Human Immunity
Objectives:
Know the difference between Specific & Non-specific defenses
Know how each non-specific defense works
Know how the specific system works and it’s relationship with vaccine production

I. What is immunity?
The ability of the body to resist pathogens
II. Human immune system includes two general categories against infection:
	A. Nonspecific defenses
	B. Specific defenses
III. Nonspecific Immunity
A. First Line of Defense:
Skin – how?
Mucus membranes - how?
B. Second Line of Defense:
Inflammation - how? 
Fever - how? 
Antimicrobial proteins
Phagocytes engulf foreign particles

IV. Specific Immunity 
     When a pathogen gets past the body’s non-specific defenses….
A. Specific Immune response is triggered
	B. Targets specific individual invaders.
	C. You are born with this system
	D. You are able to recognize millions of invaders. 
Begins with a wandering macrophage engulfing the foreign invader (antigen)
Antigen: Any substance that triggers an immune response.
The HLA protein is unique to each person.
The antigen is broken down and pieces of the surface proteins of the pathogen are moved to the surface of the macrophage.
 G. Only T-cells that have receptors that fit to the presented antigens bind to the macrophage.
 H. Binding of the T cells with the macrophage (WBC) stimulates these specific T-cells to divide many times forming many different kinds of T-cells.

Types of T-cells
1. Helper T cells stimulate B cells to release antibodies.
	a. B cells are another kind of white blood cell.
	b. Antibodies are proteins that bind to and inactivate or tag the foreign antigens.
	c. Memory B cells are also left behind for life. 
2.Killer T cells attack and destroy the invaders or body cells that contain viruses.
3. Memory T cells remain in the body for life.

Vaccines
Take a virus or other pathogen and destroy or weaken its nucleic acid. 
Why do we want to do this?
1. You can alter the DNA of the pathogen by using chemicals, radiation or growing it in a different host.
Why are you asked if you are allergic to eggs before you get a flu shot?
Leave the protein coat undamaged.  
Why?
2. Inject this mixture (the vaccine) into humans or other animals. 
Your body responds as if you had the disease and you form memory cells for this disease.
Why don’t you get this disease?
3.Next time host is exposed to the pathogen, the body will recognize and destroy pathogen before the disease affects the body.
Why can you fight it off so fast?