An immunosuppressive function of interleukin-35 in chronic hepatitis C virus infection

Interleukin (IL)-35, a newly identified member of the IL-12 cytokine family, has been reported to suppress inflammation and induce immunotolerance. However, little is known regarding the role of IL-35 during chronic hepatitis C virus (HCV) infection. Herein, we measured the serum IL-35 concentration of 73 patients with hepatitis C and 22 healthy individuals, as well as further investigated the modulatory function of IL-35 on CD4⁺ CD25⁺ CD127^dim/− regulatory T cells (Tregs) and on hepatocytes infected with HCV in cell culture (HCVcc). IL-35 expression was significantly increased in patients with chronic hepatitis C and was positively correlated with the levels of HCV RNA. Inhibition of viral replication led to decreases in the serum levels of IL-35. IL-35 stimulation not only elevated the percentage of Tregs but also robustly inhibited cellular proliferation and up-regulated the production of anti-inflammatory cytokines (e.g., IL-10 and IL-35) in a HCV-specific and non-specific manner, which indicates enhancement of the suppressive function of Tregs. Although IL-35 did not exert anti-HCV activity in HCVcc-infected Huh7.5 cells, it reduced inflammatory cytokine secretion from Huh7.5 cells. This was probably via inhibition of the STAT1 and STAT3 signaling pathways, which could suppress subsequent liver damage due to chronic hepatitis C. The current data suggested that IL-35 contributes to persistent HCV infection by inhibiting antiviral immune activity. Moreover, IL-35 might also protect against HCV-induced liver injury by down-regulating the expression of proinflammatory cytokines. Thus, the immunosuppressive properties of IL-35 might play contradictory roles in maintaining viral persistence and reducing the inflammatory responses in chronic HCV infection.     

Alloantigen specific T regulatory cells in transplant tolerance

CD4⁺CD25⁺Foxp3⁺T cells are regulatory/suppressor cells (Treg) that include non-antigen(Ag)-specific as well as Ag-specific Tregs. How non-Ag-specific naïve CD4⁺CD25⁺Treg develop into specific Tregs is unknown. We have studied DA rats tolerant to fully allogeneic PVG cardiac grafts that survived with out immunosuppression for over 100 days and identified the cellular basis of alloantigen specific tolerance. Key observations from our studies will be reviewed including how CD4⁺CD25⁺Tregs were first identified and the cytokine dependence of CD4⁺T cells that transfer alloantigen specific transplant tolerance which died in culture unless stimulated with both cytokine rich ConA supernatant and specific donor alloantigen. Both the tolerant CD4⁺CD25⁺ and CD4⁺CD25⁻ T cell populations are required to transfer tolerance, yet alone the CD4⁺CD25⁻ T cell effect rejection. Tolerance transfer occurs with a low ratio of CD4⁺CD25⁺T cells (< 1:10), whereas to induce tolerance with naive CD4⁺CD25⁺T cells requires both a ratio of > 1:1 and is not alloantigen specific.Recent findings on how naïve CD4⁺CD25⁺T cells developed into two separated pathways of alloantigen specific Tregs, by culturing them with alloAg with either IL-2 or IL-4 and donor alloantigen are described. IL-2 enhances IFN-γR and IL-5 mRNA while IL-4 induced a reciprocal profile with de novo IL-5Rα and increased IFN-γ mRNA expression. Both IL-2 and IL-4 alloactivated CD4⁺CD25⁺Tregs within 3–4 days of culture can induce alloantigen specific tolerance at ratios of 1:10. Long term, CD4⁺CD25⁺T cells from tolerant hosts given IL-2 cultured cells have increased IL-5 and IFN-γR mRNA; whereas hosts given IL-4 cultured cells had enhanced IL-5Rα mRNA expression and IL-5 enhanced their proliferation to donor but not third party alloAg.These findings suggest that Th1 and Th2 responses activate two pathways of alloantigen specific Tregs that can mediate transplant tolerance but are dependent upon cytokines produced by ongoing Th1 and/or Th2 immune responses.     

