Bacterial enzyme strips away blood types to create universal donor blood

Amazing stuff! Good news!

"... Researchers at the Technical University of Denmark (DTU) and Lund University, Sweden, have used enzymes produced by a common gut bacteria to remove the A and B antigens from red blood cells, bringing them one step closer to creating universal donor blood. ..."

"The quest to develop universal donor blood has taken a decisive step forward. Researchers at DTU and Lund University have discovered enzymes that, when mixed with red blood cells, are able to remove specific sugars that make up the A and B antigens in the human AB0 blood groups. ..."

From the abstract:

"Matching donor and recipient blood groups based on red blood cell (RBC) surface ABO glycans and antibodies in plasma is crucial to avoid potentially fatal reactions during transfusions. Enzymatic conversion of RBC glycans to the universal group O is an attractive solution to simplify blood logistics and prevent ABO-mismatched transfusions. The gut symbiont Akkermansia muciniphila can degrade mucin O-glycans including ABO epitopes. Here we biochemically evaluated 23 Akkermansia glycosyl hydrolases and identified exoglycosidase combinations which efficiently transformed both A and B antigens and four of their carbohydrate extensions. Enzymatic removal of canonical and extended ABO antigens on RBCs significantly improved compatibility with group O plasmas, compared to conversion of A or B antigens alone. Finally, structural analyses of two B-converting enzymes identified a previously unknown putative carbohydrate-binding module. This study demonstrates the potential utility of mucin-degrading gut bacteria as valuable sources of enzymes for production of universal blood for transfusions."

Bacterial enzyme strips away blood types to create universal donor blood Using enzymes produced by a bacteria that almost everyone has in their gut, researchers have removed the antigens from red blood cells that determine blood type, putting us within reach of producing universal donor blood.

Enzymes open new path to universal donor blood (original news release) Researchers at DTU and Lund University have discovered enzymes that remove hindrances that stood in the way of developing universal donor blood.

Akkermansia muciniphila exoglycosidases target extended blood group antigens to generate ABO-universal blood (no public access)

Fig. The AB0 blood group antigens found on the surface of red blood cells are also found on the mucosal layer that lines the surface of the gut.

Ex vivo enzymatic treatment converts blood type A donor lungs into universal blood type lungs

Good news! These results are preliminary and have not been tested in vivo! Can these promising results be extended to other cases, where a universal blood type matters? 

"A major challenge in lung transplantation is the need for ABO blood group matching. To address this challenge, Wang et al. used two enzymes, FpGalNAc deacetylase and FpGalactosaminidase, to convert blood group A lungs to blood group O lungs during ex vivo lung perfusion. The authors demonstrated successful removal of blood group A antigen with no overt changes in lung health. In an ex vivo simulation of transplantation, the authors showed reduced antibody and complement deposition, suggesting that this technique may reduce antibody-mediated injury in vivo. ..."

From the abstract:

"Donor organ allocation is dependent on ABO matching, restricting the opportunity for some patients to receive a life-saving transplant. The enzymes FpGalNAc deacetylase and FpGalactosaminidase, used in combination, have been described to effectively convert group A (ABO-A) red blood cells (RBCs) to group O (ABO-O). Here, we study the safety and preclinical efficacy of using these enzymes to remove A antigen (A-Ag) from human donor lungs using ex vivo lung perfusion (EVLP). ... An ABO-incompatible transplant was then simulated with an ex vivo model of antibody-mediated rejection using ABO-O plasma as the surrogate for the recipient circulation using three donor lungs. The treatment of donor lungs minimized antibody binding, complement deposition, and antibody-mediated injury as compared with control lungs. These results show that depletion of donor lung A-Ag can be achieved with EVLP treatment. This strategy has the potential to expand ABO-incompatible lung transplantation and lead to improvements in fairness of organ allocation."

Ex vivo enzymatic treatment converts blood type A donor lungs into universal blood type lungs (no public access)