Vaccines Flashcards
vaccines’ importance
protect from SYMPTOMS
control spread
elimination of disease
what makes virus a target for vaccine development
limited number of serotypes
infection is serious enough
virus doesn’t mutate fast (exceptions are influenza, HIV)
natural infection is acute, self limiting–immunity long lasting
what kind of immunity plays a role in vaccines
cellular, and humoral. depends on the virus, antigen, route of immunization, adjuvant
how do you get mucosal immunity
antigen must be prsented to the mucosa associated lykmphoid system, so the virus needs to replicate and get there
how do antibodies play a role on the surface of infected cells
can bind the microbe and block infection
passive immunization has what effect on viral replication
rarely eliminates completely viral replcation
however usually blunts infec enough to allow immune sys to take over
rhinovirus vs poliovirus difference
more than 99 serotypes for rhinovirus so evades neutralizing antibodies
poliovirus–vaccine very successful
advnatages of inactivated virus vaccine
cannot genetically mutate to increase virulence
safe for immunocompromised
disadvantages of inactivated virus vaccine
fails to elicit gut immunity
parenteral administration
expensive
needs multiple boosters
elicits ciruculating Ag but no mucosal immunity
can elicit imbalanced response–to one protein but not another
longevity?
live attenuated virus vaccine advantages
inexpensive
induces both systemic and secretory immunity
induces herd immunity
full range of gene products expressed
mimics nautral infec
elicits Ag and cell med response (longer lasting imm response)
mucosal immunity is generated if it’s relevant
disadvantages of live atten virus vaccine
can mutate to more virulent strain
less reliable in tropical places-need coolers
residual pathogenicity
can spread for those vaccinated to contacts
possible reversion to virulent strain
subject to immune evasion strategies of viruses
what is attenuation of virus usually involve
attenuation of translation effectiveness in the human
recombinant viruses
viral vector w/ genes from one or more viruses
subunit or recombinant vaccines (2nd gen)
avoids the requirement for total inactivation of live virus
cost/difficulty in production may be drawback
ex. HBV, HPV (virus like particles) vaccine
DNA inoculation (3rd gen)
introduce DNA encoding antigens into appropriate tissues–DNA taken up into cells, proteins are expressed
