Biological Evaluation of Multivalent Lewis X–MGL‐1 Interactions

TLDR

Myeloid C‑type lectin receptors on antigen‑presenting cells recognize pathogen and self‑antigens via carbohydrate ligands, but their weak affinity and limited understanding of multivalent targeting necessitate further study. The study investigates how multivalent display of the Lewis X trisaccharide epitope affects its interaction with macrophage galactose‑type lectin‑1 (MGL‑1). Glycan arrays bearing multivalent Lewis X were generated by enzymatic extension of immobilized synthetic cores with two recombinant glycosyltransferases. Multivalent Lewis X presentation increased MGL‑1 binding up to tenfold, stimulated cytokine production in dendritic‑cell/T‑cell cocultures, and altered cytokine and antibody responses in mice, showing that multivalent carbohydrate–lectin interactions can modulate immunity.

Abstract

Abstract Myeloid C‐type lectin receptors (CLRs) expressed by antigen‐presenting cells are pattern‐recognition receptors involved in the recognition of pathogens as well as of self‐antigens. The interaction of carbohydrate ligands with a CLR can trigger immune responses. Although several CLR ligands are known, there is limited insight into CLR targeting by carbohydrate ligands. The weak affinity of lectin–carbohydrate interactions often renders multivalent carbohydrate presentation necessary. Here, we have analyzed the impact of multivalent presentation of the trisaccharide Lewis X (Le X ) epitope on its interaction with the CLR macrophage galactose‐type lectin‐1 (MGL‐1). Glycan arrays, including N‐glycan structures with terminal Le X , were prepared by enzymatic extension of immobilized synthetic core structures with two recombinant glycosyltransferases. Incubation of arrays with an MGL‐1‐hFc fusion protein showed up to tenfold increased binding to multiantennary N‐glycans displaying Le X structures, compared to monovalent Le X trisaccharide. Multivalent presentation of Le X on the model antigen ovalbumin (OVA) led to increased cytokine production in a dendritic cell /T cell coculture system. Furthermore, immunization of mice with Le X ‐OVA conjugates modulated cytokine production and the humoral response, compared to OVA alone. This study provides insights into how multivalent carbohydrate–lectin interactions can be exploited to modulate immune responses.