BIOL 2002C 1st Edition Lecture 12 Current Lecture Define antigen antbody generatng Describe the function of major histocompatibility complex MHC molecules in immunity markers on our own cells self markers also glycoproteins No 2 people have the same exact MHC molecules except for identcal twins Class I MHC found in ALL nucleated body cells most are 2 chains 1 polymorphic and 1 constant Class II MHC found on immune system only 2 polymorphic chains Path of foreign antigens foreign antgen taken to rough ER where the MHC I molecules are antgens combine with MHC class I then transported to Golgi packages and transported in vesicle to plasma membrane foreign antgens combine with MHC class I molecules and stmulate destructon Antigen Presenting Cells Macrophages most common in our body free or fixed originally monocyte Kuppfer cells in liver specific kind of fixed macrophage Microglia in CNS neuroglia cell Dendritic cells epidermal in skin use pinocytosis Antibody mediated immunity B lymphocytes and plasma B cells need helper T cells Cell mediated immunity cytotoxic T cells need help t cells their functon is removal of infected abnormal cells they removal is done by actual T cells thus cell mediated Name the 2 classes of T cells their markers MHC proteins and functions Regulatory T cells Helper T cells have CD4 markers in additon recognize foreign antgens presented by Class II MHC they divide and secrete cytokines that help coordinated specific and nonspecific defense stmulate both cell mediated and antbody mediated immunity memory T helper cells are also produced Effector T cells Cytotoxic T cells Have CD8 markers can recognize and be actvated by Class I MHC proteins they kill infected damage cells memory cytotoxic T cells will be formed These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Cell mediated immune response A APC macrophages has engulfed foreign cell and it processes and presents foreign Ag on its MHC II markers B B Helper T cell Actvaton i Step 1 Antgen binding antgen binds w MHC II and specific t cell receptor ii Step 2 Co stmulaton by cytokines stmulates leukopoiesis also co stmulaton with CD4 binds to the MHC II molecules C Clonal selecton of Helper T cells exact copies many of them Helper T cells are critical to the success of both cell and Ab mediated immune responses Cytotoxic T cells can get involved Tc s circulate between blood lymph and lymphoid organs looking for a specific foreign Ag especially viral presented by the Class I MHC markers of regular body cells Tc s after co stmulaton by Helper T cells cytokines IL 2 will divide also producing memory Tc s Tc s then destroy bad cells by perforin similar to complement proteins Where and how do lymphocytes become immunocompetent T cells go to thymus for maturaton B cells mature in the bone marrow Both are produced in the bone marrow Antibody mediated immune response A B cell activation The immunocompetent but stll na ve B cell virgin B cell travels in the blood lymphatc and tssues looking for the Ag it is programmed to recognize when it s Ab finds its matching Ag it binds to it and bring the Ag inside by receptor mediated endocytosis the Ag is processed and displayed by the Virgin B cell s MHC II marker the appropriate actvated helper T cell binds to the virgin B cell s MHC II factor Ag and provides co stmulaton by releasing lymphokines and the CD4 marker binding B Co Stimulation many of these new B cells become plasma B cells and produce release lots of antbodies What organelles would be important Rough ER golgi lysosomes because fuse with vesicle brought in Diagram the structure of an antibody Fig 22 19 and describe the effects produced by antibodies Fig 22 20 a Inactvates antgen b Binds antgens together c Actvates complement cascade d Initates release of inflammatory chemicals by e Facilitates phagocytosis Name the 5 classes of antibodies and the major function of each Table 22 5 a IgM this is the first type secreted when B cell is actvated it s the type that RBC Ab s ant A and ant B are so clumping can easily occur can actvate complement proteins b IgD partcipates in antgen recogniton and the actvaton process c IgG about 80 of all Ab s targetng viruses bacteria etc can cross placenta ant Rh actvates complement B cell shifts from producton of IgM to IgG during immune response d IgA found primarily in glandular secretons like mucous tears saliva attach to pathogens before they gain access to internal tssues e IgE Secreted by plasma cells in skin GI and respiratory tracts mucosae tonsils attaches to antgens on surfaces of mast cells and stmulates them to release histamine allergic reactons role in defense against parasites Discuss the primary and secondary responses to an antigen and explain the basis for long lasting immunity memory cells Fig 22 21 a Primary response actvated first tme a pathogen is encountered produces limited of Ab s b Secondary response actvated 2nd tme or later much faster response than primary produces MANY memory B cells Memory cells Memory T cells will respond and divide to cytotoxic and helper T cells