Compare passive immunity and active immunity

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

Differenty types of vaccines

• live attenuated
• inactivated whole organism
• subunit

• Jennerian method
• long term passage method
• naturally attenuated strains
• delivery via non-pathogenic route (adenovirus given orally)

• you use a separate Ag that is cross reactive with another Ag to induce effective protective Ab's
• example: cowpox cause immunity to smallpox

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

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

• heating
• formaldehyde treatment

• advantage- safer (non living)
• disadvantage- less potent (only humoral immunity), so we usually need more administrations to produce an antigenic mass

• yearly flu vaccine
• inactivated polio virus

• 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)

• advantage- can be produce in large scale, reproducibility between batches, and safety
• disadvantage- poor immmunogenicity without adjuvants and multiple boosts

• surface protein
• toxoids
• surface carbohydrates
• conjugates

• 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

• 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

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

• 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)

• H influenza type B
• S. pneumonia conjugate
• meningitis

• use of adjuvants
• use of cytokines
• use of live vectors
• use of DNA vaccines
• alternate route of delivery

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

• act as Ag depot (hold peptide in place longer)
• promote APC activation
• promote specific profiles of cytokines

• can be salt based (only one for humans) or oil based (really good with Ag depot)
• can contain microbrial products or cytokines

• stimuate dendritic cells to secrete IL-12
• this will cause differentiation into Th1 cells

• advantage- it can induce Th2 cells, which promote Ab response
• disadvantage- not good at inducing Th1 cells

• 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)

Advantage and disadvantage of DNA vaccines

• 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)

• 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

Describe what is ment by the hygeine hypothesis

• 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)

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

• 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

Hep B Surface Ag (HBSAg)

NA for influenza