immunity

• what triggers an immune response?

  foreign antigens
• steps of phagocytosis?


  1.phagocyte recognizes antigens on a pathogen

  2.phagocyte engulfs the pathogen

  3.pathogen held in phagocytic vacuole

  4.lysosome fuses with phagocytic vacuole and breaks down the pathogen

  5.phagocyte presents the pathogens antigens on its surface
• types of t-cells?


  t-helper , cytotoxic t-cells ,
• what cells do phagocytes activate?

  t-cells
• what do t-cells activate?

  b-cells
• types of b-cells?

  plasma and memory
• what does the cellular response include?

  t-cells and phagocytes
• what does the humoral response include?

  b-cells ,clonal selection , monoclonal antibodies
• what is the structure of an antibody?

  light chains , heavy chains, variable regions , constant regions , hinge protein and disulphide bridges
• why do vaccines not work on all pathogens?

  antigen variation , the antigens activate the immune response therefore when they change the memory cell will no longer be able to fight them
• what is active immunity?

  when your immune system makes its own antibodies
• what is passive immunity?


  when you are given antibodies from another organism
• what are monoclonal antibodies?

  a single group of genetically identical antibodies made from b-cells
• what are monoclonal antibodies used for in medicine?

  cancer cells , pregnancy tests , ELISA tests
• structure of HIV?


  attachment proteins , capsid , lipid envelope, reverse transcriptase , genetic material , DNA integrase
• how does HIV replicate?

  1.attachment proteins attach to cd4 receptors on t-helper cell

  2.capsid released into cell

  3.reverse transcriptase turns viral RNA into DNA

  4.intergrase inserts this into the human DNA

  5.viral proteins are created and assembled into new viruses
• steps of cell mediated response?


  1.helper t-cells have receptors which attach to APCs

  2.helper t-cells activate and divide by mitosis to make clones

  3.clonded cells differentiate
• steps of the humoral response?


  1.b-cells stimulated by t-helper

  2.clonal expansion + differentiation

  3.b-cells undergo mitosis make memory and plasma cells

  4. plasma cells secrete antibodies
• What is the first line of defense against pathogens?

  Chemical and physical barriers
• What is the role of white blood cells in the immune system?

  They respond to pathogens
• What type of response do phagocytes have?

  Nonspecific response
• What is another name for phagocytes?

  Macrophages
• How do phagocytes respond to non-self cells?

  They destroy them regardless of type
• What happens to a pathogen once it is engulfed by a phagocyte?

  It is contained within a phagosome
• What is a phagosome?

  A vesicle containing an engulfed pathogen
• What enzyme is released by lysosomes to destroy pathogens?

  Lysozyme
• What is the function of lysozyme?

  To hydrolyze and destroy pathogens
• What happens to the soluble products after a pathogen is destroyed?

  They are absorbed and recycled
• What do phagocytes become after presenting antigens?

  Antigen presenting cells
• What type of mechanism is phagocytosis?

  Nonspecific mechanism
• How do phagocytes respond to different types of foreign particles?

  They respond the same way to all
• What is the role of lysosomes in phagocytosis?

  To fuse with phagosomes and release enzymes
• Where can phagocytes be found in the body?

  In blood and tissues
• What attracts phagocytes to pathogens?

  Chemicals released by pathogens
• How does phagocytosis differ from other immune responses?

  It is a nonspecific response to all pathogens
• What are the steps of phagocytosis?

  1. Phagocyte detects chemicals from pathogens.
  2. Phagocyte binds to the pathogen via receptors.
  3. Phagocyte engulfs the pathogen, forming a phagosome.
  4. Lysosome fuses with the phagosome.
  5. Lysozyme is released to destroy the pathogen.
  6. Soluble products are absorbed and recycled.
  7. Antigens are presented on the cell surface.
• What are the characteristics of phagocytes?

  • Type of white blood cell
  • Conduct phagocytosis
  • Nonspecific immune response
  • Found in blood and tissues
  • Engulf and destroy pathogens
• What is the significance of phagocytosis in the immune system?

  • First line of defense against pathogens
  • Engulfs and destroys foreign particles
  • Presents antigens to activate other immune responses
  • Helps maintain tissue homeostasis
• What are monoclonal antibodies?

  Antibodies created to be identical and specific
• What is the advantage of using monoclonal antibodies in cancer treatment?

  They target only cancer cells, sparing normal cells