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Chapter 23 Immune Systems

Chapter 23 Immune Systems. 4. Immune 1 adj. Derived from classical Latin Munia = duties 1. Exempt from something disagreeable or harmful 2. Not susceptible to some specified disease. 12. What can make you sick?. Cutting board Bacteria and Fungi, 300x 2. Legionella bacteria 3000x 2.

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Chapter 23 Immune Systems

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  1. Chapter 23 Immune Systems 4 Immune1 adj. Derived from classical Latin Munia = duties 1. Exempt from something disagreeable or harmful 2. Not susceptible to some specified disease 12

  2. What can make you sick? Cutting board Bacteria and Fungi, 300x2 Legionella bacteria 3000x2 Anthrax Bacteria 2200x2 Anthrax spores in lung 1225x2 Ragweed Pollen, 550x2 Polio Virus, 46,050x 2

  3. 1. Infection byPathogen Infection: Entry of pathogen into the body Pathogen: Any foreign body that can cause disease 2. Disease When the body’s cells and tissues have been damaged by the pathogen so that they no longer function The Disease Process Pathogen Patho = suffering (Greek, Latin) gen = producing (Latin) Infect In = in (Latin) fect = to do or make (Latin) Antigen = Any foreign material that activates the immune system; usually a protein. Need not be pathenogenic. Why is an antigen called an antigen? See P. 604

  4. Nonspecific Defenses Physical/Chemical Eg. Skin, bark, mucous membranes, low pH of stomach, antibacterial enzymes in sweat, tears, saliva Inflammation Fever Specific Defenses (Adaptive Immunity) Develops in 4-14 Days Cell mediated response Antibody mediated response Memory cells How does the immune system prevent disease? Resistance = “the ability to ward off infectious diseases” (447) What’s fever for? 12 13

  5. The Body’s Defenses19 20

  6. Phagocytosis Phagocytic cells have special cell surface receptors which recognize antigens Also recognize self Engulf and destroy foreign bodies Activate specific defenses Inflammation Response to injury, damage, or foreign antigens Damaged capillaries leak fluid and cells into injury Redness, swelling, warmth Phagocytes remove debris and dead cells Nonspecific Defenses Pus = Phagocytic cells, dead pathogens, debris Alveolar macrophage phagocytosis of E. coli; 1315x 2

  7. Internal Nonspecific Defenses White blood cells Defensive proteins Phagocytes NK cells Interferons Complement proteins • Engulf foreign cells or substances • Destroy infected body cells • Protect body cells against viral infection • Cause invading cells to lyse Neutrophils Macrophages Figure 24.4 Internal Nonspecific Defenses

  8. The First Line of Defense19 21 P.S. The nail was driven into that person’s hand by a nail gun. OUCH!

  9. Who am I?13 HLA = Human Leukocyte Antigen The cell “name tag” or “fingerprint Each “flag” is a protein displayed on the cell’s surface. Except in unusual cases or identical twins, a person’s combination of HLA factors is unique Specificity: Immune system is NOT supposed to react to self HLA, but IS supposed to react to everything else.

  10. Macrophages as Gatekeepers23 • Macrophages recognize and engulf any particle virus or cell that does not carry the “self” HLA protein code on its surface. • Then, they display the antigen on their surface using their MHC molecules.

  11. White blood cells to the rescue! Immunity through Leukocytes2 Blood with T Cells and Platelets; 2000x Macrophage; 950x Neutrophils; 1000x Helper T cell (small cell) and B cell (large cell); 2000x Remember… we need specificity and memory!

