Glutamine supplementation improves the activity and immunosuppressive action of induced regulatory T cells in vitro and in vivo.

BACKGROUND: Glutamine is crucial for the activation and efficacy of T cells, and may play a role in regulating the immune environment. This study aimed to investigate the potential role of glutamine in the activation and proliferation of induced regulatory T cells (iTregs). METHODS: CD4+CD45RA+T cells were sorted from peripheral blood mononuclear cells and cultured to analyze iTreg differentiation. Glutamine was then added to the culture system to evaluate the effects of glutamine on iTregs by determining oxidative phosphorylation (OXPHOS), apoptosis, and cytokine secretion. Additionally, a humanized murine graft-versus-host disease (GVHD) model was constructed to confirm the efficacy of glutamine-treated iTregs in vivo. RESULTS: After being cultured in vitro, glutamine significantly enhanced the levels of Foxp3, CTLA-4, CD39, CD69, IL-10, TGF-ß, and Ki67 (CTLA-4, IL-10, TGF-ß are immunosuppressive markers of iTregs) compared with that of the control iTregs (P < 0.05). Furthermore, the growth curve showed that the proliferative ability of glutamine-treated iTregs was better than that of the control iTregs (P < 0.01). Compared with the control iTregs, glutamine supplementation significantly increased oxygen consumption rates and ATP production (P < 0.05), significantly downregulated Annexin V and Caspase 3, and upregulated BCL2 (P < 0.05). However, GPNA significantly reversed the effects of glutamine (P < 0.05). Finally, a xeno-GVHD mouse model was successfully established to confirm that glutamine-treated iTregs increased the mice survival rate, delayed weight loss, and alleviated colon injury. CONCLUSION: Glutamine supplementation can improve the activity and immunosuppressive action of iTregs, and the possible mechanisms by which this occurs are related to cell proliferation, apoptosis, and OXPHOS.

Juzentaihoto Exerts Anti-Allergic Effects by Inhibiting Effector T-Cell Activation and Inducing and/or Activating Regulatory T Cells in a Murine Model of Contact Hypersensitivity.

BACKGROUND: Juzentaihoto (JTT) is a Kampo prescription that has been used clinically for treating skin diseases such as atopic dermatitis in Japan. We have previously studied the anti-allergic effects of JTT on 2,4,6-trinitrochlorobenzene (TNCB)-induced contact hypersensitivity (CHS) in mice and demonstrated that it significantly suppresses ear swelling in a dose-dependent manner. However, the mechanism underlying the anti-allergic actions of JTT is obscure. METHODS: We investigated the mechanism underlying the anti-allergic effects of JTT using a TNCB-induced murine CHS model and adoptive cell transfer experiments. RESULTS: We showed that the anti-allergic effects of JTT are due to inhibition of effector T-cell activation and induction and/or activation of regulatory T cells. Furthermore, ex vivo experiments confirmed the effect of JTT on the activation of effector T cells and regulatory T cells, as interferon-γ production decreased, whereas interleukin (IL)-10 production increased, in the cultured lymphocytes obtained from 5% TNCB-sensitized mice treated with anti-CD3ε and anti-CD28 monoclonal antibodies. Flow cytometry showed that the CD4+CD25+Foxp3+, CD4+CD25+Foxp3-, and CD8+CD122+ cell population increased after oral administration of JTT. Finally, the anti-allergic effect of JTT by inducing and/or activating regulatory T cells (Tregs) was confirmed to be mediated by IL-10 through in vivo neutralization experiments with anti-IL-10 monoclonal antibodies. CONCLUSION: We suggested that JTT exerts anti-allergic effects by regulating the activation of effector T cells and Tregs involved in murine CHS model.

The toxin mimic FS48 from the salivary gland of Xenopsylla cheopis functions as a Kv1.3 channel-blocking immunomodulator of T cell activation.

