Preparation and activity study of Ruoqiang jujube polysaccharide copper chelate.

Background: Polysaccharide metal chelate exhibit both immunoregulatory activity and metal element supplementation effects. Methods: In this study, Ruoqiang jujube polysaccharide copper chelate (RJP-Cu) was prepared and the preparation conditions were optimized using the response surface method. Subsequently, RJP-Cu was administered to lambs to evaluate its impact on growth performance, copper ion (Cu2+) supplementation, immune enhancement, and intestinal flora was evaluated. Results: The results indicated that optimal RJP-Cu chelation conditions included a sodium citrate content of 0.5 g, a reaction temperature of 50°C, and a solution pH of 8.0, resulting in a Cu2+ concentration of 583°mg/kg in RJP-Cu. Scanning electron microscopy (SEM) revealed significant structural changes in RJP before and after chelation. RJP-Cu displaying characteristic peaks of both polysaccharides and Cu2+ chelates. Blood routine indexes showed no significant differences among the RJP-Cu-High dose group (RJP-Cu-H), RJP-Cu-Medium dose group (RJP-Cu-M), RJP-Cu-low dose group (RJP-Cu-L) and the control group (p > 0.05). However, compared with the control group, the RJP-Cu-H, M, and L dose groups significantly enhanced lamb production performance (p < 0.05). Furthermore, RJP-Cu-H, M, and L dose groups significantly increased serum Cu2+ concentration, total antioxidant capacity (T-AOC), catalase (CAT), and total superoxide dismutase (T-SOD) contents compared with control group (p < 0.05). The RJP-Cu-H group exhibited significant increases in serum IgA and IgG antibodies, as well as the secretion of cytokines IL-2, IL-4, and TNF-α compared to the control group (p < 0.05). Furthermore, RJP-Cu-H group increased the species abundance of lamb intestinal microbiota, abundance and quantity of beneficial bacteria, and decrease the abundance and quantity of harmful bacteria. The RJP-Cu-H led to the promotion of the synthesis of various Short Chain Fatty Acids (SCFAs), improvements in atrazine degradation and clavulanic acid biosynthesis in lambs, while reducing cell apoptosis and lipopolysaccharide biosynthesis. Conclusion: Thus, these findings demonstrate that RJP-Cu, as a metal chelate, could effectively promote lamb growth performance, increase Cu2+ content, and potentially induce positive immunomodulatory effects by regulating antioxidant enzymes, antibodies, cytokines, intestinal flora, and related metabolic pathways.

Preparation and sulfate modified of Lagenaria siceraria (Molina) Standl polysaccharide and its immune-enhancing adjuvant activity.

Herbal polysaccharides and their modifiers used as vaccine adjuvants have been widely investigated due to their safety and good immunoenhancing activity. In this study, the 50% ethanol concentration precipitated Lagenaria siceraria(Molina) standl polysaccharide (LSP50) and sulfated modified LSP50 (sLSP50) was prepared, and their characterization was investigated. LSP50 and sLSP50-1.5 were used as vaccine adjuvants to immunize chickens, and the strength and type of immune responses induced by different adjuvants were detected. Our results showed that LSP50 was homogeneous polysaccharides, and the carbohydrate content was 98.6%. The sLSP50-1.5 with the DS value of 1.5 was optimized by response surface methodology. The sLSP50-1.5 has both characteristics of polysaccharide functional groups and sulfate functional groups. Adjuvant activity of LSP50 and sLSP50-1.5 showed that LSP50 and sLSP50-1.5 could induce long-lasting and high hemagglutination (HI) titers, antigen-specific lgG-NDV antibody, splenic lymphocyte proliferation, high immune organ index. Moreover, chicken immunized with sLSP50-1.5 showed a strong mixed Th1-type (IFN-γ and TNF-α) and Th2-type (IL-4 and IL-6) cytokines expression. Thus, these findings demonstrated that sLSP50-1.5 as a vaccine adjuvant can induce a mixed cellular and humoral immune response and can potentially serve as an effective vaccine adjuvant for NDV antigen.

Supplementation of Alhagi honey polysaccharides contributes to the improvement of the intestinal immunity regulating the structure of intestinal flora in mice.

Alhagi honey polysaccharides (AH), a main active component of Alhagi honey, are known to possess excellent pharmacological activities and have been widely used as dietary supplements in traditional Chinese medicine for thousands of years. This study is aimed to investigate the heath effect of AH on murine intestinal mucosal immune function and composition of the gut microbiome. ICR mice received daily intragastric administration of AH (three dosages, 200 mg kg-1, 400 mg kg-1, and 800 mg kg-1) or saline for 7 consecutive days. Results indicated an improvement in the intestinal barrier function through increases in secretory immunoglobulin A (sIgA) and ß-defensins. Simultaneously, AH also significantly stimulated IL-2, IL-4, IL-6, IL-10, IL-17, IFN-γ, and TNF-α cytokine secretion as compared to the control samples. Moreover, hematoxylin and eosin staining showed that AH enhanced the number of intraepithelial lymphocytes (IELs) in the small intestine. An obvious increase in the ratio of IgA+ cells of AH-treatment samples in the lamina propria was also detected by immunohistochemical staining. In addition, the CD3+, CD4+ and CD8+ T-cell ratio in mesenteric lymph nodes and Peyer's patches in the AH-treatment was significantly higher than that in the control group. Furthermore, 16S rDNA gene sequencing was used to monitor the dynamic changes in the gut microbiota. The result revealed that AH significantly increased the indexes of Shannon and obviously decreased the indexes of Simpson, suggesting the enhancement of the diversity and richness of the intestinal microbiome. Moreover, AH modulated the gut microbiome via increasing the abundance of probiotics and decreasing the levels of pathogenic bacteria. In summary, these results indicated that AH could be used as a prebiotic to enhance murine intestinal mucosal immunity and to modulate the gut microbiome.

