Test 3 Material – Flashcards
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| Important aspects of adaptive immunity |
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| 1. antigen-specific 2. systemic 3. is learned 4. has memory |
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| 2 types of adaptive immunity |
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| 1. cell-mediated immunity 2. antibody-mediated immunity |
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| cell mediated immunity steps |
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| 1. an antigen evades body’s innate defenses 2. antigen is taken up by an antigen-presenting cell (APC; dendritic cells) and broken down 3. antigen fragments merge with MHC proteins on the APC’s membrane 4. T-cell comes into contact with APC, recognizes the “new” MHC protein and becomes active 5. activated T-cells divide & differentiate |
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| MHC |
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| special protein imbedded in a cell’s membrane; allows for the recognition of self Stands for major histocompatability complex |
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| cytotoxic T-cells (CD8 cells) |
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| 1) primarily attack cells infected by viruses or other intracellular microbes, cancer cells, & transplanted cells 2) activation results in apoptosis of target cell a) deprives antigen of host & exposes it to antibodies 3) mechanism isn’t completely understood but some possibilities include: a) secretion of perforin & granzymes i) perforins create pores in the target cell’s membrane allowing granzymes to move in & degrade interior cellular components b) secretion of a lymphotoxin into target cell fragmenting its DNA |
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| apoptosis |
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| a specialized cell destruction that releases no toxins |
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| Helper T-cells (CD4 cells) |
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| 1) produce a # of interleukins (IL’s) a) IL-2 – stimulates T-cell proliferation b) IL-4 – promotes T-cell growth; stimulates production of IgE c) IL-5 – promotes the secretion of IgA 2) stimulates the production of other T & B cells |
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| Cells in cell mediated immunity |
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| Cytotoxic T cells Helper T cells Suppressor T cells Memory T cells |
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| Antibody-mediated immunity |
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| 1. cell-mediated response has occurred 2. helper T cells activate the response A) stimulate B cell division & differentiation 1) plasma cells & memory B cells B) enhance antibody production 3. antibody merges w/ antigen = antigen-antibody complex 4. antibody cause destruction of antigen |
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| neutralization |
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| bind to toxins or virus rendering them useless |
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| immobilization |
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| bind to cilia or flagella slowing antigen movement |
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| destruction of the antigen |
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| A) neutralization B) immobilization C) attraction of phagocytes D) enhances phagocytosis 1) aids adherance E) stimulate inflammation F) inhibit antigen metabolism |
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| 5 classes of antibodies (immunoglobulins) |
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| IgA IgE IgD IgM IgG |
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| IgA |
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| found in blood plasma 1) prevents pathogens from adhering to epithelia and penetrating tissues |
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| IgD |
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| integral part of B cell membrane 1) acts as an antigen presenter |
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| IgE |
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| found mainly in tonsils, skin, and mucus membranes 1) stimulates mast cells (basophils) to release contents and attracts eosinophils to parasitic worm infections |
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| IgG |
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| 75-85% of circulating antibodies in plasma 1) crosses placenta to confer temporary immunity to the fetus |
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| IgM |
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| found on the B cell membrane and circulating in plasma 1) presence indicates a recent infection |
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| Vaccination definition |
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| the practice of deliberately stimulating the immune system in order to protect individuals against a disease |
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| Vaccination facts |
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| 1. Edward Jenner developed the first official smallpox variolation technique using cowpox virus 2. Pasteur used the word vaccination from the Latin word vacca meaning “cow” 3. It is possible for a portion of a population to become immune to a disease, either through natural immunity or vaccination A) herd immunity – the inability of an infection to spread within a population due to the lack of susceptible hosts |
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| Naturally acquired immunity |
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| acquisition through normal events |
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| artificially acquired immunity |
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| acquisition via non-natural means |
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| Active immunity |
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| the immunized individual makes their own antibodies |
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| Passive immunity |
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| the immunized individual did not make the antibodies |
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| Naturally acquired-active immunity |
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| natural exposure to an antigen causes the person to produce their own antibodies A) ex. getting over chickenpox |
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| Naturally acquired-passive immunity |
