Beta-1,3 Oligoglucans Specifically Bind to Immune Receptor CD28 and May Enhance T Cell Activation

Exploring the immunomodulatory properties of glucan particles in human primary cells

The immunomodulatory properties of β-glucans have sparked interest among various medical fields. As vaccine adjuvants, glucan particles offer additional advantages as antigen delivery systems. This study reported the immunomodulatory properties of glucan particles with different size and chemical composition. The effect of glucan microparticles (GPs) and glucan nanoparticles (Glu 130 and 355 NPs) was evaluated on human immune cells. While GPs and Glu 355 NPs demonstrated substantial interaction with Dectin-1 receptor on monocytes, Glu 130 NPs exhibited reduced activation of this receptor. This observation was substantiated by blocking Dectin-1, resulting in inhibition of reactive oxygen species production induced by GPs and Glu 355 NPs. Notably, monocyte-derived dendritic cells (moDCs) stimulated by Glu 355 NPs exhibited phenotypic and functional maturation, essential for antigen cross-presentation. The immunomodulatory efficacy was investigated using an autologous mixed lymphocyte reaction (AMLR), resulting in considerable rates of lymphocyte proliferation and an intriguing profile of cytokine and chemokine release. Our findings highlight the importance of meticulously characterizing the size and chemical composition of β-glucan particles to draw accurate conclusions regarding their immunomodulatory activity. This in vitro model mimics the human cellular immune response, and the results obtained endorse the use of β-glucan-based delivery systems as future vaccine adjuvants.

Glucans, Paramylon and Other Algae Bioactive Molecules

Algae (macro- and micro-algae) can be defined as light-driven cell factories that synthesize bioactive compounds consisting of primary metabolites (i [...].

The Effect of Novel Selenopolysaccharide Isolated from Lentinula edodes Mycelium on Human T Lymphocytes Activation, Proliferation, and Cytokines Synthesis

Polysaccharides isolated from Lentinula edodes are bioactive compounds with immunomodulatory properties. In our previous studies from L. edodes mycelium, we have isolated a selenium(Se)-enriched fraction (named Se-Le-30), a mixture of linear 1,4-α-glucan and linear 1,3-β- and 1,6-β-glucans. In this study, we analyzed the effects of Se-Le-30 on the activation and proliferation of human T lymphocytes stimulated by anti-CD3 and anti-CD3/CD28 antibodies (Abs) and on the production of cytokines by peripheral blood mononuclear cells (PBMCs). Se-Le-30 had effects on T cell proliferation induced by Abs against CD3 and CD28. It significantly inhibited the proliferation of CD3-stimulated CD4⁺ and CD8⁺ T cells and enhanced the proliferation of CD4⁺ T cells stimulated with anti-CD3/CD28 Ab. Moreover, Se-Le-30 downregulated the number of CD3-stimulated CD4⁺CD69⁺ cells, CD4⁺CD25⁺ cells, as well as CD8⁺CD25⁺ cells, and upregulated the expression of CD25 marker on CD4+ and CD8+ T cells activated with anti-CD3/CD28 Abs. Furthermore, Se-Le-30 enhanced the synthesis of IFN-γ by the unstimulated and anti-CD3/CD28-stimulated PBMCs, inhibited synthesis of IL-2 and IL-4 by CD3-stimulated cells, and augmented the synthesis of IL-6 and IL-10 by unstimulated, CD3-stimulated, and CD3/CD28-stimulated PBMCs. Together, we demonstrated that Se-Le-30 exerts immunomodulatory effects on human T lymphocytes. These observations are of importance for the prospective use of Se-Le-30 in research or as a therapeutic compound.

Accurate determination of protein:ligand standard binding free energies from molecular dynamics simulations

Designing a reliable computational methodology to calculate protein:ligand standard binding free energies is extremely challenging. The large change in configurational enthalpy and entropy that accompanies the association of ligand and protein is notoriously difficult to capture in naive brute-force simulations. Addressing this issue, the present protocol rests upon a rigorous statistical mechanical framework for the determination of protein:ligand binding affinities together with the comprehensive Binding Free-Energy Estimator 2 (BFEE2) application software. With the knowledge of the bound state, available from experiments or docking, application of the BFEE2 protocol with a reliable force field supplies in a matter of days standard binding free energies within chemical accuracy, for a broad range of protein:ligand complexes. Limiting undesirable human intervention, BFEE2 assists the end user in preparing all the necessary input files and performing the post-treatment of the simulations towards the final estimate of the binding affinity.