Repulsive guidance molecule a blockade exerts the immunoregulatory function in DCs stimulated with ABP and LPS.

Repulsive guidance molecule a (RGMa) is an axonal guidance molecule that has recently found to exert function in immune system. This study evaluated the function of RGMa in modulation of dendritic cells (DCs) function stimulated with Achyranthes bidentata polysaccharide (ABP) and lipopolysaccharide (LPS) using a RGMa-neutralizing antibody. Compared with the Control-IgG/ABP and Control-IgG/LPS groups, DCs in the Anti-RGMa/ABP and Anti-RGMa/LPS groups 1) showed small, round cells with a few cell processes and organelles, and many pinocytotic vesicles; 2) had decreased MHC II, CD86, CD80, and CD40 expression; 3) displayed the decreased IL-12p70, IL-1ß and TNF-α levels and increased IL-10 secretion; 4) had a high percentage of FITC-dextran uptake; and 5) displayed a reduced ability to drive T cell proliferation and reinforced T cell polarization toward a Th2 cytokine pattern. We conclude that DCs treated with RGMa-neutralizing antibodies present with tolerogenic and immunoregulatory characteristics, which provides new insights into further understanding of the function of RGMa.

Effect of seeds of Achyranthes aspera on the immune responses and expression of some immune-related genes in carp Catla catla.

Evaluation of functional mechanism of immunostimulant in fish is essential for realizing their therapeutic potential. The impact of dietary supplementation of seeds of Achyranthes aspera on the immune system of Catla catla was studied. Catla (37.73 ± 6.7 g) were fed with test diets containing 0.5 (D1) and 1.0% (D2) seeds of A. aspera and control diet (D3) for 50 days. Then fish were immunized with heat-killed Aeromonas hydrophila. Blood and tissue samples were collected after 7 days of immunization. Three fish were sacrificed for each parameter. Respiratory burst activity, bactericidal activity and antibody response were significantly (P < 0.05) higher in test diets fed catla compared to the control one. Nitric oxide synthase and serum lysozyme were significantly (P < 0.05) higher in fish fed with diet D2 compared to the other treatments. There were up-regulations of TNFα, lysozyme c and g gene expressions in kidney and IL-10, lysozyme c and g expressions in hepatopancreas of test diets fed fish compared to the control one. The expression of IL-10 was down-regulated in the kidney of D2 diet fed fish compared to others. In the gill, significantly (P < 0.05) higher expressions of TNFα was found in D1 diet feed fish and lysozyme c and in D2 diet fed fish compared to the other groups. This study showed tissue-specific gene expression pattern in catla. An inverse relationship was found between the expression of TNFα and IL-10 in kidney of catla.

Modulation of phenotypic and functional maturation of murine dendritic cells (DCs) by purified Achyranthes bidentata polysaccharide (ABP).

There are a large number of interactions at molecular and cellular levels between the plant polysaccharides and immune system. Plant polysaccharides present an interesting effects as immunomodulators, particularly in the induction of the cells both in innate and adaptive immune systems. Activation of DCs could improve antitumoral responses usually diminished in cancer patients, and natural adjuvants provide a possibility of inducing this activation. ABP is a purified polysaccharide isolated from Achyranthes bidentata, a traditional Chinese medicine (TCM). The aim of this study is to investigate modulation of phenotypic and functional maturation of murine DCs by ABP. Both phenotypic and functional activities were assessed with use of conventional scanning electronic microscopy (SEM) for the morphology of the DC, transmitted electron microscopy (TEM) for intracellular lysosomes inside the DC, cellular immunohistochemistry for phagocytosis by the DCs, flow cytometry (FCM) for the changes in key surface molecules, bio-assay for the activity of acidic phosphatases (ACP), and ELISA for the production of pro-inflammatory cytokine IL-12. In fact, we found that purified ABP induced phenotypic maturation revealed by increased expression of CD86, CD40, and MHC II. Functional experiments showed the down-regulation of ACP inside DCs (which occurs when phagocytosis of DCs is decreased, and antigen presentation increased with maturation). Finally, ABP increased the production of IL-12. These data reveal that ABP promotes effective activation of murine DCs. This adjuvant-like activity may have therapeutic applications in clinical settings where immune responses need boosting. It is therefore concluded that ABP can exert positive modulation to murine DCs.

Distribution and biosynthesis of 20-hydroxyecdysone in plants of Achyranthes japonica Nakai.

There is increasing interest in phytoecdysteroids (PEs) because of their potential role in plant defense against insects. To understand the mechanism regulating their levels in plants, the fluctuation, distribution, and biosynthesis of PE 20-hydroxyecdysone (20E) examined in Achyranthes japonica. The total amount of 20E per individual plant initially remained at a constant level, and increased markedly after the first leaf pair (LP) stage, while the concentration of 20E in a given plant decreased rapidly during vegetative growth. In addition, the incorporation of [2-(14)C]-mevalonic acid into 20E did not differ significantly depending on plant organs and developmental stages, suggesting that biosynthesis of 20E is not restricted to particular organs or growth stages.

Achyranthes bidentata polysaccharide enhances immune response in weaned piglets.

The acquired immunity is underdeveloped at 3-4 weeks of age when piglets are usually weaned on commercial farms, and weaning is associated with compromised immunity. Dietary supplementation with immunomodulatory phytochemicals may enhance immune responses in the weaned piglets. This study is conducted to investigate the effects of dietary supplemental achyranthes bidentata polysaccharide (ABP) on proliferation activity of lymphocytes, and production of antibodies, complements and cytokines in weaned piglets. Results showed that lymphocyte proliferation activity in piglets fed diets supplementing with 1000 and 1500 mg/kg ABP increased (P < 0.05) on days 14 and 28 compared with the non-additive piglets, as well as serum contents of IgG, IgA, IgM, C(3), C(4), IL (interleukin)-2 and IFN (interferon)-gamma. The ABP had dose-dependent immunomodulatory activity and the dose of 1500 mg/kg presented the strongest stimulating activity in vivo. In addition, the ABP increased (P < 0.05) the proliferation activity and production of IL-2 and IFN-gamma of cultured lymphocytes in dose- or time-dependent manner. The proliferation activity of peripheral T cells and splenic lymphocytes in 400 microg/ml of ABP group arrived at their peak values, as well as the production of IL-2 and IFN-gamma at 72 and 12 h after the treatment, respectively. Collectively, these findings suggested that dietary supplementation with ABP to weaned piglets enhances cellular and humoral immune responses, and ABP addition to culture medium also increases the proliferation activity and cytokine production of lymphocytes cultured in vitro, which indicate that dietary supplementation with the herbal polysaccharide may offer an effective alternative to antibiotics for weaned piglets.