CELL MEDIATED RESPONSE

• What molecules are involved in the cell mediated response?

  T lymphocytes
• What are T lymphocytes?


  White blood cells involved in a specific immune response
• Where are T lymphocytes made and where do they mature?

  made in bone marrow, mature in thymus
• What do T cells only respond to?

  Only respond to antigens on the surface of cells, and not any which are detached from cells and are in bodily fluids such as the blood.
• What are the 4 types of antigen presenting cells?

  Infected body cell: Presents viral antigens on their surface

  Macrophage: which has engulfed and destroyed a pathogen will present the antigens on its surface.

  Cells of transplanted organ: different shape antigens on surface compared to self-cells.

  Cancer cells; will have abnormal shaped self-cell antigens
• Explain the process of the cell-mediated response?

  Once a pathogen has been engulfed and destroyed by a phagocyte this antigens are positioned on the cell surface.

  Helper T cells have receptors on their surface which attach to APC.

  Once attached this activates helper T cells to divide.

  Cloned cells differentiate

  Some remain as helper T cells and activate B cells.

  Some stimulate macrophages

  Some become memory cells

  Some become cytotoxic cells
• What do cytotoxic cells do?

  Destroy abnormal or infected cells.

  They release a protein called performing which embeds into the cells surface membrane and make a pore so that any substances enter or leave the cell causing cell death.

  Most common in viral infections because they infect body cells.

  Body cells are sacrificed to prevent viral replication which is why u get a sore throat when you get a cold.