BIOE 301 Lecture EightBIOE 301 – Lecture 8Review of Lecture 7Q3: How can technology solve health care problems?Roadmap of CS 1Connections – First day of classBone Marrow - Pluripotent Stem CellsSlide 8White Blood CellsPathogensTypes of PathogensQuestion:Slide 13BacteriaHow do Bacteria Cause Disease?VirusHow do Viruses Cause Disease?Slide 18Using Viruses for Good, not EvilPathophysiology of HIV/AIDSSlide 21The Immune SystemTypes of ImmunityTypes of Immunity - DefenseSlide 25Physical BarriersWhat happens when you get a splinter?Slide 28Slide 29Innate Immune SystemComponents of Innate Immune SystemSlide 33Adaptive Immune SystemWhat is an antibody?Slide 36Slide 37AntibodiesSlide 39Slide 40How do T Cells ID Virus Infected Cells?Slide 42Slide 43Slide 44Slide 45Immunologic MemorySlide 47Slide 48Putting it all togetherSlide 50Slide 51Slide 52Slide 53Summary of Lecture 8Slide 55For more info:BIOE 301 Lecture Eight Amit MistryFeb 6, 2007BIOE 301 – Lecture 8WARM-UPObservation: Global average near-surface atmospheric temperature rose 1.1 ± 0.40°Fahrenheit in the 20th century. What is the scientific approach to this?What is the engineering approach to it?Review of Lecture 7Science“Science is the human activity of seeking natural explanations for what we observe in the world around us.”Five steps of the scientific methodEngineeringSystematic design, production and operation of technical systems to meet practical human needs under specified constraintsSix steps of the engineering design methodQ3: How can technology solve health care problems? CS1: Prevention of infectious diseaseRoadmap of CS 1ScienceOrganisms that cause infectious diseaseImmunityEngineeringHow to make a vaccineVaccines: From idea to productSocietal ImpactHealth and economicsEthics of clinical trialsDeveloped world/Developing worldConnections – First day of classWhat caused the first bone marrow transplants to be rejected by recipients?Bone Marrow - Pluripotent Stem CellsHematopoietic stem cells differentiate into:White blood cellsRed blood cellsPlateletsMesenchymal stem cells differentiate into:Bone, cartilage, muscleWhite Blood CellsNeutrophil Lymphocyte Macrophage“The Defense”“The Good Guys”PathogensHow They Cause Disease“The Offense”“The Bad Guys”Types of PathogensBacteriaCells with membrane and cell wall (usually)Can survive outside host; reproduce without hostCan be killed or inhibited by antibioticsVirusesNucleic acid core with protein envelopeUse host intracellular machinery to reproduceCannot be killed with antibiotics>50 different viruses that can infect humansQuestion:Based on your understanding of the characteristics of bacteria, viruses, and blood cells, identify which item best represents each and be able to explain why you chose each.BacteriumVirus Blood cellPathogensHuman hair – 100,000,000 nmRed blood cell – 7,000 nmE. coli bacteria – 800 nmVirus – 100 nmwww.awcommunity.orgwww.its.caltech.edu/~boozerBacteriaHow do Bacteria Cause Disease?Invade hostReproduceProduce toxins disturb cell functionExamplesEscherichia ColiBacillus AnthracisMicrobacterium tuberculosisStreptococcus pneumoniaehttp://www.cubanology.com/Articles/Virus_vs_Bacteria.htmVirusHow do Viruses Cause Disease?Virus invades host cellBinds to cell membrane receptorsEndocytosis brings virus into cellVirus takes over cellUse viral nucleic acid and host cell resources to make new viral nucleic acid and proteinsMore virus is released from host cellVirus causes host cell to lyse ORViral particles bud from host cell surfaceVirus examples: Influenza, HIV, West Nile, HepatitisHuman Papillomavirus, Viriola MajorUsing Viruses for Good, not EvilGene Therapy: infect cells with beneficial DNADiabetesSCIDCancerSickle cell anemiaMSCystic fibrosiswww.nih.govPathophysiology of HIV/AIDSPathophysiology of HIV/AIDSThe Immune SystemHow Are We Protected Against Pathogens?Types of ImmunityThree layers of immunity:Physical BarriersInnate Immune SystemAll animals possessAdaptive Immune SystemVertebrates possessKeep pathogens outKill them if they get inTypes of Immunity - DefenseLine of scrimmagePhysical Barriers = Defensive LineInnate = Secondary DefenseAdaptive = CoachTypes of ImmunityPhysical BarriersSkin (2 square meters)Mucous Membranes (400 square meters)Innate Immune SystemProduces general inflammatory response when pathogens penetrate physical barriersAdaptive Immune SystemCan adapt to defend against any invaderImportant when innate immune system cannot defend against attack Provides immune system with “memory”Physical BarriersWhat happens when you get a splinter?What happens when you get a splinter?Pathogens gets past physical barrier1. Macrophages eat bacteria on splinterPhagocytosis2. Activated macrophages produce chemicals which:Increase local blood flow Increase permeability of blood vesselsRecruit other phagocytes to siteRednessHeatSwellingPusWhat happens when you get a splinter?Phagocytosishttp://jcs.biologists.org/cgi/content/full/119/9/1903/DC1Innate Immune SystemPrimarily effective against pathogens outside of cellsTwo main weapons:1) Professional phagocytesCells that eat stuff2) The complement systemProteins that tag stuff for destructionComponents of Innate Immune System1) Macrophages:Sentinels that patrol peripheryIf they find an invader, they become “activated”If activated, they:Send signals to recruit other immune system cells (Neutrophils)Become vicious killers Present antigen to adaptive immune system (more on this later)Components of Innate Immune System2) Complement proteinsPresent in tissues & bloodAttach to surfaces of bacteria and virusesTarget them for destruction by phagocytes Form Membrane Attack ComplexesRecruit other immune cells from bloodAdaptive Immune SystemAntibody-mediated:Fight pathogens outside of cellsCell-mediated:Fight pathogens inside of cellsWhat is an antibody?Bridge between:Pathogen Tool to kill itAntibodies have two important regions:Fab region: Binds antigen Binds surface of virus-infected cellFc region:Binds macrophages and neutrophils, induces phagocytosisBinds natural killer cell, induces
View Full Document