Henrik Clausen at the University of Copenhagen in Denmark and his team has improved on a decade old method which utilized an enzyme isolated from the coffee bean to remove the B-antigen from red blood cells. Since this enzyme proved to be too inefficient, Clausen's group decided to isolate enzymes from bacteria. They have isolated one enzyme from a gut bacterium called Bacteroides fragilis which removes the B antigen. The other enzyme is from Elizabethkingia meningosepticum and targets the A antigen.

Clausen is planning on teaming with ZymeQuest in Beverly, Massachusetts, US.

Here is the publication form Nature Biotechnology...

Abstract:

Enzymatic removal of blood group ABO antigens to develop universal red blood cells (RBCs) was a pioneering vision originally proposed more than 25 years ago. Although the feasibility of this approach was demonstrated in clinical trials for group B RBCs, a major obstacle in translating this technology to clinical practice has been the lack of efficient glycosidase enzymes. Here we report two bacterial glycosidase gene families that provide enzymes capable of efficient removal of A and B antigens at neutral pH with low consumption of recombinant enzymes. The crystal structure of a member of the -N-acetylgalactosaminidase family reveals an unusual catalytic mechanism involving NAD+. The enzymatic conversion processes we describe hold promise for achieving the goal of producing universal RBCs, which would improve the blood supply while enhancing the safety of clinical transfusions.


Reference:

Qiyong P Liu, Gerlind Sulzenbacher, Huaiping Yuan, Eric P Bennett, Greg Pietz, Kristen Saunders, Jean Spence, Edward Nudelman, Steven B Levery, Thayer White, John M Neveu, William S Lane, Yves Bourne, Martin L Olsson, Bernard Henrissat & Henrik Clausen. Bacterial glycosidases for the production of universal red blood cells. Nature Biotechnology (01 Apr 2007) Research, Published online: 1 April 2007; | doi:10.1038/nbt1298

Link:

Nature Biotechnology - Universal Red Blood Cells

The study by Clausen's group is very interesting and identifies bacterial endoglycosidases as potential tools to avoid immune reactions against blood cells.

We have studied this from a somewhat different angle. We have used the bacterial endoglycosidase EndoS to in vivo remove the glycan from IgG to block the effects of autoantibodies against platelets with successful results.

Here's the link to our recent PNAS paper and accompanying commentary:
Collin et al.