Cell%20Mediated%20Immunity

1
Cell Mediated Immunity

• Introduction
• Cytokines
• Components of Cell Mediated Immunity

2
Cell Mediated Immunity

• Introduction
• Involves specialized lymphocytes call T-cells
• T-cells mature in thymus
• Response to intracellular viruses, multicellular
  parasites, transplanted tissues and cancer

3
Cell Mediated Immunity

• Cytokines are chemical messengers
• Interleukins are cytokines that allow leukocytes
  to communicate
• Interferons are cytokines that protect against
  viruses
• Chemokines cause leukocytes to move to site of
  infection

4
Cell Mediated Immunity

• Components
• Helper T Cells (TH )
• Cytotoxic T Cells (TC )
• Delayed Hypersensitivity T Cells (TD)
• Suppressor T Cells (TS)
• Activated Macrophages
• Natural Killer Cells

5
Cell Mediated Immunity

• Helper T Cells
• Activate B-cells
• Activate cytotoxic T cells
• Activate other helper T cells

6
Cell Mediated Immunity

• Cytotoxic T Cells
• Used to attack intracellular pathogens such as
  viruses, some bacteria, multicellular parasites
• Attaches to target cell
• Releases protein perforin which pokes holes in
  target cell inducing lysis
• T cells continue as long as antigen is present

7
Cell Mediated Immunity

• Delayed Hypersensitivity T Cells
• Involved in allergic reactions like response to
  poison ivy and transplanted tissue rejection
• Originally named because transfer of cell
  transferred immunity to TB
• Probably a subpopulation TH cells and TC cells

8
Cell Mediated Immunity

• Suppressor T Cells
• Appears to regulate immune response
• Probably a subpopulation of helper cells

9
Cell Mediated Immunity

• Activated Macrophages
• Stimulated by ingestion antigens and cytokines
  from helper T cells
• Acquire enhanced ability to digest via
  phagocytosis virus infected cells and
  intracellular bacteria infected cells
• Can be antigen presenting cells

10
Cell Mediated Immunity

• Nautral Killer Cells
• Kill virus infected cells, tumor cells and large
  parasites
• Not immunologically specific like cytotoxic T
  cells