Vaccinations Flashcards
What might an ideal vaccine might have
How does vaccination work on immune system
Prevention of entry - antibodies (neutralisation, opsinisation)
Killing infected cells (CD8
Boosting immune response (CD4 T cells MHC moelcule, make Ig)
What is the R0
Number of cases on case generates over the cause of infection period
What are the different types of antigens in vaccination
Inactivated protein e.g. tetanus toxoid
Recombinant protein e.g. HepB
Live attenuated pathogen e.g. Polio/BCG
Dead Pathogen e.g. split flu vaccine
Carbohydrate e.g. S pneumoniae
Adjuvant - make vaccine work better
Stabilising agent - buffer
Inactive toxoid vaccines
Tetanus toxoid
Recombinant Portein Vaccines
Hep B Surface Antigen
Recombinant protein from pathogen
Induces classic neutralising antibodies
Pure and safe
Relatively expnesive, not very immunogenic, not answer to all infections
What is wrong with this structure
Antibodies are made against 2nd structure instead of first structure
Whats the problem with bacterial coats
Have a capsule made of polysaccharide
Not good at inducing a B cell response (T independent antigen)
Conjugates vaccines
S pneumoniae
T cell recognises protein (immunogenic carrier protein)
B cell recognise sugar part
Advantage: imporves immunogenicity, highly effective at controlling bacterial infection
Disadvantage: cost, carrier protein intereference, strain specific, polysaccharide alone is poorly immunogenic
Dead pathogen vaccines
Influenza
Induces antibody and T cell response
Leaves antigenic components intact. Immunogenic because of the inclusion of other components. Cheap. Quick
Fixing/killing can alter antigen strucutre, dirty, capacity to grow pathogen,
What is live attenuated vaccines
BCG, LAIV, OPV
Pathogens are attenuated by serial passage, loss of virulence
Because they replicate in situ, trigger innate response and boost immune response
Induce strong immune response, can induce a local immune response in site where it occurs
Disafvantages: virulence, can infect immunocompromised, attenuation may lose key antigens, competed out by other infections
What are adjuvants
Substances used in combination with a specifi antigen that produced a more robust immune response than antigen alone
Induce danger signals that activate dendritic cells to present antigen to T cells
Types of adjuvants
Vaccine barriers
Scientific challenges
Injection safety
Time, cost
Public risk free expectation
Logistics/ cold chain
High variation of the target orgnaisms
Immune response will only recognise one of the strains
