How an mRNA vaccine teaches your cells to build the spike protein
A strand of instructions, a lipid envelope, and your own ribosomes doing the work. This explainer draws each step and what the immune system learns from it.
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Transcript
The problem: virus invades
A virus has spiky proteins on its surface.
These spikes let it attach to your cells.
Your immune system does not recognize the spike.
The virus enters and multiplies.
By the time your body learns to fight back, you are sick.
The vaccine delivers mRNA
A vaccine carries mRNA inside a lipid shell.
mRNA is genetic instructions, one page long.
It tells your cells how to build the spike protein.
The lipid wraps it safely through the bloodstream.
It reaches your muscle cells intact.
mRNA enters and unfolds
The lipid shell merges with the cell membrane.
The mRNA steps out into the cytoplasm.
Now it is exposed to the cell's ribosomes.
These are the protein factories.
Ribosome builds spike protein
The ribosome reads the mRNA code.
It assembles amino acids one by one.
In minutes, the spike protein folds into shape.
Your cell now makes about one hundred spikes.
Each one sits on the cell surface.
Immune system recognizes and trains
Your immune cells patrol and spot the spikes.
White blood cells and antibody-makers recognize them.
They are not the full virus, so there is no disease.
Your body learns the spike's exact shape.
It creates antibodies to match it perfectly.
Vaccine versus real virus
After vaccination, your body knows the spike.
If the real virus arrives, antibodies are ready.
They grab the spike protein instantly.
The virus cannot attach or enter your cells.
You do not get sick.
The mRNA is broken down
Within days, your cells break down the mRNA.
It is not DNA; it does not change your genes.
The mRNA disappears.
Your immunity to the spike remains.
Your cells stop making the protein.
Future infection defeated
Months or years later, you meet the real virus.
Your memory antibodies recognize it at once.
They bind to the spike and block it.
Your immune system destroys the virus before it spreads.
You stay healthy.
Every sentence above was written before a single picture was drawn, then each object it names was painted for this video alone.
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