IMMUNE SYSTEM III PP. 961-966 & 970-972

VACCINES Using a weakened form of a pathogen to initiate an immune response to create memory cells

ALLERGIES Allergens: cause allergies Over-reaction of the immune system to a harmless invader)

IMMUNE DISORDERS Autoimmune: The immune system attacks their own body cells as though they were pathogens. EX. Rheumatoid Arthritis

Immune deficiency:  the immune system's ability to fight infectious disease is compromised or entirely absent HIV: human immunodeficiency virus AIDS (acquired immune deficiency syndrome): weakened immune system caused by the infection of HIV HIV ≠ AIDS

HIV Caused by a retrovirus 1. Enzymes to transcribe its RNA to DNA 2. New DNA inserted into host cell’s DNA 3. Host cell now makes proteins to assemble more HIV viruses

AIDS

Transmission: fluid containing the virus or cells with the virus (blood, sexually, breast-feeding) Course of the disease Phase I: (asymptomatic) few or no symptoms Phase II: worsening of symptoms Phase III: T-cell count goes below 200 cells/mL (normal 600-700) People with AIDS die from opportunistic infections (diseases that only strike because of a weakened immune system)