Vaccination

• Stages of immunity:

  1. A pathogen enters body
  2. The pathogen secretes antigens - makes you feel ill
  3. WBC of immune system create antibodies - destroy pathogens
  4. The person = now immune + unlikely to get illness again
  5. The same pathogen tries to infect again
  6. immune system remembers to make right antibodies + kills quickly - before you feel ill
• Edward Jenner created first vaccine
• body produces antibodies + antitoxins to protect us from infection
• antibody : Protein produced by WBC tin response to a foreign antigen
• antitoxins: neutralise the toxins produce by bacteria so you can't be harmed
• Phagocyte: engulf pathogens / toxins using phagocytosis
• lymphocytes: white blood cells that produce antibodies and help the immune system fight infection
• Antigens: immune system recognises antigens on cells, WBCs make antigen specific antibodies, the memory WBC's remember the right antibody required to destroy a particular pathogen
• Vaccines: made up of dead/ inactive forms of pathogen/ parts of pathogen that trigger immune response. They allow a rapid WBC response. The right antibodies are produced very quickly and it protects use from both viral and bacterial infection
• The first time, there is a lag phase of about 8 days where you will feel ill and the pathogen won't be fought. Then the antibodies start being made and will take a long time to fully destroy the pathogen. The second time, the memory cells remember which specific antibody needs to be used so there is a much quicker defence response and it is more effective than the first time.

  A) lag phase

  
• Examples of vaccinated diseases: These can kill you before your body creates the right anitbodies

  1. Meningitis - can kill/ cause permanent brain damage
  2. Tetanus
  3. Diptheria
  4. MMR - protects against measles, mumps and rubella
• Herd immunity : when a large proportion of a population is vaccinated, so that the disease cannot spread and may dissapear
• How the immune system works (6):

  1. Every cell has unique antigens
  2. Immune system recognises foreign antigen entry
  3. WBC use antibodies that target the antigen and destroy the pathogens
  4. Memory cells remember the specific antibody to destroy the pathogen and produce them quickly.
  5. If the same pathogen gets into the body again you will be immune to it and won't feel ill