The Kv1.3 channel has been widely demonstrated to play crucial roles in the activation and proliferation of T cells, which suggests that selective blockers could serve as potential therapeutics for autoimmune diseases mediated by T cells. We previously described that the toxin mimic FS48 from salivary gland of Xenopsylla cheopis downregulates the secretion of proinflammatory factors by Raw 264.7 cells by blocking the Kv1.3 channel and the subsequent inactivation of the proinflammatory MAPK/NF-κB pathways. However, the effects of FS48 on human T cells and autoimmune diseases are unclear. Here, we described its immunomodulatory effects on human T cells derived from suppression of Kv1.3 channel. Kv1.3 currents in Jurkat T cells were recorded by whole-cell patch-clamp, and Ca2+ influx, cell proliferation, and TNF-α and IL-2 secretion were measured using Fluo-4, CCK-8, and ELISA assays, respectively. The in vivo immunosuppressive activity of FS48 was evaluated with a rat DTH model. We found that FS48 reduced Kv1.3 currents in Jurkat T cells in a concentration-dependent manner with an IC50 value of about 1.42 µM. FS48 also significantly suppressed Kv1.3 protein expression, Ca2+ influx, MAPK/NF-κB/NFATc1 pathway activation, and TNF-α and IL-2 production in activated Jurkat T cells. Finally, we show that FS48 relieved the DTH response in rats. We therefore conclude that FS48 can block the Kv1.3 channel and inhibit human T cell activation, which most likely contributes to its immunomodulatory actions and highlights the great potential of this evolutionary-guided peptide as a drug template in future studies.

Evidence of immunogenic cancer cell death induced by honey-processed Astragalus polysaccharides in vitro and in vivo.

Honey-processed Astragalus is a dosage form of Radix Astragalus mixed with honey by a traditional Chinese medicine processing method which improves immune activity. This pharmacological activity of honey-processed Astragalus polysaccharide (HP-APS) might be due to structural changes during the honey roasting process. Previously, we have prepared and characterized HP-APS and preliminarily found its anti-inflammatory effects. However, whether the pharmacodynamic activity of HP-APS induces tumor cell apoptosis and the mechanisms responsible for the immunogenic death (ICD) have not been elucidated. Here, A549, MC38 and B16 cells were used to evaluate the cells viability, apoptosis and cell cycles, respectively. Cellular immunogenic cell death-related molecules calreticulin (CRT), Heat Shock Proteins (HSP)70, major histocompatibility complex I (MHC-I), and co-stimulator molecules CD80/CD86 were determined by flow cytometry. The extracellular ATP release was also detected. B16-OVA and MC38-OVA cells were treated with HP-APS and co-cultivated with OT1 mouse of CD3+T cells for assessment of proliferation, in mice model, and the establishment of C57BL/B6 mouse model bearing B16 cells for assessment of HP-APS the regulation of immune activity in vivo. Our results showed that HP-APS has an inhibitory effect on tumor cell proliferation, which induces tumor cell apoptosis, preventing cells-transforming from G1 phase to S phase in cell cycles. Furthermore, HP-APS could effectively increase the expression of HSP70, CRT, MHC-I, CD86, CD80 and ATP release. T cell proliferation index is significantly improved. CD3 cell proliferation in OT1 mice was significantly increased from the 4th generation to the 5th generation. Moreover, the results have also shown that HP-APS could inhibit tumor growth by increasing immune cell infiltration in the tumor tissues. In the mouse melanoma model with HP-APS treatment, the tumor weight and volume were significantly reduced, and the growth of melanoma was inhibited. CD8+ T is significantly increased. The ratio of CD4+ T and CD8+ T cells numbers are also significantly increased in mouse spleen, but it is less than PD-1 alone treatment separately. Altogether, these findings suggest that HP-APS exerts anti-tumor effects, and that its underlying mechanisms might be associated with the expression of immunogenicity cell death related molecules and the immunomodulatory effects of immune cells.

Vitamin D supplementation induces CatG-mediated CD4+ T cell inactivation and restores pancreatic ß-cell function in mice with type 1 diabetes.

Type 1 diabetes (T1D) is a chronic autoimmune disease accompanied by the immune-mediated destruction of pancreatic ß-cells. In this study, we aimed to explore the regulatory effects of vitamin D (VD) supplementation on pancreatic ß-cell function by altering the expression of bioinformatically identified cathepsin G (CatG) in T1D mice. A T1D mouse model was established in nonobese diabetic (NOD) mice, and their islets were isolated and purified. Pancreatic mononuclear cells (MNCs) were collected, from which CD4+ T cells were isolated. The levels of interleukin (IL)-2, IL-10, tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ) in the supernatant of mouse pancreatic tissue homogenate were assessed using ELISA. Immunohistochemistry and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labelin (TUNEL) staining were conducted to evaluate the effects of VD supplementation on pancreatic tissues of T1D mice. The pancreatic ß-cell line MIN6 was used for in vitro substantiation of findings in vivo. VD supplementation reduced glucose levels and improved glucose tolerance in T1D mice. Furthermore, VD supplementation improved pancreatic ß-cell function and suppressed immunological and inflammatory reactions in the T1D mice. We documented overexpression of CatG in diabetes tissue samples, and then showed that VD supplementation normalized the islet immune microenvironment through downregulating CatG expression in T1D mice. Experiments in vitro subsequently demonstrated that VD supplementation impeded CD4+ T activation by downregulating CatG expression and thereby enhanced pancreatic ß-cell function. Results of the present study elucidated that VD supplementation can downregulate the expression of CatG and inhibit CD4+ T cell activation, thereby improving ß-cell function in T1D.NEW & NOTEWORTHY We report that vitamin D (VD) supplementation downregulates CatG expression and inhibits CD4+ T cell activation, thereby improving ß-cell function in type 1 diabetes (T1D). This study deepens our understanding of the pathogenesis of T1D and clarifies molecular events underlying the alleviatory effect of VD for immunotherapy against T1D.

