[Buzhong Yiqi Decoction ameliorates spleen deficiency syndrome by regulating gut microbiota].

This study aims to decipher the mechanism of Buzhong Yiqi Decoction(BZYQD) in the treatment of spleen deficiency syndrome via gut microbiota. The mouse models of spleen deficiency syndrome were established by fecal microbiota transplantation(FMT, from patients with spleen deficiency syndrome) and administration of Sennae Folium(SF, 10 g·kg~(-1)), respectively, and treated with BZYQD for 5 d. The pseudosterile mice(administrated with large doses of antibiotics) and the mice transplanted with fecal bacteria from healthy human were taken as the controls. The levels of IgA, interleukin(IL)-2, IL-1ß, interferon(IFN)-γ, tumor necrosis factor-alpha(TNF-α), and 5-hydroxytryptamine(5-HT) in the intestinal tissue of two models were measured by enzyme-linked immunosorbent assay, and the CD8~+/CD3~+ ratio was determined by flow cytometry. The composition and changes of the gut microbiota were determined by 16S rRNA high-throughput sequencing and qPCR. Furthermore, the correlation analysis was performed to study the mediating role of gut microbiota in the treatment. The results showed that BZYQD elevated the IgA level, lowered the IL-1ß, TNF-α, and 5-HT levels, and decreased the CD8~+/CD3~+ ratio in the intestinal tissue of the two models. Moreover, BZYQD had two-way regulatory effects on the levels of IL-2 and IFN-γ. BZYQD inhibited the overgrowth and reduced the richness of gut microbiota in the SF model, and improved the gut microbiota structure in the two models. Algoriphagus, Mycobacterium, and CL500＿29＿marine＿group were the common differential genera in the two models compared with the control. Acinetobacter, Parabacteroides, and Ruminococcus were the differential genera unique to the FMT model, and Sphingorhabdus, Lactobacillus, and Anaeroplasma were the unique differential genera in the SF model. BZYQD was capable of regulating all these genera. The qPCR results showed that BZYQD increased the relative abundance of Akkermansia muciniphila and decreased that of Bacteroides uniformis in the two models. The correlation analysis revealed that the levels of above intestinal cytokines were significantly correlated with characteristic gut microorganisms in different mo-dels. The IL-1ß level had a significantly positive correlation with Acinetobacter and CL500＿29＿marine＿group in the two models, while the different levels of IL-2 and IFN-γ in the two models may be related to its different gut microbiota structures. In conclusion, BZYQD could regulate the disordered gut microbiota structure in different animal models of spleen deficiency syndrome to improve the intestinal immune status, which might be one of the mechanisms of BZYQD in treating spleen deficiency syndrome.

Pharmacological effects of biologically synthesized ginsenoside CK-rich preparation (AceCK40) on the colitis symptoms in DSS-induced Caco-2 cells and C57BL mice.

BACKGROUND: Despite the notable pharmacological potential of natural ginsenosides, their industrial application is hindered by low oral bioavailability. Recent research centers on the production of less-glycosylated minor ginsenosides. PURPOSE: This study aimed to explore the effect of a biologically synthesized ginsenoside CK-rich minor ginsenoside complex (AceCK40), on ameliorating colitis using DSS-induced colitis models in vitro and in vivo. METHODS: The ginsenoside composition of AceCK40 was determined by HPLC-ELSD and UHPLC-MS/MS analyses. In vitro colitis model was established using dextran sodium sulfate (DSS)-induced Caco-2 intestinal epithelial model. For in vivo experiments, DSS-induced severe colitis mouse model was established. RESULTS: In DSS-stimulated Caco-2 cells, AceCK40 downregulated mitogen-activated protein kinase (MAPK) activation (p < 0.05), inhibited monocyte chemoattractant protein-1 (MCP-1) production (p < 0.05), and enhanced MUC2 expression (p < 0.05), mediated via signaling pathway regulation. Daily AceCK40 administration at doses of 10 and 30 mg/kg/day was well tolerated by DSS-induced severe colitis mice. These doses led to significant alleviation of disease activity index score (> 36.0% decrease, p < 0.05), increased luminal immunoglobulin (Ig)G (> 37.6% increase, p < 0.001) and IgA (> 33.8% increase, p < 0.001), lowered interleukin (IL)-6 (> 65.7% decrease, p < 0.01) and MCP-1 (> 116.2% decrease, p < 0.05), as well as elevated serum IgA (> 51.4% increase, p < 0.001) and lowered serum IL-6 (112.3% decrease at 30 mg/kg, p < 0.001). Hematoxylin and eosin (H&E) and periodic acid-Schiff (PAS) staining revealed that DSS-mediated thickening of the muscular externa, extensive submucosal edema, crypt distortion, and decreased mucin droplets were significantly alleviated by AceCK40 administration. Additionally, daily administration of AceCK40 led to significant recovery of colonic tight junctions damaged by DSS through the elevation in the expression of adhesion molecules, including occludin, E-cadherin, and N-cadherin. CONCLUSION: This study presents the initial evidence elucidating the anti-colitis effects of AceCK40 and its underlying mechanism of action through sequential in vitro and in vivo systems employing DSS stimulation. Our findings provide valuable fundamental data for the utilization of AceCK40 in the development of novel anti-colitis candidates.

