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AP Biology April 10, 2012  BellRinger Quiz:  What is the difference between innate and adaptive immunity?  Give an example of each  Objective:  Review.

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Presentation on theme: "AP Biology April 10, 2012  BellRinger Quiz:  What is the difference between innate and adaptive immunity?  Give an example of each  Objective:  Review."— Presentation transcript:


2 AP Biology April 10, 2012  BellRinger Quiz:  What is the difference between innate and adaptive immunity?  Give an example of each  Objective:  Review the first, second, and third lines of defense in the immune system  Homework  Chp 18 notes

3 AP Biology Pathogenic Diseases  Read about each of the diseases and determine: 1. Is it a bacteria or virus? What type? 2. How does the pathogen disrupt human health? 3. How is the pathogen contracted? 4. How can it be avoided or treated? 5. What else is interesting about this pathogen?  Organize the info into a chart or table so you can easily compare the information

4 AP Biology Observations  List 2 similarities among the viral diseases  List 2 similarities among the bacterial diseases  How do viral and bacterial disorders differ?  Predict: Given your observations about the differences between the way viruses and bacteria affect our health, how might our immune system need to vary its response to each type of pathogen?

5 AP Biology Immune / Lymphatic System lymphocytes attacking cancer cell phagocytic leukocyte lymph system Fighting the Enemy Within!

6 AP Biology Avenues of attack  Points of entry  digestive system  respiratory system  urogenital tract  break in skin  Routes of attack  circulatory system  lymph system

7 AP Biology Why an immune system?  Attack from outside  lots of organisms want you for lunch!  animals are a tasty nutrient- & vitamin-packed meal  cells are packages of macromolecules  no cell wall  traded mobility for susceptibility  animals must defend themselves against invaders  viruses  HIV, flu, cold, measles, chicken pox, SARS  bacteria  pneumonia, meningitis, tuberculosis  fungi  yeast (“Athlete’s foot”…)  protists  amoeba, Lyme disease, malaria  Attack from inside  defend against abnormal body cells = cancers

8 AP Biology Lymph system Production & transport of leukocytes Traps foreign invaders lymph node lymph vessels (intertwined amongst blood vessels)

9 AP Biology Development of Red & White blood cells short-lived phagocytes 60-70% WBC develop into macrophages inflammatory response fight parasites Red blood cells

10 Immune system Innate (non- specific) 1 st line Surface Barriers Skin Mucous Membranes 2 nd Line Cells & Chemicals Phagocytes Natural Killers Inflammation Antimicrobial Proteins Fever 3 rd line Adaptive (specific) Humoral B Lymphocytes Plasma Cells Antibodies Memory Cells Cell Mediated T Lymphocytes Helper T (CD4) Cytotoxic T (killer) Suppressor T Antigen Presenting Cell Macrophage

11 AP Biology Lines of defense  1st line: Barriers  broad, external defense  “walls & moats”  skin & mucus membranes  2nd line: Non-specific patrol  broad, internal defense  “patrolling soldiers”  leukocytes = phagocytic WBC  macrophages  3rd line: Immune system  specific, acquired immunity  “elite trained units”  lymphocytes & antibodies  B cells & T cells Bacteria & insects inherit resistance. Vertebrates acquire immunity!

12 AP Biology 1st line: External defense  Physical & chemical defenses  non-specific defense  external barrier  epithelial cells & mucus membranes  skin  respiratory system  digestive system  uro-genital tract Lining of trachea: ciliated cells & mucus secreting cells

13 AP Biology 1st line: Chemical barriers on epithelium  Skin & mucous membrane secretions  sweat  pH 3-5  tears  washing action  mucus  traps microbes  saliva  anti-bacterial = “lick your wounds”  stomach acid  pH 2  anti-microbial proteins  lysozyme enzyme  digests bacterial cell walls

14 AP Biology Learning Check  How does an outward flow of fluid deter pathogens?  How do salts discourage pathogens?  How does a low pH discourage pathogens?

