2The Immune system is the body’s defense system Against:BacteriaVirusesProtistsOther living invadersToxinsForeign debrisCancerous cellsThe immune system is complexDefends against threats known and unknown
3Elements of the Immune system Many lines of defense, for many kinds of threatsSkinBloodThymusSpleenLymphatic systemMucous membranesBone marrow
4Innate vs. Adaptive immunity Innate ImmunityAdaptive ImmunityNon-specificDefends against known invadersSkin, lysozymePre-existingCannot adapt to changing threatsMechanisms which fight specific invadersFor unknown threatsResponsiveRequires time to build defense (days)Cannot anticipate threatsRemembers previous threats
5Humoral vs. Cell-mediated Immunity Humoral immunityLive cells kill invadersInnate: Phagocytic cells (e.g. macrophages, neutrophils)Adaptive: B lymphocytes and T lymphocytes create specific responses to unique invadersProteins in blood (“humors”)Innate- complement system, clotting factors, cytokines, etc.Adaptive: Antibodies
6Blood is a mixture of cells and plasma Human Blood after centrifugation~55% Plasma~45% Red blood cells<1% White blood cells and platelets (“buffy coat”)
7Blood plasma Water Nutrients Solutes- Na+, Cl-, wastes, CO2, etc. Contains humoral immune elementsSome innate immunity
8All blood cells are part of the hematopoetic stem cell lineage
9Hematopoetic stem cells differentiate into all blood cells Pluripotent- able to become any one of many cell typesIncludes T cells, B cells, macrophages, etc.
10Red blood cells carry oxygen and CO2 Lose nucleus in developmentShort-lived, no repairPacked solid with hemoglobinMembranes designed to maximize surface areaFacilitate gas transfer
11Hemoglobin The oxygen-carrying protein Heterotetrameric protein 2 alpha subunits, 2 betaEach subunit holds a Heme groupEach heme holds an Fe++ ionEach Fe++ can bind an O2
12Hemoglobin binding curve In areas of High O2 (e.g., lungs)- binds O2 very well (picks up O2)In areas of Low O2 (e.g., muscles) binds O2 poorly (drops off O2)Myoglobin binds O2 in muscle & organ tissues
13Platelets assist with blood clotting Recruit plasma protein fibrinogen to a cutThey release clotting factorsClotting factors convert fibrinogen to fibrinFibrin net prevents blood loss
14The liquid part of blood is called A) water. B) plasma. C) serum. D) extrastitial fluid. E) anionic fluid.
15White blood cells come in a great variety of types
33Immune cells are the only cells with different DNA VDJ recombination of light and heavy chains generate antibody diversityChange is permanentA form of Russian Roulette for the cellSuccessful recombination creates a binding antibody- cell survivesUnsuccessful- cell is destroyedFinding a good cell takes time
34Bound antibodies are the mark of death for invaders
35Breast milk contains maternal antibodies Infants have no acquired immunityMother’s acquired immunity is transferred to the baby through nursingPassive immunityIs not retained by the baby
36Vaccination gives the body active immunity An antigen sample is given to a personPerson’s immune system mounts a response to the antigenAntigen can be deactivated/destroyed virus particles, etc.No waiting time for body to develop 2o immune response
37Antibodies can be used as therapy Some growth factors are overactive in certain cancersAntibody binds to growth factors, or their receptors
38Polyclonal Antibodies From multiple B cellsBind to different epitopes of an antigen
39Monoclonal antibodies Obtained from a single B cellBind to a single epitopeA single B cell is fused to a myeloma cellMyeloma cells are immortal
40Mouse antibodies can be humanized Constant regions of mouse antibody are gradually replaced with human sequences
41Fluorescent antibodies can be used in scientific experiments Fluorescent molecules can be linked to antibodiesAntibodies show us where proteins exist in vivo
42In an ELISA, Horseradish Peroxidase is linked to a 2o antibody
43Indirect ELISA To detect the presence of an antibody Primary AntibodySecondary AntibodyWashBlockWashSubstrate
57In Autoimmune disease, the immune system attacks the self
58Allergies are immune responses to harmless antigens
59A substance that can elicit an immune response is called a(n) A) complement.B) interferon.C) histamine.D) antibody.E) antigen.
60Which one of the following statements about HIV is false? A) The genome of HIV consists of RNA.B) HIV attacks helper T cells.C) New HIV are produced inside helper T cells.D) HIV is transmitted by body fluids transporting infected cells.E) Some antibiotics have proven effective in combating the spread of AIDS.
61Which type of immune response is always disadvantageous to a person? A) cell-mediatedB) inflammatoryC) humoral-mediatedD) autoimmuneE) All immune responses are advantageous.