specific immune response

• the specific immune response involves B lymphocytes + T lymphocytes

  • they have a large nucleus a specialised receptors on their plasma membranes (cell surface membranes)
  • the immune response produces antibodies

  → the antibodies that actually neutralise foreign antigens

  • the immune response also provides long-term protection from the disease → produces immunological memory through release of memory cells, which circulate in body for a number of years
• T lymphocytes develop or differentiate in 4 types:

  • T helper cells (Th), release cytokines what stimulate B cells to develop o stimulate phagocytosis by phagocytes
  • T killer cells (Tk), attack & kill host-body cells that display foreign antigen
  • T memory cells (Tm), provide long-term immunity
  • T regulator cells (Tr), shut down immune response after the pathogen has been successfully removed

  → Also involved in preventing autoimmunity
• B lymphocytes develop into two types:

  • plasma cells, circulate in the blood, manufacturing + releasing the antibodies
  • B memory cells (Bm), remain in body for a number of years + act as the immunological memory
• Cell signalling

  specific immune response involves the coordinated action of a range of cells. To work effectively, these cells need to communicate; cell signalling

  • achieved through release of hormone-like chemicals called cytokines there is a huge range of signalling molecules, each performing a different role
  • in order to detect a signal, the ranger must have a cell surface receptor complementary in shape to the shape of their signalling molecule
• Examples of communication using cytokines

  • macrophages release monokines → some monokines attract neutrophils (by chemotaxis-movement of cells towards a particular chemical) + other stimulate B cells to differentiate + release antibodies
  • a macrophages release interleukins, stimulate the clonal expansion (proliferation) + differentiation of B + T cells
  • many cells can release interferon, which inhibits virus replication + stimulates activity of T killer cells
• Autoimmune Diseasesoccurs when immune system attacks a part of the body

  • normally, any B or T cells that an specific to our own antigens are destroyed during early development of immune system

  An autoimmune disease arises when antibodies start attacking antigens - possibly due to antigens that are not normally exposed become exposed to attack