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| natural activities provide the individual with antibodies that someone else made after natural exposure to the antigen A) ex. antibodies transferred from mother to child via breast milk or across the placenta |
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| Artificially acquired-active immunity |
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| deliberate exposure to the antigen via an injection causes the person to make their own antibodies to the antigen A) ex. immunization of children for measles |
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| Artificially acquired-passive immunity |
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| deliberate introduction of antibodies made by some other individual into the body of the patient A) ex. RhoGAM & antivenom |
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| Vaccine |
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| a preparation of living or inactivated (dead) microorganisms, viruses, or their components used to induce active immunity |
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| Requirements of an effective vaccine |
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| A) Safe B) Few side effects C) Provide lasting immunity against a specific illness by inducing antibodies, immune cells, or both D) Low cost E) Stable with a long shelf life F) Easy to administer |
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| Attenuated vaccine (alive) |
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| weakened form of disease-causing agent 1) generally unable to cause disease but can still induce immune response 2) attenuated strains typically produce infection w/ undetectable/mild symptoms 3) often only single dose is needed to induce long-lasting immunity 4) can be spread from immunized individual to non-immunized people, inadvertently immunizing the contacts a) attenuated strains can cross the placenta and can be passed in breast milk 5) BC they can spread, they have potential of causing disease in immunosuppressed people 6) some can revert or mutate back into the disease-causing form 7) examples include tuberculosis, MMR, oral polio, and chickenpox |
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| Inactivated vaccines (dead) |
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| forms unable to replicate but still cause an immune response 1) Can't cause infection, revert to dangerous forms, or be passed on to others 2) the magnitude of the immune response by inactivated vaccines is very limited a) most require multiple exposures 3) many inactivated vaccines contain an adjuvant a) ex: include aluminum phosphate & aluminum hydroxide 4) There are 2 general categories of inactivated vaccines: Whole agents, & fractions of the agent |
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| Adjuvant |
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| a substance that enhances the immune response to antigen |
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| Whole agents |
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| dead microorganisms or inactivated viruses; ex. influenza, rabies, and the injectable polio |
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| Fractions of the agent |
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| only pieces of the microorganism that can induce an immune response |
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| Toxoids |
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| inactivated toxins; ex. diphtheria and tetanus vaccines (fractions of the agent) |
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| Protein subunit vaccines |
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| composed of key protein antigens of the infectious agent; ex. Hepatitis B and anthrax vaccines (fractions of the agent) |
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| Polysaccharide vaccines |
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| composed of the polysaccharides that make up the capsule of certain microorganisms; ex. Streptococcus pneumoniae vaccine (fractions of the agent) |
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| Serology |
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| use of serum antibodies to detect and identify antigens, or conversely, use of known antigens to detect antibodies |
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| Titer |
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| is a measure of the amount of specific antibody in serum A) can determine a person’s level of immunity to a specific antigen B) individuals exposed to an antigen for the first time usually do not have detectable antibodies in the blood serum until about 7-10 days after infection |
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| Monoclonal antibodies |
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| contain only one antibody with one specificity A) commonly used in immunoassays |
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| Mechanism of Enzyme-Linked Immunosorbent Assay |
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| a) Known antigen is attached to plastic wells. b) The serum to be tested is added & incubated. If antibodies are present, they will bind to the antigen. c) To detect if antigen-antibody reactions have occurred, anti-HGG is added. d) The anti-HGG reacts with any bound antibodies & the excess is washed away. e) A chromogen is added & colored end product is produced if antibodies were present. |
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| Examples of immunoassays |
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| Enzyme-Linked Immunosorbent Assay (Elisa) Western Blot Fluorescent Antibody Technique |
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| What is ELISA used for? |
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| detect HIV Home pregnancy tests |
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| Western Blot |
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| combination of electrophoresis with ELISA to separate and identify protein antigens in a mixture |
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| Fluorescent Antibody Technique |
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| involves mixture of antigens, antibodies, and a fluorescent dye |
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| Indirect method of Fluorescent Antibody Technique |
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| detects the presence of antibodies produced in response to an antigen; used to detect syphilis i) a known antigen (ex. syphilis) is added to a sample of the patient’s serum along with a fluorescence-labeled antiglobulin antibody (a) the antiglobulin antibody will only bind to an antibody bound to an antigen (i.e. it only binds if syphilis antibodies are present and bind to the added syphilis antigen) ii) binding of the antiglobulin antibody causes illumination of the fluorescent dye |