Screening for Active Compounds Targeting Human Natural Killer Cell Activation Identifying Daphnetin as an Enhancer for IFN-γ Production and Direct Cytotoxicity.

Natural killer (NK) cells are a potent weapon against tumor and viral infection. Finding active compounds with the capacity of enhancing NK cell effector functions will be effective to develop new anti-cancer drugs. In this study, we initially screened 287 commercially available active compounds by co-culturing with peripheral blood mononuclear cells (PBMCs). We found that five compounds, namely, Daphnetin, MK-8617, LW6, JIB-04, and IOX1, increased the IFN-γ+ NK cell ratio in the presence of IL-12. Further studies using purified human primary NK cells revealed that Daphnetin directly promoted NK cell IFN-γ production in the presence of IL-12 but not IL-15, while the other four compounds acted on NK cells indirectly. Daphnetin also improved the direct cytotoxicity of NK cells against tumor cells in the presence of IL-12. Through RNA-sequencing, we found that PI3K-Akt-mTOR signaling acted as a central pathway in Daphnetin-mediated NK cell activation in the presence of IL-12. This was further confirmed by the finding that both inhibitors of PI3K-Akt and its main downstream signaling mTOR, LY294002, and rapamycin, respectively, can reverse the increase of IFN-γ production and cytotoxicity in NK cells promoted by Daphnetin. Collectively, we identify a natural product, Daphnetin, with the capacity of promoting human NK cell activation via PI3K-Akt-mTOR signaling in the presence of IL-12. Our current study opens up a new potential application for Daphnetin as a complementary immunomodulator for cancer treatments.

Study on the Killing Effect of γδT Cells Activated by Rukangyin on Breast Cancer MDA-MB-231 Cells.

OBJECTIVE: To investigate the killing effect of rukangyin (RKY) activated γδT cells on breast cancer cells MDA-MB-231 and to provide a basis for Chinese medicine combined with immunotherapy for breast cancer. METHODS: Thus, study isolates peripheral blood mononuclear cells (PBMC) and uses CCK8 to select the optimal concentration of Rukang drink, ZOL (zoledronic acid), and PHA (phytoagglutinin) to activate γδT cells. There are 8 groups including the ① PBMC control group, ② RKY group, ③ ZOL group, ④ PHA group, ⑤RKY+ZOL group, ⑥RKY+PHA group, ⑦ZOL+PHA group, and ⑧ RKY+ZOL+PHA group. At 0 and 14 days of culture, cell viability and γδT cell expansion were detected by flow cytometry. The 8 groups of amplified γδT were cocultured with breast cancer MDA-MB-231 cells labeled with fluorescent dye CFSE at a ratio of 10 : 1 to determine the lethality of γδT cells on breast cancer MDA-MB-231 cells. RESULTS: The optimal concentrations of RKY, ZOL, and PHA to activate γδT cell proliferation were 4.5 mg/l, 3 µM, and 60 µg/ml, respectively. On day 0 of culture, the values ( x ¯ ± s , %) of γδT cells in groups ① to ⑧ were 3.50 ± 0.72, 3.97 ± 0.45, 3.99 ± 0.15, 4.37 ± 0.24, 4.47 ± 0.97, 4.59 ± 1.35, 3.45 ± 0.40, and 3.89 ± 0.48, while when a comparison between groups was made, F = 1.093 and p = 0.412; there is no significant difference between groups. Besides, when being cultured for 14 days, the values ( x ¯ ± s , %) of γδT cells in groups ① to ⑧ were 4.77 ± 0.78, 23.22 ± 2.73, 26.4 ± 0.92, 28.66 ± 1.43, 27.99 ± 1.10, 30.21 ± 1.91, 32.51 ± 0.74, and 33.21 ± 0.42. Then, based on the comparison between groups, F = 119.917 and p < 0.001, there are obvious statistical differences between groups. Furthermore, the expansion values of γδT cells were compared before and after culture for 0 and 14 days. The t values of group ① to group ⑧ were 2.072, 12.051, 41.641, 29.015, 27.777, 18.972, 59.836, and 79.622. Except for the PBMC control group (p = 0.107), there are significant statistical differences (p < 0.001). The number of γδT cell expansion at 14 days was the RKY+ZOL+PHA group>ZOL+PHA group>RKY+PHA group>PHA group>RKY+ZOL group>ZOL group>RKY group>PBMC control group. From group ① to group ⑧, the γδT cell expansion multiples were 1.14 ± 0.44, 5.25 ± 0.77, 5.70 ± 0.89, 6.05 ± 1.03, 6.21 ± 0.09, 6.76 ± 1.46, 7.52 ± 1.05, and 7.97 ± 1.55, respectively, while the comparison between groups was F = 17.772 and p < 0.001. As for the amplification factor, there was RKY+ZOL+PHA group>ZOL+PHA group>RKY+PHA group>RKY+ZOL group>PHA group>ZOL group>RKY group>PBMC control group. In the killing experiment, the killing rate ( x ¯ ± s , %) of group ① to group ⑧ was 1.08 ± 0.03, 1.89 ± 0.14, 1.22 ± 0.11, 1.31 ± 0.09, 1.48 ± 0.10, 2.02 ± 0.21, 2.18 ± 0.27, and 2.37 ± 0.35, whereas the comparison between groups was F = 20.498 and p < 0.001. In terms of killing rate, there was RKY+ZOL+PHA group>ZOL+PHA group>RKY+PHA group>RKY group>RKY+ZOL group>PHA group>ZOL group>PBMC control group. CONCLUSION: Rukangyin can increase the lethality of γδT cells against MDA-MB-231 cells by activating the proliferation of γδT cells, which provides a basis for Chinese medicine combined with immunotherapy for breast cancer.

