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 ±-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.
