Immune system

• What is a lymphocyte?

  Type of white blood cell involved in defense
• How do lymphocytes identify foreign cells?

  By specific molecules on their surface
• What are the two types of defense mechanisms?

  Specific and non-specific defenses
• What is an example of a non-specific defense?

  Physical barriers like skin
• What is an example of a specific defense?

  Cell-mediated response by T lymphocytes
• What type of white blood cell is involved in phagocytosis?

  Phagocytes
• What is a pathogen?

  Organism that causes disease
• What happens during phagocytosis?

  Pathogen is engulfed and digested by phagocyte
• What is an antigen?

  Molecules that generate an immune response
• What are T cells involved in?

  Cell-mediated immunity
• What is the process of cell-mediated immunity?

  Phagocyte presents antigens to T cells
• How do cytotoxic T cells work?

  They produce perforin to kill infected cells
• What is the purpose of memory cells?

  Faster response to the same antigen
• Describe the process of the humoral response.

  B cells produce antibodies after antigen binding
• What is antigenic variability?

  Frequent changes in pathogen surface antigens
• What are antibodies?

  Proteins with specific binding sites for antigens
• Describe the structure of antibodies.

  Quaternary protein with heavy and light chains
• What are some roles of antigens?

  Identify pathogens and neutralize toxins
• What are monoclonal antibodies?

  Antibodies made in labs specific to antigens
• How do pregnancy tests work?

  Detect HCG hormone in urine
• What are some ethics involved with using monoclonal antibodies?

  Animal testing and potential side effects
• What do direct ELISA tests test for?

  Presence of a specific antigen in a patient
• How does a direct ELISA test work?

  Antigen binds to plate, MAB added, color change
• How does an indirect ELISA test work?

  Antigen binds, patient sample added, secondary antibody added
• What is passive immunity?

  Immunity from transferred antibodies
• What is active immunity?

  Immunity from antibody production after infection
• What is a vaccination?

  Introducing antigens to stimulate antibody production
• What are features of a successful vaccination program?

  Economically available, few side effects, herd immunity
• What is herd immunity?

  Large proportion vaccinated, limiting pathogen spread
• What are some ethics involving vaccines?

  Potential harmful side effects and animal testing
• Describe the structure of HIV.

  Lipid envelope, attachment proteins, RNA
• Why are viruses acellular and non-living?

  Not made of cells and can't reproduce independently
• How does HIV replicate?

  Attaches to T helper cells and integrates DNA
• How can HIV be transmitted?

  Sexually, needles, open wounds
• How can HIV cause AIDS?

  Kills T helper cells, weakening immune response
• Why are antibiotics ineffective against AIDS?

  Antibiotics target bacteria, not viruses