Open AccessCharacterization of sheep erythrocyte glycosphingolipids recognized by human anti-Forssman antibodies
Author(s) -
Leandro L. Santos,
Chunsheng Jin,
Cristiana Mourato,
Fernando Mendes,
Camilla Hesse,
Susann Teneberg
Publication year - 2020
Publication title -
glycobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.757
H-Index - 128
eISSN - 1460-2423
pISSN - 0959-6658
DOI - 10.1093/glycob/cwaa032
Subject(s) - antibody , hemagglutination , glycosphingolipid , biochemistry , antigen , chemistry , biology , microbiology and biotechnology , immunology
The FORS histo-blood group system is the most recently discovered carbohydrate-based human blood group system. FORS is a rare blood group system, and most individuals have naturally occurring anti-FORS1 antibodies in plasma. Screening for anti-FORS1 antibodies is often done by hemagglutination assays using FORS1-expressing sheep erythrocytes, since FORS1-positive human erythrocytes are most often not available. Here, we have characterized the non-acid glycosphingolipids from sheep erythrocytes and isolated subfractions, with mass spectrometry, binding of antibodies and lectins, and by enzymatic hydrolysis. This demonstrated the presence of Forssman and Galili pentaosylceramides, and a Galili heptaosylceramide. Two complex glycosphingolipids recognized by human anti-FORS1 antibodies were characterized as a Forssman neolacto hybrid hexaosylceramide (GalNAcα3GalNAcβ3Galβ4GlcNAcβ3Galβ4Glcβ1Cer) and a Forssman Galili hybrid heptaosylceramide (GalNAcα3GalNAcβ3Galα3Galβ4GlcNAcβ3Galβ4Glcβ1Cer). These are novel glycosphingolipid structures, and to our knowledge, the first case of an elongated Galili antigen. Thus, the anti-Forssman antibodies in human serum bind not only to the classical Forssman pentaosylceramide (GalNAcα3GalNAcβ3Galα4Galβ4Glcβ1Cer), but also when the GalNAcα3GalNAcβ3 sequence is presented on a neolacto core chain and even on a Galili carbohydrate sequence.