Zwitterionic Phosphodiester-Substituted Neoglycoconjugates as Ligands for Antibodies and Acute Phase Proteins

Abstract

Zwitterionic modifications of glycans, such as phosphorylcholine and phosphoethanolamine, are known from a range of prokaryotic and eukaryotic species and are recognized by mammalian antibodies and pentraxins; however, defined saccharide ligands modified with these zwitterionic moieties for highthroughput studies are lacking. In this study, we prepared and tested example mono-and disaccharides 6-substituted with either phosphorylcholine or phosphoethanolamine as bovine serum albumin neoglycoconjugates or printed in a microarray format for subsequent assessment of their binding to lectins, pentraxins, and antibodies. C-Reactive protein and anti-phosphorylcholine antibodies bound specifically to ligands with phosphorylcholine, but recognition by concanavalin A was abolished or decreased as compared with that to the corresponding nonzwitterionic compounds. Furthermore, in array format, the phosphorylcholine-modified ligands were recognized by IgG and IgM in sera of either non-infected or nematode-infected dogs and pigs. Thereby, these new compounds are defined ligands which allow the assessment of glycan-bound phosphorylcholine as a target of both the innate and adaptive immune systems in mammals.

Recognition of Highly Branched N-Glycans of the Porcine Whipworm by the Immune System

“…Amongst the lower molecular weight N-glycans, the anti-mannose 100-4G11-A antibody ( 32 ) bound, as expected, fractions containing Man 3–5 GlcNAc 2 and Man 3 GlcNAc 2 Fuc 1–2 . The TEPC-15 IgA antibody and the pentraxin C-reactive protein bound almost all of the fractions judged to contain phosphorylcholine-modified N-glycans in keeping with their known specificity ( 62 ).…”

Recognition of highly branched N-glycans of the porcine whipworm by the immune system

“…Amongst the lower molecular weight N-glycans, the anti-mannose 100-4G11-A antibody ( 50 ) bound, as expected, fractions containing Man 3-5 GlcNAc 2 and Man 3 GlcNAc 2 Fuc 1-2 . The TEPC-15 IgA antibody and the pentraxin C-reactive protein bound almost all of the fractions judged to contain phosphorylcholine-modified N-glycans in keeping with their known specificity ( 51 ) .…”

Serum antibody screening using glycan arrays

“…In order to screen for antibodies against these unique glycosylation motifs, mono- and disaccharides were synthesized with these modifications, coupled to BSA, and printed in microarrays. Profiling experiments revealed that these glycan antigens were recognized by IgG and IgM in sera of dogs and pigs, 193 including those infected with Dirofilaria immitis , Ascaris suum , and Oesophagostomum dentatum . 193 Dogs infected with A. suum have also been found to possess IgM and IgG antibodies to a wide variety of other nematode glycans, including those with motifs involving LDN, LDNF, glucuronylation, polyfucosylation and unusual chitobiose-containing glycans.…”

“…Profiling experiments revealed that these glycan antigens were recognized by IgG and IgM in sera of dogs and pigs, 193 including those infected with Dirofilaria immitis , Ascaris suum , and Oesophagostomum dentatum . 193 Dogs infected with A. suum have also been found to possess IgM and IgG antibodies to a wide variety of other nematode glycans, including those with motifs involving LDN, LDNF, glucuronylation, polyfucosylation and unusual chitobiose-containing glycans. 194 Some of these antigenic epitopes are shared by Schistosoma species.…”