Microbiology B.E Pruitt & Jane J. Stein AN INTRODUCTION EIGHTH EDITION TORTORA FUNKE CASE 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

Another look 1 o Ag 2 o Ag Total Ab IgM Ab IgG Ab D a y s A f t e r I m m u n i z a t i o n A b T i t e r

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

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

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

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:

Dendritic cells present antigens Figure 17.12

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

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

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 Figure B cell

T-Dependent Antigens Figure 17.16

Antibody-Dependent Cell- Mediated Cytotoxicity Figure 17.18

T-dependent and independent antigens