Immunoenhancement effects of chitosan-modified ginseng stem-leaf saponins-encapsulated cubosomes as an ajuvant.

Nanoparticle delivery of functional molecules and vaccine is a promising method for enhancing the immune response. The objective of this study was to design chitosan (CS)-modified ginseng stem-leaf saponins (GSLS)-encapsulated cubosomes (Cub-GSLSCS) as a vaccine delivery system and explore its immunologic activity and adjuvanticity. In this study, CS-modified GSLS-encapsulated cubosomes (Cub-GSLSCS) were prepared. The storage stability of GSLS and that of ovalbumin (OVA) were measured. Additionally, the immunopotentiation of Cub-GSLSCS were assessed on potentiating macrophage in vitro, and the adjuvant activity was evaluated through immune response triggered by OVA model antigen. The encapsulation efficiency of optimized Cub-GSLSCS was about 65 % with Im3m nanostructure. The Cub-GSLSCS showed excellent stability and sustained release for up to 28 days. In vitro, Cub-GSLSCS nanoparticles improved cellular uptake, stimulated cytokines secretion of IL-6, IL-12, TNF-α, and generated more inducible nitric oxide synthase (iNOS) to produce higher levels of nitric oxide (NO) compared with other groups. Furthermore, the immunoadjuvant effects of OVA encapsulated Cub-GSLSCS nanoparticles (Cub-GSLSCS-OVA) were observed through immunized mice. Results showed that the ratio of CD4+/CD8 + T lymphocytes was increased in Cub-GSLSCS-OVA group. In addition, Cub-GSLSCS-OVA nanoparticles induced dramatically high OVA-specific IgG, IgG1, and IgG2a levels and stimulated the secretion of cytokines. Cub-GSLSCS may be a potential vaccine delivery system and induce a long-term sustained immunogenicity.

Immune-adjuvant activity of lentinan-modified calcium carbonate microparticles on a H5N1 vaccine.

In recent years, the high prevalence of avian influenza viruses especially H5N1 subtype isolated from poultry and human has become a major public health concern. Vaccination is still a major strategy for preventing H5N1 infections. Lentinan (LNT), a ß-1,3-glucohexaose with ß-1,6-branches, is extracted from Lentinus edodes and has been extensively studied for its immunoenhancement effects. In this study, we synthesized and characterized calcium carbonate (CaCO3) microparticles which modified with LNT as an adjuvant for H5N1 vaccine and investigated their ability to enhance immune responses. We prepared spherical and uniform CaCO3-LNT microparticles with a mean hydrodynamic size was around 2 µm. The H5N1 antigen-loaded CaCO3-LNT particles were injected into mice to evaluate their effectiveness as an adjuvant for H5N1 vaccines. The results demonstrated that CaCO3-LNT/H5N1 significantly enhanced the expression of MHC-II and CD86 in lymph node dendritic cells, and increased the ratio of CD4+ to CD8+ T cells in lymphocytes. Moreover, CaCO3-LNT/H5N1 surprisingly increased the HI titers and induced the secretion of IgG subtypes (IgG1 and IgG2b) and Th-associated cytokines (TNF-α, IFN-γ and IL-4) in immunized mice. Therefore, by combining with the immunostimulatory activity of LNT and the drug/antigen delivery capabilities of CaCO3, the CaCO3-LNT/H5N1 could induce a stronger cellular and humoral immune response and could be a potential adjuvant for the H5N1 vaccine.

Preparation of lentinan-calcium carbonate microspheres and their application as vaccine adjuvants.

Adjuvants improve vaccine potency by enhancing immunogenicity and sustaining long-term immune responses. Lentinan (LNT), a ß-1,3-glucohexaose with ß-1,6-branches, is extracted from the mushroom Lentinus edodes and functions as an effective immunostimulatory drug. Previous studies have demonstrated the adjuvant activity of calcium carbonate (CaCO3) microspheres as well as their use as antigen delivery systems. In this study, we successfully loaded CaCO3 microspheres with LNT and evaluated their physicochemical characteristics prior to the adsorption of ovalbumin. Our experimental results demonstrated that LNT-CaCO3 significantly enhanced lymphocyte proliferation, and boosted the frequency of CD69 + B cells and the ratio of CD4+ to CD8 + T cells in spleen lymphocytes. Moreover, LNT-CaCO3 unexpectedly induced the secretion of IgG and Th-associated cytokines (IL-2, IL-4, IFN-γ, and TNF-α) in immunized mice. Therefore, LNT-CaCO3 microspheres induce robust cellular and humoral immune responses and have potential utility as vaccine delivery systems.