American ginseng with different processing methods ameliorate immunosuppression induced by cyclophosphamide in mice via the MAPK signaling pathways.

This study aimed to clarify the effects of two processed forms of American ginseng (Panax quinquefolius L.) on immunosuppression caused by cyclophosphamide (CTX) in mice. In the CTX-induced immunosuppressive model, mice were given either steamed American ginseng (American ginseng red, AGR) or raw American ginseng (American ginseng soft branch, AGS) by intragastric administration. Serum and spleen tissues were collected, and the pathological changes in mice spleens were observed by conventional HE staining. The expression levels of cytokines were detected by ELISA, and the apoptosis of splenic cells was determined by western blotting. The results showed that AGR and AGS could relieve CTX-induced immunosuppression through the enhanced immune organ index, improved cell-mediated immune response, increased serum levels of cytokines (TNF-α, IFN-γ, and IL-2) and immunoglobulins (IgG, IgA, and IgM), as well as macrophage activities including carbon clearance and phagocytic index. AGR and AGS downregulated the expression of BAX and elevated the expression of Bcl-2, p-P38, p-JNK, and p-ERK in the spleens of CTX-injected animals. Compared to AGS, AGR significantly improved the number of CD4+CD8-T lymphocytes, the spleen index, and serum levels of IgA, IgG, TNF-α, and IFN-γ. The expression of the ERK/MAPK pathway was markedly increased. These findings support the hypothesis that AGR and AGS are effective immunomodulatory agents capable of preventing immune system hypofunction. Future research may investigate the exact mechanism to rule out any unforeseen effects of AGR and AGS.

Immunoglobulin A in Bovine Milk: A Potential Functional Food?

Immunoglobulin A (IgA) is an anti-inflammatory antibody that plays a critical role in mucosal immunity. It is found in large quantities in human milk, but there are lower amounts in bovine milk. In humans, IgA plays a significant role in providing protection from environmental pathogens at mucosal surfaces and is a key component for the establishment and maintenance of intestinal homeostasis via innate and adaptive immune mechanisms. To date, many of the dairy-based functional foods are derived from bovine colostrum, targeting the benefits of IgG. IgA has a higher pathogenic binding capacity and greater stability against proteolytic degradation when ingested compared with IgG. This provides IgA-based products greater potential in the functional food market that has yet to be realized.

Therapeutic Potential of Monoclonal IgA Antibodies in Allergic Diseases: Suppressive Effect of IgA on Immune Responses Induced By Re-exposure to Antigen in Sensitized Mice by Monoclonal IgE Antibody That Binds to a Different Epitope of the Same Antigen.

Repeated exposure to an allergen induces allergic symptoms by activating mast cells that express anti-allergen IgE, which results in further sensitization to an allergen. Considering that additional sensitization elicits more severe allergic reactions upon the next allergen challenge, suppression of the boosting phase represents an efficacious way to prevent and ameliorate allergic diseases. In this study, we investigated the therapeutic potential of allergen-specific monoclonal IgA on allergic diseases. This antibody acts by decreasing immune responses upon exposure to allergens in mice previously sensitized by a monoclonal IgE that recognizes the allergen. The lack of inhibitory effects of anti-ovalbumin monoclonal IgA (OA-4) on either the binding of anti-ovalbumin monoclonal IgE (OE-1) to ovalbumin by ELISA or on ovalbumin-induced degranulation of rat basophilic leukemia RBL2H3 cells sensitized with OE-1 indicated that OA-4 and OE-1 recognized different epitopes on ovalbumin. Immune responses (anti-ovalbumin IgG1 production and cytokine release from splenocytes) induced by intravenous ovalbumin challenge in DBA/1J mice passively sensitized with OE-1 were inhibited by intravenous injection of OA-4 15 min before challenge without affecting anaphylaxis. Moreover, OA-4 injection 1 h after ovalbumin challenge also effectively suppressed immune responses. The achievement of immunosuppression by IgA injection occurred even after allergen challenge in mice in an epitope-independent fashion. These findings suggest that monoclonal IgA administered at the time of hospitalization of a patient with allergic symptoms, who was already exposed to the allergen in the presence of IgE recognizing an undefined epitope(s) on the allergen, should effectively relieve allergic disease through its immunosuppressive effects.

