Vaccination Against Bacteria Flashcards
(29 cards)
Definition of vaccine
Suspension of live or inactivated microorganisms or fractions thereof administered to induce immunity and prevent infectious disease or its sequelae
What is natural passive immunisation
Placental trasnfer of IgG
Colostral trasnfer of IgA
What is artificial passive immunisation?
Immunoglobulin
Immune cells - transfer
Horses are often source of immunoglobulins used in passive activation of immunity
What 3 diseases are largely mediated by toxins?
Diphtheria
Tetanus
Botulism
Why dont you use the toxins in vaccine and what do you use instead?
Use toxoids instead as they may have been treated with heat or formaldehyde
Pros of passive immunisation?
Immediate protection
Cons of passive immunisation?
No long term protection
Serum sickness
Risk of infectious diseases - particularly if immunoglobulins are derived from humans
Graft v host disease (cell graft only)
What is natural active immunisation?
Exposure to sub-clinical infection
Exposure to cross-reactive non-pathogens
What is artificial active immunisation?
Attenuated organisms
Killed organisms
Heterologous organisms - mycobacterium bovis used in BCG vaccine
Sub-cellular fractions
What is the effect of Th2 cells on interferon gamma production?
Th2 cells inhibit interferon gamma production
What type of immunity does Th1 mainly lead to?
Cell mediated immunity
Produces interferon gamma, inhibits proliferation of Th2 cells
What are bacterial vaccine targets?
Secretion proteins
Polysaccharide
Wall assocaited proteins in gram +ve
What is an ideal vaccine?
Given orally
Generates long lasting protective immunity
Stimulates B and T cells
Provides cross-protective immunity
Is effective in all age groups
Safe, cheap, stable
What are the criteria for the antigen in vaccine development?
Conservation
Accessibility
Generation of functional immunity
Cross-protective
What are the criteria for safety of vaccines?
Risks from natural disease must outweigh risks of vaccination
Strict good manufacturing practice observed
Records kept of administration and manufacturing details
What is the problem with RNA vaccines?
RNA is very labile, doesn’t last long in the lab when handled, can be easily degraded so have to be clinically modified
How are bacterial mini cells created?
Certain mutations in bacterial chromosomes give rise to mini cells, dont contain a chromosome but do contain plasmids
What is an example for salmonella using minicells vaccine?
Getting expression of type 3 secretion system, get them to express this but dont replicate so dont cause disease
Can put this into body and get immunity
What does the BCG vaccine offer immunity against?
Protection against mycobacterium tuberculosis
What are the 6 major serogroups responsible for human disease in meningitis ?
A B C W X Y
What were the first vaccines that were developed for meningitis?
Developed against A and C 30 years ago and were T cell independent vaccines
What is the problem with capsular polysaccharide vaccines?
Are safe and effective but do not induce class switching or immunological memory
Not good for young children
Why have polysaccharide vaccines based on serogroup B polysaccharide not been possible?
There is a molecule found in the body in this, so it is a self antigen so immune system doesn’t respond to this
Why is cuban vaccine only successful in Cuba?
Due to heterogeneity of porA in Cuba
