When you need an emergency blood
transfusion, what happens if the hospital or blood bank doesn't have your blood
type? It has been an issue that researchers have been trying to resolve for
Scientific world has been looking
at using enzymes derived from bacteria to remove antigens from red blood cells
to produce Type O blood group
, which is a universal donor. However, those enzymes
haven't been effective and since a huge amount of enzymes was required to make
a difference, it was also considered impractical.
Scientists at the Center for Blood Research Center of the
University of British Columbia (UBC) say that they have found a possible
solution to this issue. They have created an enzyme that could change any blood
group into Type O.
The norm at present is that Type
A blood group can only be used to treat A or AB people, and Type B can only be
given to B or AB people. Type O is transfusion-friendly and can be given to
anyone because it contains no A or B antigens. People with Type O group can
donate to all blood groups but they can only receive from their own group.
According to the scientists,
however, the new enzyme works by removing antigens from Type A and Type B
blood, making it work like Type O. They used a new technology called directed
evolution to create a mutant enzyme that's much more effective.
In their experiment, scientists
inserted mutations into the bacterial gene that codes for the enzyme.
Subsequently, they selected mutants that were particularly effective at
removing the antigens. They did this for five generations and created an enzyme
that was 170 times more efficient at antigen-clipping than its original
David Kwan, the lead author of
the study and a postdoctoral fellow at Department of Chemistry, UBC, said that
the enzymes were able to snip off wide majority of the antigens in Type A and B
"We produced a mutant enzyme that
is very efficient at cutting off the sugars in A and B blood types, and also
much more proficient at removing the subtypes of the A-antigen that the parent
enzyme struggles with. The conversion process with very small amounts of enzyme
is cheaper and less problematic when retrieving the enzyme (after the blood
conversion). This process takes over a few hours. It could also be done in minutes using a lot of
enzyme. Overall, the speed of this
technology depends completely onhow much enzyme we use," Kwan
Steve Withers, a professor in the
Department of Chemistry, UBC, said that some more basic research and safety
tests are required to substantiate these findings and bring this technology
into everyday practice.†
"The concept is not new but until
now, we needed so much of the enzyme to make it work that it was impractical.
Now I'm confident that we can take this a whole lot further. However, it will take at-least 10 years to
use the technology in clinical practice. Some more basic research is necessary
and the process should go through the same safety and efficacy testing as any
drug," he said.
The enzyme would need to remove
all of the antigens before it can be used in clinical settings because the
immune system is highly sensitive to blood groups
. Even a few incompatible antigens
in a transfusion could activate an immune response and can be very harmful for
The study was published in the Journal of the American Chemical Society
The study was supported by the Canadian Institutes of Health Research and
Canadian Blood Services.