Chapter 22, part 3SECTION 22-4 Specific DefensesForms of immunityFigure 22.14 Types of ImmunityProperties of immunityThe immune system responseFigure 22.15 An Overview of the Immune ResponseSECTION 22-5 T cells and Cell-mediated ImmunityMajor types of T cellsAntigen presentationMHC classesLymphocytes respond to antigens bound to either class I or class II MHC proteinsFigure 22.16 Antigens and MHC ProteinsSlide 14Slide 15Activation of CD8 cellsFigure 22.17 Antigen Recognition and the Activation of Cytotoxic T CellsSlide 18Activation of CD4 T cells by antigens presented on class II MHC proteinsFigure 22.18 Antigen Recognition and Activation of Helper T cellsFigure 22.19 A Summary of the Pathways of T Cell ActivationCopyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Fundamentals of Anatomy & PhysiologySIXTH EDITIONFrederic H. MartiniPowerPoint® Lecture Slide Presentation prepared by Dr. Kathleen A. Ireland, Biology Instructor, Seabury Hall, Maui, HawaiiChapter 22, part 3The Lymphatic System and ImmunityCopyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsSECTION 22-4 Specific DefensesCopyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsForms of immunity•Innate immunity •Genetically determined •Present at birth•Acquired immunity •Not present at birth •Achieved by exposure to antigen •Active immunity•Passive immunityCopyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 22.14 Types of ImmunityFigure 22.14Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsProperties of immunity•Specificity – activated by and responds to a specific antigen•Versatility – is ready to confront any antigen at any time•Memory – “remembers” any antigen it has encountered•Tolerance – responds to foreign substances but ignores normal tissuesCopyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsThe immune system response•Antigen triggers an immune response •Activates T cells and B cells•T cells are activated after phagocytes exposed to antigen•T cells attack the antigen and stimulate B cells•Activated B cells mature and produce antibody•Antibody attacks antigenCopyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 22.15Figure 22.15 An Overview of the Immune ResponseCopyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsSECTION 22-5 T cells and Cell-mediated ImmunityCopyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsMajor types of T cells•Cytotoxic T cells (TC) – attack foreign cells•Helper T cells (TH) – activate other T cells and B cells•Suppressor T cells (TS) – inhibit the activation of T and B cellsCopyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsAntigen presentation•Antigen-glycoprotein combination appears on a cell membrane•Called MHC proteins (Major Histocompatibility Complex)•Coded for by genes of the MHC •T-cells sensitive to the antigen are activated upon contactCopyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsMHC classes•Class I – found on all nucleated cells•Class II – found on antigen presenting cells and lymphocytesCopyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsLymphocytes respond to antigens bound to either class I or class II MHC proteins•Antigen recognition•T cell membranes contain CD markers•CD3 markers present on all T cells•CD8 markers on cytotoxic and suppressor T cells•CD4 markers on helper T cellsCopyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 22.16 Antigens and MHC ProteinsFigure 22.16Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 22.16 Antigens and MHC ProteinsFigure 22.16aCopyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 22.16 Antigens and MHC ProteinsFigure 22.16bCopyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsActivation of CD8 cells•Responds quickly giving rise to other T cells•Cytotoxic T cells – seek out and destroy abnormal cells•lymphotoxin•Memory TC cells – function during a second exposure to antigen•Suppressor T cells – suppress the immune responseCopyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 22.17Figure 22.17 Antigen Recognition and the Activation of Cytotoxic T CellsCopyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 22.17Figure 22.17 Antigen Recognition and the Activation of Cytotoxic T CellsAnimation: Cytotoxic T Cell ActivationPLAYCopyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsActivation of CD4 T cells by antigens presented on class II MHC proteins•Produces helper T cells and memory T cells•Activated helper T cells•Secrete lymphokines that coordinate specific and nonspecific defenses•Enhance nonspecific defenses•Stimulate the activity of NK cells•Promote activation of B cellsCopyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 22.18Figure 22.18 Antigen Recognition and Activation of Helper T cellsAnimation: Antigen Recognition and Helper T Cell ActivationPLAYCopyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 22.19Figure 22.19 A Summary of the Pathways of T Cell