Immunosuppressant flavonoids from Scutellaria baicalensis.

Some plants used in Traditional Chinese Medicine serve as treatment for disease states where a suppression of the cellular immune response is desired. However, the compounds responsible for the immunosuppressant effects of these plants are not necessarily known. The immunosuppressant compounds in the roots of Scutellaria baicalensis, one of the most promising plants identified in a previous screening, were tracked by HPLC activity profiling and concomitant on-line spectroscopic analysis. Compounds were then isolated by preparative chromatography, and structures elucidated by spectroscopic methods. Twelve flavonoids (5-16) were identified from the active time windows, and structurally related flavones 2, 4, and 17, and flavanones 1 and 3 were isolated from adjacent fractions. All flavonoids possessed an unusual substitution pattern on the B-ring, with an absence of substituents at C-3 and C-4. Compounds 11, 13, 14, and 16 inhibited T-cell proliferation (IC50 values at 12.1-39 µM) at non-cytotoxic concentrations. The findings may support the use of S. baicalensis in disorders where a modulation of the cellular immune response is desirable.

Intranasal Administration of Codium fragile Polysaccharide Elicits Anti-Cancer Immunity against Lewis Lung Carcinoma.

Natural polysaccharides have shown promising effects on the regulation of immunity in animals. In this study, we examined the immune stimulatory effect of intranasally administered Codium fragile polysaccharides (CFPs) in mice. Intranasal administration of CFPs in C57BL/6 mice induced the upregulation of surface activation marker expression in macrophages and dendritic cells (DCs) in the mediastinal lymph node (mLN) and the production of interleukin-6 (IL-6), IL-12p70, and tumor necrosis factor-α in bronchoalveolar lavage fluid. Moreover, the number of conventional DCs (cDCs) was increased in the mLNs by the upregulation of C-C motif chemokine receptor 7 expression, and subsets of cDCs were also activated following the intranasal administration of CFP. In addition, the intranasal administration of CFPs promoted the activation of natural killer (NK) and T cells in the mLNs, which produce pro-inflammatory cytokines and cytotoxic mediators. Finally, daily administration of CFPs inhibited the infiltration of Lewis lung carcinoma cells into the lungs, and the preventive effect of CFPs on tumor growth required NK and CD8 T cells. Furthermore, CFPs combined with anti-programmed cell death-ligand 1 (PD-L1) antibody (Ab) improved the therapeutic effect of anti-PD-L1 Ab against lung cancer. Therefore, these data demonstrated that the intranasal administration of CFP induced mucosal immunity against lung cancer.

