BIOL 320 1 st Edition Lecture 12 Outline of Last Lecture I Specific Lymphoid Tissues II Lymphatic Pathology III Developmental Aspects of Lymphatic System I Immune System a Functions b Innate Defenses i Surface Barriers ii Internal Defenses c Adaptive Defenses Outline of Current Lecture II Internal Defenses a Tissue Injury Healing b Phagocytic Mobilization III Adaptive Defenses a Antigens b Cells of Adaptive Immune System c Humoral Immune Response d Cell Mediated Immune Response e Homeostatic Imbalance Current Lecture Innate Defenses Internal Defenses o Tissue Injury Healing o Phagocytic Mobilization 1 Leukocytosis neutrophils enter blood from bone marrow 2 Margination neutrophils cling to capillary wall 3 Diapedesis neutrophils flatten and squeeze out of capillaries 4 Chemotaxis neutrophils follow chemical trail o Inflammatory chemical diffusing from the inflamed site act as chemotactic agents o Antimicrobial Protein Interferons help neighboring cells resist attack medical use Hepatitis C and Herpes virus Complement amplifies inflammatory response Fever induced by pyrogins pyrogins act on hypothalamus to raise temperature sequester iron and zinc in liver and spleen starve microbes and allow unfavorable temperature for microbes Steps for Interferon Response o 1 Virus enters cell o 2 Interferon genes switch on o 3 Cell produces interferon molecules o 4 Interferon binding stimulates cell to turn on genes for antiviral proteins o 5 Antiviral proteins block viral production Adaptive Defenses Key Features o 1 SPECIFIC o 2 SYSTEMIC o 3 MEMORY Divisions o 1 HUMORAL o 2 CELLULAR Functions o 1 Immobilize neutralize destroy o 2 Amplify inflammatory response o 3 Activates complement Self cells cover selves with major histocompatibility complex MHC glycoprotein self antigen unique to individual MHC I on all body cells MCH II only on certain tissue cells Antigens o Antigens can mobilize adapt Defense provoke immune response o Complete Antigens Immunogenicity stimulate lymphocyte proliferate lymphocytes Reactivity can react with lymphocytes antibodies o Haptens small molecules only immunogenic when attached to body proteins o Antigenic Determinants where antibodies lymphocyte receptors bind Ex Knee replacements metals and plastics are large simple molecules that aren t immunogenic and don t have binding sites antigenic determinants Cells of Adaptive Immune System o Requires activation to interpret antigens in lymphoid tissues o CELLS B Lymphocytes recognize bind to foreign antigens in fluids Produced and mature in bone marrow Oversee humoral immune response in response to bloodstream T Lymphocytes recognize fragments of foreign antigens on APCs antigen preventing cells Produced in bone marrow Mature in thymus Oversee cell mediated immune response Selection process eliminate cells that attack self want a population that recognize foreign antigens well and not as picky with self cells Antigen Presenting Cells Functions o Engulf foreign cells o Present foreign antigen on own plasma membrane to be recognized by T cells Major APCs o Dendritic cells DC o Macrophages o Activated B cells Major initiators of adaptive immunity DCs macrophages secrete particles that activate T cells Activated T cell response o 1 Speed DC maturation o 2 Stimulate macrophage activation o Immunocompetence have the ability to carry out immune response when properly stimulated 1 Lymphocytes destined to become T cells migrate in blood to the thymus and develop immunocompetence there B cells develop immunocompetence in red bone marrow 2 Immunocompetent but still na ve lymphocytes leave the thymus and bone marrow They seed the lymph nodes spleen and other lymphoid tissue where they encounter their antigen 3 Antigen activated immunocompetent lymphocytes effector cells and memory cells circulate continuously in the bloodstream and lymph and throughout the lymphoid organs of the body Humoral Immune Response Cell Mediated Immune Response Homeostatic Imbalance