Immunochemical study of the human blood group P₁, P, and P^k glycosphingolipid antigens

Abstract

The erythrocyte PK and P blood group antigens have been identified as ceramide trihexoside (CTH), Gal-(alpha, 1 leads to 4)Gal(beta, 1 leads to 4)Glc-Cer, and globoside, GalN-Ac(beta, 1 leads to 3)Gal(alpha, 1 leads to 4)Gal(beta, 1 leads to 4)Glc-Cer, respectively, and the following structure has been proposed for the P1 antigen: Gal(alpha, 1 leads to 4)Gal(beta, 1 leads to 4)GlcNAc(beta, 1 leads to 3)Gal(beta, 1 leads to 4)Glc-Cer. Although the P1 and PK determinants have identical terminal disaccharides, CTH did not inhibit anti-P1. The P1 glycolipid and hydatid cyst glycoprotein inhibited the agglutination of P1K erythrocytes by anti-P1 and unabsorbed anti-P1PPK sera, but neither antigen inhibited a specific anti-PK serum. The P1 and PK glycolipids were equally effective in inhibiting the hemagglutinating activity of a lectin with alpha-galactosyl specificity obtained from ova of Salmo trutta. Anti-P sera were inhibited most effectively by human erythrocyte globoside, and to a lesser extent by Forssman glycolipid and rat kidney globoside. In the latter glycolipid the linkage between the internal galactosyl residues is alpha, 1 leads to 3, rather than alpha, 1 leads to 4, as in erythrocyte globoside. No cross-reactions between P and P1 or PK antigens were detected. New hypotheses are offered to explain the genetic regulation and biosynthesis of the P1, P, and PK antigens.

TLR4–MD-2 complex is negatively regulated by an endogenous ligand, globotetraosylceramide

“…These results are consistent with a recent report that Gb4 was induced in response to TNF-α in human umbilical vein endothelial cells (20). Gb4 is the most prominent neutral GSL in human erythrocytes (21) and is an essential structure of blood group P antigen (22). The physiological function of Gb4 in vivo has not been demonstrated, although it has been shown to be an adhesion molecule on epithelial cells for bacteria (23), cancer cells (24), and some toxins (25).…”

Virulence factors in Escherichia coli urinary tract infection

“…However, rat uroepithelial cells do not express receptors for P fimbriae (179,279), and the form of globoside isolated from rat kidneys contains a Gal(al-3)Galp linkage in place of the critical Gal(al-4)Gal, linkage present in human globoside (365). Thus, the rat is a species of questionable value for evaluating the pathogenic role of P fimbriae in UTI (179).…”

The Blood Group P1 Synthase Gene Is Identical to the Gb3/CD77 Synthase Gene

“…Namely, P k is globotriaosylceramide (Gb3) synthesized from lactosylceramide with the action of Gb3/CD77 synthase. Lack of Gb3 synthase results in p phenotype expressing neither Gb3 nor P (Gb4), because P is generated from Gb3 with Gb4 synthase (12). In fact, multiple mutations in the Gb3/CD77 synthase gene leading to functional loss of the enzyme activity were identified in the individuals with p phenotype (9,13).…”