TABLE 4

Examples of A-active antigens, expression, and synthesis

AntigenStructureaRBC type or other cell typebFucosyltransferase
A1A2/AwkFUT1FUT2FUT3
Type 1 A (A-1)GalNAcα1→3Galβ1→3GlcNAc→Rc ++
↑2
Fucα1
Type 1, ALeb GalNAcα1→3Galβ1→3GlcNAc→R+↓/0++
↑2 ↑4
Fucα1 Fucα1
Type 2 A (A-2)GalNAcα1→3Galβ1→4GlcNAc→R++
↑2
Fucα1
Type 2, ALeY GalNAcα1→3Galβ1→4GlcNAc→R+++
↑2 ↑3
Fucα1 Fucα1
Type 3 A (A-3)d (mucinous A)GalNAcα1→3Galβ1→3GalNAcβ1→3Galβ1→R+0++
↑2 ↑2
Fucα1 Fucα1
Type 4 A (A-4)e (globo-A)GalNAcα1→3Galβ1→3GalNAcβ1→3Galα1→4Galβ1→4Glc→Cer+0++
↑2
Fucα1
Ganglio-Ae GalNAcα1→3Galβ1→3GalNAcβ1→4Galβ1→4Galβ1→4Glc→CerPig red cells, intestine +/−+
↑2
Fucα1
O-glycanf A, H activeFucα1→2Galβ1→3GalNAc-O-Ser/ThrGastric mucosa (ALeb) +
↑6
GalNAc1→3Gal1→3GlcNAcβ1
↑2
Fucα1
  • a Abbreviations: Cer, ceramide; Fuc, fucose; Gal, galactose; GalNAc, N-acetylgalactosamine; Glc, glucose; GlcNAc, N-acetylglucosamine.

  • b Relative expression on A1 versus A2 and other Aweak subtypes.

  • c R, upstream sequence of various sizes, which may be expressed on the glycoprotein or glycosphingolipid.

  • d Found on A1 cells only and composed of repeating terminal A motifs, also known as repetitive A motifs.

  • e Found as glycosphingolipids only.

  • f Core 2 O-glycan with A and H activity found on gastric mucosa (15% of total ALeb individuals).