Edexcel A (SNAB) A Level Biology:复习笔记6.2.5 T Cell Response

T Cell Response

  • T cells, sometimes known as T lymphocytes, are a type of white blood cell involved with the specific immune response
    • They are produced in the bone marrow and finish maturing in the thymus, which is where the T in their name comes from
  • Mature T cells have specific cell surface receptors called T cell receptors
  • These receptors have a similar structure to antibodies and are each specific to a particular type of antigen

 Mature T cells have many different types of receptor on the cell surface membrane; these receptors will bind to different antigens on antigen presenting cells

  • T cells are activated when they encounter and bind to their specific antigen on the surface of an antigen presenting cell
    • This antigen-presenting cell might be a macrophage, an infected body cell, or the pathogen itself
  • These activated T cells divide by mitosis to increase in number
    • Dividing by mitosis produces genetically identical cells, or clones, so all of the daughter cells will have the same type of T cell receptor on their surface
  • As they divide by mitosis the T cells differentiate into three main types of T cell
    • T helper cells
      • Release chemical signalling molecules that help to activate B cells
    • T killer cells
      • Bind to and destroy infected cells displaying the relevant specific antigen
    • T memory cells
      • Remain in the blood and enable a faster specific immune response if the same pathogen is encountered again in the future