  12. Tonsil Lymph nodes Lymphatic vessels, entering veins Thymus Spleen Appendix Bone marrow Lymphatic vessels Lymphocytesa kind of leukocyte 2 Trillion in your body Originate in bone marrow • Mature in Primary Lymph Tissues • Thymus (T Cells) • Bone Marrow (B Cells) • Collect in Secondary Tissues • Lymph nodes • Spleen • Tonsils • Appendix • Circulate in Lymph and Blood Vessels (via Thoracic Duct) Look at P. 609 Figure 24.7

  13. B Lymphocyte from bone marrow (bursa) Produce antibodies “Against antigen” Antibody mediated (Humoral) immune response T Lymphocyte from thymus Recognize antigens on pathogens Cell mediated immune response Adaptive Immunity Helper T cell (small cell) and B cell (large cell); 2000x 2 Immune Surveillance: Both have receptors on their membranes to recognize antigens and travel through the body to “seek out and destroy.”

  14. Leukocyte Production3 The point is thatstem cellscan turn into many different kinds of leukocytes! T Cells need further development in the Thymus, B cells mature in the Bone marrow

  15. B and T Cell Development 24

  16. Helper T Cells (TH) Secrete cytokines Stimulate the production of antibodies by B cells Cytotoxic T Cells (CTL) Attack foreign cells Attack infected “self” cells Suppressor T Cells Shut down the immune system Reduce B and T cell activities Memory T Cells Cell Mediated Immunity and T Lymphocytes2 Activated by Antigen display by macrophages

  17. Activation of T Cells19 Antigen fragments activate Helper and Cytotoxic T cells.

  18. Helper T Cells at the Center24 Macrophage displays antigen Cytokines APC stimulates the Helper T cell Cytotoxic T Cells and B cells both need the cytokines of the Helper T cells to become active

  19. CTLs at Work24 After activation by TH cellsT-Cells destroy ~ non-self cells ~ altered or infected self cells

  20. 1. B Cell receptors bind to an antigen 2. B Cell digests and displays a “ready” complex 3a. Helper T Cell recognizes complex and produces lymphokines 3b. Rapid mitosis occurs Plasma cells make antibodies Memory cells last a long time. Can make antibodies and more plasma cells. Antibodies bind to antigen to mark it for destruction Antibody Mediated Immunity and B Lymphocytes3

  21. Protein 4 polypeptides held together with disulfide bonds Each B cell makes only one kind Each kind binds one antigen ~106 different kinds So, what is this thing called an Antibody?3 12

  22. Each antibodybinds one antigenin a lock and key arrangement Remember enzyme-substrate fit. Antibody-Antigen Binding14 Variable Region Antigen Complement Binding Site

  23. Clonal Selection Theory3 Remember… Each B cell only makes one antibody So how is the immune response specific?

  24. Antibodies bind to antigens making it easier for macrophages to surround and destroy Binding of complement proteins to antibody also enhances phagocytosis Antibodies in Action5

  25. 1. Antibodies bind antigen 2. Binding activates complement proteins 3. Those complement proteins activate others 4. Complement proteins “drill” holes in microbe membrane (lyse cells), letting fluid pressure burst the cell Activated complement also stimulates inflammation Antibodies and Complement8 3 1 2 4

  26. The Role of Antibodies

  27. Antibody Diversity3 • Each antibody needs • 1 kind of light chain • 1 kind of heavy chain • There is DNA recombination involved to produce22 • 7500 kinds of light chains • 2.4 million kinds of heavy chains 7500 x 2.4 million = 18 billion possible kinds of antibodies!

  28. Primary Immune Response After initial exposure to antigen 7-14 days Stimulates specific B cells that respond to the antigen/pathogen Secondary Immune Response Subsequent exposure 2-6 days Memory cells immediately begin dividing to produce plasma cells (B cells) Antibody production begins more quickly 1st Exposure Amount of Antibody 1st Exposure 2nd Exposure Time (days) Categories of Immunity9 Look at speed of response and amount of antibody produced the second time!