Potential prophylactic value of bovine colostrum in necrotizing enterocolitis in neonates: an in vitro study on bacterial attachment, antibody levels and cytokine production.

Necrotizing enterocolitis (NEC) is an important disease of low birth-weight neonates. The immaturity of the gut mucosa may result in close contact between the host epithelium and microorganisms which are normally confined to the gut lumen. Damage of the mucosa due to endotoxin, cytokine production or other factors is believed to then occur. The aim of this study was to determine whether spray-dried bovine colostrum demonstrated potential in vitro as a prophylactic for NEC. Antiadherence was measured using a tissue culture assay and antibody levels against Enterobacteriaceae were determined by ELISA. The effect of bovine colostrum on the production of cytokines implicated in NEC was determined by a multiplex bead assay. Enterobacter cloacae, Klebsiella oxytoca, Escherichia coli, Serratia marcescens and Klebsiella pneumoniae ssp. pneumoniae were common in both NEC positive and NEC negative infants and IgA and IgG1 antibodies to these species were present in the bovine colostrum. Pretreatment with bovine colostrum produced a significant decrease (P<0.001) in attachment of bacteria to HT-29 cells. Bovine colostrum significantly increased the production of IL-8 in HT-29 cells and IL-8, IL-6 and TNF-alpha in THP-1 cells (P<0.001). The potential of bovine colostrum to increase the production of inflammatory mediators could limit its usefulness.

A method for titration of inhibiting antibodies to bacterial immunoglobulin A1 proteases in human serum and secretions.

Bacterial IgA1 proteases specifically cleave IgA1, including S-IgA1, molecules into Fab alpha and Fc alpha fragments. Hereby these enzymes interfere with the protective functions of antibodies belonging to this isotype. Antibodies inhibiting IgA1 proteases have been detected in humans, but the titration of such antibodies is a matter of methodological concern. Because human serum and secretions contain IgA1 substrate, it is impossible to provide uniform substrate conditions for samples of IgA1 protease incubated with inhibitors differing in their origin and state of dilution. This study demonstrates that such variations in substrate are not prohibitive for a reliable titration of inhibiting antibodies. This was evident from experiments demonstrating that the variations do not interfere with the quantification of residual IgA1 protease activity provided the activity is measured in terms of the proportion of IgA1 substrate cleaved during incubation. Proportions of cleaved IgA1 were measured by exploiting the differential reactivity of cleaved and intact IgA1 molecules in an ELISA using anti-Fc alpha and enzyme-conjugated anti-light chain antibodies for catching and development, respectively. A protocol for the titration of IgA1 protease-inhibiting antibodies based on this ELISA is described. By application of the protocol to chromatographic fractions of saliva, IgA1 protease-inhibiting activity was found to co-purify with salivary S-IgA.

Acceleration of dextransucrase activity of Streptococcus mutans by secretory immunoglobulin A.

The effect of immunoglobulins on the activity of dextransucrase purified from Streptococcus mutans strain HS-6 is described. When human salivary immunoglobulin A (IgA) or colostral IgA, either natured or denatured, was incubated with dextransucrase, the rate of the dextran synthesis was markedly accelerated, whereas human serum IgA or IgG neither accelerated nor inhibited the enzyme activity. The results suggest that a portion unique for secretory IgA, the secretory component, might be related to the enzyme acceleration. On the other hand, specific rabbit antiserum against the dextransucrase inhibited completely dextran synthesis by the enzyme.

Inhibition of enzymes by human salivary immunoglobulin A.

Human whole saliva inhibited bacterial neuraminidases and the inhibition was found to reside in the salivary IgA fraction. Further, salivary immunoglobulin (Ig)A inhibited various bacterial enzymes and toxins: neuraminidases from Streptococcus mitis, Streptococcus sanguis, and Clostridium perfringens, hyaluronidase and chondroitin sulfatase from oral bacteria, diphtheria toxin, and streptolysin O. The inhibitory activity of salivary IgA did not correlate with that of serum on the basis of minimum inhibitory dose. A small amount of salivary IgA was required to inhibit oral bacterial neuraminidases, whereas a large amount was required to inhibit other bacterial neuraminidase. Therefore, it is concluded that the absence of neuraminidase activity of oral bacteria in whole saliva may be due to specific inhibition by salivary IgA.