOW? Phagocytes, Interferons, Complement, Histamines (red, hot, swollen), inflammatory response
Third Line – very specific immune response to a particular antigen
HOW? Macrophages, Helper T cells, B-cells, antibodies, Killer T cells
STOP

3. Immunity – First Line Keep pathogens out
STOP
Skin
Mucus & Cilia
Lysozyme (enzyme that breaks down bacterial walls) in tears & saliva
HCl in stomach to kill bacteria,

4. Immunity’s Second Line–something got in so start PItCHIN’ a general defense!
Phagocytes – WBC that engulf pathogens by phagocytosis (neutrophils, macrophages)
InTerferons – chemicals secreted by virus-infected cells that stimulate neighboring cells to produce defensive proteins
Complement – group of proteins that attract phagocytes to foreign cells and cause cell lysis
Histamines are secreted by basophils and lead to the INFLAMMATORY RESPONSE (redness, heat, swelling) b/c of more blood in the damaged area
Natural Killer Cells – attack and lyse tumor and virus-infected body cells

5. 3rd Line of Defense = Immune Response

6. Immunity – Third Line – very specific immune response to a particular antigen
HOW? See the immune system in action!
Click here
Click here also
What do A, B, and C represent? B A C
A = pathogen with antigens on surface
B = macrophage
C = antigen presented on surface of macrophage

7. What is the difference between B cells and T cells?
Used in the production of antibodies in fighting bacteria, viruses and tumor cells “NON-SELF CELLS”
Used in identifying antigens and releasing chemicals which attract macrophages (big immune cells which “eat” antigens)
When they encounter a new antigen, plasma and memory cells are formed from the division of a B cell. The memory cell remembers the antigen and which antibody to use while the plasma cell makes the antibodies.
They play a large role in destroying virus-infected cells, foreign tissues and tumor cells- “NON-SELF CELLS”
Main types are Helper T cells (assist in activating B cells) and cytotoxic T cells (recognize foreign cells and destroy them) .
Play a role in the HUMORAL response
Play a role in CELL-MEDIATED response
Made in the bone marrow
Formed in the thymus gland.

8. Read a bit about the immune system by going to this website…click here.

9. Primary vs. Secondary Immune Response
10-14 days to mount effective response
Reaction to first exposure to antigen
Stimulates “naïve” helper T, B and/or killer T cells
Lower antibody concentration
SECONDARY
2-3 days to mount effective response
Reaction to second or later exposure to antigen
Stimulates memory helper T, B, and/or killer T cells
Higher antibody concentration
2nd exposure
1st exposure
Concen-tration of antibody

10. Review of the Immune System Match the cell type with the description
Activate either B or T cells, depending on the type of pathogen. ____
Eat and present antigen to Helper T cells.____
Produce antibodies. ____
Involved in a secondary immune response. ___
Are attacked by HIV. ____
Cause lysis of cancer cells.____
Macrophages
Helper T cells
Killer T cells
Memory Killer T cells
Plasma B cells
Memory B cells B A E
D, F B C