Practical Applications (PowerPoint download)

							Practical Applications
   Variolation
   Jenner and the dairy maid
   Cowpox vaccine and then the vaccinia virus
   Vaccines
       Injection of antigens used to induce immunity—Production of Memory
        Cells!!!
            Memory cell production of antibodies after exposure to similar antigen
             associated with pathogen or actual antigen associated with pathogen
       6 basic types
            Toxoid
            Attenuated whole-agent vaccines:
            Inactivated whole-agent vaccines
            Subunit vaccines:
            Conjugated vaccines
            Nucleic acid vaccines
       Something that mimics the real organism the most will inherently be the
        most effective vaccine, but could be dangerous
            Whole agent
                  Tend to give more effective immunity than toxoid and subunit
            Live versus inactivated
                  Live tend to give more effective immunity
                                Vaccine Types
   Toxoid
       Inactivated toxin produced by pathogen
        Usually require boosters (what is a booster?)
       ex) diptheria and tetanus vaccines
   Attenuated whole-agent vaccines
       Live, but weakmutants
       Most dangerous, but most effective type of vaccine
            Don’t usually require boosters
            Mutant reversal could cause danger
            Not for immunocompromised individuals
       Ex) MMR, Sabin polio and small pox vaccines
   Inactivated whole-agent vaccines
       Dead
            Killed with formalin or phenol
       Safer, but sometimes less effective than live
            Require boosters
       EX) Salk polio or rabies or influenza
                        Vaccine Types
   Subunit vaccines:
       Antigenic fragments (like what?)
       Recombinant versus acellular vaccines
       Extremely safe
       EX) hepatitis B
   Conjugated vaccines
       For antigens that are capsular polysaccharides (T-independent)
       For children under 2 b/c of poor response to T-independent antigens*
       Polysaccharides are linked to protein antigen
       EX) Haemophilus influenzae
   Nucleic acid vaccines
       Experimental
       Gene gun: injection of naked DNA
       DNA for the antigen is transcribed and translated in the muscle
              Vaccine Considerations
   Cost
       If the cost is high and normal risk is low then no vaccine
   Safety
       Sometimes a toxoid, subunit or inactivated vaccine are not
        effective for certain organisms (small pox)
       Attenuated whole agent vaccines cannot be used on everyone
        without some risk
   Allergies
       Viral vaccines (ex--influenza) are often grown in embryonated
        eggs
   Effectiveness
       Some vaccines are not as effective as safe practice
   If herd immunity already exists why risk lives and force
    people to spend money on a vaccine.
                       Dream Vaccine
   Eaten instead of injected
       Problems: stomach acids destroy the vaccine
       Plant use: cell walls of plants can protect them until they
        reach the small intestine
   Safe, lifelong immunity with single dose
       Problem: greater the immunity often means more dangerous
        vaccine
            Use of adjuvants to improve effectiveness
   Stable without refrigeration
   Affordable
       Need cheaper and more reliable ways to produce them
       Recombinant Vaccines tend to be produced more cheaply
New Golden Age of Immunology
   Golden Age of Immunology 1870-1910
   New Golden Age
       75 new vaccines being developed
       EX) AIDS, malaria and cancer
       Improvements in old vaccines
            Adjuvants—chemicals that may increase the effectiveness of response
             to an antigen in a vaccine
       Improvements in delivery (pressure gun, in food, patches,
        etc)
       Safer vaccines
            Nucleic acid vaccines, acellular vaccines, recombinant vaccines
Childhood Vaccine Schedule
                   Are Vaccines Safe?
   Not Always
   Why put my child at risk of getting the disease or having a bad
    reaction?
        There are fewer adverse reactions to the vaccines than there are to the
         actual diseases
   My friend told me that her child has autism because he got the
    MMR vaccine
        The diagnosis of autism coincidentally occurs at 18-30 months; the same
         time the first MMR vaccine schedule is complete.
   My friend’s, friend’s, friend’s sister’s brother died from getting a
    vaccine!
        While this is possible; is it common?
   Prior to vaccine use childhood mortality rate was MUCH greater
    than it is today!
                                Diagnosis

   Step 1: signs and symptoms
   Step 2: Disease
   Step 3: Organism
   Step 4: Treatment
   Diagnostic techniques help us determine the etiology of the disease
   Diagnostic techniques
       Microscopy
       Culture
            Test biochemical properties of microbe
       Molecular
            Use PCR to amplify a gene associated with the disease
            Identify the gene on a gel
       Immunological
            How big is an antibody? Can we see it under a microscope?
First Diagnostic Immunology Test




