There is disclosed a method of modifying red blood cells, comprising:(i) suspending group B or group AB erythrocytes in a buffer solution having a neutral pH,(ii) incubating the erythrocytes of step(i) with an enzyme having a-galactosidase activity, and(iii) isolating the converted erythrocytes of step(ii) from the enzyme and the enzymatically-cleaved immunodominant galactose residues,thereby cleaving the branched immunodominant B epitopes on the group B or group AB erythrocyte as determined by serological typing or hemagglutination assays.
