lecture 12) vaccines and vaccinology Flashcards
what is the only infection to have been eradicated worldwide due to vaccination?
smallpox
why does the oral vaccination for polio give a continued risk for the virus circulating in the population?
IPV induces low levels of immunity in the intestine
when immunised with this vaccine the inactivated virus can multiply in the intestines
it is excreted in faeces therefore will continue to be in circulation
what disease can arise years after the measles infection?
subacute sclerosing panencephalitis (SSPE)
rare and chronic inflammation of the brain due to persistent infection of measles
give 2 potential outcomes of being naturally infected with a pathogen
succumb to disease/potentially die
make recovery due to natural immunity and be against re-infection
will you be protected against re-infection of all diseases if you have had the infection once?
not true for all disease
some dont offer immunity to re-infection
these diseases are the hardest to design a vaccine for
give 3 characteristics of vaccines
mimic natural disease
trick body into thinking it has been infected
only work if the body can generate a protective response
what are the 2 types of protective responses the body has when infected?
antibodies
cellular immunity
what type of cells are antibodies made from?
B cells
what do CD4+T cells do?
orchestrate immune response
what do CD8+T cells do?
kill infected cells
name the 4 main types of vaccines
live
killed
sub-unit
naked DNA
describe live vaccines
living microbes that cannot cause disease due to some genetic disruption but can still infect
best mimic
most traditional approach
describe killed vaccines
killed microbes by heating or exposure to chemicals
chemicals not favoured as they are introduced into body
traditional approach
describe sub-unit vaccines
fragments of microorganisms eg proteins
only need some components of microorganism to cause infection
describe naked DNA fragments
piece of DNA of a microbe
makes proteins after injection
what is the disadvantage of only having 1 mutation being the difference between a disease causing microorganism and an attentuated microorganism for a vaccine?
more potential for reversion of that mutation
greater likelihood of the vaccine cause infection
what cause the outbreak of polio in Hispaniola in 1999?
reversion of the polio vaccine
what is the most ideal immune response for subunit vaccines?
antibody mediated response
what are the advantages of having pure components in subunit vaccines?
more potent
fewer side effects
good responses
what 2 components are combined to make a vaccine against plague?
F1
V antigen
what is F1 in plague?
peptide that assembles on the cell surface to form a capsule
what is the V antigen in plague?
peptide on cell surface that forms the tip to the T3SS
T3SS essential for bacterium to cause disease
acts as needle that punches host cell to inject it
describe the concept of having vaccines in plants?
grow a crop of vaccine
transfer genes into plants that will produce proteins
humans eat the plants - become immune
what are the pros of having vaccines in plants?
easy to produce
focused immune response
nonreactive
highly protective
what are the cons of having vaccines in plants?
no CD8 cells therefore wont be effective for diseases that require more than just antibodies eg TB
what are some of the main problems of naked DNA vaccines
DNA could mutate
works well in mice but mostly failed in humans
rely on the DNA naturally decaying but could be integrated into the host’s genome
what 4 areas are vaccines hoping to help in the future?
infectious diseases (public health/AB resistance, bioterrorism, animal health vaccines)
cancer
degenerative diseases eg alzheimers
addition eg heroin addiction
