Micro 18

  1. Naturally acquired immunity
    the acquisition of adaptive immunity through normal events, such as exposure to infectious agent
  2. artificially acquired immunity
    • immunity that results from an immune response in an individual after vaccination
    • can be either active or passive
  3. Active immunity
    • result of immune response in an individual upon exposure to antigen
    • Specific B and T cells are activated & proliferate, giving lasting protection due to immunological memory
    • Can develop either naturally from actual infection or artificially from vaccination
  4. Passive immunity
    • occurs naturally during pregnancy; mother's IgG cross placenta and protect fetus
    • These antibodies remain active in newbody during first few months of life, while his/her immune system is developing
    • Also occurs as result of breastfeeding: secretory IgA in breast milk protects digestive tract
  5. Natural passive immunity
    immunity that results when antibodies from a woman are transferred to her developing fetus during prego & to infant during breast feeding
  6. Artificially acquired passive immunity
    • involves injecting person with antibodies produced by other people or animals
    • Can be used to:
    • Prevent disease immediately before or after likely exposure to antigen
    • limit duration of certain diseases
    • block action of microbial toxins
  7. antiserum
    a preparation of serum (the fluid portion of blood that remain after blood clots) containing protective antibodies
  8. antitoxin
    type of antiserum that protects against a given toxin
  9. What 2 types of antisera are used?
    • Antisera is antitoxin
    • Hyperimmune globulin
    • immune globulin
  10. Hyperimmune globulin
    • one type of antitoxin
    • prepared from sera of donors with high amounts of antibodies to certain disease agents
    • used to prevent or treat specific disease
    • If given during incubation period, can often prevent severe disease from developing
    • Ex: tetanus, rabies, Hep B
  11. Immune globulin
    • the IgG fraction of pooled blood plasma from many donors
    • has variety of antibodies due to typical infections and vaccines experienced by donors
    • used to protect unvaccinated people who were recently exposed to measles virus and immunosuppressed who have low antibody levels
  12. vaccine
    a preparation of a pathogen or it's products used to induce active immunity
  13. Polio vaccine
    • two forms:
    • inactivated virus (Salk vaccine)
    • attenuated virus (Sabin vaccine)

    Children should get it, attenuated virus is used for global control
  14. 2 types of vaccines
    • attenuated (live)
    • inactivated (killed)
  15. Attenuated vaccine:
    What is it?
    Antibody response (memory)
    Cell-mediated immune response
    Is a weakened form of pathogen that generally can't cause disease

