Cell mediated response

• What is the cell mediated response?

  The activation of phagocytic cells, B lymphocytes and T lymphocytes
• What are T lymphocytes?

  • activated in the thymus gland
  • receptors on their cell membranes respond to antigens, and they divide into T memory cells, T killer cells and T helper cells
• What do T memory cells do?

  Remain dormant in the blood and divide into more T lymphocytes if the same antigen is encountered
• What do T killer cells do?

  Lyse pathogenic cells
• What do T helper cells do?

  Release cytokines
• What are cytokines and what do they do?

  Chemicals released by T helper cells which stimulate:

  1. Phagocytic cells (macrophages, monocytes and neutrophils) to engulf pathogens and digest them
  2. B and T lymphocytes to undergo clonal expansion (divide)
  3. B lymphocytes to make antibodies
• What is antigen presentation?

  • on first exposure to an antigen, there is a short latent period where macrophages engulf the foreign antigen/cell/virus to which it is attached
  • the antigen is then incorporated into the cell membrane of the macrophage (antigen presentation)
  • T helper cells detect these antigens and release cytokines
  • B plasma cells secrete antibodies for about 3 weeks until symptoms subside