In Pursuit of a Universal Blood Type

Scientists have identified a new, efficient method of transforming types A and B blood into a neutral blood type that can potentially be donated to any patient, according to new research published in the Journal of the American Chemical Society.

The study was performed by researchers from the University of British Columbia and the Centre for Blood research. They created an enzyme that snips off the antigens found in Types A and B blood, which resulted in a blood type that was similar to the universal kind that can be donated to all patients—Type O. To accomplish this, the researchers used a technology called directed evolution, which includes inserting mutations into the gene responsible for codes in the enzyme, as well as selecting mutants that were effective in cutting the antigens. The enzyme became 170 times more effective in five generations, according to a press release.

"We produced a mutant enzyme that is very efficient at cutting off the sugars in A and B blood, and is much more proficient at removing the subtypes of the A-antigen that the parent enzyme struggles with," lead study author David Kwan, a postdoctoral fellow in the department of chemistry at the University of British Columbia, said in a prepared statement.

Specifically, the researchers found that “enzymatic removal of the terminal N-acetylgalactosamine or galactose of A- or B-antigens, respectively, yields universal O-type blood, but is inefficient,” according to the study. “Starting with the family 98 glycoside hydrolase from Streptococcus pneumoniae SP3-BS71 (Sp3GH98), which cleaves the entire terminal trisaccharide antigenic determinants of both A- and B-antigens from some of the linkages on RBC surface glycans, through several rounds of evolution, we developed variants with vastly improved activity toward some of the linkages that are resistant to cleavage by the wild-type enzyme.”

The researchers were able to remove the “wide majority” of antigens in Type A and Type B blood. Future research could build upon this work and eventually develop a way to generate universal blood types that can be used in clinical settings. "The concept is not new, but until now we needed so much of the enzyme to make it work that it was impractical," says Steve Withers, a professor of chemistry at the University of British Columbia. "Now I'm confident that we can take this a whole lot further."