Immunology Flashcards
What are the 3 types of vaccine?
Live attenuated e.g. polio, BCG
Inactivated e.g. influenza
Subunit and adjuvant e.g. Hep B, tetanus, typhoid
What are the purposes of vaccines?
Activate the immune response to make a memory response to a pathogen (create antibodies) this activates adaptive immunity to drive clonal expansion of T and B cells and antibodies that recognise the pathogen/
The adaptive response is in the lymph nodes (lymphocyte dendritic cells). If person becomes infected with it in the future then the immune response will be generated and protect the individual against infection
What are the components of vaccines?
Antigen - what the immune response is generated to
Adjuvent - activates the antigen and promotes. immune response to drive inflammation
Prevent physical or chemical degradation of. antigen
Preservative. to prevent microbial growth
What is the importance of cold chain storage with vaccines? i.e not freezing
2-8degrees celsius. They cannot be frozen.
- freezing would irreversibly denature proteins(antigens) in the vaccine - would change the antigenicity and inactivate it so ineffective
- Can cause emulsions in the vaccine to become unstable
- can cause hairline cracks in the ampuoles - subject to microbial contamination
- Glass spicules could cause local adverse effects
- vaccines are unstable so cold chain helps with this.
Why is the IM route preferred for vaccines?
- less local reactions
- higher blood supply to allow the antigen to move and mobilise immune response
- lymph nodes are located there
What situations would it be more appropriate to go via the subcutaneous route for vaccinations?
if the patient has a bleeding disorder e.g. haemophilia, Von-Willebrands disease, Vitamin K or D deficiency, low platelets post cardiac sugery
What is a contra-indication of live attentuated (fluenza tetra) vaccine in a young person under 20 who is on aspirin for a cardiac problem?
Live attentuated viruses can give rise to Reye syndrome in patients taking salicylates under 20. Symptoms begin a few days after viral infection e.g. vomiing, listleness, lack of energy
What else is live-attentuated vaccines contra-indicated in?
Cancer as immunocompromised (give inactivated)
immunocompromised patients generally
Still possibility that it could replicate and immune system not strong enough to fight it off
Why is the nasal vaccine Fluenza tettra used in children?
Live attenuated has a better response in children, very effective
Easier to administer, less worrying for parents and children, less distress
How do vaccines work?
Occurs within the lymph nodes. Immunisation drives clonal expansion of T and B cells and antibodies that are able to recognise the pathogenic microbes made. Memory cells respond extremely rapidly if exposed to it in the future as antibody is long lived.
- They activate pathogen specific. adaptive immune responses. Activate antigen specific priming so we can create memory artificially and make immune system reject infections
what is the similarity between hypersensitivity and autoimmunity
Both generate an unwanted adaptive immune response with no known benefit to the person
What is the adaptive immune system?
Recognises anything antigen, only after priming, and has memory of the encounter.
- learnt over the lifetime
- recognises antigens
Define hypersensitivity
Damage caused by. adaptive immune mechanisms where there is an external source of antigen (sensitisation to external antigens), with no known benefits
Define autoimmunity
Damage caused by adaptive immune mechanisms with no hazard identified. - an internal antigen, with no known benefits. It is chonic and progressive
Why do you not use a steroid cream on broken skin?
Interferes with wound healing - decreased fibroblast function interferes with with wound healing
