Medical Immunology (Exam IV Material) Lecture 13

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Medical Immunology (Exam IV Material) Lecture 13
2015-04-28 23:03:41
Immunology Failures Defenses

PHS 109: Medical Immunology Failures of the Body’s Defenses
Show Answers:

  1. What are two reasons why the body's defenses fail?
    1. Pathogens have mechanisms to escape or subvert immune system

    2. Individual has inherited deficiency of the immune system
  2. Evasion: 

    Different strains of a pathogen, display different _______  _______.
    surface epitopes
  3. Evasion:

    Strep pneumo causes pneumonia, meningitis, endocarditis, otitis media, etc.. During these different disease states, Strep pneumo is displaying different surface _______.
  4. Evasion:

    How many serotypes is Strep pneumo estimated to have?
  5. Evasion:

    True or False. Each serotype is reactive with a different Ab generated in response to infection.
  6. Evasion:

    During infection with Influenza, what do neutralizing Ab's bind to, to provide protective immunity?
    the viral capsid
  7. Evasion:

    What does the Flu virus undergo due to its RNA being error-prone during replication?
    antigenic shift
  8. Evasion:

    What changes occur in viruses during antigenic shift?
    Small to moderate changes in epitopes of the viral capsid so that existing Ab's are no longer effective.
  9. What is the consequence of antigenic shift in viruses in regards to infection?
    Antigenic shift allows the virus to infect an individual, but if the individual has bean exposed a seasonal form of that virus, that individual will have some degree of protection.
  10. Besides genetic errors, what is another way that the flu virus undergoes antigenic shift?

    What is an example?
    1. Recombination of the flu virus genome between different species.

    2. Swine flu and Avian flu
  11. Does recombination of flu viruses change the epitopes? If so, what are the consequences?
    1. Yes. Recombination changes the epitopes so that the existing Ab's are NOT AT ALL effective.

    2. Pandemics (or worldwide epidemics)
  12. Which sickness and organism changes its cell surface glycoproteins by gene rearrangement due to Ab response?
    Sleeping sickness (Chagas disease); caused by trypanosomes ( a protozoan parasite)