Blood Cells - Tissue Functioning and Remodeling in the Circulatory and Ventilatory Systems - page 70

The Colton blood group is associated with aquaporin-1 with allelic diversity
(Co-a and Co-b alleles). Aquaporin-3 is a determinant for the GIL blood group.
The Cromer blood group is related to decay accelerating factor (CD55) that
prevents the assembly of the C3-convertase of the alternative pathway or accelerates
the disassembly of preformed convertase.
The Dombrock blood group that comprises many variant alleles corresponds to
ADP ribosyltransferase Art4 (CD297) [ 133 ].
The Knops blood group squares with RBC complement receptor-1 (CR1, CD35,
C3b/C4b receptor, and immune adherence receptor), a member of the the family of
receptors of complement activation.
The Indian blood group (In) antigen tallies with glycoprotein CD44 that is
involved in intercellular interactions.
The John Milton Hagen blood group (JMH) antigen coincides with

semaphorin-7a that is expressed on RBCs and activated lymphocytes.
The OK blood group relies on glycoprotein CD147 that is also termed basigin
and extracellular matrix metallopeptidase inducer.
The Ii antigen group corresponds to branched (I) or linear (i) polysaccharides,
the synthesis of which depends on enzymes encoded by genes on chromosome 6.
The unbranched i antigen, the precursor of I antigen, is synthesized by the
sequential action of 2 glycosyl transferases, β (1,3)acetyl glucosaminyl transferase

and (1,4)galactosyl transferase. The I antigen is formed by branching initiated by

a third transferase, the I

β

(1,6) N acetylglucosamine transferase type 2. The GCNT2
gene encodes this N acetylglucosaminyltransferase 34 that converts active straight
chains of carbohydrates to I-active branched chains. Three isoforms are created by
alternative splicing (IGNT1-IGNT3 or IGNTa-IGNTc).
The i and I antigens are carbohydrate linear and branched repeats of N acetyl
lactosamine, i.e., n being the number of repeating lactosamine units (6 in average
for i antigen, 8-25 for I antigen) and

β

β i - j the linkage type:

Gal −−−−−−
β 1 −− 4

Glc N Ac n --G l −−−−−−

Glc N Ac −−−−−−
β 1 −− 3

Gal-

β 1 −− 4

and

Gal Gal

| β 1-4 | β 1-4

Glc N Ac Glc N Ac

| β | β

1-6 1-6

Gal −−−−−−
β 1 −− 4

Glc N Ac n --G l −−−−−− Glc N Ac −−−−−−

β 1 −− 3

Gal-

β 1 −− 4

34 A.k.a. glucosaminyl ( N acetyl) transferase-2 I-branching enzyme (IGNT), N acetyl lactosaminide
β

(1,6) N acetylglucosaminyl-transferase isoform-A, -B, and -C.