                  Cell mediated immune reaction.
                  Inflammation response.
                         Diagnostic Tests
   Diagnostic immunology involves using the principles of the
    immune system or antibody—antigen reaction to diagnose
    diseases or detect antigens in bodily fluids
   5 important diagnostic tests
       Direct agglutination
       Indirect agglutination
       Hemagglutination
            Regular and viral
       Direct ELISA
       Indirect ELISA
                   Principles of Diagnostic
                        Immunology
   Physician collects a sample (2 choices)
       Antigen sample
            A bodily fluid that contains the infecting microbe or the microbes toxin
                  Urine, feces, blood, skin, pus, throat swab, mucous, etc.
       Blood antiserum sample
            Blood antiserum contains the antibodies that the patient made against an
             infection; if the patient is infected with the suspected pathogen then
             his/her serum has those antibodies in it.
   If the sample is…
       Antigen then the physician exposes it to pre-made antibodies for
        the suspected pathogen
            Antibodies are produced by a rabbit when the rabbit is infected with that
             organism; they are collected in sterile vials and sold by pharmaceutical
             companies
     When patient antigen sample is
     exposed to pre-made antibody


Throat swab taken (antigen     Antibodies to Streptococcus made
from suspected Streptococcus   by pharmaceutical company and
invader)                       sold to physician.
                                                                  Antigens from throat swab
                                                                  exposed to antibodies specific to
                                                                  Streptococcus. If the patient is
                                                                  infected with Strep then a reaction
                                                                  occurs as seen above.
                  Principles of Diagnostic
                       Immunology
   If the sample is…
       Blood antiserum then physician exposes it to an antigen
        from the suspected pathogen
            Antigen from microorganism is prepared by pharmaceutical
             company pharmaceutical company
                 It could be a toxin, an inactivated whole agent, or any subunit from
                  the suspected pathogen
     When patient antiserum is
    exposed to pre-made antigen.


                 Blood containing   Antiserum        HIV antigen is exposed to blood
Blood is drawn   many WBCs          separated from   serum. If the patient is infected
                                    blood            with HIV then a reaction occurs
                                                     as seen above.
               What is a Titer?
   The amount of antibody in the antiserum
   Can be used to determine how far a disease has
    progressed
   Direct agglutination tests can be used to detect
    the antibody titer of a person.
   When a person goes from no antibody to
    elevated antibody then this is called
    seroconversion.
                                    Agglutination Tests
   Agglutination occurs when antibody binds to more than one antigen at
    a time.
   Direct*
       Used to detect antibodies in antiserum that are specific for large cellular
        antigens
       Used mostly to determine titer
            Determine stage of disease
   Indirect agglutination*
            For soluble antigens
            To detect antigens in pateint sample or antibodies in patient antiserum
            Soluble antigens or antibodies are adsorbed onto beads
                  BEAD test
            Quick!
            10 min. Strep A throat test
                  Throat swab sample exposed to beads coated with antibody specific for Streptococcus A
Direct agglutination: IgM
Least serum
              No serum
Indirect
agglutination
                 Hemagglutination

   When blood cells are agglutinated due to antigens
    present on blood
       Blood is the antigen in the agglutination test
   Test used to determine blood type.
   If blood has type A antigens then it will agglutinate
    in the presence of type A antibodies.
   We will discuss blood typing further in lab and in
    the next chapter.
             Viral Hemagglutination
   Some viruses agglutinate RBCs
       Mumps, measles, influenza
   If antibodies bind to virus first then they cannot clump
    RBCs when blood is added.
   Test:
       Take serum sample from patient and mix with suspected
        virual pathogen
       Add blood
            If clumping occurs? Negative or positive?
Viral Hemagglutination Test
                                  ELISA
   Enzyme Linked Immunosorbent Assay
   Colorimetric assay
   Enzyme reacts with substrate to produce colored product
   Direct
       Enzyme is linked to an antibody (made by pharmaceutical
        company)
       Detects antigen from patient sample
       EX) Home pregnancy test to test for hCG hormone
            hCG hormone is a protein present in urine when a woman is pregnant
   Indirect
       Enzyme is linked to anti-HISG (an artificial antibody that reacts
        with ANY human antibody that is already bound to an antigen)
       Detects antibody in patient’s serum
       EX)Home HIV tests
Direct   Indirect
        False Positives versus False
                Negatives
   Which are more likely?
   What can cause false negatives?