Specific Defenses of the Host: The Immune Response Chapter 17, part B Specific Defenses of the Host: The Immune Response

The Results of Ag-Ab Binding Figure 17.9

Antibody titer: Is the amount of Ab in serum Figure 17.10

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 antigen-presenting 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 that destroy virus-infected cells, tumor Figure 17.15

T-independent Antigens B cell Figure 17.17

T-independent Antigens Figure 17.16

Antibody-Dependent Cell-Mediated Cytotoxicity Figure 17.18