A Versatile Nanoplatform for Broad-Spectrum Immunotherapy by Reversing the Tumor Microenvironment.

Immunotherapy is currently an important adjuvant therapy for malignant tumors besides surgical treatment. However, the heterogeneity and low immunogenicity of the tumor are two main challenges of the immunotherapy. Here, we have constructed a nanoplatform (CP@mRBC-PpIX) to realize reversion of the tumor acidosis and hypoxia through alkali and oxygen generation triggered by tumor acidosis. By targeting tumor universal features other than endogenous biomarkers, it was found that CP@mRBC-PpIX could polarize tumor-associated macrophages to anti-tumor M1 phenotype macrophages to enhance tumor immune response. Furthermore, under regional light irradiation, the reactive oxygen species produced by photosensitizers located in CP@mRBC-PpIX could increase the immunogenicity of tumors, so that tumor changes from an immunosuppressive "cold tumor" to an immunogenic "hot tumor," thereby increasing the infiltration and response of T cells, further amplifying the effect of immunotherapy. This strategy circumvented the problem of tumor heterogeneity to realize a kind of broad-spectrum immunotherapy, which could effectively prevent tumor metastasis and recurrence.

Tregitopes Improve Asthma by Promoting Highly Suppressive and Antigen-Specific Tregs.

Tregitopes (T regulatory epitopes) are IgG-derived peptides with high affinity to major histocompatibility complex class II (MHCII), that are known to promote tolerance by activating T regulatory cell (Treg) activity. Here we characterized the effect of IgG Tregitopes in a well-established murine model of allergic asthma, demonstrating in vivo antigen-specific tolerance via adoptive transfer of Tregitope-and-allergen-activated Tregs. Asthma is a heterogeneous chronic inflammatory condition affecting the airways and impacting over 300 million individuals worldwide. Treatment is suppressive, and no current therapy addresses immune regulation in severely affected asthmatics. Although high dose intra-venous immunoglobulin (IVIg) is not commonly used in the asthma clinic setting, it has been shown to improve severe asthma in children and in adults. In our laboratory, we previously demonstrated that IVIg abrogates airway hyperresponsiveness (AHR) in a murine model of asthma and induces suppressive antigen-specific T-regulatory cells. We hypothesized that IgG-derived Tregitopes would modulate allergic airway disease by inducing highly suppressive antigen-specific Tregs capable of diminishing T effector cell responses and establishing antigen-specific tolerance. Using ovalbumin (OVA-) and ragweed-driven murine models of allergic airway disease, we characterized the immunoregulatory properties of Tregitopes and performed Treg adoptive transfer to OVA- and ragweed-allergic mice to test for allergen specificity. Treatment with Tregitopes attenuated allergen-induced airway hyperresponsiveness and lung inflammation. We demonstrated that Tregitopes induce highly suppressive allergen-specific Tregs. The tolerogenic action of IgG Tregitopes in our model is very similar to that of IVIg, so we foresee that IgG Tregitopes could potentially replace steroid-based treatment and can offer a synthetic alternative to IVIg in a range of inflammatory and allergic conditions.

Medicinal Plant Leaf Extract From Sage and Lemon Verbena Promotes Intestinal Immunity and Barrier Function in Gilthead Seabream (Sparus aurata).

The inclusion of a medicinal plant leaf extract (MPLE) from sage (Salvia officinalis) and lemon verbena (Lippia citriodora), rich in verbascoside and triterpenic compounds like ursolic acid, was evaluated in gilthead seabream (Sparus aurata) fed a low fishmeal-based diet (48% crude protein, 17% crude fat, 21.7 MJ kg-1, 7% fishmeal, 15% fish oil) for 92 days. In particular, the study focused on the effect of these phytogenic compounds on the gut condition by analyzing the transcriptomic profiling (microarray analysis) and histological structure of the intestinal mucosa, as well as the histochemical properties of mucins stored in goblet cells. A total number of 506 differentially expressed genes (285 up- and 221 down-regulated) were found when comparing the transcriptomic profiling of the intestine from fish fed the control and MPLE diets. The gut transcripteractome revealed an expression profile that favored biological mechanisms associated to the 1) immune system, particularly involving T cell activation and differentiation, 2) gut integrity (i.e., adherens and tight junctions) and cellular proliferation, and 3) cellular proteolytic pathways. The histological analysis showed that the MPLE dietary supplementation promoted an increase in the number of intestinal goblet cells and modified the composition of mucins' glycoproteins stored in goblet cells, with an increase in the staining intensity of neutral mucins, as well as in mucins rich in carboxylated and weakly sulfated glycoconjugates, particularly those rich in sialic acid residues. The integration of transcriptomic and histological results showed that the evaluated MPLE from sage and lemon verbena is responsible for the maintenance of intestinal health, supporting gut homeostasis and increasing the integrity of the intestinal epithelium, which suggests that this phytogenic may be considered as a promising sustainable functional additive for aquafeeds.

