immune responses & vaccines

• Inactivated vaccines contain dead or damaged pathogens which cannot reproduce but still trigger an immune response
• Primary immune response:

  1. The production of antibodies is slow after the first exposure to the pathogen (longer lag phase). 
  2. The concentration of antibodies increases slowly. 
  3. This is because there are very few B cells that are specific to the pathogen's antigens. 
  4. It takes time for the B cells to divide into plasma cells to produce the correct antibody, so the individual experiences symptoms of the disease. 
  5. During this process, some B cells divide into memory cells to make the individual immune to this disease.
• Secondary immune response:

  1. The production of antibodies is much quicker after exposure to the pathogen (shorter lag phase).
  2. The concentration of antibodies increases quickly. 
  3. This is because memory cells recognise the pathogen's antigens and quickly divide into plasma cells. 
  4. These plasma cells secrete larger numbers of antibodies to quickly destroy the pathogen before the individual experiences any symptoms. 
• vaccines expose a person to an antigen - initiates primary immune response to create memory B & T cells
• Active immunity:

  • This type of immunity develops when the immune system makes its own antibodies after exposure to a pathogen's antigens. 
  • It takes a while to become immune to the disease, but it is long-term protection because memory cells are produced. 
• Passive immunity:

  • This type of immunity develops when an individual is given antibodies made by a different organism (the individual's immune system does not make these antibodies).
  • This method provides immediate immunity to the disease, but it is short-term protection because the antibodies are broken down and memory cells are not produced.
• passive - natural immunity= antibodies inherited by a baby from mother during the pregnancy and breastfeeding
• passive - artificial immunity= antibodies are received directly from a vaccine or transfusion
• active - natural immunity= antibodies produced after exposure to an illness
• active - artificial immunity= antibodies produced by the body after being given a vaccine