Influence of Core β-1,2-Xylosylation on Glycoprotein Recognition by Murine C-type Lectin Receptors and Its Impact on Dendritic Cell Targeting

Abstract

Targeting antigens to dendritic cell subsets is a promising strategy to enhance the efficacy of vaccines. C-type lectin receptors (CLRs) expressed by dendritic cells are particularly attractive candidates since CLR engagement may promote cell uptake and may further stimulate antigen presentation and subsequent T cell activation. While most previous approaches have involved antibody-mediated CLR-targeting, glycan-based CLR targeting has become more and more attractive in recent years. In the present study, we show that small structural glycan modifications may markedly influence CLR recognition, dendritic cell targeting, and subsequent T cell activation. A biantennary N-glycan (G0) and its analogous O-2 core xylosylated N-glycan (XG0) were synthesized, covalently conjugated to the model antigen ovalbumin, and analyzed for binding to a set of murine CLR-Fc fusion proteins using lectin microarray. To evaluate whether the differential binding of G0 and XG0 to CLRs impacted dendritic cell targeting, uptake studies using murine dendritic cells were performed. Finally, effects of the ovalbumin glycoconjugates on T cell activation were measured in a dendritic cell/T cell cocultivation assay. Our results highlight the utility of glycan-based dendritic cell targeting and demonstrate that small structural differences may have a major impact on dendritic cell targeting efficacy.

Myeloid C-Type Lectin Receptors in Viral Recognition and Antiviral Immunity

“…Since an efficient inhibition of virus/CLR interactions by glycan-based carrier systems requires a high binding avidity, multivalent ligand display using different scaffolds has been employed, including nanoparticles, dendrimers, polymers, fullerenes, and glycan-modified antigens [135,136,137,138,139,140]. Besides the inhibition of viral entry into host cells, multivalent CLR targeting also represents a promising strategy to stimulate APC effector functions to boost immune responses [141,142,143]. …”

Engineering of CHO Cells for the Production of Recombinant Glycoprotein Vaccines with Xylosylated N-glycans

“…The latter one seems to be activated via the lectin pathway by the mannose binding lectins, MASP1 and MASP2. The role of C-type lectin receptors in activation of murine DC by stimulation with core β1,2-xylosylated glycoprotein was investigated by Brzezicka et al [ 34 ]. They report enhanced uptake, presentation and subsequent T-cell activation by artificially glycosylated ovalbumin; however, xylosylated glycans did not significantly enhance the activation potential in this experimental setup.…”

Glycan-Based Cell Targeting To Modulate Immune Responses

“…Immunization studies in mice revealed augmented antibody responses against C. albicans β-mannan. Rational design of glycan ligands of CLRs as well as the optimization of the respective protein or peptide antigen can further increase targeting efficacy [82,83]. A particularly attractive strategy is targeting multiple CLRs simultaneously to enhance targeting or to induce synergistic responses through cross-talk.…”