Lecture 22 - Immunisation Flashcards
(33 cards)
what is the reason deadly viral infections are far less prevalent today?
vaccination success
what did edward jenner do in terms of vaccination birth?
with trying to cure deadly disease smallpox, noticed that cowpox was similar to smallpox and innoculated a dilute amount of pus in an 8 year old boy
how was it discovered that vaccination could prevent against diseases?
by realising that milkmaids with cowpox lesions were protected from smallpox
where is smallpox today?
eradicated in 1980, but two vials remain in the US and russia in level 4 containment
who developed the first lab-generated vaccines?
louis pasteur
how did louis pasteur develop the first successful lab generated vaccine?
accidentally let bacteria attenuate and weaken for a month and then it was found to protect against a normally lethal dose of cholera
- live attenuated cholera vaccine
describe the principle of vaccination in terms of memory
receiving a vaccine allows naive B and T cells to respond and generate memory cells so the second exposure is rapidly eliminated and disease doesn’t occur
what does a vaccine need to have to be effective?
- must elicit a protective and strong antibody response
- must elicit a memory T cell response
why is it more important for a vaccination to elicit a T cell response?
T cell response is rqd to maintain a strong B cell response and to generate memory B cells
true or false, a vaccination is always dose of an entire pathogen into our system
false, it more commonly contains epitopes (recognisable parts) of the pathogen, so it won’t cause disease when injected
what are the four types of vaccination?
- whole live organisms that are either from a different species that is cross-reactive or are attenuated
- whole killed organisms (whooping cough, cholera, thypoid)
- components of organisms (tetanus)
- mRNA vaccines as of 2021
what examples of vaccines use whole live organisms
- smallpox
- measles
- mumps
how does using a whole live organism for a vaccine work?
- immune responses clear infection after 1-2 weeks
- allows for prolonged exposure to the organism due to low-level replication (live attenuated organisms) and therefore lots of antibody production
what examples of diseases have vaccines that use whole killed or component organisms?
- hepatitis B
- tetanus
- HiB
how does using a whole killed or component organism for a vaccine work?
- briefly expose vaccinated person to antigens of the organism
- immune responses clear antigens within a few days
- three or more doses to stimulate good immunity
what are polysaccharide vaccines?
a vaccine that can be conserved across multiple pathogens through recognising polysaccharides in their cell wall
why are first generation polysaccharide vaccines not as commonly used now?
- induce weak antibody responses
- polysaccharides are T cell independent antigens, so there is little immunological memory
why are polysaccharides T cell independent?
because they cannot be presented in the same way on the MHC
what are conjugate vaccines?
Conjugate vaccines link polysaccharides to a carrier protein like tetanus toxoid, allowing B cells to present protein peptides on MHC II and receive T cell help.
when is the best time for a human to be immunised?
while the infant still has the maternal protective antibodies, so when that wears off, the infant is protected
true or false, babies require vaccination to have sufficient antibodies
false, vaccination just provides infants with the tools to create more specific ones against specific pathogens
what feature of the virus is the covid vaccine based on?
spike protein
how does the covid-19 virus enter host cells
the spike protein binds ACE2 receptor on the cell membrane of airway cells
what kind of antibodies will be most effective against covid-19?
neutralising antibodies that bind directly to the spike protein
