Immune system

• What is a non-specific response?

  A response not specific to a pathogen. Example: A physical barrier.
• Define a specific response.

  A response specific to a pathogen. E.g T or B cells
• Define an antigen.

  A protein / glycoprotein / glycolipid on the surface of a pathogen which trigger immune response
• Compare B cells and T cells

  Both are made in the bone marrow

  B cells remain in bone marrow to mature whilst T cells mature in the thymus

  B cells are used in humoral response whilst T cells are used in the cell mediated response
• What do T cells respond to?

  Cancer or transplated cells
• Describe the process of the cell mediated response.

  Pathogen infects a cell / taken up by a phagocyte

  Foreign antigens are displayed on a cells membrane and becomes an antigen presenting cell

  A specific T helper cell binds to a complimentary receptor on the antigen

  T helper cell is activated and divides by mitosis
• When dividing by mitosis what can T cells do?

  Stimulate phagocytosis

  Stimulate B cells to start dividing

  Stimulate memory cells to stay in the blood

  Activate cytotoxic t cells which kill infected / abnormal cells by perferating the membrane using perforin