Plumbagin suppresses non-small cell lung cancer progression through downregulating ARF1 and by elevating CD8+ T cells.

Non-small cell lung cancer (NSCLC) is one of the most frequently diagnosed cancers and the leading causes of cancer death worldwide. Therefore, new therapeutic agents are urgently needed to improve patient outcomes. Plumbagin (PLB), a natural sesquiterpene present in many Chinese herbal medicines, has been reported for its anti-cancer activity in various cancer cells. In this study, the effects and underlying mechanisms of PLB on the tumorigenesis of NSCLC were investigated. PLB dose-dependently inhibited the growth of NSCLC cell lines. PLB promoted ROS production, activated the endoplasmic reticulum (ER) stress pathway, and induced cell apoptosis, accompanied by the decreased expression level of ADP-ribosylation factor 1 (ARF1) in NSCLC cancer cells, and those effects of PLB could be reversed by the pretreatment with N-acetyl-L-cysteine (NAC). More importantly, the calcium chelator (BM) significantly reversed PLB-induced cell apoptosis. Furthermore, PLB significantly inhibited the growth of both H1975 xenograft and LLC1 tumors and exhibited antitumor activity by enhancing the number and the effector function of CD8+ T cells in KRASLA2 mice model and the LLC1 xenograft. Our findings suggest that PLB exerts potent antitumor activity against NSCLC in vitro and in vivo through ARF1 downregulation and induction of antitumor immune response, indicating that PLB is a new novel therapeutic candidate for the treatment of patients with NSCLC.

Nigella sativa oil inhibits proliferation and stimulates apoptosis of human lymphocytes in vitro.

The study aimed to examine the in vitro influence of Nigella sativa oil on human lymphocytes. Cells were stimulated with a monoclonal anti-CD3 antibody in the presence of serial oil ethanol dilutions. Then their proliferation and apoptosis rates were assessed using flow cytometry. Our results demonstrate that the lowest dilutions (1:1 and 1:10) of Nigella sativa oil inhibited lymphocytes' proliferation. The number of cell divisions was 8, 1.25, 1.88 after stimulation with anti-CD3, or its combination with 1:1 and 1:10 oil dilution. The percentage of proliferating cells was 92.48%, 8.75%, 24.3% after stimulation with anti-CD3 antibody, or its combination with 1:1 and 1:10 oil dilution. The mean percentage of living cells was 81% after stimulation with anti-CD3, 13.6%, 19.9% in the presence of 1:1 and 1:10 oil dilution. The preliminary studies show that black seed oil has a potent antiproliferative and proapoptotic effect on human lymphocytes in vitro.

In-vitro Immunomodulatory activity of Azadirachta indica A.Juss. Ethanol: water mixture against HIV associated chronic CD4+ T-cell activation/ exhaustion.

BACKGROUND: In Sub-Saharan Africa, herbal therapy continues to be utilized for HIV-1 disease management. However, the therapeutic benefits of these substances remain ambiguous. To date, little is known about the effects of these plant extracts on chronic CD4 + T-cell activation and exhaustion which is partly driven by HIV-1 associated microbial translocation. METHODS: Effects of Azadirachta indica, Momordica foetida and Moringa oleifera ethanol: water mixtures on cell viability were evaluated using the Guava PCA system. Then, an in-vitro cell culture model was developed to mimic CD4+ T cell exposures to antigens following HIV-1 microbial translocation. In this, peripheral blood mononuclear cells (PBMCs) isolated from HIV negative (n = 13), viral load < 1000 copies per mL (n = 10) and viral load > 1000 copies per mL (n = 6) study participants from rural Uganda were treated with Staphylococcus enterotoxin B (SEB). Then, the candidate plant extract (A. indica) was added to test the potential to inhibit corresponding CD4+ T cell activation. Following BD Facs Canto II event acquisition, variations in %CD38, %CD69, Human Leukocyte Antigen -DR (HLA-DR), Programmed cell death protein 1 (PD-1), T-cell immunoglobulin and mucin domain-containing protein 3 (Tim-3), interferon gamma (IFN γ) and interleukin 2 (IL-2) CD4 + T cell expression were evaluated. RESULTS: Following exposure to SEB, only A. indica demonstrated a concentration-dependent ability to downregulate the levels of CD4 + T cell activation. At the final concentration of 0.500 µg/mL of A. indica, a significant downregulation of CD4 + CD38 + HLA-DR+ expression was observed in HIV negative (p < 0.0001) and both HIV infected groups (P = 0.0313). This plant extract also significantly lowered SEB induced % CD4+ T cell HLADR, PD-1 and Tim-3 levels. PD-1 and CD69 markers were only significantly downmodulated in only the HIV negative ((p = 0.0001 and p = 0.0078 respectively) and viral load< 1000 copies per ml (p = 0.0078) groups. CONCLUSION: A. indica exhibited the in-vitro immunomodulatory potential to inhibit the continuum of SEB induced CD4+ T-cell activation/ exhaustion without impacting general T-cell specific functions such as cytokine secretion. Additional studies are needed to confirm A. indica as a source of natural products for targeting persistent immune activation and inflammation during ART.

