Immunity and antigens

• What is the first function of the immune system mentioned?

  Recognizing healthy self cells from unhealthy ones
• What are foreign substances that can harm the body called?

  Pathogens
• What type of cells can identify non-self cells?

  Lymphocytes
• What do lymphocytes recognize on the surface of cells?

  Unique specific molecules
• What are the identifying molecules on cell surfaces called?

  Antigens
• What is the typical structure of antigens?

  Proteins with 3D tertiary structures
• What triggers the immune response?

  Detection of foreign substances or pathogens
• What can lymphocytes identify in relation to organ transplants?

  Cells from another organism
• How do lymphocytes detect abnormal body cells?

  By recognizing different antigens
• What do some pathogens release into the blood?

  Toxins
• How many different types of lymphocytes are in the body?

  Approximately 10 million
• What happens to lymphocytes that are complementary to self cells?

  They die or are suppressed
• Where do lymphocytes mature after being exposed to non-self cells?

  Thymus or bone marrow
• What can result from lymphocytes attacking self cells?

  Autoimmune diseases
• What are antigens typically made of?

  Proteins
• What is antigen variability?

  Frequent mutations in pathogen DNA
• Why do new flu vaccines need to be created annually?

  Pathogens mutate and change antigen shapes
• What should happen to lymphocytes that may harm self cells?

  They should be destroyed
• What are the implications of antigen variability for vaccination?

  • Frequent mutations in pathogens change antigens.
  • Previous immunity from infections or vaccines may fail.
  • New vaccines are needed to match current antigens.
  • Annual flu vaccines are an example of this necessity.