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Chapter 22, part 3. The Lymphatic System and Immunity. SECTION 22-4 Specific Defenses. Forms of immunity. Innate immunity Genetically determined Present at birth Acquired immunity Not present at birth Achieved by exposure to antigen Active immunity Passive immunity. - PowerPoint PPT Presentation
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Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Fundamentals of
Anatomy & PhysiologySIXTH EDITION
Frederic H
. Martini
PowerPoint® Lecture Slide Presentation prepared by Dr. Kathleen A. Ireland, Biology Instructor, Seabury Hall, Maui, Hawaii
Chapter 22, part 3
The Lymphatic System and Immunity
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
SECTION 22-4 Specific Defenses
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Forms of immunity
• Innate immunity
• Genetically determined
• Present at birth
• Acquired immunity
• Not present at birth
• Achieved by exposure to antigen
• Active immunity
• Passive immunity
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 22.14 Types of Immunity
Figure 22.14
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Properties 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 tissues
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
The 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 antigen
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 22.15
Figure 22.15 An Overview of the Immune Response
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
SECTION 22-5 T cells and Cell-mediated Immunity
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Major 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 cells
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Antigen 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 contact
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
MHC classes
• Class I – found on all nucleated cells
• Class II – found on antigen presenting cells and lymphocytes
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Lymphocytes 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 cells
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 22.16 Antigens and MHC Proteins
Figure 22.16
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 22.16 Antigens and MHC Proteins
Figure 22.16a
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 22.16 Antigens and MHC Proteins
Figure 22.16b
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Activation 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 response
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 22.17
Figure 22.17 Antigen Recognition and the Activation of Cytotoxic T Cells
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 22.17
Figure 22.17 Antigen Recognition and the Activation of Cytotoxic T Cells
Animation: Cytotoxic T Cell ActivationPLAY
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Activation 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 cells
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 22.18
Figure 22.18 Antigen Recognition and Activation of Helper T cells
Animation: Antigen Recognition and Helper T Cell ActivationPLAY
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 22.19
Figure 22.19 A Summary of the Pathways of T Cell Activation
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