Chapter 22, part 4

1. Chapter 22, part 4 The Lymphatic System and Immunity

2. SECTION 22-6B Cells and Antibody-mediated Immunity

3. B cell sensitization of activation • Sensitization – the binding of antigens to the B cell membrane antibodies • Antigens then displayed on B cell Class II MHC • TH cells activated by same antigen stimulate B cell • Active B cell differentiates into Memory B Cell or Plasma cell • Plasma cells synthesize and release antibody

4. Figure 22.20 The Sensitization and Activation of B Cells PLAY Animation: B Cells and Antibody Production Figure 22.20

5. Antibodies structure • Antibodies are Y-shaped proteins consisting of: • Two parallel polypeptide chains • Heavy chains and light chains • Constant region and variable region • Antigen binding site

6. Figure 22.21 Antibody Structure Figure 22.21

7. Figure 22.21 Antibody Structure Figure 22.21a

8. Figure 22.21 Antibody Structure Figure 22.21b-d

9. Actions of antibodies include: • Neutralization • Agglutination and precipitation • Activation of complement • Attraction of phagocytes • Opsinization • Stimulation of inflammation • Prevention of adhesion

10. Classes of Antibodies (immunoglobins) • IgG – resistance against many viruses, bacteria and bacterial toxins • IgE – accelerates local inflammation • IgD – found on the surface of B cells • IgM – first type secreted after antigen arrives • IgA – primarily found in glandular sec

11. Primary and secondary antibody response • Primary response • Takes about two weeks to develop • Produced by plasma cells • Secondary response • Rapid increase in IgG • Maximum antibody titer app

12. Figure 22.22 The Primary and Secondary Immune Responses Figure 22.22

13. Figure 22.23 An Integrated Summary of the Immune Response Figure 22.23

14. Figure 22.25 The Course of the Body’s Response to Bacterial Infection Figure 22.25a, b

15. Focus on Hormones of the Immune System • Interleukins • Increase T cell sensitivity • Stimulate B cell activity, plasma formation, and antibody production • Enhance nonspecific defenses • Moderate the immune system • Interferons • Tumor Necrosis Factors (TNFs) slow tumor growth • Colony Stimulating Factors (CSFs)

16. SECTION 22-7Normal and Abnormal Resistance

17. Development of the Immune Response • Immunological competence • The ability to demonstrate an immune response after exposure to an antigen • Fetuses receive immunity from the maternal bloodstream • Infants acquire immunity following exposure

18. Immune disorders • Autoimmune disorders • Immune response mistakenly targets normal cells • Immunodeficiency diseases • Immune system does not develop properly or is blocked

19. Allergies • Inappropriate or excessive immune response to allergens • Immediate hypersensitivity (type I) • Cytotoxic reactions (type II) • Immune complex disorders (type III) • Delayed hypersensitivity (type IV) • Anaphylaxis • Circulating allergen affects mast cells throughout body

20. Figure 22.26 The Mechanism of Anaphylaxis Figure 22.26

21. Stress and the immune response • Interleukin-1 released by active macrophages • Triggers release of ACTH resulting in glucocorticoid release • Moderates the immune response • Lowers resistance to disease

22. Stress can cause the following: • Depression of the inflammatory response • Phagocytic reduction • Inhibition of interleukin secretion

23. SECTION 22-8Aging and the Immune Response

24. With age • Immune system becomes less effective • Increased susceptibility to infection • Immune surveillance declines

25. You should now be familiar with: • The structure and function of lymphatic cells, tissues and organs • The body’s nonspecific defenses and the components and mechanisms of each • Specific resistance, cell-mediated immunity and antibody mediated immunity • The role of the T cell, B cell and antibodies in specific immunity • The origin, development, activation and regulation of normal resistance to disease • The effects of stress and aging on the immune system