Specific Immune System

• What are antibodies also known as?

  Immunoglobulins
• What is the structure of antibodies?

  They are Y-shaped glycoproteins.
• How many different antibodies can bind to a specific antigen?

  Millions of different antibodies can bind to a specific antigen.
• What are the components of an antibody?

  • Two identical long polypeptide chains (heavy chains)
  • Two identical short chains (light chains)
  • Held together by disulfide bridges
  • Antigen binding sites with a “lock and key” mechanism
  • Hinge region for flexibility
• What is the function of the hinge region in antibodies?

  It allows flexibility to bind with two antigens at a time.
• What are the three main types of antibodies and their functions?

  1. Opsonins: Bind to antigens on pathogens, assisting in phagocytosis.
  2. Neutralisation: Stop antigens from functioning and prevent entry into host cells.
  3. Agglutinins: Crosslink pathogens, making them easier to engulf by phagocytes.
• How do antibodies act on invading pathogens?

  They bind to antigens, agglutinate pathogens, and attract phagocytes.
• What is the role of opsonins?

  They bind to antigens on the pathogen’s surface.
• What do anti-toxins do?

  They bind to toxins released by pathogens, rendering them harmless.
• What are the key terms related to secondary defenses in the immune system?

  • Antigens
  • Opsonins
  • Cytokines (monokines, interleukins, interferons)
  • Antibodies
  • Phagocyte
  • Neutrophil
  • Macrophages (monocytes, dendritic cells)
  • Antigen presenting cell
• What is the specific immune response?

  It is the production of antibodies specific to antigens on a particular pathogen.
• Where are antigens found?

  On the pathogens themselves and on the plasma membranes of infected cells.
• What do antigen presenting cells (APCs) do?

  They stimulate other cells in the immune system.
• What type of cells are T lymphocytes?

  White blood cells
• What are the types of T lymphocytes and their functions?

  • T helper cells: Activate other immune cells.
  • T killer cells: Destroy infected cells.
  • T memory cells: Provide long-term immunity.
  • T regulator cells: Stop the immune response after the pathogen is cleared.
• What do plasma cells do?

  They make and release many antibodies to a particular antigen.
• How are B cells activated?

  By helper T cells.
• What is the role of B memory cells?

  They remember the pathogen and provide long-term immunity.
• What do T helper cells release to stimulate other immune cells?

  Interleukins
• What is the function of T killer cells?

  They release perforin to destroy infected cells.
• What do T memory cells do upon re-exposure to the same antigen?

  They rapidly produce many clones of T killer cells.
• What is the role of T regulator cells?

  They stop the immune response once the pathogen has been removed.
• What are cytokines and their roles in the immune response?

  • Cell signalling molecules involved in the immune response.
  • Produced by T-helper cells to stimulate B cells.
  • Released by mast cells and macrophages to attract neutrophils.
  • Act in low concentrations over short distances.
• What are the types of cytokines and their functions?

  • Monokines: Attract neutrophils by chemotaxis.
  • Interleukins: Stimulate proliferation and differentiation of B and T cells.
  • Interferon: Inhibit virus replication and stimulate T killer cell activity.
• What is the difference between cell-mediated response and humoral immunity?

  • Cell-mediated response: Destroys infected or altered cells.
  • Humoral immunity: Releases antibodies into body fluids.