Vaccination Flashcards
What is the principle behind vaccination?
Immunological memory and specificity
What is the antigen in a vaccine?
attenuated organisms; alive but do not cause pathology, mimic natural infection), dead organisms, subunits such as protein/polysaccharide, inactivated toxin (toxoid for bacteria)
What is an adjuvant?
Any substance that non-specifically enhances the specific immune response. Can activate dendritic cells. Carriers are used (particularly if not using the whole organism) polypeptide sequences that can be processed into peptides for presentation to T helper ceells.
What are the general requirements for any successful vaccine?
Effective: appropriate adaptive response; if infection route is via mucosal surfaces then mucosal immunity is desirable) Availability Stable Inexpensive Safe (as little side effects)
What are the components of a vaccine?
Antigen, carrier (provides helper T cell epitopes, and an adjuvant: non-specifically stimulates a specific immune response.
When was smallpox eradicated?
1979
When was rinderpest eradicated?
2011
Vaccines for which diseases are urgently required?
HIV; main hurdle in vaccine development. REquires broad long lasting CTL immunity and production of broadly neutralising antibodies; Thailand trial showed limited protective effect - efficacy was 25-30%
Influenza: difficult to develop because of antigenic drift and zoonotic transfers. Constant changes in it haemagglutinin and neuraminidase antigens a different vaccine formulation has to be produced each year.
TB (BCG vaccine is only effective in certain parts of the world)
Malaria; The RTS,s/AS01 malaria vaccine -phase 3 reduced malaria episodes by 50%
What is a potential new way of vaccine delivery?
DNA vaccine, biolistics of cytotoxic T cells.
Conjugate vaccines; couple carbohydrate onto protein; peptide presentation
