Molecular factors in dendritic cell responses to adsorbed glycoconjugates

Abstract

Carbohydrates and glycoconjugates have been shown to exert pro-inflammatory effects on the dendritic cell (DC), supporting pathogen-induced innate immunity and antigen processing, as well as immunosuppressive effects in the tolerance to self-proteins. Additionally, the innate inflammatory response to implanted biomaterials has been hypothesized to be mediated by inflammatory cells interacting with adsorbed proteins, many of which are glycosylated. However, the molecular factors relevant for surface displayed glycoconjugate modulation of DC phenotype are unknown. Thus, in this study, a model system was developed to establish the role of glycan composition, density, and carrier cationization state on DC response. Thiol modified glycans were covalently bound to a model protein carrier, maleimide functionalized bovine serum albumin (BSA), and the number of glycans per BSA modulated. Additionally, the carrier isoelectric point was scaled from a pI of ~4.0 to ~10.0 using ethylenediamine (EDA). The DC response to the neoglycoconjugates adsorbed to wells of a 384 well plate was determined via a high throughput assay. The underlying trends in DC phenotype in relation to conjugate properties were elucidated via multivariate general linear models. It was found that glycoconjugates with more than 20 glycans per carrier had the greatest impact on the pro-inflammatory response from DCs, followed by conjugates having an isoelectric point above 9.5. Surfaces displaying terminal α1–2 linked mannose structures were able to increase the inflammatory DC response to a greater extent than did any other terminal glycan structure. The results herein can be applied to inform the design of the next generation of combination products and biomaterials for use in future vaccines and implanted materials.

Presentation modality of glycoconjugates modulates dendritic cell phenotype

“…al. 10 . Briefly, mass spectra of the glycoconjugates were determined using Matrix Assisted Laser Desorption Ionization (MALDI) Mass Spectrometry.…”

Biomaterial Strategies for Immunomodulation

“…Recently, Babensee and coworkers (52) showed that the charge of a carrier can enhance DC maturation in response to glycoconjugates (Figure 2 e ). In this study, it was shown that the conjugate charge induced the second largest increase in proinflammatory DC maturation, falling behind only ligand density in potency (52).…”

“…Recently, Babensee and coworkers (52) showed that the charge of a carrier can enhance DC maturation in response to glycoconjugates (Figure 2 e ). In this study, it was shown that the conjugate charge induced the second largest increase in proinflammatory DC maturation, falling behind only ligand density in potency (52). It has also been shown that the surface charge of NPs influences the adsorption of opsonins (and other plasma proteins), leading to macrophage recognition, which is followed by phagocytosis and elimination (53).…”

“…NC-BSA: no EDA added; L-BSA: 0.05 M EDA, low pI; M-BSA: 0.15 M EDA, medium pI; H-BSA: 0.90 M EDA, high pI. (Panels a -- d adapted with permission from 41; panel e adapted with permission from 52. )…”

Glycomaterials for probing host–pathogen interactions and the immune response

“…Hotaling et al recently conducted a study on BSA conjugates of various glycans to clarify the molecular determinants (glycan composition, density, carrier cationicity) that influence DC responses. 103 …”