Bee venom phospholipase A2 alleviates collagen-induced polyarthritis by inducing Foxp3+ regulatory T cell polarization in mice.

The mechanism underlying bee venom (BV) therapy is still controversial, with opinions ranging from constituent-based pharmacological action to homeopathic-like activity. The purpose of this study was to examine whether BV phospholipase A2 (bvPLA2), an enzymatic component of BV, is a novel anti-inflammatory and anti-arthritic mediator capable of stimulating CD25+ Foxp3+ regulatory T cell (Treg) polarization in a mouse model of human rheumatoid arthritis (RA). An experimental model of RA was established in male DBA/1 mouse by 2-week-interval injections of 100 µg type II collagen emulsified in complete (first injection) or incomplete Freund's adjuvant (second injection) at the base of the tail. During arthritis development, bvPLA2 (0.1, 0.5, 1.0 mg/kg) and/or Treg inhibitors such as anti-CD25 antibodies and peptide 60 (P60) were injected intraperitoneally for 5 weeks. Arthritic symptoms and the expansion of Tregs were then assessed by behavioral assessments, histological and micro-CT imaging, and flow cytometry. bvPLA2 injections significantly alleviated arthritic behaviors such as squeaking and joint swelling, consistent with changes seen on both histological and micro-CT images. The anti-arthritic effects of bvPLA2 were blocked by intraperitoneal injections of 0.25 mg/kg anti-CD25 antibody and 10 µg/kg P60, as determined by behavioral assessments. Flow cytometric analysis of dendritic cells, B cells, and major T cell subsets from spleens revealed a significant depletion of Tregs following anti-CD25 antibody, but not P60, treatment. bvPLA2 treatment exerted significant anti-inflammatory and anti-arthritic activities in a mouse model of RA via the induction of Tregs.

6,7,4[Formula: see text]-Trihydroxyflavanone Prevents Methamphetamine-Induced T Cell Deactivation by Protecting the Activated T Cells from Apoptosis.

Methamphetamine (METH) is an extremely addictive drug that has raised serious public health concerns recently. METH addiction not only results in neuronal cytotoxicity, but it also affects immune cell activity, including T lymphocytes. 6,4,7[Formula: see text]-trihydroxyflavanone (THF), isolated from Dalbergia odorifera, has been studied for its antibacterial activity, but evidence for whether THF has an anti-cytotoxic and protective effect on T cell activation exposed to METH is lacking. In this study, results showed that treatment with THF was not cytotoxic to Jurkat T cells but dose-dependently mitigated the cytotoxicity induced by exposure to METH. The Western blot results demonstrating pre-treatment with THF maintained the expression of anti-apoptotic proteins and phosphorylation of PI3K/Akt/mTOR downregulated by treatment with METH. Furthermore, we found that decreased expression of IL-2 and CD69 by METH exposure was partially restored, and viability was significantly prevented by pre-treatment with THF in activated T cells. These findings were involved in re-elevated expression of anti-apoptotic proteins as well as recovered pathways including MAPK/PI3K/Akt/mTOR in activated T cells pre-exposed to METH. Our results suggest beneficial effects of THF against the cytotoxic and immune-modulating effect of METH on T cells and therapeutic potential of THF for patients with immunodeficiency caused by METH addiction.

Immunostimulatory and anti-allergic potential of novel heterotrimeric lectin from seeds of Zizyphus mauritiana Lam.

