Download Immune System

Immune System
Disease
• Any change in the body not due to injury
that disrupts homeostasis
• Pathogens = Sickness makers
How do we know pathogens make you sick?
Koch’s Postulates
1.
The suspected causal organism must be constantly
associated with the disease.
2.
The suspected causal organism must be isolated from an
infected organism and grown in pure culture.
3.
When a healthy susceptible host is inoculated with the
pathogen from pure culture, symptoms of the original
disease must develop.
4.
The same pathogen must be re-isolated from the organism
infected under experimental conditions.
Lyme Disease
Risk
Lyme Disease Etiology
• Allen Steere (1975) Yale University
• 39 children from Lyme Connecticut
• All had pain and joint inflammation
• All had insect bites and rashes
• Dr. Willy Burgdorfer found spirochete in ticks
• Steere found same bacterium in his patients
Non-Specific Immunity
1st Line of Defense
• Skin
• Mucous membranes
• Saliva
• Mucus
• Nasal hair
• Tracheal cilia
• Stomach acid
• Sweat
• Tears
Non-Specific Immunity
2nd Line of Defense
• Phagocytes
• Natural killer (NK) cells
• Inflammatory response
• Pyrogens (Reset thermostat in hypothalamus)
• Complement proteins
• Interferon (Prevents viral replication)
• Lysozyme (Pokes holes in bacterial cell walls)
Non-Specific Immunity
• Complements identify
antigen
• Granulocytes attack
antigen creating pus
• Macrophages perform
phagocytosis on bacteria
Inflammatory Response
1.
Damaged tissue releases histamine
2.
Capillaries become “leaky”
3.
Blood flow increases to area
4.
Clotting factors and phagocytes released into the wound
5.
Phagocytes engulf bacteria, cellular debris, & dead cells
6.
Macrophages release cytokines which attract immune
system cells
7.
Platelets seal the wound with a clot
Specific Defenses
• Humoral immunity – immunity against
pathogens in body fluids (blood and lymph)
• Immune response carried out by
lymphocytes
• Cell-Mediated immunity – Antibody
production
Antibodies
• Antibody = a protein that helps to
destroy pathogens
• Substrate specific
• Cause agglutination which attracts
phagocytes
• Made by plasma cells
• Plasma cells made by b-lymphocytes
Humoral Immunity
Antibodies
IgM
IgG
IgA
Cell Mediated Immunity
• Active immunity - vaccination with antigen (lasts
for years)
• Passive immunity – transferring antibodies from
one person to another (lasts several weeks)
Dr. Edward Jenner