primary and secondary response

• When an individual is infected by a pathogen for the first time, a primary immune response takes place
• primary immune response:

  Slow

  • The primary response is slow because it takes time for the antigens to be detected and the specific plasma cells to be activated.
  • It may take several days for the pathogen to be removed by the immune system.
• primary immune response:

  Symptoms

  • In the primary immune response, the individual is likely to show the symptoms of the pathogen.
  • The pathogen has time to cause harm to the individual before it is removed by the immune system.
• primary immune response:

  Memory cells

  • T cells and B cells can produce memory cells after an infection.
  • Memory cells remain in the body after the infection has been removed.
  • If the individual is infected again, there will be a much quicker response to the antigens.
• secondary immune response:

  Fast

  • The secondary response is rapid because of the presence of memory cells in the body.
  • The memory cells can quickly identify the antigens and produce the correct antibodies.
• secondary immune response:

  Stronger

  • The secondary immune response is also stronger than the primary immune response.
  • More plasma cells can be produced more quickly.
• secondary immune response:

  Symptoms

  • In the secondary immune response, the individual is unlikely to show the symptoms of the pathogen.
  • The pathogen is removed by the immune system before it has time to cause harm.
  • The individual is said to be immune.
• • Types of response
  • Primary response
  • Slow
  • May present symptoms
  • Secondary response
  • Rapid
  • Unlikely to present symptoms