One of the weapons you use to fight viruses are special molecules called antibodies that patrol your body and stick to viruses to help your cells destroy them. Every person can make more than 10 billion different kinds of antibody – that means there are more different antibody types inside you right now than there are people in the world.

Antibodies may look the same but they can have any shape at their 'ends', so for every type and shape of virus there is an antibody to match. Once you’ve detected an invading virus, a single cell can make over 2,000 copies per second of a matching shaped antibody.

Antibodies that find viruses in your blood cling on to the viruses as they try to infect your cells. If the virus gets inside a cell, the antibody will alert the cell and call for reinforcements.

Rescue comes in the form of TRIM21, a protein that recognizes the antibody and brings in the cells’ recycling machines. These machines pull the virus apart and the battle is won.

Check out our film animation of TRIM21 in action.

Work on TRIM21 could help to develop new antiviral drugs to treat diseases such as the common cold, the ‘winter vomiting bug’ and gastroenteritis.

Interested in how our scientists make their discoveries? Watch our short video showing some of our scientists at work in the MRC Laboratory of Molecular Biology.