Gut bacteria enzyme can turn A, B and AB blood types into O type


Veteran member
Reaction score
Ethnic group
It's not just interesting from a biological point of view, but that discovery could increase the supply of usable blood available for transfusions.

LiveScience: Gut Bacteria Enzyme Can Transform a Blood Cell's Type

"The key to changing blood types may be in the gut.

Enzymes made by bacteria in the human digestive tract can strip the sugars that determine blood type from the surface of red blood cells in the lab, a new study finds. That's important, because those sugars, or antigens, can cause devastating immune reactions if introduced into the body of someone without that particular blood type. A few enzymes discovered in the past can change type B blood to type O, but the newly discovered group of enzymes are the first to effectively change type A to type O.


As anyone who has given blood at the Red Cross can attest, type O blood is in high demand. That's because it lacks antigens on its cell membranes, making it the "universal donor" blood type — people of any blood type can take a type O transfusion without their immune system reacting to the red blood cells.

In contrast, type A, B and AB red blood cells have specific antigens on their surfaces, meaning that people with type A blood can donate only to type A or type AB recipients, and people with type B blood can donate only to those with type B or type AB. Stripping these blood types of their antigens before a transfusion could turn all blood types into universal donors, but researchers have yet to find enzymes safe and efficient enough to do the job.

Now, however, Withers and his colleagues think they might have some good candidates. In a presentation at the ACS meeting yesterday (Aug. 20), Withers shared study results showing that enzymes made with DNA extracted from human-gut microbes could remove type A and B antigens from red blood cells.

This thread has been viewed 3921 times.