Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings PowerPoint ® Lecture Slide Presentation prepared by Christine L. Case Microbiology B.E Pruitt & Jane J. Stein AN INTRODUCTION EIGHTH EDITION TORTORA FUNKE CASE Chapter 17 Specific Defenses of the Host: The Immune Response
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Differentiate between innate and acquired immunity.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Specific Defenses of the Host: The Immune Response Innate (nonspecific)Defenses against any pathogen, genetically predetermined resistance (gender, age, nutrition) ImmunitySpecific antibody and lymphocyte response to an antigen (counteract infection) Antigen (Ag)A substances that causes the body to produce specific antibodies or sensitized T cells Antibody (Ab)Proteins made in response to an antigen Differentiate between immunity and nonspecific resistance.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Terminology Acquired immunityResistance to infection during life of host Naturally acquiredResulting from infection, may be active immunitylong-lasting SerologyStudy of reactions between antibodies and antigens AntiserumGeneric term for serum because it contains Ab GlobulinsSerum proteins Gamma ( ) globulinSerum fraction containing Ab
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Serum Proteins – separation by gel electrophoresis Figure 17.2 Immune serum globulin or gamma globulin
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings The Immune Response Acquired immunityDeveloped during an (vaccination)individual's lifetime Humoral immunityInvolves Ab (antibodies) (in body fluids)produced by B cells Defend against bacteria, viruses, toxins in blood plasma and lymph Cell-mediated immunityInvolves T cells (certain lymphocytes) Response to intracellular bacteria, viruses, parasites, transplanted tissue, cancer cells Differentiate between humoral (antibody-mediated) and cell-mediated immunity.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Acquired Immunity Naturally acquired active immunity Resulting from infection Naturally acquired passive immunity Transplacental or via colostrum Artificially acquired active immunity Injection of Ag (antigen - vaccination) Artificially acquired passive immunity Injection of Ab (antibody) or antiserum Contrast the four types of acquired immunity.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Antigenic Determinants (epitopes) Antibodies recognize and react with antigenic determinants or epitopes (specific regions on surface of antigen). Antigens cause body to produce specific antibodies. Are components of invading microbes generally. Figure 17.3 Define antigen and hapten.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Haptens Figure 17.4 Hapten is a molecule too small to stimulate antibody formation by itself, until combined with larger carrier molecule like a serum protein, becoming an antigen.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Antibody Structure (Immunoglobulin) – protein produced by B cells in response to antigen Figure 17.5a-c Explain the function of antibodies and describe their structural and chemical characteristics.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Monomer (single bivalent antibody unit) 80% of serum antibodies Fix complement In blood, lymph, intestine Cross placenta Enhance phagocytosis; neutralize toxins & viruses; protects fetus & newborn Half-life = 23 days IgG antibodies Name one function for each of the five classes of antibodies.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Pentamer (5 monomers) 5-10% of serum antibodies Fix complement In blood, lymph, on B cells Agglutinates microbes; first Ab produced in response to infection Half-life = 5 days IgM antibodies
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Dimer 10-15% of serum antibodies In secretions Mucosal protection Half-life = 6 days IgA antibodies
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Monomer 0.2% of serum antibodies In blood, lymph, on B cells On B cells, initiate immune response Half-life = 3 days IgD antibodies
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Monomer 0.002% of serum antibodies On mast cells and basophils, in blood Allergic reactions; lysis of parasitic worms Half-life = 2 days Involved in allergic reactions IgE antibodies
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Humoral (fluid) immunity involves antibodies produced by B cells Bone marrow gives rise to B cells. Mature B cells migrate to lymphoid organs. A mature B cells recognizes epitopes (antigen receptor). Clonal Selection Name the function of B cells.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Differentiation of T cells and B cells, both from stem cells in adult red bone marrow or fetal liver
