Adjuvants Flashcards
Main types of vaccines
live, killed, sub-unit and naked dna
many vaccines developed now just contain specific elements
subunit vaccines contain individual proteins or polysaccharides- which evokes an immune response
what is an adjuvant
a substance that is formulated as part of a vaccine to enhance its ability to induce protection against infection
the word adjuvant comes from the latin meaning
to help
adjuvants help to activate the immune system..
allowing the antigens in the vaccine to induce long-term protective immunity
an effective vaccine will
stimulate both arms of the immune system- innate and adaptive
when does innate immunity start
within hours
- the adaptive developed several days later and involves coordination and expansion of immune cells called T and B cells
adaptive memory including b and t cells leads to
adaptive memory
why are adjuvant important
the whole point of a vaccine is to provoke immune memory, this makes sure the adaptive immune system is suitably stimulated
summary of importance of adjuvants
important for activating the innate immune response, resulting in improved adaptive immunity with enhanced activation of T and B cells
why ar they needed
- to increase magnitude of response
- to increase the duration of protective immunity
- may allow the type of immune response to be modified
- allow lower dose of vaccine to be used
types of adjuvant
depot delivery vehicles immune stimulators (modifiers)
- often adjuvants will have a combination of these properties
main activities of adjuvants
1) sustain release of antigen at site of injection 9depot)
2) up regulation of cytokines and chemokine
3) cellular recruitment at the site of injection
4) increase antigen uptake and presentation to APCs
5) activation and maturation of APC (increases MJHC II expressing and co-stimualtory molecules) and migration to the lymph nodes
6) activation of inflammation
depot effect
sustained released of antigen at site of injection
depot effect explained
- antigen is sequestered at the site of injection and released over time
benefit of depot
exposes immune system to antigen for prolonged period of time
- means constant stimulation off immune system for production of high antibody titres
two ways in which adjuvants are delivered
Entrapped in a physical strictures that break down slowly-in liposomes
Entrapped in a matrix that dissociates slowly- Al+ salts
Lipsosomes
double phospholipid bilayer- encapsulates the antigens and breaks down slowly- depot effect
Aluminium salt
trap antigens in a matrix that dissociated slowly
- most widely used
adjuvant antigens are targeted to
APCs
- bacterial proteins are processed by APCs
- -> to trigger CD4/8 responses- cytotoxic and antibodies
Vaccines attach dot articles can be taken up by APCs and
enter the MHC II pathway to stimulate CD4 response- helper T cell
lipsoosme delivery means that antigens enter the
cytosolic pathway- stimulation of CD8 T cells- cytoxicity
lipsosmal carriers..
fuse with the membrane of APCs
how do cytokines, chemokine and tnerferons shape the immune response
bacterial proteins (vaccines) ar reprocessed by APCs
- Toll agonists activate APCs like dendritic cells to present antigens
- cytokines produced activated CD4+ AND CD8+