BY 124 1st Edition Lecture 19 Outline of Last Lecture Chapter 43I. Things that the immune system must doII. Types of immunitya. Innateb. AcquiredIII. Lymphatic systemOutline of Current Lecture Chapter 43 ContI. To rememberII. B cellsIII. To “kill” toxins with B cell systemIV. Classes of AntibodiesV. Antibodies are proteinsVI. Primary and Secondary ResponseVII. Active ImmunityVIII. Passive ImmunityIX. Cytotoxic T Cells X. Figure 43.20 XI. When Immune Response gets confusedCurrent LectureChapter 43 (Cont.)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.I. To remember:a. MHC cellsb. T cells – cytotoxic/effector or Helper T must see a self AND non-self marker II. B cellsa. Differ in antigen specificityi. Binds to different epitopes b. Forms a clone that will start to secrete antibodiesc. Effector cells are what actually do the attackingd. B cells are looking for something that is freei. If it is found in the cell then T cells will be used, not B cellse. Figure 43.14 – humoral responsei. Found in fluidsii. If toxin is found free within fluids then B cells will be activatediii. Some do not need T cells → “T-independent” 1. Do not form memory cells 2. BUT most are T-dependentiv. B cells bind to antigen by antigen receptors → multiply → form more plasma cells that release the antibodiesf. Figure 4.12 - T-dependent B cellsi. Dendritic cells – antigen-presenting cells1. Important in first encounter with antigen2. Immune cells3. Main function – process antigen to create antigen material to be presented on surface of cell → Activates cytokines → calls in B cells → B cells bind to ii. Helper T cell sends out chemicals (when it binds) that calls out for B cellsiii. T-dependent B cells will turn into plasma cells and memory cells iv. B cell binds to receptor on T cell which then releases cytokines to help clone B cells will then turn into plasma cells and memory B cellsg. Figure 43.18i. Better representation of above figureIII. To “kill” toxins with B cell system (Figure 4.19)a. Neutralization (Figure 43.19)i. Antibody “blocks” docking sites in virus so that it cannot get into the cell and replicateb. Osponizationc. Activation of complement system and pore formationi. Antibodies form a membrane attack complex that allows water to get in that makes cell explodeIV. Classes of Antibodiesa. IgM (pentamer) – (Ig – immunoglobin)i. 1st Ig class that appears on scene after exposure, then it gradually declinesas time goes onii. Promotes neutralization and cross-linking of antigensiii. Good at activating complement systemb. IgG (monomer) i. Most abundantii. Only Ig that crosses the placenta1. Passive immunity to fetusc. IgA (dimer)i. Present in bodily secretions like tears, saliva, breast milkii. Helps with protecting fetus too (passive immunity)d. IgE (monomer)i. Present in low concentrationii. Triggers release of mast cells and basophils of histamine that causes allergic reactione. IgD (monomer)i. Present primarily on surface of “virgin” B cells that is important in deciding clonal selection (plasma or memory cell)V. Antibodies are proteins (Figure 43.13)a. 40 V genes, 5 J genes, 5 C genesb. Start linking V (variable) genes together, add J (joiner) gene, and then add C (constant) gene = exon shuffling c. Transcribe above into pre-mRNA → RNA processing → translation → creation of antigen receptorVI. Primary and Secondary Response (Figure 43.15)VII. Active Immunity – You make your own antibodies a. Can also get by vaccinationVIII. Passive Immunitya. Usually comes from momi. Placentaii. Breast milkb. Does not lasti. Eventually you will have to “fight” to make your ownIX. Cytotoxic T Cells (Figure 43.17)a. Only works when they see a self and non-selfb. Places marker on MHC 1 (self) → helps bind accessory protein → releases cytokines → lyses your cells that have been infected X. Figure 43.20 – everything comes togethera. Really good figure to studyb. Antigen presenting cellsi. Dendritic cell if first exposureii. Macrophage if second exposurec. Memory cells (B and T) are pretty much the same. Their main function is just to remember past infections and fights and help you fight more efficiently the second time you are exposedXI. When Immune Response gets confuseda. Rheumatoid arthritis – attacks joints b. Rheumatic Heart Disease - antigen on heart valves signals immune response andstarts attacking heart valvesc. Lupus – nucleus (?) in cellsd. Graves – thyroide. Allergies (Figure 43.22)i. IgE → histamines release granulesii. Anaphylactic shock – severe inflammation of blood vesselsf. AIDS – Helper T cells get attacked → ruins immune