ImmunizationTwo Artificial Methods of ImmunityActive immunizationAdministration of antigens so patient actively mounts a protective immune responsePassive immunization Individual acquires immunity through the transfer of antibodies formed by immune individual or animal 2012 Pearson Education Inc.

ImmunizationBrief History of ImmunizationChinese noticed children who recovered from smallpox did not contract the disease againThey infected children with material from a smallpox scab to induce immunity This process known as variolationVariolation spread to England and America but was stopped because of risk of death 2012 Pearson Education Inc.

ImmunizationBrief History of Immunization1796 Edward Jenner discovered process of vaccination1879 Louis Pasteur developed a vaccine against Pasteurella multocidaAntibody transfer developed when it was discovered vaccines protected through the action of antibodies 2012 Pearson Education Inc.

Figure 17.1 Effect of immunization-overview

ImmunizationBrief History of ImmunizationMany developing nations do not receive vaccinesEffective vaccines not developed for some pathogensVaccine-associated risks discourage investment in developing new vaccines 2012 Pearson Education Inc.

ImmunizationActive ImmunizationVaccine typesAttenuated (live) vaccinesUse pathogens with reduced virulenceCan result in mild infectionsActive microbes stimulate a strong immune responseCan provide contact immunityModified microbes may retain enough residual virulence to cause disease 2012 Pearson Education Inc.

ImmunizationActive ImmunizationVaccine typesInactivated (killed) vaccinesWhole-agent vaccinesSubunit vaccinesBoth safer than live vaccinesMicrobes dont provide many antigenic molecules to stimulate the immune responseOften contain adjuvants Chemicals added to increase effective antigenicity 2012 Pearson Education Inc.

ImmunizationActive ImmunizationVaccine typesToxoid vaccinesChemically or thermally modified toxins used to stimulate immunityUseful for some bacterial diseasesStimulate antibody-mediated immunityRequire multiple doses because they possess few antigenic determinants 2012 Pearson Education Inc.

Immunization 2012 Pearson Education Inc.ANIMATION Vaccines: Function

Immunization 2012 Pearson Education Inc.ANIMATION Vaccines: Types

ImmunizationActive ImmunizationVaccine typesCombination vaccinesAdministration of antigens from several pathogens Vaccines using recombinant gene technologyAttempts to make vaccines more effective, cheaper, saferVariety of techniques used to improve vaccines 2012 Pearson Education Inc.

Figure 17.2 Some uses of recombinant DNA technology for making improved vaccines-overview

ImmunizationActive ImmunizationVaccine manufactureMass-produce many vaccines by growing microbes in culture vesselsViruses are cultured inside chicken eggsIndividuals with egg allergies must avoid some vaccines 2012 Pearson Education Inc.

Figure 17.3 The CDC's recommended immunization schedule for the general population

ImmunizationActive ImmunizationVaccine safetyProblems associated with immunizationMild toxicity most common Risk of anaphylactic shockResidual virulence from attenuated virusesAllegations that certain vaccines cause autism, diabetes, and asthmaResearch has not substantiated these allegations 2012 Pearson Education Inc.

ImmunizationPassive ImmunotherapyAdministration of antiserum containing preformed antibodiesImmediate protection against recent infection or ongoing diseaseAntisera have several limitationsContain antibodies against many antigensCan trigger allergic reactions called serum sicknessViral pathogens may contaminate antiseraAntibodies of antisera are degraded relatively quicklyLimitations are overcome through development of hybridomas 2012 Pearson Education Inc.

Figure 17.4 The production of hybridomasMouse is injected with antigen.Plasma cells, which secrete antibodies, are removed.AntibodiesLong-lived myeloma cell lines are grown in culture.Hybridomas are formed by mixing and fusing plasma cells and myeloma cells; they are long lived and produce antibodies.HybridomaHybridomas are placed individually in small wells, and their antibodies are tested for reactivity against the antigen.A hybridoma that makes antibodies that react with the antigen is cloned.Monoclonal antibodiesHybridoma clone

Figure 17.5 The characteristics of immunity produced by active immunization and passive immunotherapyPassive immunotherapyInjectionBoostersActive immunizationTimeInitial inoculationAntibody (IgG, IgM) concentration (titer)

Antibody-Antigen Immune TestingUses serology Study and diagnostic use of antigenantibody interactions in blood serumTwo categories of immune testingDirect testing Looking for presence of antigensIndirect testing Look for antibodies that have formed against antigensTest chosen based on the suspected diagnosis, cost, and speed with which a result can be obtained 2012 Pearson Education Inc.

Immune TestingPrecipitation TestsOne of the easiest of serological testsAntigens and antibody mixed in the proper proportion form large complexes called precipitatesImmunodiffusionDetermines optimal antibody and antigen concentrations 2012 Pearson Education Inc.

Figure 17.6 Characteristics of precipitation reactions-overview

Figure 17.7 Immunodiffusion, a type of precipitation reaction-overview

Figure 17.8 Radial immunodiffusion, a type of precipitation reaction-overview

Immune TestingPrecipitation TestsRadial immunodiffusionUsed to measure specific antibodies in a persons serumProduces anti-antibodiesThe human antibodies are the antigen in the testAntibody is anti-human antibody 2012 Pearson Education Inc.

