Each year, doctors regularly face type O blood shortages because of its high demand. As a result, scientists around the world have scrambled to find solutions to this pressing issue. While it may seem like a far-fetched concept created by science-fiction authors, scientists at the University of British Columbia of Canada (UBC) have developed an enzyme that can change a person’s blood type from type A, B, or AB into type O.
Blood is categorized into four major types under the ABO blood group system: type A, type B, type AB, and type O. Type A blood contains erythrocytes, or red blood cells, with A antigens on the red blood cells and B antibodies floating through their bloodstream in plasma. Likewise, type B blood has B antigens on its erythrocytes and A antibodies floating through the surrounding plasma. Type AB blood contains a mix of both A and B antigens on its erythrocytes and no antibodies in the plasma. Type O blood has no antigens on its erythrocytes and both the A and B antibodies in the plasma.
If different blood types mix, antibodies and antigens will bind together in a process called agglutination, which in turn will lead to a life-threatening immune response. For example, if a patient with type A blood receives type B or type AB blood, agglutination will occur as a result of Anti-B antibodies binding with the B antigens. Only AB type blood can receive blood from all donors and only type O blood can donate blood to people of all blood types (which is why type O blood is sometimes referred to as the universal donor blood type). It should be no surprise, then, that type O blood remains in high demand.
Image Source: Science Photo Library – SCIEPRO
Since the 1980s, scientists have been trying to engineer enzymes to remove the extra residues that are found on type A, B and AB blood without much success. Like scissors, these enzymes “snip” away the antigens that distinguish A, B, and AB blood types from O. However, the enzymes previously created have not been efficient at removing enough antigens to prevent a life-threatening immune response.
Recently, researchers at UBC followed a similar approach to their predecessors, using enzymes to snip away antigens, but they managed to create a more efficient enzyme through the process of directed evolution. In directed evolution, scientists carry out several rounds of mutations on a gene until a more desirable protein is eventually produced. In other words, scientists alter the DNA that codes for the production of the enzyme until it produces a more desirable enzyme. By conducting directed evolution on the family of enzymes known as 98 glycoside hydrolase, UBC researchers were able to engineer an enzyme 170 times more effective than its original strain. Though it is not yet 100% effective at removing A and B antigens, this newly developed enzyme holds great promise in the field of medicine and hematology. If this technology is further developed, we may one day find that even blood from an AB type blood donor can be given to non-AB blood type victims in need.
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