Immunity & Vaccines

• Active immunity

  • Involves memory cells
  • involves the production of antibody by plasma cells
  • Long term because antibody produced in response to antigen
  • Takes more time to work
• Passive immunity


  • Does not involve memory cells
  • involves antibody introduced into body from an outside source
  • short term, because the antibody given is broken down
  • It is fast acting
• Describe how a vaccine leads to the production of antibodies

  • Vaccine contains antigen from pathogen
  • Macrophage presents antigen on its surface
  • T cell with complementary receptor protein binds to antigen
  • T cell stimulates B cell with complementary antibody on its surface
  • B cell secretes large amounts of antibody
  • B cell divides to form clone all producing the same antibody
• Explain why an animal is initially injected with a small volume of antigen but is injected with a larger volume of antigen later

  
  

  • B cells are specific to the antigen that is cloned
  • B cells produce memory b cells and plasma cells
  • The second dose produces antibodies in secondary immune response in higher concentration and quickly
  • The first dose must be small so the animal is not killed