Immune cell activation and cytokine release after stimulation of whole blood with pneumococcal C-polysaccharide and capsular polysaccharides

Identification and Quantification of a Pneumococcal Cell Wall Polysaccharide by Antibody-Enhanced Chromatography Assay

Multivalent pneumococcal vaccines have been developed successfully to combat invasive pneumococcal diseases (IPD) and reduce the associated healthcare burden. These vaccines employ pneumococcal capsular polysaccharides (PnPs), either conjugated or unconjugated, as antigens to provide serotype-specific protection. Pneumococcal capsular polysaccharides used for vaccine often contain residual levels of cell wall polysaccharides (C-Ps), which can generate a non-serotype specific immune response and complicate the desired serotype-specific immunity. Therefore, the C-P level in a pneumococcal vaccine needs to be controlled in the vaccine process and the anti C-P responses need to be dialed out in clinical assays. Currently, two types of cell-wall polysaccharide structures have been identified: a mono-phosphocholine substituted cell-wall polysaccharide C-Ps1 and a di-phosphocholine substituted C-Ps2 structure. In our effort to develop a next-generation novel pneumococcal conjugate vaccine (PCV), we have generated a monoclonal antibody (mAb) specific to cell-wall polysaccharide C-Ps2 structure. An antibody-enhanced HPLC assay (AE-HPLC) has been established for serotype-specific quantification of pneumococcal polysaccharides in our lab. With the new anti C-Ps2 mAb, we herein extend the AE-HPLC assay to the quantification and identification of C-Ps2 species in pneumococcal polysaccharides used for vaccines.

Upregulated complement receptors correlate with Fc gamma receptor 3A-positive natural killer and natural killer-T cells in neuromyelitis optica spectrum disorder

BACKGROUND AND OBJECTIVES

Inhibition of terminal complement in neuromyelitis optica spectrum disorder (NMOSD) using eculizumab helps prevent relapses, but the exact mechanism of action of the drug remains unclear. Similarly, genetic variants in the Fc Gamma receptor 3A (FCGR3A), also known as CD16, are correlated with outcomes in NMOSD, but the immune cells expressing those CD16 are unknown. We compared CD16 expression on immune cells modulated by complement activity in natural killer (NK) cells and natural killer-T (NKT) cells in NMOSD to disease and normal-healthy controls.

METHODS

Peripheral blood cell (PBMC) samples from 45 patients with NMOSD with aquaporin 4 (AQP4)-IgG, 18 disease controls, and 19 normal controls were analyzed for CD16 expression and complement receptors in vitro.

RESULTS

At baseline, the number of NKT cells was increased in NMOSD (p < 0.001), but the proportion that was CD16 positive was lower compared to normal and disease controls (p = 0.0012). NK cell count was normal, but the ratio that was CD16 positive was also significantly lower (p < 0.001). In both NK cells and NKT cells from NMOSD, C5 complement receptor expression was much higher than normal and disease controls (p < 0.001 for both). We also evaluated activation markers CD69 and CD83, which were also significantly higher in NK and NKT cells from NMOSD patients. FCGR3A p158 V/V genotype group in NMOSD patients showed decreased NK cell proportion with activation, and fewer CD16-expressing NKT cells than the F/F genotype group.

DISCUSSION

Our results support an immunopathogenesis model in which complement pathway activation in NK/NKT cells upregulates CD16 expression that binds to antibody/antigen complexes. In the context of NMOSD, these complement-sensitive cells may be responsible for the escalating autoimmune activity.

Purification, characterization, and determination of biological activities of water-soluble polysaccharides from Mahonia bealei

Mahonia bealei is one of the important members of the genus Mahonia and Traditional Chinese Medicine (TCM). Several compounds isolated from this plant have exhibited useful biological activities. Polysaccharides, an important biomacromolecule have been underexplored in case of M. bealei. In this study, hot water extraction and ethanol precipitation were used for the extraction of polysaccharides from the stem of M. bealei, and then extract was purified using ultrafiltration membrane at 50,000 Da cut off value. Characterization of the purified M. bealei polysaccharide (MBP) was performed using Fourier Transform Infrared Spectroscopy (FT-IR), along with Scanning Electron Microscopy (SEM), X-ray crystallography XRD analysis and Thermal gravimetric analysis (TGA). The purified polysaccharide MBP was tested for antioxidant potential by determining its reducing power, besides determining the DPPH, ABTS, superoxide radical, and hydroxyl radical scavenging along with ferrous ion chelating activities. An increased antioxidant activity of the polysaccharide was reported with increase in concentration (0.5 to 5 mg/ml) for all the parameters. Antimicrobial potential was determined against gram positive and gram-negative bacteria. 20 µg/ml MBP was found appropriate with 12 h incubation period against Escherichia coli and Bacillus subtilis bacteria. We conclude that polysaccharides from M. bealei possess potential ability of biological importance; however, more studies are required for elucidation of their structure and useful activities.

