Relationship of the Blood Sub-Groups A₁, A₂ and A₁B, A₂B to Hæmagglutinins Present in the Seeds of Dolichos biflorus

Abstract

To identify the blood sub-groups of A and AB, an anti-A₁ serum is used. This is prepared by completely absorbing a human anti-A serum with A₂ cells¹. The absorbed serum agglutinates A₁ and A₁B cells, but not A₂ or A₂B cells. A-specific hæmagglutinins have been demonstrated in saline extracts of the seeds of Dolichos biflorus by Bird², and it has been suggested³ that because extracts of Dolichos biflorus seemed predominantly A₁-specific, they may be used to differentiate the sub-groups A₁ and A₂) A₁B and A₂B. The seed extracts have the advantage of being cheaper and more easy to prepare than human sera.