15 AP Biology 2nd line: Internal, broad range patrol leukocytes  Innate, general defense  rapid response  Patrolling cells & proteins  attack invaders that penetrate body’s outer barriers  leukocytes  phagocytic white blood cells  complement system  anti-microbial proteins  inflammatory response

16 AP Biology Leukocytes: Phagocytic WBCs  Attracted by chemical signals released by damaged cells  enter infected tissue, engulf & ingest microbes  lysosomes  Neutrophils  most abundant WBC (~70%)  ~ 3 day lifespan  Macrophages  “big eater”, long-lived  Natural Killer Cells  destroy virus-infected cells & cancer cells

17 AP Biology Phagocytes yeast macrophage

18 AP Biology  Natural Killer Cells perforate cells  release perforin protein  insert into membrane of target cell  forms pore allowing fluid to flow into cell  cell ruptures (lysis)  apoptosis Destroying cells gone bad! perforin punctures cell membrane cell membrane natural killer cell cell membrane virus-infected cell vesicle perforin

19 AP Biology Anti-microbial proteins  Complement system  ~20 proteins circulating in blood plasma  attack bacterial & fungal cells  form a membrane attack complex  perforate target cell  apoptosis  cell lysis plasma membrane of invading microbe complement proteins form cellular lesion extracellular fluid complement proteins bacterial cell

20 AP Biology Inflammatory response  Damage to tissue triggers local non-specific inflammatory response  release histamines & prostaglandins  capillaries dilate, more permeable (leaky)  increase blood supply  delivers WBC, RBC, platelets, clotting factors  fight pathogens  clot formation  accounts for swelling, redness & heat of inflammation & infection

21 AP Biology Inflammatory response Bacteria Blood vessel Chemical alarm signals Pin or splinter Blood clot Phagocytes swelling  Reaction to tissue damage

22 AP Biology Fever  When a local response is not enough  systemic response to infection  activated macrophages release interleukin-1  triggers hypothalamus in brain to readjust body thermostat to raise body temperature  higher temperature helps defense  inhibits bacterial growth  stimulates phagocytosis  speeds up repair of tissues  causes liver & spleen to store iron, reducing blood iron levels  bacteria need large amounts of iron to grow

23 AP Biology Learning Check  How is the 2 nd line of defense different from the 1 st line of defense?  What does it mean for a cell to be “phagocytic”?  What are some cell secretions that aid in non-specific defense against pathogens?

24 AP Biology  Specific defense  lymphocytes  B lymphocytes (B cells)  T lymphocytes (T cells)  antibodies  immunoglobulins  Responds to…  antigens  specific pathogens  specific toxins  abnormal body cells (cancer) 3rd line: Acquired (active) Immunity

25 AP Biology “self”“foreign” How are invaders recognized: antigens  Antigens  proteins that serve as cellular name tags  foreign antigens cause response from WBCs  viruses, bacteria, protozoa, parasitic worms, fungi, toxins  non-pathogens: pollen & transplanted tissue  B cells & T cells respond to different antigens  B cells recognize intact antigens  pathogens in blood & lymph  T cells recognize antigen fragments  pathogens which have already infected cells

26 AP Biology Lymphocytes  B cells  mature in bone marrow  humoral response system  “humors” = body fluids  produce antibodies  T cells  mature in thymus  cellular response system  Learn to distinguish “self” from “non-self” antigens during maturation  if they react to “self” antigens, they are destroyed during maturation bone marrow

27 AP Biology B cells  Humoral response = “in fluid”  defense against attackers circulating freely in blood & lymph  Specific response  produce specific antibodies against specific antigen  Types of B cells  plasma cells  immediate production of antibodies  rapid response, short term release  memory cells  long term immunity

28 AP Biology Antibodies  Proteins that bind to a specific antigen  multi-chain proteins produced by B cells  binding region matches molecular shape of antigens  each antibody is unique & specific  millions of antibodies respond to millions of foreign antigens  tagging “handcuffs”  “this is foreign…gotcha!” each B cell has ~100,000 antigen receptors Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y antigen antigen- binding site on antibody variable binding region

29 AP Biology s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s Structure of antibodies light chains antigen-binding site heavy chains antigen-binding site light chain light chain heavy chains B cell membrane variable region antigen-binding site Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y

30 AP Biology How antibodies work macrophage eating tagged invaders invading pathogens tagged with antibodies Y Y Y Y Y Y

31 AP Biology  Immunoglobulins  IgM  1st immune response  activate complement proteins  IgG  2nd response, major antibody circulating in plasma  promote phagocytosis by macrophages  IgA  in external secretions, sweat & mother’s milk  IgE  promote release of histamine & lots of bodily fluids  evolved as reaction to parasites  triggers allergic reaction  IgD  receptors of B cells??? macrophage eating tagged invaders invading pathogens tagged with antibodies Y Y Y Y Y Y Classes of antibodies Weeks 0246 IgMIgG Exposure to antigen Antibody levels

32 AP Biology B cell immune response tested by B cells (in blood & lymph) 10 to 17 days for full response invader (foreign antigen) B cells + antibodies Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y recognition Y Y Y Y Y Y Y Y clone 1000s of clone cells Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y plasma cells release antibodies Y Y Y Y Y Y Y Y Y Y Y Y Y memory cells “reserves” Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y YY Y Y captured invaders

