Vaccination & Immunological Memory Flashcards
What is immunological memory?
It is the enhanced response of the immune system when re-encountered with an antigen, compared to the 1st encounter of the same antigen.
What occurs due to immunological memory?
- Rapid migration to tissue/lymph nodes
- More cytokines produced
- Long-lasting cells
- Responder cells being more readily available
- More efficient antigen recognition/activation
What does the IgM antibody do?
It activates complement when bound to the antigen
What does the IgG antibody do?
They are antibodies of higher affinity, and can neutralise toxins/viruses/bacteria, opsonise them for phagocytosis, and activate the complement system.
Out of IgG and IgM, which one increases more in a secondary antigen response?
IgG
What is the process for generation of B cell memory?
- A naive B cell is activated by a CD4 T helper cell in the primary antigen response.
- A germ cell is formed, where memory B cells and long-lived plasma cells (LLPCs) are generated
- These LLPC’s reside in the bone marrow
- The memory B cell is re-exposed to the antigen, where short/long lived plasma cells are released
What are the 3 phases of T cell memory?
- Expansion phase - initial activation & clonal expansion of CD8 T cells
- Contraction or death phase - activated effector CD8 T cell die via apoptosis
- Establishment and maintenance - of CD8 T cell memory
Which 2 pathways can naive T cells undergo, and what do they depend on?
- Differentiation into effector & memory cells
- Undergo deletion
These outcomes depend on the strength of antigenic & cytokine stimulation that the T cells receives
What are the benefits of vaccinations?
- It modifies the immune system to the hosts benefit
- It induces long lasting immune effects (making you resistant to infection)
- It aims to do all of these with minimal side effects
What are some factors for an ideal vaccine?
- Completely safe
- Easy administration
- Cheap
- Stable
- Active against all variants
- Life-long protection
- Single dose, needle free
What are Pateur’s principles?
They are 3 techniques used to weaken microbes using a vaccine. It involves:
- Isolate
- Inactivate
- Inject
What are the 2 classifications of human vaccines?
- Whole organisms
- Purified macromolecules
- Surface antigens; recombinant proteins
- Toxoids; toxins released by a bacteria to stimulate the immune system, e.g. tetanus
- Capsular polysaccharides; influenza
What are adjuvants?
They are agents which stimulate the immune system and increase the response to a vaccine through 5 mechanisms.
What are the 5 mechanisms of adjuvants?
- Translocation of antigens to lymph nodes leading to greater T cell activity
- Physical protection to antigens, enabling prolonged vaccine delivery and up-regulating B/T cells for greater immunological memory
- Increase the capacity to cause local reactions at injection site, inducing greater chemokine release
- Induce inflammatory cytokine release
- Increase the innate response by interacting with PAMP receptors, e.g. toll-like
What are some examples of adjuvants?
- Cytokines
- Liposomes
- Vitamins
- Mucosal binding proteins
- Lipid tails
