The Immune System Essentials: Defending the Body and Immunological Responses

1. Chapter 43 The Immune System

2. Videos • Stress, Emotions, and Our Health • NOVA PBS: Immunity Explained

3. Assignment • Friday – Independent Notes on Chapter 43 • YOU NEED TO READ THE CHAPTER!!!

4. Let’s Get Defensive! Agenda: Natural Born Killer Review Notes on Defense Counting Blood Cells (Activity)

5. Let’s Get Defensive! Agenda: Natural Born Killer Review Notes on Defense Counting Blood Cells (Activity) What’s snot fun about biology? (Activity)

6. The Lymphatic System • Plays an active role in defending the body from pathogens • Network of tissues and organs that help rid the body of toxins, waste and other unwanted materials. • Transport lymph, a fluid containing WBCs

8. 10m 3m Innate Immunity • First line defense? • Second line of defense? • How does the first line of defense use chemical barriers? • Hepatitis A and the Stomach

9. 5. Four types of phagocytic WBCs What are they? 6. How do phagocytic WBCs work? What is the enzyme involved?

10. 7. Interferons • Another set of proteins that provide innate defense against….

11. 8. The Inflammatory Response

12. Adaptive or Acquired Immunity • Specific defense • Works WITH innate immunity • As cells phagocytize microbes, release cytokines to activate other lymphocytes and cells of the immune system 9. Antigen?

13. Antigen- binding sites Epitopes (antigenic determinants) Antibody A Antigen Antibody B Antibody C Acquired Immunity • An antigen is any foreign molecule • That is specifically recognized by lymphocytes and elicits a response from them • A lymphocyte actually recognizes and binds • To just a small, accessible portion of the antigen called an epitope Figure 43.7

14. Acquired Immunity: • The humoral immune response: involves the activation and clonal selection of B cells, resulting in the production of antibodies or immunoglobulins (IG) • The cell-mediated immune response: involves the activation and clonal selection of cytotoxic T cells – target cells like cancer Both receive help by helper T cells

15. B and T cells recognize antigens. • 1 million diff. B • 10 million diff. T • A lymphocyte recognizes antigen… • Stimulates and differentiate • One clone short-lived fighters • Other clone memory cells • First time: 10-17 days • Second time: 2-7 days

16. Antibodies • The five classes of immunoglobulins

17. After a dendritic cell engulfs and degrades a bacterium, it displays bacterial antigen fragments . A specific helper T cell binds to the displayed complex. This interaction promotes secretion of cytokines by the dendritic cell. Cytotoxic T cell Dendritic cell Peptide antigen Helper T cell Cell-mediated immunity (attack on infected cells) Class II MHC molecule Bacterium TCR Humoral immunity (secretion of antibodies by plasma cells) CD4 Dendritic cell Cytokines B cell The cells in this clone secrete other cytokines that help activate B cells and cytotoxic T cells. 3 1 2 3 2 1 Figure 43.15 The role of helper T cells in acquired immunity

18. The Immune System Explained

19. Microscope Activity

20. Tuesday • Immune System Problems • Can You Boost Your Immunity? • Kahoot • FRQ and Peer Review

21. Organ Transplants and Transfusions • The immune system can wage war against cells from other individuals • Transplanted tissues are usually destroyed by the recipient’s immune system • Mismatched antigens • Use medicine to suppress the immune system

22. Allergies • Allergies are exaggerated (hypersensitive) responses to certain antigens called allergens • Perceives harmless substances as dangerous, body tries to fight them off • Releases antibodies, IgE, Release Histamine

23. IgE Allergen Histamine 1 3 2 Granule Mast cell Degranulation of the cell, triggered by cross-linking of adjacent IgE molecules, releases histamine and other chemicals, leading to allergy symptoms. 1 IgE antibodies produced in response to initial exposure to an allergen bind to receptors or mast cells. 2 3 On subsequent exposure to the same allergen, IgE molecules attached to a mast cell recog- nize and bind the allergen. Figure 43.20 • The allergic response

24. Age and the Immune System • Researchers believe that aging – leads to a reduction of immune response capability -contributes to more infections, more inflammatory diseases, and more cancer.  • Possible causes: • Atrophying thymus, reduction in T cells • Nutrient deficiency • Less responsive to medications/vaccines • Can’t recognize self from non-self

25. Outgrowing allergies

26. Figure 43.21 Autoimmune Diseases • In individuals with autoimmune diseases • The immune system loses tolerance for self and turns against certain molecules of the body • Results from hereditary or congenital defects that prevent proper functioning of innate, humoral, and/or cell-mediated defenses • Examples: • Rheumatoid arthritis- damage and painful inflammation of the cartilage and bone of joints • Lupus • - Multiple sclerosis • - Insulin-dependent diabetes (Type 1)

27. Stress and the Immune System • Growing evidence shows • That physical and emotional stress can harm immunity • Brain sends stress signals to the endocrine system • Releases hormones for fight/flight • Weakens immune response (Cortisol suppresses inflammation)

28. 1µm Figure 43.22 HIV and AIDs • Highly susceptible to opportunistic infections and cancers that take advantage of an immune system in collapse • Because AIDS arises from the loss of helper T cells • Both humoral and cell-mediated immune responses are impaired