33 AP Biology 1° vs 2° response to disease  Memory B cells allow a rapid, amplified response with future exposure to pathogen

34 AP Biology Transcription of gene mRNA chromosome of undifferentiated B cell B cell C C D J DNA of differentiated B cell rearrangement of DNA V Translation of mRNA How do vertebrates produce millions of antibody proteins, if they only have a few hundred genes coding for those proteins? antibody By DNA rearrangement & somatic mutation vertebrates can produce millions of B & T cells

35 AP Biology What if the attacker gets past the B cells in the blood & actually infects some of your cells? You need trained assassins to kill off these infected cells! T Attack of the Killer T cells!

36 AP Biology T cells  Cell-mediated response  immune response to infected cells  viruses, bacteria & parasites (pathogens) within cells  defense against “non-self” cells  cancer & transplant cells  Types of T cells  helper T cells  alerts immune system  killer (cytotoxic) T cells  attack infected body cells

37 AP Biology How are cells tagged with antigens  Major histocompatibility (MHC) proteins  antigen glycoproteins  MHC proteins constantly carry bits of cellular material from the cytosol to the cell surface  “snapshot” of what is going on inside cell  give the surface of cells a unique label or “fingerprint” MHC proteins displaying self-antigens T cell

38 AP Biology How do T cells know a cell is infected  Infected cells digest pathogens & MHC proteins bind & carry pieces to cell surface  antigen presenting cells (APC)  alerts Helper T cells MHC proteins displaying foreign antigens infected cell T cell antigen receptors T cell WANTED

39 AP Biology T cell response stimulate B cells & antibodies Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y YY Y Y killer T cell activate killer T cells or interleukin 1 interleukin 2 infected cell helper T cell activated macrophage

40 AP Biology Attack of the Killer T cells Killer T cell binds to infected cell  Destroys infected body cells  binds to target cell  secretes perforin protein  punctures cell membrane of infected cell infected cell destroyed cell membrane Killer T cell cell membrane target cell vesicle perforin punctures cell membrane

41 AP Biology Learning check  Explain the various situations in which you would get a humoral response vs. a cell mediated response

42 AP Biology Vaccinations  Immune system exposed to harmless version of pathogen  triggers active immunity  stimulates immune system to produce antibodies to invader  rapid response if future exposure  Most successful against viral diseases

43 AP Biology Jonas Salk  Developed first vaccine  against polio  attacks motor neurons 1914 – 1995 April 12, 1955 Albert Sabin 1962 oral vaccine

44 AP Biology Polio epidemics 1994: Americas polio free

45 AP Biology  Obtaining antibodies from another individual  Maternal immunity  antibodies pass from mother to baby across placenta or in mother’s milk  critical role of breastfeeding in infant health  mother is creating antibodies against pathogens baby is being exposed to  Injection  injection of antibodies  short-term immunity Passive immunity

46 AP Biology Blood donation clotting

47 AP Biology Immune response summary free antigens in bloodantigens on infected cells humoral responsecellular response B cellsT cells macrophages (APC) helper T cells plasma B cells memory B cells memory T cells cytotoxic T cells Y Y Y Y YY Y Y antibodies Y Y Y skin pathogen invasion antigen exposure

48 AP Biology Learning Check  Compare:  Antigen vs. Antibody  Natural vs. Acquired Immunity  Active vs. Passive Immunity  Immunization vs. Immunoglobulin

49 AP Biology HIV & AIDS  Human Immunodeficiency Virus  virus infects helper T cells  helper T cells don’t activate rest of immune system: T cells & B cells  also destroy T cells  Acquired ImmunoDeficiency Syndrome  infections by opportunistic diseases  death usually from other infections  pneumonia, cancer

50 AP Biology Immune system malfunctions  Auto-immune diseases  immune system attacks own molecules & cells  lupus  antibodies against many molecules released by normal breakdown of cells  rheumatoid arthritis  antibodies causing damage to cartilage & bone  diabetes  beta-islet cells of pancreas attacked & destroyed  multiple sclerosis  T cells attack myelin sheath of brain & spinal cord nerves  Allergies  over-reaction to environmental antigens  allergens = proteins on pollen, dust mites, in animal saliva  stimulates release of histamine

51 AP Biology Key attributes of immune system  4 attributes that characterize the immune system as a whole  specificity  antigen-antibody specificity  diversity  react to millions of antigens  memory  rapid 2° response  ability to distinguish self vs. non-self  maturation & training process to reduce auto-immune disease


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