Expansion of the Knops blood group system and subdivision of Sl^a

Abstract

The antigen formerly known as Sl(a) can now be subdivided. A new terminology is proposed that recognizes both linear and conformational epitopes on the CR1 protein. At amino acid 1601, Sl 1 (Sl(a)) is represented by R, Sl 2 (Vil) is represented by glycine, and Sl 3 requires both R1601 and S1610. Sl 4 and Sl 5 are hypothetical epitopes represented by S1610 and T1610, respectively.