PSL301H Blood and Immune System Adaptive Immunity PDF

PSL301H—Blood and Immune System Adaptive Immunity: T cells and the Immune System in Health and Disease Learning outcomes Describe T cell activation Give examples of when our immune system helps us and when it does not Describe the process of immediate hypersensitivit...

PSL301H—Blood and Immune System Adaptive Immunity: T cells and the Immune System in Health and Disease Learning outcomes Describe T cell activation Give examples of when our immune system helps us and when it does not Describe the process of immediate hypersensitivity Explain why knowing your blood type important Explain the connection between Rh factor and pregnancy Provide the immunological basis of how doctors prevent hemolytic disease of the newborn  Defence against pathogens Innate Immunity rapid, non-specific Adpative Immunity slower, specific Figure from Interactive Physiology  Recall: T cell receptors bind to antigens that are bound to MHC T cell receptor Viral antigen Major histocompatability complex (MHC) Figure from Interactive Physiology  T cell activation 1 Cell binds to 2 Signal transduction T lymphocyte. activates MHC-antigen T lymphocyte. complex T-cell receptor MHC receptor T lymphocyte Copyright © 2010 Pearson Education, Inc. Types and function of T cells  MHC class II Located on dendritic cells, macrophages and B cells Present exogenous antigen Activate helper T cells Figure from Martini (2006) Fundamentals of Dendritic cell Anatomy and Physiology  Activation of helper T cells Co-stimulation Cytokines will stimulate – helper T cells, cytotoxic T cells and B cells Figure from Martini (2006) Fundamentals of Anatomy and Physiology  Recall activation of B cells T cell receptor MHC class II B cell receptor B cell Helper T cell Antigen + cytokines  MHC class I Located on all nucleated cells Present endogenous antigen Activate cytotoxic T cells Figure from Martini (2006) Fundamentals of Anatomy and Physiology Infected/cancerous cell or dendritic cell  Activation of cytotoxic T cells Dendritic cell + IL-2, interferon  By activating Fas Infected cell Figure from Martini (2006) Fundamentals of Anatomy and Physiology Putting it together: Immune response to a virus  Immune system: Friend or foe? Immune response 1. 2. Grafted organ 3. Unmatched blood 4. Allergy Immune response to a nonpathogenic antigen Two types: Immediate hypersensitivity Delayed hypersensitivity Immediate hypersensitivity Memory B cells Re-exposure A very strong and rapid response Can result in local rashes or most severely anaphylaxis Memory T cells  Blood types and blood donation ABO blood groups 42% 9% 3% 46% Rh blood group Europeans: Rh positive = 85%; Rh negative =15% Asians, Africans, Native Americans: Rh pos= 99%; Rh neg = 1% Why is knowing your blood type important? Cross-reactions occur during blood transfusions if antigens on donor RBC meet antibodies in recipient’s plasma Figure from Martini (2006) Fundamentals of Anatomy and Physiology 16  For example: Type B blood donor to Type A recipient type B antigens on anti-B antibodies in donor’s red blood cells recipient 17 Predict what would happen with the following combinations of donors and recipients Donor Recipient O A B AB O (anti-A, anti-B) - + + + A (anti-B) - - + + B (anti-A) - + - + AB - - - - + = agglutination - = no agglutination  What is the connection between Rh factor (D antigen) and pregnancy? Unlike the ABO blood group, Rh- individuals do not normally have anti-D antibodies, but these can develop by: transfusion of Rh- individual with Rh+ (D antigen) blood pregnancy Rh- mother and Rh+ baby 19  Rh antigen and pregnancy Hemolytic disease of the newborn: Anemia, jaundice, enlarged liver and spleen, and severe edema. Figure from Martini (2006) Fundamentals of Anatomy and Physiology Rh+ means that the red blood cells have the D antigen 20  How do doctors prevent hemolytic disease of the newborn? Inject anti-D antigen antibodies into Rh- mother during and following her pregnancy The antibodies bind to and remove fetal red blood cells in mother’s bloodstream before they can trigger an immune response in the mother Thus, B cells are not activated in the mother and no immunological memory of the D antigen is acquired Therefore in a subsequent pregnancy with an Rh+ fetus, the mother does not produce anti-D antigen antibodies upon exposure to fetal red blood cells with D antigen  Summary: Cells of the immune system Types of Cells Monocytes Lymphocytes Basophils Neutrophils Eosinophils Dendritic Cells Mast Cells Macrophages Plasma Cells Classifications Phagocytes Granulocytes Cytotoxic Cytotoxic cells cells (some types) Antigen-presenting cells % of WBCs Rare 50–70% 1–3% 1–6% 20–35% NA in blood Subtypes and Called “polys” Called the mononuclear B lymphocytes Also called nicknames or “segs.” phagocyte system Plasma cells Langerhans cells, Immature Memory cells veiled cells forms called T lymphocytes “bands” or Cytotoxic T cells “stabs.” Helper T cells Natural killer cells Primary Release chemicals Ingest and Destroy Ingest and destroy Specific responses Recognize pathogens function(s) that mediate destroy invaders, invaders. to invaders, including and activate other inflammation and invaders particularly Antigen presentation antibody production immune cells by allergic responses antibody- antigen presentation coated parasites Summary Repressor T cells inhibit Figure from Martini (2006) Fundamentals of Anatomy and Physiology Summary T cells are activated through the binding of the T-cell receptor to MHC bound to antigen Immediate hypersensitivity is an exaggerated immune response to an allergen and involves IgE antibodies Knowing your blood type can prevent transfusion reactions. Remember to think about the donor’s red blood cells and the recipient’s antibodies Rh- individuals who are pregnant with an Rh+ fetus are treated with anti-D antibodies to prevent hemolytic disease of the newborn