1. Immune Response The way the body recognizes or defends itself against
bacteria and other microorganisms
viruses
fungi
parasites
Can be broken down into three stages:
Physical Defense
Inflammatory Response
Immune Response

2. Immune Response: Physical Defense
Physical Defense - The bodies first line of defense
Skin provides a protective barrier (largest physical defense)
Mucus traps foreign particles in respiratory system
Acid in stomach digests invaders
Human tears destroy cell walls of microbes
Hairs or cilia trap foreign materials

3. Immune Response: Inflammatory Response
Inflammatory Response (non-specific) - Once invaders have entered the body, second line of defense is mobilized
Increased blood flow and permeability of capillaries
** macrophage, neutrophils and monocytes**
Microbes are absorbed during phagocytosis by neutrophils and monocytes
Blood rushes out of a wound to prevent microbes from entering further

4. Immune Response: Specific defenses (antibody mediated immunity)
The appearance of foreign invaders in the body activates plasma proteins, known as complimentary proteins
Antibodies recognize foreign substances and work with T cells to destroy them

5. The first stage occurs when a macrophage, a specialized WBC, recognizes a virus and consumes it
The virus looks for neighbouring cells to infect
Next, the macrophage digests the virus and displays pieces of the virus called antigens on its surface
Nearby cells have now become infected by the attacking viruses.

6. Helper T cells, another class of leukocytes now recognizes the foreign antigen displayed and binds to the macrophage.
This stimulates the production of chemical transmitters by the macrophage that allow intercellular communication.

7. As part of the continuing process, the chemicals released instruct other helper T's and a different class of T cells, the killer T's, to multiply.
The proliferating helper T's in turn release substances that cause B cells to multiply and produce antibodies.

8. The killer T cells now begin shooting holes in host cells that have been infected by viruses

9. The antibodies released by the B cells bind to antigens on the surfaces of free-floating viruses. Besides making it easier for macrophages to destroy viruses, this binding signals blood components called complement proteins to puncture holes in the viruses.

10. Finally, as the infection is brought under control, the activated T and B cells are turned off by suppressor T cells. However, a few "memory B cells" remain behind to respond quickly if the same virus attacks again.