Cell mediated response

• What type of lymphocytes are involved in the specific immune response?

  T lymphocytes
• Why are T cells called T cells?

  They mature in the thymus
• What is the cell mediated response primarily focused on?

  The response involving T cells
• What does a specific immune response target?

  An exact antigen or cell surface molecule
• What are antigen presenting cells abbreviated as?

  APC
• What is the role of antigen presenting cells?

  To present non-self antigens on their surface
• What type of cells can be antigen presenting cells?

  Infected body cells, macrophages, and cancer cells
• Why is the response called cell mediated?

  Because T cells respond to presented antigens
• What happens to antigens after phagocytosis?

  They are placed on the surface of the phagocyte
• What activates helper T cells?

  Binding to antigens on antigen presenting cells
• What occurs after helper T cells are activated?

  They divide by mitosis to replicate
• What can activated helper T cells differentiate into?

  Memory cells, cytotoxic T cells, and more helper T cells
• What do cytotoxic T cells do?

  They destroy abnormal or infected cells
• What protein do cytotoxic T cells release?

  Perforin
• What is the function of perforin?

  To create pores in infected cell membranes
• What happens to a cell when perforin creates pores in its membrane?

  It causes cell death
• Why do cytotoxic T cells destroy infected cells during a cold?

  To prevent virus replication
• What are the steps of the cell-mediated response?

  1. Pathogen engulfed by phagocyte
  2. Antigens presented on phagocyte surface
  3. Helper T cells bind to antigens
  4. Helper T cells activate and divide
  5. Differentiate into memory cells or cytotoxic T cells
  6. Cytotoxic T cells release perforin to kill infected cells
• What is the role of memory cells in the immune response?

  To store memory of specific antigens
• What is the result of cytotoxic T cells releasing perforin?

  Cells shrivel or lyse