Chapter 15

• Innate immunity


  Has an immediate response, has a low specificity and diversity, and does not have a memory response
• Adaptive immunity


  Has a lag phase, the response takes a couple days, has a high specificity and only targets the pathogens that initiated the response, has a wide range of diversity and results in a wide range of antigens and has a memory response, repeat exposure intensifies response
• Th cell markers


  • CD4 and TCR
• Cytotoxic T cells markers

  • TCR and CD8
• B cell markers


  • BCR, MCHII
• T memory cells markers

  • CD4
• T helper cells Signal 1


  APC presents pathogen on MHCII to Th cell TCR bind to the Antigen
• T helper cells Signal 2

  CD4 binds to MHCII to confirm is self MHC
• Cytotoxic T cells Signal 1

  MHCI presents foreign antigen to TCR TCR binds to foreign antigen
• Cytotoxic T cells Signal 2

  CD8 from cytotoxic T cell reaches over and checks if is self cell
• B lymphocytes Signal 1

  B cell receptor binds to foreign receptor
• B lymphocytes Signal 2

  Antigen is put onto MHCII on B cell TCR binds with foreign receptor CD4 confirms MHCII is self
• Immunologic Diversity


  More than 500 DNA segment performDNA reagrangment randomly which creates an receptor to 1 antigen. This occurs when the B and T cells are maturing in the bone marrow and thymus respectively
• Phases of B and T cells

  1. Within the bone marrow stem cells turn into granulocytes and agranulocytes

  2. In the agranulocytes lymphocytes differentiate into B and T cells

  3. The B cells remain in the bone marrow and T cells migrate to the thymus to mature

  4. During maturation B and T cells go through DNA rearrangement and develop their receptors

  5. Both B and T cells migrate to the lymphoid organs and circulation to start doing their job as leukocytes
• Clonal deletion


  Killing of lymphocyte clones that recognize and bind to self antigens. (Prevents autoimmune reactions)
• Clonal selection


  Where only the cell that has the receptor to an antigen will recognize it and be able to bind, be activated and proliferate. This prevents the binding of cells that should not be binding together such as autoimmune reactions
• Clonal expansion


  Rapid proliferation of the clone that recognized its antigen and was activate— all sunsequent daughter cells have identical specificity. This is important because it develops memory cells as well as other types of b and t cells
• B cells


  • Produce memory cells and plasma cells
• T cells


  • Tc,T1,T2,T17, Treg and TMcells
• Memory cells


  Remember the antigen so next time the response will be quicker and stronger
• Plasma cells


  Secrete antibodies which help fight disease and infection
• Tc cells


  Destroy and kill infected and diseased self cells
• T1 cells


  Drain back into the blood at the thoratic duct and tell phagocytes to keep going
• T2 cells


  Activate B cells
• T17 cells


  Increase inflammation
• Treg cells


  Decrease inflammation and help immune tolerance
• Tm cells


  Remember antigen so next time the response will be quicker and stronger
• IgG

  Cross the placenta and are the most prevalent
• IgA


  Secreted and leave the body and is a dimer. Can be secreted in breast milk and the gut
• IgM


  The first to be excreated and are a pentomer. Is the second most prevalent. Is a BCR
• IgE


  Fight against allergies and helminths
• IgD


  Is a BCR
• Aggulation


  Clumping by the antibody binding to 2 of the same antigen. This makes the antigen more attractive to phagocytes. Do not bind on ABS
• Neutralization


  Exotoxin and viruses are bound by antibodies
• Oppsonization


  Antigen is coated with antibodies. This makes the antigens more attractive to the phagocytes