immune response 2012
DESCRIPTION
TRANSCRIPT
How does the body protect itself from the invasion of pathogens?
What are pathogens?
bacteria virusesPathogens
fungi protists
“Germs”
International Pathogens
Pathogen - an infectious agent that can cause disease in its host
How does the body defend itself ?
Defense
Offense
First Line of DefenseFirst Line of Defense
Physical BarriersPhysical Barriers
Chemical BarriersChemical Barriers
How does the body prevent How does the body prevent pathogens from entering?pathogens from entering?
Where can pathogens enter the Where can pathogens enter the body?body?
Physical Barriers
Chemical Chemical BarriersBarriers
Second Line Of Defense
Inflammation
What happens if the pathogens get through the first line of
defense?
phagocytosis
phagocytosisphagocytosis
http://www.youtube.com/watch?v=fpOxgAU5fFQ
What happens if the first and second lines of defense are not enough to stop the pathogens?
The Immune Response
The third (and last) line of defense:
Antigen - any substance that is recognized as foreign to the body and stimulates an immune response
Lymphatic systemLymphatic system
Lymphatic System
• absorbs and transports digested fat from the small intestine
villus
• transports lymph - a tissue- cleaning fluid
• transports white blood cells
A Lymph Node
Paul Revere
How is a lymph node like a police How is a lymph node like a police station?station?
Helper T cell
Phagocyte
Receptorr
Antigen
Helper T cell- Sounds the alarm
What does a helper T-cell “say”?
Phagocyte Helper T cell
-Why?
Help!!!The helper T-cell activates the rest of the
immune system
YYY
YY
YY
YY
Y
Y
Y
B Cells
Killer T Cells
Antibodies
Helper T cell
Antibody
B Cell
B cell
B CellMemory B Cell
Antibodies
What does a memory B cell say?
Memory B Cell
NEVER FORGET!!!
What is Immunity?the ability of the body to resist a disease
The Immune ResponseThe Immune Response
The Immune Response
Macrophages engulf, destroy antigen
Macrophage displays antigen to Helper T cell
Helper T cell activated
Helper T cells activate B cells and Killer T cells
Activated B cells and T cells divide; form more B and T cells and memory cells
“Army” of B and T cells attack antigen & infected cells (B cells make antibodies etc…)
Macrophages “clean up” debris
Antigen enters body
Memory cells remain ready JIC…
What is the first line of defense?
What is the second line of defense?
What is the third line of defense?
Physical and chemical barriers
Inflammation
The Immune Response
If you have the chicken pox once why don’t you
(usually) get it again?
Memory B Cell
NEVER FORGET!!!
How is the secondary response different from the primary response?
How is the secondary response How is the secondary response different from the primary response?different from the primary response?
Secondary immune response is stronger, faster, Secondary immune response is stronger, faster, and longer than the primary response.and longer than the primary response.
What is a vaccine?What is a vaccine?A weakened or dead pathogen put into the body to stimulate the production of antibodies and memory cells (immune response)
How is a vaccine like How is a vaccine like sparring?sparring?
How do vaccines protect us from How do vaccines protect us from disease?disease?
Vaccines activate the primary Vaccines activate the primary immune response (stimulate immune response (stimulate the body to produce the body to produce antibodies and memory cells)antibodies and memory cells)
A boy became ill with the chicken pox and recovered. A year later, he was exposed to the same disease again but did not become ill. Why didn’t he develop chicken pox after the second exposure? Explain using the following terms:
primary immune response, secondary
immune response, memory cells, antibodies, antigen
When the boy got infected the first time his primary immune response was activated and he made antibodies to attack the antigen. His immune cells divided and left behind memory cells. When he got infected the second time his memory cells made the secondary immune response fight the disease faster and stronger, so he didn’t even get sick..
Antibody
What is this?
For each kind of pathogen the body makes specific antibodies (and cells of the immune system) that recognize it
Active Immunity Passive Immunity
You make You don’t make
the antibodies the antibodies
Exposure to antigen
- vaccine
- infection
- injection
- breastfeeding
Active immunity
Passive Immunity
1. Antigen enters body
2. Macrophages engulf and destroy antigen or cell infected with antigen
The Immune Response
3. Macrophage displays antigen to helper T cells (activating them)
4. Activated Helper T cell activates B cells and Killer T cells
The Immune Response
5. Activated B cells form memory B cells and plasma cells (which make antibodies)
Activated T cells form memory T cells and killer T cells
The Immune Response
6. Antibodies bind to free antigen and target them for destruction by macrophages
Killer T cells destroy infected cells
The Immune Response
http://www.youtube.com/watch?v=Rpj0emEGShQHow viruses infect cells
http://www.youtube.com/watch?v=U2h0ECyMWhEHIV destroying Helper T cells
The Immune ResponseThe Immune Response
The Immune ResponseThe Immune Response