Immunisation Flashcards
What is the aim of immunisation?
Manipulating the immune system to generate a persistent protective response against pathogens
What is active immunisation?
Challenging the immune system to induce a state of immunity
by introducing a weakened/dead form of the pathogen to the body
How does active immunity work?
Pathogen is introduced
The body produces an immune reaction to it
Produces high affinity protective antibodies against the pathogen
Inducing immunological memory
What immunoglobulins are involved in active immunity?
IgG
Possibly IgA - with pathogens that infect mucous surfaces
Which branch of the immune system is used in active immunity?
Innate & adaptive!
B & T cells
Why is influenza really hard to make a vaccine for?
Rapid onset, infection is established in the body long before the body can produce an immune response & memory can be generated
The virus is constantly mutating too.
What are the 5 types of vaccine?
- Whole organism
- Live attenuated
- Killed/inactivated - Subunit
- Peptides
- DNA vaccines
- Engineered virus
Give some pros & cons of live attenuated vaccines.
PROS
Vaccine sets up a transient infection which activates a full natural immune response
This results in immunological memory
CONS
Can cause actual infections in immunocompromised
Needs refrigeration: can’t get to remote parts of the world
What is a live attenuated vaccine?
Uses the actual pathogen or toxin that has been weakened by chemical treatment, or grown in a lab to reduce its virulence
What is an inactivated vaccine?
Pathogen is boiled or heated so it can’t cause disease, but an immune response is still generated
Give some pros & cons of inactivated vaccines.
PROS
No risk of infection
Refrigeration is less critical
CONS
Tends to just activated humoral response (B cells)
NO transient infection so weaker immune response
Repeated boosters are required
What are subunit vaccines?
Use a piece of the pathogen sufficient to give an immune response but not enough to cause disease
Can be inactivated endotoxins, antigenic extracts, peptides
Give some pros & cons of subunit vaccines.
PROS
No pathogen so no infection, no risk
Easy to store & preserve
CONS
Immune response is weaker
Boosters are needed
People have different HLAs so the subunits have to be chosen so they’ll generate the required response in most of the population, but it won’t work in all.
What are DNA vaccines?
Implanting pathogenic DNA with the aim to transiently express genes from the pathogen in host cells.
The body will start producing pathogenic proteins which will generate an immune response
Give some pros & cons of DNA vaccines?
PROS
Easy to store & transport
CONS
No transient infection so weaker immune response
Requires boosters
