Enzymatic Production of Universal Donor Erythrocytes

摘要

The aims of this research contract were: 1) to isolate in pure culture strains of human enteric bacteria with the specialized ability to produce strong activities of extracellular glycosidases that convert blood type A or B erythrocytes to universal donor blood type O erythrocytes; 2) to purify the blood type B-degrading enzyme produced by a fecal strain of Ruminococcus AB; 3) to determine whether human type B red cells could be safety converted by this glycosidase to universal donor type O red cells for use on blood transfusion. Aim 1 was accomplished with the isolation of 2 strains that produce strong blood group A-degrading activity but no B-degrading activity. These complement our previous isolation of the strain of Ruminococcus AB that produces B-degrading but no A-degrading activity. Aim 2, purification of the B-degrading enzyme in culture supernates of Ruminococcus AB, resisted a wide variety of classical protein separation methods until the last 2 months of the contract. As detailed in the report, major purification appears to have been achieved by digestion with papain followed by gel exclusion of chromatography on Sephadex G-200 in 3M NaC1. With successful completion of Aim 2 it will now be possible to meet the objectives of Aim 3.