Card Set Information
vaccine vaccines bod pathology
End of 'viruses' lecture series, on vaccines.
5 types of public health control measures
quarantine/isolation/slaughter eg with smallpox, rabies
: notifiable diseases eg influenza, measles, rabies, AIDS. Allows swift action eg vaccination/anti-viral drugs
sanitary engineering/food hygiene regulations
: polio and Hep A spread by faeco-oral route
: eg yellow fever spread by mosquitoes
screening of blood and blood products
: Hep B and C, HIV
what virus causes smallpox?
2 strains of variola, mortality difference
: 30-40% mortality
variola minor aka alastrim
: 1% mortality
visual difference between smallpox and chickenpox
smallpox more centrifugal (pustules more abundant on face than trunk)
first measure for controlling smallpox
variolation: injection of pus under skin
what is ring vaccination?
Vaccinating people in close contact with the disease to prevent it spreading
Why is variola virus still under testing? (2)
developing a safer vaccine
drugs that prevent smallpox because of the fear of bioterrorism
6 reasons why smallpox eradication was possible
no animal reservoir
: potent at single dose, low cost, abundant, heat stable, easy to administer, induced both cellular and humoural immunity
no antigenic variation
what is the only other infectious disease to have been eradicated?
Rinderpest, by vaccination
What did Pasteur produce vaccines for in 1885? (2) how?
Anthrax and rabies
drying spinal cord of rabbits with rabies so that infectivity had pretty much gone but virus antigen remained
How is rabies vaccine produced now?
Grown in cell culture
treated with B-propriolactone to inactivate virus infectivity
How did Theiler produce a vaccine for yellow fever?
Passing virus multiple times: retained infectivity but had lost virulence - 1st live attenuated vaccine
How are influenza vaccines produced now?
Grown in eggs, purifying HA and NA and using these with an adjuvant: a subunit vaccine
How were the 2 types of polio vaccines created?
: purification, chemical inactivation, injection
: serial passage - live attenuated
What was the first genetically engineered vaccine? How was it made?
Hep B: expressing Hep B surface antigen (HBsAg) in yeast, purifying, and injecting with adjuvant
3 types of vaccine
2 types of live vaccines, with examples. Pros and cons.
Attenuated mutants of wild type (yellow fever, MMR, Sabin polio)
: vaccinia for smallpox, turkey herpes virus for Marek's disease (chicken tumours)
: cellular and humoural immunity, self replicating (cheaper), long lived
: can mutate to become virulent, may be dangerous in immunocompromised hosts
2 types of dead vaccines, with examples. Pros and cons.
Purified and inactivated whole virus preparations (Salk polio)
subunit vaccines from whole vaccine/genetically engineered parts (influenza, HBV, HPV)
: multiple injection, only antibody responses (not cellular)
describe passive immunisation
administration of antibodies (human monoclonal)
eg after exposure to rabies or HBV as neonate
: immediate protection
: serum sickness (formerly), short lived
4 new approaches to vaccine development
: specific modification/deletion f a virus gene that confers virulence eg thymidine kinase deletion in pseudorabies virus
vector-mediated sub-unit delivery
: rabies glycoprotein gene into vaccina virus for foxes
: eg HPV 16 and 18 vaccine is made of only capsid, with no genome
nucleic acid immunisation
: prime-boost. Inject DNA encoding the desired antigen under a strong promoter. Boost with a live virus vector expressing the same antigen.
what is the main challenge with antiviral chemotherapy? How is this dealt with?
: viral things not human
target nucleic acid polymerases, proteases, influenza NA, HIV integrase
made into dNTP form by cellular kinases
incorporated into DNA by reverse transcriptase
chain terminator (no 3' hydroxyl)
made into dNTP by HSV thymidine kinase
4 types of antiviral chemotherapy
protease inhibitors (for cleaving gag and pol of HIV
Tamiflu (Oseltamivir phosphate)
: analogue of sialic acid, inhibits NA. Agglutination happens.
4 useful things about viruses
studying cell biology and immunology
cancer therapy (oncolytic viruses)