Lecture 7 Organization of the Immune System Species Resistance humans are resistant to most plant and animal pathogens o Most virus s need a specific target molecule to bind to there is differentiation between the specific target molecules between animals and humans why most dog viruses cannot infect cats or humans etc Innate Immunity o Generalized response always there always active o 1st response that happens occurs immediately o Only slows down growth of the pathogen does NOT clear the pathogen o Holds down the fort until the adaptive response bring in the calvary o 1st line of defense preventing stuff from entering body barriers Outside skin skin o Phagocytosis o Inflammation o Complement Inside cuts scratches etc mucous membranes mucosa Majority of infection go through the mucosa bc they re thinner than Pathogens get gobbled up neutrophils eat pathogens Movement of the cells to the area where the infection is Inflammatory process Neutrophils normally found in the blood stream move into the tissues where infection is occurring Series of protein in the blood that can help tag the bad guy so the immune system knows what to target Flags pathogen immune system can easily recognize the pathogen Adaptive Immunity o Highly specific response takes 2 3 weeks to develop Takes time bc B T cells have to be selected o Completely clears the pathogen o CREATES IMMUNOLOGICAL MEMORY The reason why we vaccinate o Needs to have a specific response o Production of Immunoglobulins aka Antibodies AB done by B cells o Two arms of adaptive immunity Humoral Immunity bloodstream liquid immunity gets everywhere in the body by the b cells responsible for this Immunoglobulins aka Antibodies are proteins dissolved in blood plasma Cell Mediated Immunity t cells responsible for this Functional cells that must interact with each other to do their jobs o Antigen processing presentation Links innate immunity to adaptie immunity Involves MHC major histocompatibility complex Physical Barriers o Skin o Mucosa GI tract Respiratory tract Urogenital tract Eyes Hematopoiesis formation of all blood cells in the human body all cells involved in immune functions o Happens in the red bone marrow long bone o Cells in blood will further differentiate once they reach the tissues Ex b cells will eventually become plasma cells t cells will eventually become effector t cell Cells in blood o b cells o t cells o Neutrophils o Basophils o Eosinophils o Monocytes LEUKOCYTES o Platelets o Erythrocytes ERYTHROCYTES Cells in Tissues o Plasma cells evolved from b cells entering tissues o Effector t cells evolved from t cells entering tissues o NK cells o Mast cells o Dendritic cells evolved from monocytes entering tissues o Macrophages evolved from monocytes entering tissues Antigen presenting cells Antigen presenting cells Immune System Cytokines o Interleukins ILs Signal among leukocytes and other tissues made by leukocytes lymphocytes o Interferons IFs antiviral proteins that may act as cytokines Initially shown to interfere with viral infection proteins that stimulate cells to divide o Growth Factors o Tumor Necrosis Factor TNF secrete fluid into area causing swelling inflammation o Chemokines signal leukocytes to move to areas where they are needed acts on the walls of blood vessels and allows them to Chemotactic cytokines chemoattractant Circulating myeloid cells o Neutrophils 40 75 of WBC o Monocytes 2 10 of WBC o Basophils 1 of WBC o Eosinophils 1 6 of WBC Myeloid cells in tissues o Macrophages o Dendritic cells o Mast cells Secrete histamine Neutrophils o PMNs polymorphonuclear cells single multiple shaped nucleus Strung out nucleus looks like multiple but is just 1 looks like sausage links o MOST ABUNDANT LEUKOCYTE IN THE BLOOD o Short life 1 2 days our bodies are continuously making these in large amounts o MOST ACTIVE PHAGOCYTES Gobble up what they recognize to be foreign o Migrate to areas of inflammation o 30 fold reserve in bone marrow to help fight infections BAND FORMS o MAJOR ROLE IN INNATE IMMUNE RESPONSE ELIMINATE BACTERIA Responds to signals from macrophages Phagocytosis and destruction Phagocytose bad guy destory themselves in the process o White pus in an injury dead neutrophils Monocytes o Longer life span than neutrophils o n u shaped nucleus o Tissue specific differentiation different form depending on what tissue they re in Alveolar macrophage in lung Microglial cells in the brain Langerhans cells in skin Kupffer cells in the liver tissue Macrophages o MAJOR ROLE IN IMMUNE RESPONSE Directly recognizes bacteria PHAGOCYTE Secrete cytokines recruit neutrophils o ANTIGEN PROCESSING AND PRESENTATION TO T CELLS Take a piece of the Ag chop it up inside the cell present that on an MHC molecule on surface of cell MHC molecule gets presented to t cells so the Ag can be recognized next time Some will go back to where t cells are and try to activate the adaptive immune response Eosinophils o Eliminate parasites worms o Acidic granules stain red Basophils o Basic granules stain blue Mast cells NK cells o Innate function o Found in places where pathogens enter the body all connective tissues Skin GI where most pathogens enter the body lungs o Responsible for allergic responses t cells b cells antigen presenting cells dendritic cells and macrophages are required for an adaptive immune response o There to eliminate viruses o In the lymphocyte family Lymphocytes b cells t cells B cell lymphopoiesis o b cells leave the bone marrow almost mature get released into the bloodstream will collect in the lymphatic system o b cells can recognize Ag via an immunoglobulin molecule on the surface of the cell BCR o IF AND ONLY IF they get selected turn in to plasma cells produce immunoglobulins that get released into the bloodstream o Majority found in the lymphatic system lymph nodes T cell lymphopoieis o Leave bone marrow as immature precursor cells Enter thymus for final development o Make their own Ag receptors TCR develops the ability to recognize pieces of the Ag pathogen o TCR CANNOT RECOGNIZE THE Ag DIRECTLY ONLY RECOGNIZE IT IS THE Ag IS PRESENTED TO IT ON AN MHC MOLECULE BY A DIFFERENT CELL o Macrophages DC b cells present pieces of the Ag to the TCR allows TCR to recognize it o Majority found in lymph nodes Dendritic cells o Residence in most tissues o MAJOR ROLE IN IMMUNE RESPONSES Move Ag to secondary lymph tissues from infection site Ag processing and presenting to t cells MOST IMPORTANT CELL THAT DOES THIS Primary