chapter 22, part 3

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


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


Figure 22.14 Types of Immunity

Figure 22.14


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


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


SECTION 22-5 T cells and Cell-mediated Immunity


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


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


MHC classes

• Class I – found on all nucleated cells

• Class II – found on antigen presenting cells and lymphocytes


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


Figure 22.16 Antigens and MHC Proteins

Figure 22.16



Figure 22.16a



Figure 22.16b


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


Figure 22.17 Antigen Recognition and the Activation of Cytotoxic T Cells


Figure 22.17 Antigen Recognition and the Activation of Cytotoxic T Cells

Animation: Cytotoxic T Cell ActivationPLAY


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


Figure 22.18 Antigen Recognition and Activation of Helper T cells

Animation: Antigen Recognition and Helper T Cell ActivationPLAY


Figure 22.19 A Summary of the Pathways of T Cell Activation

chapter 22, part 3

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