Inhibition of Human Anti‐Gd Cold Agglutinins by Sialyllactose

Abstract

Two examples of IgM kappa-monotopic cold agglutinins occurring in patients with non-Hodgkin lymphomas, reacted with erythrocyte autoantigens, which were protease-resistant but were inactivated by neuraminidase. The cold agglutinins were inhibited by the trisaccharide sialyllactose [NeuNAc(alpha,2 leads to 3) Gal (beta, 1 leads to 4)Glc], which is not related to oligosaccharides known to inhibit anti-I/-i cold agglutinins, Anti-Pr cold agglutinins are not inhibited by sialyllactose, although N-acetylneuraminic acid (NeuNAc) is an essential component not only of Gd but also of Pr determinants. Gd determinants are not bound to erythrocyte membrane glycoproteins, but are apparently bound to membrane glycolipids (gangliosides).

Reaction of Anti‐Gd, Anti‐Fl and Anti‐Sa Cold Agglutinins with p Erythrocytes

“…They recognize N-acetylneuraminic acid (Neu-Ac)-determined protease-resistant, glycolipid-dependent Gd antigens [l]. They are inhibited by sialyllactose [2]. The isomer NeuAca2-3Galpl-4Glc has been shown to be responsible for inhibition [3].…”

A Further Cold Agglutinin, Fl, Recognizing a N-Acetylneuraminic Acid-Determined Antigen

“…Since anti-Gd and Sa-type CA were in hibited by sialyllactose [3,10], inhibition experiments were done with the absorbed serum FI. No inhibition could be detected except for a 10 mg/ml solution.…”

Reaction of Anti-Gd, Anti-Fl and Anti-Sa Cold Agglutinins with p Erythrocytes

“…They recognize N-acetylneuraminic acid (NeuAc)-determined protease-resistant, glycolipid-dependent Gd antigens [1]. They are in hibited by sialyllactose [2], The isomer NeuAca2-3Galßl-4Glc has been shown to be responsible for inhibition [3]. The disac charide NeuAca2-3Galßl... structure is the terminal structure also of sialosylparagloboside (SPG) NeuAca2-3Galßl-4GlcNAcßl-3Galßl-4Glc-Cer [4], Since SPG has been shown to be an inhibitor of anti-Gd CA [5], and since SPG is enriched in p RBC [6], p RBC were tested for reaction strength with anti-Gd CA.…”