Specific immunity

• What is an antigen?

  Usually proteins that are part of the cell-surface membranes or cell wall of organism.
• How are they used in the immune response?

  They're used to recognise substances that are non-self.
• What do they trigger?

  They trigger the production of an antibody as part of the body's defence mechanism.
• How is specific immunity different to non specific?

  Phagocytosis happens whatever the infection, but specific immunity reacts to specific antigens. This is slower at first but provides long-term immunity.
• An antigen and it's complementary antibody have complementary molecular shapes, what does this mean?


  Their molecular structures fit into each other.
• What happens when an antibody collides (randomly) with a foreign cell that possesses non-self antigens with a complementary shape?


  It binds with one of the antigens
• What happens when an antigen binds with an antibody?

  They form an antigen-antibody complex.
• What does the binding of antibodies do to antigens?

  Eitther neutralises or acts like a marker to atract phagocytes to engulf and detroy pathogens.