mRNA Vaccines Flashcards
What are mRNA vaccines
Vaccine given where subject is injected with mRNA encoding for an antigen
Rather than being injected with the antigen itself
How do mRNA vaccines work
Sequences are injected into muscle cells
Sequence is take up by host cells, translated and expressed
The body will now produce the foreign antigen
List the 3 types of mRNA
- Non-replicating
- Self-amplifying
- Trans-amplifying
How is mRNA used in vaccines kept stable?
5’ CAP & 3’ Poly A tail are critical for stability in cytoplasm of cell
Increasing the G-C content also increases stability
What effect does increasing the Poly-A tail have on an mRNA molecule?
Increases the translational efficiency
What is codon optimisation?
The use of synonymous codons
(Different codons which encode for the same amino acid)
Describe the structure of a LNP (lipid nano particle) used in mRNA vaccines
Cationic lipids
PEG lipids
Helper phospholipids
Cholesterol
mRNA
Describe the function of each part of a LNP in a mRNA vaccine
Cationic lipids - require for complexation with mRNA
PEG lipids - shielding surface charge
Helper phospholipids - support bilayer structure
Cholesterol - gives structural stability
Describe the mRNA vaccine mechanism of action
Genetic sequence of virus spike used to make mRNA sequence
mRNA is packed into a nanoparticle which can deliver it to immune cells
Immune cells take up mRNA
Immune cells follow the mRNA code and produce spike proteins
This stimulates an immune response
What parts of the immune response does an mRNA generate? (4)
- Activates CD8+ T cells
- Activates CD4+ T cells
- Activates IFN-1 pathway
- Stimulates B cells
Describe the composition of LNP’s
4 different lipids
In different molar ratios
(Cationic lipid, neutral lipid, cholesterol + PEG lipid)
Describe the Pfizer mRNA vaccine for COVID-19
BNT162b2
Lipid nanoparticle
Nucleoside modified mRNA
Encode for spike glycoprotein
What type of delivery system do Moderna & Pfizer use for their COVID-19 vaccine
Lipid nanoparticles