    Antibody response: IgG; secretory IgA if administered orally or nasally

    Cell mediated immune response: Good!
  16. Attenuated vaccine:
    Duration of protection
    Need for adjuvant?
    Number of doses?
    Risk of mutation to virulence?
    • Duration is long-term
    • No need for adjuvant
    • Usually only single dose is needed
    • Very low risk for mutation to virulence
  17. Attenuated vaccine:
    Risk to immunocompromised pt
    Route of administration
    Stability in warm temp
    • Can be of significant risk to immunocompromised pt
    • Route of administration: injection, oral or nasal
    • Has POOR stability in warm temps
    • Types: attenuated viruses and bacteria
  18. Disadvantages to attenuated vaccine
    • sometimes cause disease in immunocompromised
    • generally not advised for prego
    • Require refrigeration to keep them active
  19. Attenuated vaccines currently in widespread use
    • MMR 
    • Chicken pox
    • Rotavirus
    • Yellow fever
    • Sabin vaccine
  20. Inactivated vaccine:
    What is it?
    Antibody response (memory)
    Cell-mediated immune response?
    • Unable to replicate, but retains the immunogenicity of the pathogen or toxin
    • Antibody response: IgG
    • POOR cell mediated immune response
  21. Inactivated vaccine:
    Duration of protection
    Need for adjuvant
    Number of doses
    Risk of mutation to virulence?
    • Duration of protection is short term
    • Needs an adjuvant
    • Multiple doses are needed
    • No risk of mutation to virulence
  22. Inactivated Vaccine:
    Risk to immunocompromised
    Route of administration
    Stability in warm temp
    • No risk to immunocompromised
    • Route of administration is only injection
    • Stability in warm temps is good
  23. What types of inactivated vaccines are there?
    • Inactivated whole agents
    • toxoids
    • subunit vaccines
    • VLP's
    • Polysaccharide vaccines
  24. Inactivated whole agent vaccines
    • Type of inactivated vaccine
    • contains killed microorganism or inactivated viruses
    • Vaccines are made by treating the pathogen with formalin or other chemical that doesn't significantly change the surface epitopes
    • Tx leaves agent immunogenic even though it can't reproduce
    • Includes:
    • Flu, rabies, and Salk vaccine (polio)
  25. Toxoids
    • type of inactivated vaccine
    • are inactivated toxins used to protect against diseases caused by bacterial toxins
    • prepared by treating toxins to destroy the toxic part of molecules while retaining antigenic epitopes
    • Ex: diphtheria and tetanus
  26. Subunit vaccines
    • type of inactivated vaccine
    • consist of key protein antigens or antigenic fragments of pathogen
    • Developed after research reveals which microbes components are most important in triggering protective immune response
    • Advantage is cell parts that may cause undesirable side effects are not included
    • Ex: pertussis (whooping cough) vaccine
  27. Recombinant vaccines
    • Type of subunit vaccine produced by genetically engineered microorganisms
    • Ex: vaccine for hep B; produced by yeast cells engineered to produce part of viral protein coat
  28. VLP vaccines
    • Virus-Like Particle
    • Type of inactivated vaccine
    • Are empty capsids
    • Lab organisms are genetically engineered to produce the major capsid proteins of virus, which then self-assemble
    • Ex: HPV vaccine
  29. Polysaccharide vaccine
    • type of inactivated vaccine
    • contain the polysaccharides that make up the capsules of certain organisms
    • not effective in young kids as polysaccharides are T-independent antigens; recall these antigens generally elicit poor response in this age group
    • Ex: pneumococcus vaccine given to adults
  30. Conjugate vaccines
    • type of inactivated vaccine
    • are polysaccharides linked to proteins, a modification that converts the polysaccharides into T-dependent antigens
    • First conjugate vaccine developed was against Haemophilus influenzae type b (Hib) & nearly eliminated Hib meningitis in kids
  31. Adjuvant
    • substance that enhances the immune response to antigens
    • Necessary additives as purified antigens such as toxoids and subunit vaccines are often poorly immunogenic by themselves as they lack the danger signals
    • Thought to function by providing the danger signals
    • Many inactivated vaccines require them
  32. Poliomyelitis
    • virus enters body orally, infects throat and intestinal tract, and then invades the bloodstream. from there it can invade nerve cells
    • Are 3 types of poliovirus, any of which can cause poliomyelitis
  33. Salk vaccine
    • First polio vaccine developed in mid-1950's
    • Consists of inactivated viruses of all 3 types
    • successfully lowered rate of disease dramatically, but disadvantage of requiring a series of injections for max protection
    • Provides better protection against transmission of wild-type virus
  34. Sabin vaccine
    • 2nd polio vaccine, developed in 1961
    • advantage of cheaper oral administration
    • That attenuated vaccine strains replicate the in intestine, but vaccine still has to be given in series of 3 doses because of interactions among viruses
    • Better induces mucosal immunity (secretory IgA response) and therefore provides better herd immunity
    • Disadvantage is attenuated vaccine can mutate to become virulent
  35. Immunoassays
    Take advantage of specificity of antibody-antigen interactions and use them for dx
  36. seroconverstion
    • the change from seronegative to seropositive
    • Seronegative refers to someone who lacks specific antibodies against a microbe in their serum
    • Seropositive refers to someone who becomes infected, will begin producing specific antibodies in about a week/10 days, and will have antibiodies
  37. Plasma
    fluid portion of blood treated with an anticoagulant to prevent clotting
  38. serology
    • the study of in vitro antibody-antigen interactions
    • Testing a pt for specific antibodies to dx disease
  39. New types of vaccines
    Include peptide vaccines, edible vaccines, and DNA based vaccines
  40. Peptide vaccines
    • composed of key antigenic peptides from disease-causing organisms
    • stable to heat and don't contain extra material that might cause unwanted side effects or reactions
  41. Edible vaccines
    • created by transferring genes encoding key antigens from infectious agents into plants
    • If appropriate plants can be genetically engineered to function as vaccines, could potentially be grown world wide & eliminate difficulties involving transport and storage
  42. DNA-based vaccines
    • segments of naked DNA from infectious organisms that can be introduced directly into muscle tissue
    • Host tissue actually expresses the DNA for a short period, producing encoded microbial antigens, which induces immune response
  43. Polyclonal antibodies
    • Obtained by using lab animals that produce antibodies known to bind to certain infectious agent
    • recognize a variety of epitopes 
    • animals are immunized with either whole agent or part, and resulting antibodies are then collected by harvesting animals serum
  44. Anti-human IgG antibodies
    • Antibodies that bind to the constant region of human IgG molecules
    • are produced by animals that have been immunized the IgG from human serum
    • Used in certain serological tests
  45. Monoclonal antibodies
    • recognize only a single epitope
    • difficult and expensive to develop
    • Have been used to treat non-Hodgkin's lymphoma that has not responded to traditional tx
  46. precipitation reactions
    • reaction of an antibody with soluble antigen to form an insoluble substance
    • can be used to detect specific antibodies/antigens
    • when antibodies bind to soluble antigens, the molecules sometimes cross-link to form lattice-like insoluble complexes that then precipitate out of solution
  47. agglutination reactions
    • Like precipitation reaction, also relies on cross-linking and lattice formation
    • Involves relatively large insoluble particles 
    • Includes:
    • Direct agglutination test
    • Passive agglutination test
  48. Direct agglutination test
    • an antibody suspension is mixed with insoluble antigen, such as RBC, bacteria, or fungi
    • If antibody bind to antigens, visible clumping will occur - positive test
    • The agglutination of RBC by antibody binding or other means is referred to as hemagglutination, is used in blood typing
  49. Passive agglutination test
    • used either antibodies or antigens attached to particles such as latex beads to make the aggregates larger and therefore easier to see
    • Beads are mixed with drop of body fluid or suspended microbial culture
    • If specific antigen is present, visible clumps form
  50. Basic principles of using labeled antibodies to detect antigen/antibody interactions:
    Direct vs indirect test
    Direct tests typically used to id an unknown antigen.Labeled antibodies of known specificity are added to preparation of antigen attached to solid surface.