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Apoptosis – normal B cell below, B cell above undergoing apoptosis (bubble- like blebs) Programmed cell death to prevent overpopulation of B cells Define apoptosis, and give a potential medical application.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Clonal Selection & Differentiation of B cells Figure 17.8 Each particular B cell recognizes only one type of antigen, activating the B cell Produces clone of plasma cells (antibodies) and memory cells Describe the clonal selection theory.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Self-tolerance Antigen-antibody complex can result in agglutination, inflammation, lysis Body doesn't make Ab against self Clonal deletion The process of destroying B and T cells that react to self antigens Amount of antibody in serum called antibody titer Explain how an antibody reacts with an antigen; identify the consequences of the reaction.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Protective Mechanism of Ag-Ab Binding Figure 17.9 Result of antigen- antibody binding Tags foreign cells and molecules for destruction by phagocytes and complement (serum proteins for phagocytosis and lysis of cells)
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Primary and secondary immune response to antigen IgM appears first (primary response) IgG follows and provides longer-term immunity (high antibody titer) Figure Distinguish a primary from a secondary immune response.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Monoclonal Antibodies Hybridomas are produced by fusing a cancer cell with an Ab-secreting plasma cells The hybridoma cell culture is immortal and produces monoclonal Abs (Mabs) – serologic identification tests, prevent tissue rejections Immunotoxins: Mabs conjugated with a toxin to target cancer cells Chimeric Mabs:Genetically modified mice that produce Ab with a human constant region Humanized Mabs: Mabs that are mostly human, except for mouse antigen-binding Define monoclonal antibodies and identify their advantage over conventional antibody production.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Monoclonal Antibodies
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Interleukin-1Stimulates T H cells Interleukin-2Activates T H, B, T C, and NK cells Interleukin-12Differentiation of CD4 cells -InterferonIncrease activity of macrophages ChemokinesCause leukocytes to move to an infection Immune system cells communicate via cytokines Identify at least one function of each of the following in cell- mediated immunity: cytokines, interleukins, interferons.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Chemical messengers: Cytokines Cells of immune system communicate via cytokines Interleukins (IL) are cytokines between leukocytes Interferons protect cells against viruses Chemokines cause leukocytes to move to infection site
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Specialized lymphocytes, mostly T cells, respond to intracellular Ags After differentiating in the thymus, T cells migrate to lymphoid tissue T cells differentiate into effector T cells when stimulated by an Ag Some effector T cells become memory cells Cell-Mediated Immunity
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings M (microfold) cells in Peyer's patches which contains Dendritic cells which are antigen-presenting cells and T cells Pathogens entering the gastrointestinal or respiratory tracts pass through:
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Dendritic cells present antigens Figure 17.12
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Helper T Cells (CD4, T H ) T H 1Activate cells related to cell-mediated immunity T H 2Activate B cells to produce eosinophils, IgM, and IgE Cytotoxic T Cells (CD8, T C ) Destroy target cells with perforin T Cells Describe at least one function for each of the following: T H 1 cell, T H 2 cell, T C cell, T D cell, T S cell, APC, MHC,activated macrophage, NK cell.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Delayed Hypersensitivity T Cells (T D ) Associated with allergic reaction, transplant rejection, and tuberculin skin test Suppressor T cells (T S ) Turn off immune response when Ag no longer present T Cells
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Helper T Cells Figure 17.13
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Cell-mediated Cytotoxicity Figure 17.14
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Nonspecific Cells – Activated Macrophages Activated macrophages: Macrophages stimulated by ingesting Ag or by cytokines Natural killer cells: Lymphocytes that destroy virus- infected cells, tumor Figure 17.15
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings T-independent Antigens B cell T-indep. antigen has repeating units that cross-link several antigen receptors on same B cell Compare and contrast T-dependent antigens and T-independent antigens.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Describe the role of antibodies and NK cells in antibody-dependent cell- mediated cytotoxicity.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings T-independent Antigens Figure How helper T cells may activate B cells to make antibodies against T- dependent antigens
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Antibody-Dependent Cell-Mediated Cytotoxicity Figure Eosinophils adhering to larval stage of parasitic fluke Compare and contrast cell-mediated and humoral immunity.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Duality of immune system