Zizyphus mauritiana Lam. seeds (ZMS) have been used medicinally as sedative or hypnotic drugs in most of Asian countries. ZMS has significant benefits to the human health. Therefore, we have evaluated immunomodulatory effect of lectin extracted from these ZMSL in both in vitro and in vivo study. Anaphylaxis is a severe life-threatening allergic reaction and Arthus reaction is deposition of immune complex and complement system activation, so we hypothesized that if ZMSL can protect these severe allergic diseases. We have studied the effect of ZMSL on macrophages and Wistar albino rats and confirmed its protective effect against anaphylaxis and Arthus reaction. Results of this study suggest ZMSL have immunostimulatory and antiallergic activity.

The Immuno-Modulatory Activities of Pentaherbs Formula on Ovalbumin-Induced Allergic Rhinitis Mice via the Activation of Th1 and Treg Cells and Inhibition of Th2 and Th17 Cells.

Allergic rhinitis (AR) is a highly prevalent allergic disease induced by immunoglobulin (Ig) E-mediated hypersensitivity reaction at the nasal epithelium against inhaled allergens. Previous studies have demonstrated that Pentaherbs formula (PHF), a modified herbal formula comprising five herbal medicines (Flos Lonicerae, Herba Menthae, Cortex Phellodendri, Cortex Moutan and Rhizoma Atractylodis), could suppress various immune effector cells to exert anti-inflammatory and anti-allergic effects in allergic asthma and atopic dermatitis. The present study aimed to further determine the anti-inflammatory activities of PHF in an ovalbumin (OVA)-induced AR BALB/c mouse model. Nasal symptoms such as sneezing and nose rubbing were recorded and the serum total IgE and OVA-specific IgG1, as well as interleukin (IL)-4, IL-5, IL-10, IL-13, chemokines CXCL9 CXCL10, and tumor necrosis factor (TNF)-α concentrations in nasal lavage fluid (NALF) were measured during different treatments. Effects of PHF on the expression of inflammatory mediators in the sinonasal mucosa were quantified using real-time QPCR. PHF was found to suppress allergic symptoms, infiltration of inflammatory cells, and hyperplasia of goblet cells in the nasal epithelium of the OVA-induced AR mice. PHF could reduce OVA-specific IgG1 level in serum, and TNF-α and IL-10 in nasal lavage fluid (NALF), significantly up-regulate the splenic regulatory T (Treg) cell level, increase the Type 1 helper T cell (Th1)/Type 2 helper T cell (Th2) ratio, and reduce the Th17 cells (all p < 0.05). PHF could also alleviate in situ inflammation in sinonasal mucosa of OVA-induced AR mice. In conclusion, oral treatment of PHF showed immuno-modulatory activities in the OVA-induced AR mice by regulating the splenic T cell population to suppress the nasal allergy symptoms and modulating inflammatory mediators, implicating that PHF could be a therapeutic strategy for allergic rhinitis.

Effect of chitosan oligosaccharide-conjugated selenium on improving immune function and blocking gastric cancer growth.

Selenium (Se) is a potential chemopreventive or chemotherapeutic agent against malignant tumor. Selenium-oligosaccharides are important selenium source of dietary supplementation. Due to the insufficient natural production, it is therefore urgent to develop selenium-oligosaccharides by artificial synthesis. Chitosan, the N-deacetylated derivative of chitin, has been applied widely in biomedical field, owing to its nontoxicity, hydrophilicity, biocompatibility, and biodegradation. While chitosan is water insoluble at neutral pH, limiting its application in physiological conditions. Chitosan oligosaccharide (COS), the hydrolysate of chitosan, is readily soluble in water because of the shorter chain lengths of the oligomers and the free amino groups in the D-glucosamine units. This study was aimed at preparing COS-conjugated selenium (COS-Se) and examining the toxicity and ability on improving immune function and blocking gastric cancer growth. Our results demonstrated that COS-Se displayed directly co-mitogenic and mitogenic actions on mouse splenocytes proliferation in vitro. Besides, COS-Se treatment could effectively elevate phagocytosis and increase the secretion of anti-inflammatory cytokine in mouse peritoneal macrophages. Further in vivo experiments showed that COS-Se exhibited immuno-enhancing effects through promoting the phagocytic index, spleen index and thymus index with no obvious toxicity to Kunming mice. Moreover, COS-Se inhibited proliferation and metastasis of human gastric cancer cells, with non-toxic effects on the normal fibroblast cells in vitro. COS-Se supplementation could significantly repress the growth of gastric adenocarcinoma through reducing levels of CD34, vascular endothelial growth factor and matrix metalloproteinase-9 of nude mice. In conclusion, COS-Se was non-toxic and showed great potential as a functional food ingredient in cancer prevention.