    Indirect tests are often used to detect antibodies of a given specificity in a pt's serum. Called indirect as they require labeled secondary antibody to detect 1st (or primary) antibody
  51. Indirect tests
    • To determine is serum sample contains antibodies of given specificity, serum is added to a known antigen attached to solid surface.
    • Any unbound serum antibodies are washed off.
    • Secondary antibody is then added, when in this case would be labeled anti-human IgG antibodies. These bind to any IgG bound to the antigen
    • After another washing, presence of labeled secondary antibody id's primary antibody bound to antigen
    • *Note usefulness of labeled 2ndary antibodies as they can bind to any human IgG & can be used to detect specific antibodies in a variety of different pts'
  52. fluorescent antibody (FA) Test
    • use fluorescence microscopy to locate fluorescently labeled antibodies bound to antigens fixed to microscope slide
    • Antigens are often bacterial cells & antibodies may be bound directly or indirectly
  53. ELISA
    • Enzyme-linked immunosorbent assay test
    • uses antibodies labeled with an enzyme such as peroxidase from the horseradish plant
    • Enzyme can be detected using colorimetric assay, which measures enzymatic conversion of colorless substrate into colored product
  54. Direct ELISA
    • Uses known antibody
    • Antigen is sometimes "captured" by antibodies that have been attached to surface
    • Ex: Tests for giardia used wells in ELISA plates; bottom of "wells" on plates were coated with antibodies for giardia antigen.
    • Ex: Home preg tests and rapid group A strep tests done in doc office done this way also
  55. Indirect ELISA
    • Uses known antigen 
    • routinely used to test blood and serum for antibodies against HIV
    • Again, use bubbled or plate with wells in it. Except in this case, known antigen is attached to well.
  56. Western blotting technique
    • The various proteins that make up an antigen are separated by size before reacting them with antibodies
    • Makes it possible to determine exactly which proteins the antibodies are recognizing, an essential part of accurate HIV testing
  57. How are proteins separated for Western blotting technique
    • a special type of gel electrophoesis called SDS-PAGE is used
    • Separates proteins of different sizes into a series of bands, as smaller proteins move faster than larger ones
    • Separated proteins are then transferred to a nylon membrane to immobilize them before a solution of antibody molecules is added
  58. FACS
    • Fluorescence-activated cell sorter
    • Used to count and separate antigens labeled with fluorescent antibodies
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Micro 18
Micro 18