Immune TestingAgglutination TestsCross-linking of antibodies with particulate antigens causes agglutinationAgglutination is the clumping of insoluble particles Precipitation involves the aggregation of soluble moleculesReactions are easy to see and interpret with the unaided eyeHemagglutinationAgglutination of red blood cellsCan be used to determine blood type 2012 Pearson Education Inc.

Figure 17.9 The use of hemagglutination to determine blood types in humans-overview

Figure 17.10 Titration, the use of agglutination to quantify the amount of antibody in a serum sampleSerum added in increasing dilutionsAntigen (identical in each well)1:11:101:1001:10001:10,000Control (no specimen added)Control No agglutination Very strong agglutination

Immune TestingNeutralization TestsViral neutralizationCytopathic effectViruses will kill appropriate cell culturesVirus is first mixed with antibodies against itAbility of virus to kill culture cells is neutralizedAbsence of cytopathic effect indicates presence of antibodiesIdentify whether individual has been exposed to a particular virus or viral strain 2012 Pearson Education Inc.

Immune TestingNeutralization TestsViral hemagglutination inhibition testUseful for viruses that arent cytopathicBased on viral hemagglutinationAbility of viral surface proteins to clump red blood cellsIndividuals serum will stop viral hemagglutination if the serum contains antibodies against the specific virusUsed to detect antibodies against influenza, measles, mumps 2012 Pearson Education Inc.

Immune TestingThe Complement Fixation TestBased on generation of membrane attack complexes during complement activationDetect presence of specific antibodies in an individuals serum Can detect antibody amounts too small to detect by agglutination 2012 Pearson Education Inc.

Immune TestingLabeled Antibody TestUses antibody molecules linked to some label that enables them to be easily detectedUsed to detect either antigens or antibodies 2012 Pearson Education Inc.

Immune TestingLabeled Antibody TestFluorescent antibody testsUse fluorescent dyes as labels Fluorescein is one dye used in these testsFluorescein-labeled antibodies used in two types of testsDirect fluorescent antibody testsIndirect fluorescent antibody tests 2012 Pearson Education Inc.

Figure 17.11 The direct fluorescent antibody test

Figure 17.12 The indirect fluorescent antibody test-overview

Immune TestingLabeled Antibody TestELISAEnzyme-linked immunosorbent assayUses an enzyme as the labelReaction of enzyme with its substrate produces colored productCommonly used to detect presence of antibodies in serum 2012 Pearson Education Inc.

Figure 17.13 The enzyme-linked immunosorbent assay (ELISA)Antigen is attached to well in plate.A protein such as gelatin is added to block the uncoated surface.Patient serum is added; complementary antibody binds to antigen.EnzymeAnti-antibodyEnzyme-linked anti-antibody is added and binds to bound antibody.Enzymes substrate is added, and reaction produces a visible color change.SubstrateColored product

Immune TestingLabeled Antibody TestELISAAntibody sandwich ELISAModification of the ELISA techniqueCommonly used to detect antigenAntigen being tested for is sandwiched between two antibody molecules 2012 Pearson Education Inc.

Figure 17.14 An antibody sandwich ELISA-overview

Immune TestingLabeled Antibody TestELISAAdvantages of the ELISACan detect either antibody or antigenCan quantify amounts of antigen or antibodyEasy to perform and can test many samples quicklyPlates coated with antigen and gelatin can be stored for later testing 2012 Pearson Education Inc.

Immune TestingLabeled Antibody TestWestern blot testTechnique to detect antibodies against multiple antigensAdvantages over other testsCan detect more types of antibodies Less subject to misinterpretation 2012 Pearson Education Inc.

Figure 17.15 A western blot-overview

Immune TestingRecent Developments in Antibody-Antigen Immune TestingSimple immunoassays that give results in minutesUseful in determining a preliminary diagnosisImmunofiltration and immunochromatography are most common 2012 Pearson Education Inc.

Immune TestingRecent Developments in Antibody-Antigen Immune TestingImmunofiltrationRapid ELISA that uses antibodies bound to membrane filters rather than polystyrene platesMembrane filters have large surface areaAssay quicker to complete 2012 Pearson Education Inc.

Immune TestingRecent Developments in Immune TestingImmunochromatographyVery rapid and easy-to-read ELISAsAntigen solution flows through a porous strip and encounters labeled antibodyVisible line produced when antigen-antibody immune complexes encounter antibody against themUsed for pregnancy testing and rapid identification of infectious agents 2012 Pearson Education Inc.

Figure 17.16 Immunochromatographic dipstickZone of antibodies linked to colloidal metal, color too diffuse to seeLine of fixed anti-antibodyMovement of fluid containing complexes of antibodies bound to antigenAnti-antibodies stop movement of antibody- antigen complexes. Color becomes visible because of density of complexes.Prepared antigen extract from patients nasal sampleDipDipStrep AStrep A

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