London, Apr 2 : An international team of researchers has discovered enzymes that can convert blood groups- A, B and AB into group O, which is a universal blood group, but is mostly in short supply.

The researchers led by Henrik Clausen believe that the enzymes will help to deal with unreliable supplies of blood around the world, and also ensure the safety of transfusions. Clinical trials to test the safety and efficacy of their converted blood are being planned.

The ABO blood-type system is based on stripping off the sugar-based antigens ‘A’ and ‘B’ on red blood cells. Type O blood cells have neither A nor B antigens, so it is safely transfused into anyone. But types A, B and AB blood do, and cause grave immune reactions if they are given to patients with a different blood group. The bacterial glycosidase enzymes strip these antigens away from A, B and AB blood, reports Nature.

The concept of such antigen-stripping goes back to the early 1980s, with the discovery of an enzyme in coffee beans that removes B antigens from red blood cells1. Early-stage clinical trials showed that the converted blood could be safely transfused into individuals of different blood groups; no traces of enzyme or antigen remained to cause reactions2. But the enzyme reaction was far too inefficient to make large-scale conversion practical.

Clausen’s team studied 2,500 extracts from different bacteria and fungi for their ability to cleave off A and B antigens. The newly discovered bacterial ‘B’ enzyme is almost 1,000 times more proficient then the coffee-bean B enzyme — the additional discovery of an enzyme to remove A antigens means that all blood types can now be changed. The work is reported in Nature Biotechnology. (ANI)