Antibodies

• Describe the basic definition of an antibody.

  Proteins with specific binding sites.
• What are antibodies synthesised by?

  B lymphocytes
• How many binding sites does an antibody have?

  2- they're identical
• Describe the structure of antibodies.

  They're made of 4 polypeptide chains.

  One pair are long and called heavy chains, while the other pair of chains are short and called light chains. The antigen binding site is known as the variable region because its different for each antigen. The rest of it is known as the constant region.
• What is the name for when an antibody and antigen bind?

  Antigen-antibody complex
• How do antibodies destroy antigens directly?


  They don't- they prepare the antigen for destruction.
• Describe agglutination.


  Antibodies have at least two antigen-binding sites.

  This means they can bind to more than one bacterium or virus at the same time.

  This cause groups of the same pathogens to become clumped together.
• What happens after agglutination?

  The binding of antibodies to the antigens either neutralises the pathogen or acts like a marker to attract phagocytes to engulf and destroy the pathogens.

  Due to agglutination, phagocytes can often phagocytose many pathogens at the same time, as they are all clumped together.
• What kind of protein are antibodies?

  globular glycoproteins called immunoglobulins.
• How many types of mammalian antibodies are there?

  5
• What are the two heavy polypeptide chains and light chains held together by?

  Disulfide bonds
• What does the constant region determine?

  The mechanism used to destroy the antigens.
• Where do antibodies attach to form antigen-antibody complex?

  The variable regions
• What is at the end of the variable region?

  The antigen-binding site
• How many amino acids does each antigen-binding site composed of?

  110 to 130 and includes both the ends of the light and heavy chains.
• What is the epitope?

  The part of the antigen that binds to the antibody.
• What is the specific part of an antigen that binds to an antibody called?

  Epitope
• Why might a pathogen or virus require the production of multiple antibodies?

  Because it presents multiple antigens
• What is the relationship between an epitope and an antibody?

  The epitope is the part of the antigen that binds to the antibody
• How does the presence of multiple antigens on a pathogen affect the immune response?

  It requires the production of different antibodies
• What is the significance of an epitope in the context of antibody-antigen interactions?

  It determines the specificity of the antibody binding
• What is the role of epitopes in the immune system?

  • Epitopes are the specific parts of antigens that antibodies bind to
  • They determine the specificity of the immune response
  • Multiple epitopes on a pathogen can lead to the production of different antibodies
• How do multiple antigens on a pathogen influence the immune response?

  • Multiple antigens can lead to the production of different antibodies
  • This increases the complexity of the immune response
  • It allows the immune system to target different parts of the pathogen
• What is the term for the part of the antigen that binds to the antibody?

  Epitope
• Why is it important for the immune system to produce different antibodies for a single pathogen?

  Because the pathogen may present multiple antigens
• What is the implication of a pathogen presenting multiple antigens?

  It requires the immune system to produce multiple antibodies
• What is the part of the antigen that binds to the antibody?

  Epitope
• How does the presence of multiple antigens on a pathogen affect antibody production?

  It leads to the production of different antibodies
• What is the significance of multiple antigens on a pathogen?

  It requires the immune system to produce multiple antibodies
• What does the hinge region (where the disulfide bonds join the heavy chains) do?

  gives flexibility to the antibody molecule which allows the antigen-binding site to be placed at different angles when binding to antigens.