L15- Vaccination Flashcards
1
Q
What is immunisation?
A
A procedure designed to increase concentrations of antibodies and/or effector T cells which are protective against infectious agents
• immunoprophylaxis or immunotherapy
2
Q
What is a vaccine?
A
A preparation of a pathogen that is used to establish immunity without causing disease
3
Q
What are the features of a good vaccine?
A
- Safe- must not cause illness or death
- Protective- protect against illness resulting from exposure to live pathogen
- Gives long-term protection
4
Q
What is the appropriate immune response?
A
- Induces neutralising antibody
* Induces protective T cells
5
Q
What are the practical considerations?
A
- Low cost per dose
- Biology stability
- Ease of administration
- Few side effects
6
Q
What are the mechanisms of immunisation?
A
- Passive immunisation- transfer of protective antibodies to a non-immune individual, temporary and done at short notice
- Active immunisation- induction of an adaptive immune response protection and memory
Secondary immune response is quicker and greater
7
Q
What are examples of passive immunity?
A
- Transfer of maternal Abs accross placenta, Abs in colostrum- natural
- Injection with preformed antibodies protects against HepA, rabies, tetanus
- Injection with humanised monoclonal antibodies (respiratory syncytial virus)
- Injection with antitoxins (botulism, bites)
8
Q
What are examples of active immunity?
A
- Naturally following exposure to infection
- Medically via a vaccination
- Elicit protective immunity and immunological memory
9
Q
What is used in vaccinations?
A
- Inactivated organisms
- Attenuated organisms
- Purified microbial macromolecules
- Cloned genes of microbial antigen
10
Q
How are inactivated organisms used?
A
- Treated by heat or chemical means, chemical preferred
- Requires boosters
- Predominantly antibody response
11
Q
How are attenuated organisms used?
A
- Lose the ability to cause significant disease but can still grow
- Prolonged immune system exposure to antigenic epitopes
- Single immunisation
- Possibility of reversion to pathogenic strain
12
Q
How are subunit vaccines used?
A
- Purified and inactivated with formaldehyde to produce a toxoid
- Induces toxin neutralising Abs
13
Q
How are human pathogens attenuated?
A
- Growth in an unusual condition
- Growth in unusual host cells
- Animal homologue of human pathogen
- Molecular biology to knock out virulence genes
