Transcript Chapter 17b
TORTORA • FUNKE • CASE Microbiology AN INTRODUCTION EIGHTH EDITION B.E Pruitt & Jane J. Stein Chapter 17, part B Specific Defenses of the Host: The Immune Response The Results of Ag-Ab Binding Figure 17.9 • Is the amountAntibody of Ab in serumtiter: Figure 17.10 Another look Ab Titer Total Ab 1o Ag IgG Ab IgM Ab 2o Ag Days After Immunization 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) • 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 Monoclonal Antibodies Figure 17.11 Immune system cells communicate via cytokines • Interleukin-1 Stimulates TH cells • Interleukin-2 Activates TH, B, TC, and NK cells • Interleukin-12 Differentiation of CD4 cells • -Interferon Increase activity of macrophages • Chemokines Cause leukocytes to move to an infection Cell-Mediated Immunity • 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 Pathogens entering the gastrointestinal or respiratory tracts pass through: • M (microfold) cells in • Peyer's patches which contains • Dendritic cells which are antigenpresenting cells and • T cells Dendritic cells present antigens Figure 17.12 T Cells • Helper T Cells (CD4, TH) – TH1 Activate cells related to cell-mediated immunity – TH2 Activate B cells to produce eosinophils, IgM, and IgE • Cytotoxic T Cells (CD8, TC) – Destroy target cells with perforin T Cells • Delayed Hypersensitivity T Cells (TD) – Associated with allergic reaction, transplant rejection, and tuberculin skin test • Suppressor T cells (TS) – Turn off immune response when Ag no longer present Helper T Cells Figure 17.13 Cell-mediated Cytotoxicity Figure 17.14 Nonspecific Cells • Activated macrophages: Macrophages stimulated by ingesting Ag or by cytokines • Natural killer cells: Lymphocytes Figure 17.15 T-independent Antigens B cell Figure 17.17 T-Dependent Antigens Figure 17.16 Antibody-Dependent CellMediated Cytotoxicity Figure 17.18 T-dependent and independent antigens •