Antibodies

• What is an antibody?

  A protein created by a B-cell. It has two, identical, specific binding sites and a quaternary structure
• What is an APC?

  An APC is formed when a phagocyte has engulfed and hydrolysed a pathogen and presents its antigens on its own cell-surface membrane. This can activate the specific immune system.
• How are antibodies made?

  1. Selected B cell has a receptor with a complementary shape to the pathogen antigen; once the B cell binds to the pathogen antigen, it undergoes endocytosis and presents the antigen on its surface
  2. The activated Th cell binds to the antigens on the B cell
  3. This stimulates the B cell to divide by mitosis, creating clones
  4. These B cell clones then differentiate into memory or plasma cells: the plasma cells secrete specific antibodies