15 Virus 3 Flashcards
types of immunity required
sterile immunity
T-cell or humoral
systemic or mucosal
how is sterile immunity achieved
it is difficult to achieve
what is most effective in T-cell or humoral
both arms most effective
what does systemic or mucosal need
class of Ig required mucosal = IgA (short lived)
what do the most effective vaccines induce
do not induce sterile immunity - rather it builds up an amnestic response
what is the problem with HIV and HCV
Problematic for hypervariable persistent viral infections
as sterile immunity not induced
live viral vaccines effect
related non-pathogenic virus that gives cross-protection
example of live attenuated virus
cow pox protects against small pox
live viruses
- Attenuated
- Reduce pathogenicity of a virus by passage in cell culture or non-human host
where is pathogenic virus located
from a patient and grown in human cultured cells
what is used to infect monkey cells
Cultured virus is used to infect monkey cells
what allows a virus to grow in monkey cells
Virus acquires many mutations that allow it to grow well in monkey cells
Advantages of live vaccines
- development and production straightforward
- low cost
- cell-mediated (and mucosal) immunity stimulated
- can be highly immunogenic, giving long lasting protective immunity
- fewer inoculations that other systems required
- live microorganisms provide continual antigenic stimulation giving sufficient time for memory cell production
Disadvantages of live vaccines
- many cause (generally mild) disease
- reversion to virulence may occur
- virus shedding – potentially infect others
- potential harm to immunocompromised individuals
- unstable – requires continuous refrigeration
- less safe than inactivated vaccines
why are recombinant proteins safe
No infectious agent - safe
Antigenicity of prokaryotic-expressed proteins sometimes poor - yeast or insect cell expression better
Recombinant surface antigen disadvantages
> Poorly immunogenic
Requires multiple boosts
Expensive
Problem for developing countries
Recombinant surface antigen advantages
> Safe
> Also protects against Hepatitis delta virus
what does the recombinant protein - Human Papilloma Virus cause
genital warts associated with cancer
Squamous cell carcinoma
Malignancy in genital tract
Inactivated (killed) viruses
- Chemical treatment, safe, poor antigenicity, humoral immunity only
- Side effects - inflammatory responses, Purified subunits overcome this
- Mainly induced circulatory IgG
- Continual shedding of virus from vaccines
- Requires repeated boosting
what is Hepatitis A vaccine like
Inactivated cell culture-grown virus
rabies injections
Pre and post-contact vaccination by IM injection
rabies vaccine
human diploid cell vaccine
Influenza vaccine like
Inactivated viral vaccine “split” or purified H and N from virus in hen eggs - allergy risk (rare)
what does influenza protect against
Protects against 2 ‘Flu A strains plus 2 ‘Flu B
Enhancing immunogenicity
Adjuvants improve immune response potency
what are immunogenicity incorporated in
several human vaccines in the form of particulate aluminium salts, such as Al(OH)3 and AlPO4
examples of licensed adujvants
MF59
AS03
Virosomes
AS04
MF59
Oil in water adjuvant effect in the influenza vaccine, but not when used with HSV-2 Glycoprotein
AS03
contains α-tocopherol, squalene and polysorbate 80 in an oil-in-water emulsion, used in pandemic influenza vaccine
Virosomes
Phospholipids that reconstitute influenza virosomes, used in the hepatitis A vaccine
AS04
Monophosphoryl lipid A (MPL) and aluminium hydroxide, approved for use in HBV (Fendrix) and HPV (Cervarix) vaccines
Safety concerns
Pandemic influenza vaccine associated with sudden onset narcolepsy in children
DNA vaccines
Inject DNA containing antigenic coding region plus promoters
- Site of injection, Persistance, Presentation pathway, Safety
Live vector vaccines
Use of a non-pathogenic virus or bacterium to elicit an immune response to target virus
how are live vector vaccines produced
genetic modification to express foreign viral genes
