1. Immune System

2. Immune System
Defends the body against foreign invaders or abnormal cells that invade or attack it

3. Three Lines of Defense 1st: mechanical or physical barriers
skin, cornea of the eye, and the membranes lining the respiratory, digestive, urinary, and reproductive tracts

4. Three Lines of Defense
2nd : Nonspecific (innate) immunity is present at birth
treat all foreign substances in a similar way
monocytes (which develop into macrophages), neutrophils, eosinophils, basophils, and natural killer cells

5. Three Lines of Defense 3rd : Specific (adaptive) immunity is acquired
as the immune system encounters different antigens, it begins to develop a memory for that antigen
takes time to develop specific immunity after initial exposure to a new antigen
when the antigen is encountered in the future, the response is more rapid and effective than nonspecific immunity

6. Vaccines work by stimulating the development of specific immunity
developed for many diseases
effective at enhancing the immune response
Why do puppies and kittens under 5 months require booster vaccines?
If you do not want to continuously vaccinate your animal, what are the alternatives?

7. Immune Response: Launching an Attack
First, the immune system must recognize there is a foreign invader
All cells have cell surface markers which is a protein that identifies the cell
If the immune cells do not recognize a cell, it attempts to destroy it

8. Immune Response: Launching an Attack
B cells (WBC)
recognize invaders/antigens directly
attaches to the antigen and produces antibodies, which coat the surface of the virus or bacteria to stop it from multiplying or infecting other cells (neutralization)
antibodies “label” the antigen so other immune defenses can find and attack them

9. Immune Response: Launching an Attack
T cells (WBC)
require help from cells that first ingest the invader and break it into fragments (antigen presenting cells)
fragments are presented to T cells so they can recognize and destroy them

10. After the Immune Response/Attack
once the antigen has been eliminated, most of the immune cells and antibodies that fought the infection disappear
small group of “memory” immune cells remain (clones of the B- and T-cells)
if the memory cells are exposed to the same antigen in the future, they help the body respond faster, with a stronger response
reason why vaccinations are successful in preventing many diseases
vaccinations prime the immune system