1. Immune System “Do I still have to go to school doc?”

2. What Does My Immune System Do? Discriminates between “self” and “foreign” Response by immune system protects us – INVADERS!!!! ATTACK!!!

3. Important Terms & Their Definitions Antigen Anything causing an immune response, usually foreign material but may be our own tissues. Pathogen Any disease causing micro-organism. Chemokines Molecules released by pathogens and infected tissues to attract cells of the immune system. Cytokines Signaling molecules released by one cell to cause a response in another. Signaling is extremely important in our immune response. Innate Immunity Protection that is always present. Adaptive Immunity Protection that arises by an immune response B Cells Make antibodies for antigens, perform role of APC, and develop into memory B cells Helper T Cells (T h ) When activated, they divide rapidly and secrete cytokines Cytotoxic T Cells (T c ) Induce the death of cells Phagocytes Cells that engulf the foreign material

4. Process Our body gets infected by pathogen – Bacteria, Virus, Fungus The antigens of the microbe are recognized The body response is either “Humoral” or “Cell-Mediated”

5. Humoral Immunity Free antigens activate B Cells into Plasma Cells – Plasma cells secrete antibodies These antibodies defend against pathogens by binding to antigens and making the pathogens easier targets for being destroyed by phagocytes

6. Cell Mediated Immunity Infected cells displays antigens Antigens displayed by infected cells activate Cytotoxic T-cells (T C ) when bounded The activated T-cell (T C ) releases chemicals that cause pores in the infected cell Water and ions enter infected cell and cell gets destroyed

7. The Role of Helper T-Cells (T h ) Antigen can be engulfed by macrophages Macrophages will present the antigen on their surface Helper T-cells are stimulated and differentiate Helper T-cells secrete cytokines that stimulate either B-cells or Cytotoxic T-cells

8. Secondary Response Memory cells are created to initiate a quicker secondary response if antigen is presented in body again Mimic the same type of B-cell or T-cell but have a higher ability to bind and recognize antigen