Presentation modality of glycoconjugates modulates dendritic cell phenotype

Abstract

The comparative dendritic cell (DC) response to glycoconjugates presented in soluble, phagocytosable, or non-phagocytosable display modalities is poorly understood. This is particularly problematic, as the probing of immobilized glycans presented on the surface of microarrays is a common screen for potential candidates for glycan-based therapeutics. However, the assumption that carbohydrate-protein interactions on a flat surface can be translatable to development of efficacious therapies, such as vaccines, which are delivered in soluble or phagocytosable particles, has not been validated. Thus, a preliminary investigation was performed in which mannose or glucose was conjugated to cationized bovine serum albumin and presented to DCs in soluble, phagocytosable, or non-phagocytosable display modalities. The functional DC response to the glycoconjugates was assessed via a high throughput assay. Dendritic cell phenotypic outcomes were placed into a multivariate, general linear model (GLM) and shown to be statistically different amongst display modalities when comparing similar surface areas. The GLM showed that glycoconjugates that were adsorbed to wells were the most pro-inflammatory while soluble conjugates were the least. DC interactions with mannose conjugates were found to be calcium dependent and could be inhibited via anti-DC-SIGN antibodies. The results of this study aim to resolve conflicts in reports from multiple laboratories showing differential DC profiles in response to similar, if not identical, ligands delivered via different modalities. Additionally, this study begins to bridge the gap between microarray binding data and functional cell responses by highlighting the phenotypes induced from adsorbed glycoconjugates as compared to those in solution or displayed on microparticles.

Controlled Delivery of Immunomodulators from a Biomaterial Scaffold Niche to Induce a Tolerogenic Phenotype in Human Dendritic Cells

“…63 Expression of ILT-3 increased when CD86 expression decreased on immunosuppressant-treated DCs and vice versa has been shown in the previous work. 63 Since the ILT-3 signal was cumulatively low (<10% of the total cells), by dividing with the value of CD86, the data quality can be improved. Thus, ILT-3/CD86 rather than ILT-3 79 expression only was used to represent tolerogenicity (Figure 10).…”

“…Due to the modular nature of the scaffold system and the mathematical model, it is possible to engineer the controlled release of virtually any combination of biomolecules given similar time duration of release but not necessarily identical molecular size. For example, an additional cytokine such as IL-4, 63 which may be used for DC development from monocytes, may be incorporated using the existing scaffold formulation.…”

“…CD86/DC-SIGN is defined as the maturation marker that is based on the previously published studies, , which is shown to be a value independent of cell number. CD86/DC-SIGN indicates the MFI ratio of CD86 over DC-SIGN from each donor, which were then averaged across n = 6 donors.…”

Systematic Dual Targeting of Dendritic Cell C-Type Lectin Receptor DC-SIGN and TLR7 Using a Trifunctional Mannosylated Antigen

“…With the field of dendritic cell-based immunotherapy in acceleration, the range of glycoconjugates aimed at modulating the dendritic cell phenotype has rapidly expanded (Hotaling et al, 2014). Our paper documents a systematic array of DC-SIGN-targeting clusters, with well-defined mannoside structures (mono-, di-, and tri-mannosides) and controlled (mono-, di-, tri-, hexavalent) presentation.…”

Biomaterial Strategies for Immunomodulation

“…For example, glycan--bovine serum albumin constructs displayed from the surface of beads, from flat-well surfaces, or delivered in a range of soluble concentrations have been shown to differentially enhance DC maturation (71). Glycoconjugates presented from a nonphagocytosable flat-well surface showed the highest amount of DC maturation, and soluble conjugates showed the lowest.…”