Molecular factors in dendritic cell responses to adsorbed glycoconjugates

Multiepitope Subunit Peptide-Based Nanovaccine against Porcine Circovirus Type 2 (PCV2) Elicited High Antibody Titers in Vaccinated Mice

Porcine circovirus 2 (PCV2) infection is one of the most serious threats to the swine industry. While the disease can be prevented, to some extent, by commercial PCV2a vaccines, the evolving nature of PCV2 necessitates the development of a novel vaccine that can compete with the mutations of the virus. Thus, we have developed novel multiepitope vaccines based on the PCV2b variant. Three PCV2b capsid protein epitopes, together with a universal T helper epitope, were synthesized and formulated with five delivery systems/adjuvants: complete Freund's adjuvant, poly(methyl acrylate) (PMA), poly(hydrophobic amino acid), liposomes and rod-shaped polymeric nanoparticles built from polystyrene-poly(N-isopropylacrylamide)-poly(N-dimethylacrylamide). Mice were subcutaneously immunized with the vaccine candidates three times at three-week intervals. All vaccinated mice produced high antibody titters after three immunizations as analyzed by the enzyme-linked immunosorbent assay (ELISA), while mice vaccinated with PMA-adjuvanted vaccine elicited high antibody titers even after a single immunization. Thus, the multiepitope PCV2 vaccine candidates designed and examined here show strong potential for further development.

The role of dendritic cells in the immunomodulation to implanted biomaterials

Considering the substantial role played by dendritic cells (DCs) in the immune system to bridge innate and adaptive immunity, studies on DC-mediated immunity toward biomaterials principally center on their adjuvant effects in facilitating the adaptive immunity of codelivered antigens. However, the effect of the intrinsic properties of biomaterials on dendritic cells has not been clarified. Recently, researchers have begun to investigate and found that biomaterials that are nonadjuvant could also regulate the immune function of DCs and thus affect subsequent tissue regeneration. In the case of proteins adsorbed onto biomaterial surfaces, their intrinsic properties can direct their orientation and conformation, forming “biomaterial-associated molecular patterns (BAMPs)”. Thus, in this review, we focused on the intrinsic physiochemical properties of biomaterials in the absence of antigens that affect DC immune function and summarized the underlying signaling pathways. Moreover, we preliminarily clarified the specific composition of BAMPs and the interplay between some key molecules and DCs, such as heat shock proteins (HSPs) and high mobility group box 1 (HMGB1). This review provides a new direction for future biomaterial design, through which modulation of host immune responses is applicable to tissue engineering and immunotherapy.

Silicone Implants Immobilized with Interleukin-4 Promote the M2 Polarization of Macrophages and Inhibit the Formation of Fibrous Capsules

Breast augmentations with silicone implants can have adverse effects on tissues that, in turn, lead to capsular contracture (CC). One of the potential ways of overcoming CC is to control the implant/host interaction using immunomodulatory agents. Recently, a high ratio of anti-inflammatory (M2) macrophages to pro-inflammatory (M1) macrophages has been reported to be an effective tissue regeneration approach at the implant site. In this study, a biofunctionalized implant was coated with interleukin (IL)-4 to inhibit an adverse immune reaction and promoted tissue regeneration by promoting polarization of macrophages into the M2 pro-healing phenotype in the long term. Surface wettability, nitrogen content, and atomic force microscopy data clearly showed the successful immobilization of IL-4 on the silicone implant. Furthermore, in vitro results revealed that IL-4-coated implants were able to decrease the secretion of inflammatory cytokines (IL-6 and tumor necrosis factor-α) and induced the production of IL-10 and the upregulation of arginase-1 (mannose receptor expressed by M2 macrophage). The efficacy of this immunomodulatory implant was further demonstrated in an in vivo rat model. The animal study showed that the presence of IL-4 diminished the capsule thickness, the amount of collagen, tissue inflammation, and the infiltration of fibroblasts and myofibroblasts. These results suggest that macrophage phenotype modulation can effectively reduce inflammation and fibrous CC on a silicone implant conjugated with IL-4.

Nanoparticles for mucosal vaccine delivery

Mucosal surfaces represent important routes of entry into the human body for the majority of pathogens, and they constitute unique sites for targeted vaccine delivery. Nanoparticle-based drug delivery systems are emerging technologies for delivering and improving the efficacy of mucosal vaccines. Recent studies have provided new insights into formulation and delivery aspects of importance for the design of safe and efficacious mucosal subunit vaccines based on nanoparticles. These include novel nanomaterials, their physicochemical properties and formulation approaches, nanoparticle interaction with immune cells in the mucosa, and mucosal immunization and delivery strategies. Here, we present recent progress in the application of nanoparticle-based approaches for mucosal vaccine delivery and discuss future research challenges and opportunities in the field.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2013-2014

This review is the eighth update of the original article published in 1999 on the application of Matrix-assisted laser desorption/ionization mass spectrometry (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2014. Topics covered in the first part of the review include general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation, and arrays. The second part of the review is devoted to applications to various structural types such as oligo- and poly- saccharides, glycoproteins, glycolipids, glycosides, and biopharmaceuticals. Much of this material is presented in tabular form. The third part of the review covers medical and industrial applications of the technique, studies of enzyme reactions, and applications to chemical synthesis. © 2018 Wiley Periodicals, Inc. Mass Spec Rev 37:353-491, 2018.

