10.5 Vaccination Mechanics Flashcards
What is a live/attenuated vaccine?
Weakened infectious pathogen, used in vaccines
Vaccination vs immunisation
Vaccination: taking vaccine (orally/injection)
Immunisation: The process of taking the vaccine and developing immunity to the pathogen
Which type of vaccine (attenuated/dead) vaccine needs to be administered more times?
- Attenuated usually only once
- Dead more times (keep reminding the immune system)
What cells are the first to be activated in order to mount an adaptive immune response?
CD4 cells
What are the components of the TCR? Recall what they recognise
Alpha and beta. Recognise processed antigens
Which cells permit CD8 cells and B naive cells to differentiate
T helper cells (this is why we need to activate CD4 first)
Is natural immunity preferable?
Always yes. Once infected, you will acquire immunity and memory cells against pathogen.
Which receptors recognise the butt end of antigens?
Fc receptors
Which proteins are presented on MHC class 1?
All of them; even normal body ones
Why is their a lag period for an immune response, even if vaccinated?
Lag time for B and T cells to migrate to secondary lymph tissue at site of infection
Which type of vaccine gives humoral immunity, and which gives both humoral and cell mediated immunity?
Attenuated gives both, since it is alive, and can move into cells
What are the four types of vaccines?
- Live attenuated
- Inactivated
- Purified Subunit
- Cloned
Can an activated CD4 T cell activate any B cell? How does it do this?
No; only the B cells that have independently discovered the same antigen as the dendritic cells in the periphery. Like dendritic cells, these are expressed on MHC class 2
It does this using cytokines
Which type of antibody do plasma cells express?
IgM (pentameric)
What type of Ig is expressed on B memory cells?
IgG
What is “affinity maturation”
When B memory cells are formed, they change their recognition sites are improved
Why does the IgM peak go down?
The cells that are making IgM begin making IgG
How are attenuated pathogens produced
Passaged through many wells of monolayers of cells and culture fluid until they mutate and are no longer dangerous.
Pros and cons of live attenuated vaccines
Pros: Only need one does
Cons: Reversion to wild type
Pros and cons of inactivated vaccine
Pros: Stimulate humoral immunity
Cons: Little to no cell mediated immunity, multiple doses
Pros and cons of purified subunit vaccines
Pros: stimulate humoral immunity
Cons: minimal/no cell mediated immunity
Pros and cons of cloned vaccines (e.g. mRNA vaccines)
Pros: Stimulates humoral immunity, and no reversion to wildtype
Cons: Multiple doses required
What is passive immunity
- Direct injection of antibodies (from someone who actually has the active immunity)
- Antibodies are found in the serum after centrifuging
Why can’t B cells just activate themselves via autocrine signalling?
We need verification by T cells to minimise chances of autoimmunity. Therefore, the screening of naive B cells is not 100%. This is also why B cells are T cells are educated separately.