  29. Cell or antibody mediated Chemical change in cell surface proteins Cells no longer recognized as self Immune system attacks those cells See p. 624 Eg. Poison Ivy Reaction Cell mediated Cell destruction causes swelling, redness, blisters When the system doesn’t work right Hypersensitive Immune Systems 10 Also read about diseases and chemicals… 11

  30. Allergies Hypersensitive Immune Systems 16 Histamine 24

  31. Autoimmune Diseases Immune system stops recognizing self HLA Immune system attacks the body’s own cells Caused by Genetic susceptibility Environment Autoimmunity15

  32. Vaccination from Latin Vacca = cow ation =action or process Generally only works for one specific disease Edward Jenner (1798) Cowpox exposure Immune system remembers the cowpox Vaccinated personimmune to smallpox Last smallpox deaths occurred in 1978 Immune System Memory and Vaccinations 6 Will the smallpox vaccine protect against other viruses? 7 The last known person in the world to have smallpox of any kind. Here 23-year-old Ali Maow Maalin of Merka, Somalia exhibits the pox of Variola minor.7

  33. NaturallyAcquiredActive from reaction of immune system with antigen NaturallyAcquiredPassive fetus/newborn gets antibodies directly from mother, in colostrum/milk ArtificiallyAcquiredActive from vaccination ArtificiallyAcquiredPassive from direct injection of antibodies Kinds of Immunity18 Which ones do you have NOW?

  34. Literature Cited Cool Web Sites: www.iir.suite.dk/ IIR/IIRimsys.htm, www.mansfieldct.org/schools/mms/ staff/hand/Warriorsimm.htm http://www.primaryimmune.org/library/immune/ ----- This is cartoons! ----- www.cellsalive.com/ antibody.htm Macrophage Epitope Display: http://www.cat.cc.md.us/~gkaiser/microrlo/unit3/intro/mhc/mhctwo.html http://www.blc.arizona.edu/courses/181gh/SCHEDULES/exam4.html 1. Immunity: Webster’s New World Dictionary and Thesaurus, 1996. 2. www.denniskunkel.com, with permission. 3. Leukocyte Production, B Cell and Macrophage activation, antibody schematic, clonal selection: http://http://www.blc.arizona.edu/courses/181gh/Lectures_WJG.01/immunol_F.01/immunology.html 4. http://www.acm.uiuc.edu/sigbio/project/updated-lymphatic/lymph3.html 5. Macrophage ingesting bacteria covered with antibody: http://gened.emc.maricopa.edu/bio/bio181/BIOBK/BioBookIMMUN.html 6. http://www.nlm.nih.gov/exhibition/smallpox/sp_vaccination.html 7. http://www.rnceus.com/biot/small.html 8. Complement: http://www.sciam.com/explorations/2000/012400preg/IMG/complement.gif

  35. Cites, cont. 9. Immune Response Graph: www-immuno.path.cam.ac.uk/~immuno/ part1/lec05/lec6_99.html 10. Poison Ivy Picture: http://www.leelanau.com/manitou/images/poison-ivy.jpg 11. Poison Ivy Face 1: http://www.sims.berkeley.edu/~mgebbie/Pictures/Timmons%20Spring%202000%20vacation/pages/Poison%20Ivy.htm 12. http://www.karenika.com/pictures/nikon/neighborhood/neighborhood21.html 13. HLA: http://www.med.umich.edu/trans/public/hla/hla_&_you.html 14. Antibody Fit:www.nycornell.org/uo/ graphics/epitope.gif 15. Autoimmune Diseases: www.niaid.nih.gov/publications/ autoimmune/autoimmune.htm 16. Histamine Structure: http://www.perl.com/1999/08/onion/pix/histamine.gif 17. Allergy Diagram: http://www.mc.uky.edu/allergy/sneeze.asp 18 www.rush.edu/happening/ images/hiv-vaccine.jpg 19. BioCD. From Biology, Fifth Edition. Campbell, Reece, Mitchell. Addison, Wesley, Longman. 1999. 20. http://www.valkyriearms.com/images.htm 21. www.indianahandcenter.com/ handsafe.html 22. http://www.mun.ca/biochem/courses/3107/Lectures/Topics/Antibodies.html 23. http://www.cancerresearch.org/immresp.html 24. Bioshow: for Biology: Concepts and Connections, Second Edition. Campbell, Mitchell, and Reece

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