Problem: patient needs a blood transfusion but you don’t have their blood type in the blood bank

Scientists have been trying to find an economic solution to this issue for many years.

Blood types:

The defining difference between A, B and O blood types is the presence of slightly different sugar structures on the outside of the red blood cells of each type.

• Type A and B blood cells each have a single additional sugar attached to their surface
• Type O blood is known as the universal donor and can be given to patients of all blood types

Now they might have the answer. How does it work? Researchers produced a mutant enzyme that is very efficient at cutting off the sugars in A and B blood.

The enzyme works by snipping off the sugars, also known as antigens, found in Type A and Type B blood, making it more like Type O. To produce the enzyme used a new technology called directed evolution. Directed evolution: involves inserting mutations into the gene that codes for the enzyme, and selecting mutants that are more effective at cutting the antigens.

In just five generations, the enzyme became 170 times more effective. With this enzyme were able to remove the wide majority of the antigens in Type A and B blood.

What now?

Before it can be used in clinical settings, the enzyme would need to remove all of the antigens. Immune system is highly sensitive to blood groups and even small amounts of residual antigens could trigger an immune response.