The roles of galectins in parasitic infections

Galectins is a family of multifunctional lectins. Fifteen galectins have been identified from a variety of cells and tissues of vertebrates and invertebrates. Galectins have been shown to play pivotal roles in host-pathogen interaction such as adhesion of pathogens to host cells and activation of host innate and adaptive immunity. In recent years, the roles of galectins during parasite infections have gained increasing attention. Galectins produced by different hosts can act as pattern recognition receptors detecting conserved pathogen-associated molecular patterns of parasites, while galectins produced by parasites can modulate host responses. This review summarizes some recent studies on the roles of galectins produced by parasitic protozoa, nematodes, and trematodes and their hosts. Understanding the roles of galectins in host-parasite interactions may provide targets for immune intervention and therapies of parasitic infections.

Dendritic cells in host response to biologic scaffolds

Tissue regeneration and repair require a highly complex and orchestrated series of events that require inflammation, but can be compromised when inflammation is excessive or becomes chronic. Macrophages are one of the first cells to contact and respond to implanted materials, and mediate the inflammatory response. The series of events following macrophage association with biomaterials has been well-studied. Dendritic cells (DCs) also directly interact with biomaterials, are critical for specific immune responses, and can be activated in response to interactions with biomaterials. Yet, much less is known about the responses by DCs. This review discusses what we know about DC response to biomaterials, the underlying mechanisms involved, and how DCs can be influenced by the macrophage response to biomaterials. Lastly, I will discuss how biomaterials can be manipulated to enhance or suppress DC function to promote a specific desirable immune response - a major goal for implantable biologically active therapeutics.

Glycomaterials for probing host-pathogen interactions and the immune response

The initial engagement of host cells by pathogens is often mediated by glycan structures presented on the cell surface. Various components of the glycocalyx can be targeted by pathogens for adhesion to facilitate infection. Glycans also play integral roles in the modulation of the host immune response to infection. Therefore, understanding the parameters that define glycan interactions with both pathogens and the various components of the host immune system can aid in the development of strategies to prevent, interrupt, or manage infection. Glycomaterials provide a unique and powerful tool with which to interrogate the compositional and functional complexity of the glycocalyx. The objective of this review is to highlight some key contributions from this area of research in deciphering the mechanisms of pathogenesis and the associated host response.

Biomaterial Strategies for Immunomodulation

Strategies to enhance, suppress, or qualitatively shape the immune response are of importance for diverse biomedical applications, such as the development of new vaccines, treatments for autoimmune diseases and allergies, strategies for regenerative medicine, and immunotherapies for cancer. However, the intricate cellular and molecular signals regulating the immune system are major hurdles to predictably manipulating the immune response and developing safe and effective therapies. To meet this challenge, biomaterials are being developed that control how, where, and when immune cells are stimulated in vivo, and that can finely control their differentiation in vitro. We review recent advances in the field of biomaterials for immunomodulation, focusing particularly on designing biomaterials to provide controlled immunostimulation, targeting drugs and vaccines to lymphoid organs, and serving as scaffolds to organize immune cells and emulate lymphoid tissues. These ongoing efforts highlight the many ways in which biomaterials can be brought to bear to engineer the immune system.

Biomolecular strategies to modulate the macrophage response to implanted materials

The material-induced foreign body response is a major challenge for implanted medical devices. This review highlights recent developments in biomimetic approaches to create biomaterials that mitigate the host response to biomaterials. Specifically, we will describe strategies in which biomaterials are decorated with endogenously expressed biomolecules that naturally modulate the function of immune cells. These include molecules that directly bind to and interact with immune cells, as well as molecules that control complement activation or thrombosis and indirectly modulate immune cell function. We provide perspective on how these approaches may impact the design of materials for medical devices and tissue engineering.

Polyelectrolyte Multilayers Assembled Entirely from Immune Signals on Gold Nanoparticle Templates Promote Antigen-Specific T Cell Response

Materials that allow modular, defined assembly of immune signals could support a new generation of rationally designed vaccines that promote tunable immune responses. Toward this goal, we have developed the first polyelectrolyte multilayer (PEM) coatings built entirely from immune signals. These immune-PEMs (iPEMs) are self-assembled on gold nanoparticle templates through stepwise electrostatic interactions between peptide antigen and polyanionic toll-like receptor (TLR) agonists that serve as molecular adjuvants. iPEMs do not require solvents or mixing, offer direct control over the composition and loading of vaccine components, and can be coated on substrates at any scale. These films also do not require other structural components, eliminating the potentially confounding effects caused by the inherent immune-stimulatory characteristics of many synthetic polymers. iPEM loading on gold nanoparticle substrates is tunable, and cryoTEM reveals iPEM shells coated on gold cores. These nanoparticles are efficiently internalized by primary dendritic cells (DCs), resulting in activation, selective triggering of TLR signaling, and presentation of the antigens used to assemble iPEMs. In coculture, iPEMs drive antigen-specific T cell proliferation and effector cytokines but not cytokines associated with more generalized inflammation. Compared to mice treated with soluble antigen and adjuvant, iPEM immunization promotes high levels of antigen-specific CD8(+) T cells in peripheral blood after 1 week. These enhancements result from increased DC activation and antigen presentation in draining lymph nodes. iPEM-immunized mice also exhibit a potent recall response after boosting, supporting the potential of iPEMs for designing well-defined vaccine coatings that provide high cargo density and eliminate synthetic film components.

Presentation Modality of Glycoconjugates Modulates Dendritic Cell Phenotype

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.