Physio exam

• Names and functions of different white blood cells

  • Neutrophils - attack bacteria
  • Lymphocytes - specific immunity
  • Monocytes - become macrophages
  • Eosinophils - attack parasites
  • Basophils - inflammation
• Names and functions of different types of lymphocytes

  • T-cells: cell-mediated immunity, made in thymus
  • Cytotoxic Tc - do the killing
  • Helper Th - secrete factor to proliferate cytotoxic cells
  • Suppressor Ts - kick in after infection
  • B-cells: antibody mediated immunity, make antibodies, develop into plasma cells
  • NK cells: natural killer cells, immune surveillance
  • Memory T cells - can easily become Tc and Th cells to quickly take care of pathogen
• Types of (innate) nonspecific defenses

  1. NK Cells - notice different proteins on infected/cancerous cells, create immune synapse, secrete perforin to break open cell

  2. Interferons - small proteins released by macrophages or activated lymphocytes that interfere with viral replication

  3. Complement System - 1) Attracts phagocytes 2) stimulates phagocytosis 3) destroy plasma membrane 4) promotes inflammation

  4. Fever - Activated by pyrogens acting on hypothalamus, stimulates metabolism and raises body temperature

  5. Inflammation - Mast cells secrete Histamine that increases blood flow, brings in more cells, slows spread of pathogens
• Active immunity


  Requires exposure: natural, getting disease and building antibodies or vaccination, creates memory cells
• Passive immunity


  Receives protection from another source, e.g. breast milk, placenta, immunotherapy, temporary
• Classes of antigen presentation

  • Class 1 MHC - expressed by all cells, present to Tc and Ts cells
  • Class 2 MHC - expressed by antigen presenting cells, present to Th cells
• How COVID-19 vaccine activates antibody production


  Puts a little of the virus into you, body makes memory cells and antibodies to recognize it easily in the future. RNA vaccine copies and presents spike protein to helper T cells.
• T cell receptor


  Cell surface recognizer on T cells
• Activation of CD8, CD4 T cells


  1. Tc have random cell surface recognizer

  2. Self is eliminated

  3. Non-self goes into blood

  4. Needs costimulation

  5. CD = cluster of differentiation
• CD8 T cells (Tc)


  • Activated by exposure to antigen bound to MHC 1
  • Activation causes more Tc cells to proliferate and go find more of the same antigen
  • Tc can kill by secreting perforin, cytokines, lymphotoxins
• CD4 T cells (Th)


  • Activated by antigen binding to MHC 2
  • They then divide to produce more helper and memory Th cells
  • Th cells secrete cytokines and stimulate cell-mediated (Tc) and antibody-mediated (B cells)
• How Covid-19 vaccine activates antibody production

  1. Puts a little of the virus into you

  2. Body makes memory cells and antibodies to recognize it easily in the future

  3. RNA vaccine: Spike protein is copied and presented to helper T cell
• B cell activation


  1. Every B cell has its own antibody that can bind to a certain antigen

  2. When bound, antigen enters B cell through endocytosis and is presented on surface with MHC 2

  3. Activated T cell with same antigen can then activate and secrete cytokines to promote B cell activation and stimulation

  4. B cells become plasma cells that secrete large amounts of antibodies