Chapter 43: Immune System

1. Chapter 43: Immune System

2. Learning Targets • I can explain innate immunity by: • Describing barrier defenses • Describing internal defenses • I can explain adaptive immunity by:describing humoral response which includes: • B cells • Plasma cells • Antibodies • Memory cells • Helper T cells • Describing cell mediated response which includes • Cytotoxic T Cells and memory cells • I can identify and explain parts of immune system that represent how cells communicate via paracrine communication. • I cam explain the difference between a primary and secondary immune response • I can explain the difference between active and passive immunity.

3. Focus Questions • What is the functional difference between cell mediated and humoral immunity? Why do we have both types? • Which blood cells are involved in cell mediated immunity? • Which blood cells are involved in humoral immunity? • Why is it that you don’t get the chicken pox, once you have already had it? • If you are bit by a venomous snake, what type of immunity are you given when you receive an anti venom injection? When you received your hepatitis vaccination, what type of immunity are you given?

4. Figure 43.2 Recognition of traits sharedby broad ranges ofpathogens, using a smallset of receptors Recognition of traits specific to particularpathogens, using a vastarray of receptors • • Pathogens(such as bacteria,fungi, and viruses) Barrier defenses: INNATE IMMUNITY(all animals) SkinMucous membranesSecretions Internal defenses: Phagocytic cellsNatural killer cellsAntimicrobial proteinsInflammatory response • Rapid response Humoral response: ADAPTIVE IMMUNITY(vertebrates only) Antibodies defend againstinfection in body fluids. Cell-mediated response: Cytotoxic cells defendagainst infection in body cells. • Slower response

5. Figure 43.15 Primary immune responseto antigen A producesantibodies to A. Secondary immune response toantigen A produces antibodies to A;primary immune response to antigenB produces antibodies to B. 104 103 Antibodiesto A Antibody concentration(arbitrary units) Antibodiesto B 102 101 100 7 35 56 49 0 14 21 28 42 Exposure to antigens A and B Exposureto antigen A Time (days)

6. 1 3 2 Cell mediated Immunity Antigen-presentingcell Antigen fragment Pathogen Class II MHC molecule Accessory protein Antigen receptor Helper T cell   Cytokines Cell-mediatedimmunity Humoralimmunity   B cell Cytotoxic T cell

7. Figure 43.17-1 1 Cytotoxic T cell Accessoryprotein Antigenreceptor Class I MHCmolecule Infectedcell Antigenfragment

8. Figure 43.17-2 1 2 Cytotoxic T cell Accessoryprotein Antigenreceptor Perforin Class I MHCmolecule Gran-zymes Pore Infectedcell Antigenfragment

9. Figure 43.17-3 3 1 2 Cytotoxic T cell ReleasedcytotoxicT cell Accessoryprotein Dyinginfected cell Antigenreceptor Perforin Class I MHCmolecule Gran-zymes Pore Infectedcell Antigenfragment

10. 1 Humoral Response Antigen-presentingcell Pathogen Antigenfragment Class IIMHCmolecule Accessoryprotein Antigenreceptor Helper T cell

11. 1 2 HumoralResponse Antigen-presentingcell Pathogen Antigenfragment B cell Class IIMHCmolecule  Accessoryprotein Cytokines Antigenreceptor Activatedhelper T cell Helper T cell

12. 3 1 2 Humoral Response Antigen-presentingcell Pathogen Antigenfragment B cell Memory B cells Class IIMHCmolecule  Accessoryprotein Cytokines Antigenreceptor Activatedhelper T cell Plasma cells Helper T cell Secretedantibodies

13. Figure 43.19 Activation of complement system and poreformation Opsonization Neutralization Complement proteins Antibody Formation of membraneattack complex Bacterium Virus Flow of waterand ions Pore Antigen Foreigncell Macrophage

14. Figure 43.20 Humoral (antibody-mediated) immune response Cell-mediated immune response Key Antigen (1st exposure)  Stimulates Engulfed by Gives rise to Antigen-presenting cell    Helper T cell Cytotoxic T cell B cell   Memoryhelper T cells    Antigen (2nd exposure) Memorycytotoxic T cells Active cytotoxic T cells  Plasma cells Memory B cells Secretedantibodies Defend against extracellularpathogens Defend against intracellularpathogens and cancer

15. Figure 43.UN02 Stem cell Cell division andgene rearrangement Elimination ofself-reactiveB cells Antigen Clonalselection Formation ofactivated cellpopulations Antibody Plasma cells Memory B cells Pathogen Receptors bind to antigens

16. Figure 43.UN03