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Immunology
Vaccines/Immunization (T Pierce)
32
Medical
Post-Graduate
03/02/2009

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Cards

Term

Compare passive immunity and active immunity

Definition
  • passive
    • examples
      • maternal Ab's
      • antitoxins (ex: antivenom)
      • Ig's
    • temporary protection
  • active
    • examples
      • natural infections (most effective- Leishmanization)
      • vaccines
Term

Differenty types of vaccines

Definition
  • live attenuated
  • inactivated whole organism
  • subunit
Term
Different methods of producing live attenuated vaccines
Definition
  • Jennerian method
  • long term passage method
  • naturally attenuated strains
  • delivery via non-pathogenic route (adenovirus given orally)
Term
Explain the Jennarian method of producing live attentuated virus
Definition
  • you use a separate Ag that is cross reactive with another Ag to induce effective protective Ab's
  • example: cowpox cause immunity to smallpox
Term
Mechanism of long term passage
Definition
  1. you isolate the pathogenic virus from humans
  2. you "pass" them to different species
  3. while in each species, they undergo mutliple mutations that render it avirulent
Term
What method has been used to replace long term passage
Definition
genetic recombination
Term
Live attenuated vacccines are considered the most effective types of vaccines. Why?
Definition

able to induce high levels of both Ab and cell mediated immune responses and have long term protection

Term
How do you produce an inactivated whole organism?
Definition
  • heating
  • formaldehyde treatment
Term
Adv. and disadv. of inactivated whole organism vaccines
Definition
  • advantage- safer (non living)
  • disadvantage- less potent (only humoral immunity), so we usually need more administrations to produce an antigenic mass
Term
Goal of inactivation of an organism in producing vaccine
Definition
kill the organism while preserving its structural antigenicity
Term
Examples of inactivated whole organism vaccines
Definition
  • yearly flu vaccine
  • inactivated polio virus
Term
Composition of subunit vaccines
Definition
  • consist of single or multiple fragments of organism
  • can be proteins, peptides, carbs
  • can be fragments cleaved from organism or can be expressed in recombination form (ex: Guardasil)
Term
Adv./Disadv. of subunit vaccine
Definition
  • advantage- can be produce in large scale, reproducibility between batches, and safety
  • disadvantage- poor immmunogenicity without adjuvants and multiple boosts
Term
Examples of subunit vaccines composition
Definition
  • surface protein
  • toxoids
  • surface carbohydrates
  • conjugates
Term
Mechanism of action of toxoid subunit vaccine
Definition
  • toxins made of two chains with different functions
    • toxic function
    • receptor binding function 
  • toxoids are the toxins that have had the chain that mediates the toxic function inactivated
  • so the vaccination with toxoid will induce neutralizing Ab's against receptor binding chain of native toxin
Term
Example of toxoid subunit vaccine
Definition
DTP
Term
How are polysaccharide subunit vaccines made and how do they work?
Definition
  • isolate polysaccharides from capsular coats of some bacteria
  • these polysac. are T cell independent, meaning they will activate the B cells directly to secrete IgM Ab
Term

How do conjugates in subunit vaccines work? why are they needed?

Definition
  • needed because polysac. vaccines poorly immunogenic in young children
  • conjugating a protein (often toxoid) to polysaccharides (this make T cells help B cells produce Ab's)
Term
Examples of conjugate vaccines
Definition
  • H influenza type B
  • S. pneumonia conjugate
  • meningitis
Term
Different approaches to get cell mediated immunity
Definition
  • use of adjuvants
  • use of cytokines
  • use of live vectors
  • use of DNA vaccines
  • alternate route of delivery
Term

How do adjuvants enahcne, accelerate, and prolong specific response to vaccine Ag's?

Definition
  • act as Ag depot (hold peptide in place longer)
  • promote APC activation
  • promote specific profiles of cytokines
Term
Describe potential nature/contents of adjuvants
Definition
  • can be salt based (only one for humans) or oil based (really good with Ag depot)
  • can contain microbrial products or cytokines
Term
Use of adjuvants: use of the TLR's: LPS and CpG DNA
Definition
  • stimuate dendritic cells to secrete IL-12
  • this will cause differentiation into Th1 cells
Term
Why is the advantage of using aluminum hydroxide as an adjuvant?
Definition
  • advantage- it can induce Th2 cells, which promote Ab response
  • disadvantage- not good at inducing Th1 cells
Term
Effect of mixin vaccine with IL-12
Definition
induces good Th1 cell priming, but does not cause long lived protective immmunity
Term
Advantage and disadvantage of using live attentuated organsims as vectors for vaccines
Definition
  • advantage
    • live, so they can replicate
    • proteins expressed in cytosol, so can access MHC Class I, activating CTL response
    • express multiple genes
  • disadvantage- ethical, cannot use for bosting (immune system response wont be benificial to vaccine)
Term

Advantage and disadvantage of DNA vaccines

Definition
  • advantage
    • in vivo expression of designer vaccine
    • induce Ab, CD4 response, and CTL response
    • no risk of infection
    • cheap, easy production, easy transport, easy storage
  • disadvantage
    • less impressive results in larger animals
    • lower transfection efficeincy, so low protein expression
    • risk of chromosomal integration/oncogene activation
    • risk of tolerance induction (due to long term Ab)
Term
Define what is ment by a prime boost. What were the results of its use in monkeys with HIV?
Definition
  • this is when a DNA vaccine is combined with a live attentuated vector
  • in monkeys with HIV, they had higher numbers of HIV specific CTL cells, but these responses were not protected
Term
Example of natural route of infection delievery of vaccines
Definition
HIV peptides deliverd via mucosal (intra rectal) delivery, lead to most potent CTL responses
Term

Describe what is ment by the hygeine hypothesis

Definition
  • those who are in low hygeine environments get more microbial infections (means higher Th1 response), so decreased atopy (low Th2)
  • those who are in high hygeine environments get lesss microbial infections (lower Th1), so there is an increased atopy (high Th2)
Term

How can womrs violate hygeine hypothesis? How is this corrected?

Definition
  • worms induce a very strong Th2 response, as do allergies/asthma
  • according to hygeine hypothesis, those with these infections should have a greater risk of allergy
  • but they create a immunosuppressive environment by producing IL-10 which induced differentiation into Treg cells
  • people with perpetual worm infection are predisposed to regulatory immune environment
    • those 20-39 without infection responded to vaccine (restored normal immune system)
    • those over 40 couldnt respond to vaccine
Term
Example of surface protein subunit vacines
Definition

Hep B Surface Ag (HBSAg)

NA for influenza

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