Study on Adsorption Performance of Benzoic Acid in Cyclocarya paliurus Extract by Ethyl Cellulose Microspheres

Polymer microspheres with inter-connecting pores are widely used as microsphere materials. In the study, the ethyl cellulose microspheres (ECM) were prepared by using the solvent-evaporation method. Based on that, a method for the separation and purification of benzoic acid from crude extract of Cyclocarya paliurus was established by the ECM and high performance liquid chromatography (HPLC). The ECM after the sorption equilibrium was desorbed by using 40% methanol as the analytical solvent. The content of benzoic acid in eluent is up to 0.0216 mg/mL, and the benzoic acid can be obtained with a high purity of 82.22%. Furthermore, the adsorption-desorption behavior of benzoic acid onto ECM was investigated. The results of adsorption kinetics of benzoic acid showed that the adsorption followed the pseudo-first-order kinetic model. The ECM was characterized by using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscope (SEM), and X-ray diffraction (XRD). The results showed that the ECM has a high adsorption property due to its more porous structure, phenolic hydroxyl group, and other oxygen-containing functional groups. This method and the ECM can be used stably, continuously, and efficiently to purify the benzoic acid from the methanol extract of C. paliurus on a large scale.

A review on polysaccharides from Artemisia sphaerocephala Krasch seeds, their extraction, modification, structure, and applications

Artemisia sphaerocephala Krasch (ASK) is an important member of Compositae (Asteraceae) family. Its seeds have been widely used as traditional medicine and to improve the quality of food. Water soluble and water insoluble polysaccharides are found in the seeds of this plant. Research has been conducted on the extraction of polysaccharides, their modification and determination of their structure. To date different techniques for extraction purposes have been applied which are reviewed here. Antioxidant, antidiabetic, anti-obesogenic, antitumor, and immunomodulatory activities have been explored using in vivo and in vitro methods. Moreover, these polysaccharides have been used as packaging material and as a sensing component for monitoring the freshness of packaged food. Some experimental results have shown that the quality of foods is also improved by using them as a food additive. We have also indicated some of the potential areas that are needed to be explored.

A review on structure, extraction, and biological activities of polysaccharides isolated from Cyclocarya paliurus (Batalin) Iljinskaja

Cyclocarya paliurus is essential and only living specie of the genus Cyclocarya Iljinskaja. The leaves of this plant have been extensively used as food in the form of tea and green vegetable. Many compounds have been isolated from this plant, and their useful aspects explored, including the polysaccharides. Studies conducted on leaves show that different methods of extraction have been used, as well as a combination of different techniques that have been applied to isolate polysaccharides from the leaves. Their structure has been elucidated because the activity of polysaccharides mainly depends upon their composition. It has been reported that different activities exhibited by the isolated crude, purified as well as modified polysaccharides include, anticancer, anti-inflammatory, antioxidant, antimicrobial, anti-hyperlipidemic and anti-diabetic activities. In some studies, a comparison of crude extract, as well as purified polysaccharide, has been performed. In this review, we have summarized all the available literature available on the methods of extraction, structure, and biological activities of polysaccharides from the leaves of C. paliurus and indicated the potential research areas that should be focused on future studies. We believe that this review will provide an up to date knowledge regarding polysaccharides of C. paliurus for the researchers.

Anticancer Effects of Cyclocarya paliurus Polysaccharide (CPP) on Thyroid Carcinoma In Vitro and In Vivo

In this study, we explored the role and mechanisms of Cyclocarya paliurus polysaccharide on cell apoptosis in thyroid cancer (TC) cells. The apoptosis of thyroid cancer cells in vitro and tumor tissues in vivo induced by Cyclocarya paliurus polysaccharide was determined by MTT assay and flow cytometric assay. The downstream molecules including phosphop-protein kinase B (p-Akt), Akt, B-cell lymphoma 2 (Bcl-2), and Bcl-2-associated X protein (Bax) in tumor tissue were evaluated by western blotting. MTT and flow cytometry assay in vitro revealed Cyclocarya paliurus polysaccharide-induced apoptosis of thyroid cancer cell line in a manner of time-dependent and dose-dependent. In vivo assay showed 50 mg/kg and 100 mg/kg Cyclocarya paliurus polysaccharide significantly suppressed the proliferation of thyroid cancer in mice. Western blotting showed downregulation of p-Akt, Akt, and Bcl-2 and upregulation of Bax. These results suggest that Cyclocarya paliurus polysaccharide may enhance thyroid cancer cell apoptosis by suppressing the activation of p-Akt, Akt, and Bcl-2 and activating Bax, which provide a novel use of CPP as a thyroid cancer treatment.

Identification of genes underlying the enhancement of immunity by a formula of lentinan, pachymaran and tremelia polysaccharides in immunosuppressive mice

The efficacy of polysaccharides is widespread, especially in immune regulation. However, the genetic basis of the changes in polysaccharides regulating immunity is unclear. To obtain genome-wide insights into transcriptome changes and regulatory networks, we designed a polysaccharide formula, comprising lentinan, pachymaran and tremelia, to increase the availability of their optimized active sites. In this case, we focused on a model of immunosuppression to investigate genes by digital gene expression (DGE) tag profiling in T and B cells. These genes were further validated by qRT-PCR and Western blot experiments. Consequently, polysaccharide formula treatment helped to recover the expression of immune-related genes, including CADM1, CCR2, IGLL1, LIGP1, and FCGR3, FCGR2 in B cells, as well as S100A8, S100A9, ChIL3, MMP8 and IFITM3 in T cells. These results suggest that treatment with polysaccharides improves the immunity of immunosuppressive mice by regulating genes associated with T and B cell functions.