Lactococcus lactis subsp. cremoris FC triggers IFN-γ production from NK and T cells via IL-12 and IL-18

Lactic acid bacteria (LAB) benefit health as probiotics in a strain-dependent way. In this study, we investigated the immunomodulatory effects of Lactococcus lactis subsp. cremoris FC (LcFC) on dendritic cells (DCs), natural killer (NK) cells and T cells. LcFC induced the production of cytokines such as IL-10, IL-12, IL-6 and TNF-α from murine bone marrow DCs (BMDCs) via MyD88-dependent pathway. In comparison with the type strain L. lactis subsp. cremoris ATCC 19257, LcFC induced particularly high production of IL-12 while induction of IL-6 was moderate. Consequently, LcFC triggered IFN-γ production in splenic NK, CD8⁺, and CD4⁺ cells. Most prominent effect of LcFC on IFN-γ production was observed in NK cells, followed by CD8⁺ cells, which was completely inhibited by combination of neutralizing anti-IL-12 and anti-IL-18 mAbs. Moreover, oral administration of LcFC enhanced the production of IFN-γ and IL-10 from splenocytes of treated mice. These findings suggest that this LAB strain is an efficient activator of protective cellular immunity via stimulation of myeloid cells including DCs.     

Comparison of peripheral blood B cell subset ratios and B cell-related cytokine levels between ocular and generalized myasthenia gravis

BackgroundThe pathogenesis of myasthenia gravis (MG) depends upon T and B cells, as well as complement and cytokines. The activation of functional subpopulations of T and B cells is the basis of the immune response. However, the activation levels of T and B cell subsets remain unclear in the pathogenesis of MG. Here, we evaluated the proportions of T and B cell subsets and related cytokines in ocular MG (oMG) patients and generalized MG (gMG) patients, and analyzed the potential roles of T and B cell subsets in the pathogenesis of oMG.MethodsIn total, 16 patients with oMG, 31 patients with gMG, and 20 healthy controls (HCs) were included in this study. Peripheral blood mononuclear cells (PBMCs) were separated from venous blood via density centrifugation. The percentages of CD3⁺CD4⁺ T cells, CD3⁺CD8⁺ T cells, CD4⁺CD25⁺CD127^- regulatory T cells (Tregs), CD19⁺CD27⁺CD38^- memory B cells, CD19⁺CD24^hiCD27⁺ regulatory B cells (Bregs), CD19⁺CD38⁺CD138⁺ plasma cells, and CD19⁺CD40⁺ B cells in PBMCs were detected by flow cytometry. The levels of interleukin (IL)-2, IL-4, IL-6, IL-10, IL-17, and interferon (IFN)-γ in serum were detected by enzyme linked immunosorbent assay (ELISA). Differences in T and B cell subsets and related cytokines were compared among the three groups of participants.ResultsThe proportions of CD19⁺CD27⁺CD38^- memory B cells were significantly higher in the oMG and gMG groups than in the HC group (P = 0.004; P < 0.001), whereas the proportion of CD19⁺CD27⁺CD38^- memory B cells was significantly lower in the oMG group than in the gMG group (P < 0.001). Moreover, the proportion of CD19⁺CD24^hiCD27⁺ Bregs was significantly higher in the oMG group than in the gMG and HC groups (P = 0.001). The proportion of CD4⁺CD25⁺CD127^- Tregs was significantly lower in the gMG group than in the oMG and HC groups (P < 0.001). Finally, the level of serum IL-10 was significantly higher in the oMG group than in the gMG and HC groups (P < 0.05). Compared with the HC group, serum IL-2 levels were significantly increased in the oMG and gMG groups (P = 0.016; P = 0.002).DiscussionThe reduced ratios of Tregs and Bregs may contribute to the progression of oMG to gMG, and the increased proportion of memory B cells may be closely related to the progression of oMG. IL-2 and IL-10 are important in the development of oMG.     

CD4+ Foxp3+ regulatory T cells induced by TGF-β, IL-2 and all-trans retinoic acid attenuate obliterative bronchiolitis in rat trachea transplantation

Obliterative bronchiolitis (OB) is the major obstacle for long-term allograft survival in lung transplantation, and the underlying mechanism is still not well understood. Regulatory T cells (Tregs) have been shown to be essential in the maintenance of immune tolerance. In this study we investigated the role of Tregs in protecting OB in rat. We show that the combination of TGF-β, Interleukin (IL)-2, and all-trans retinoic acid (atRA) could induce naïve rat CD4⁺CD25⁻ T cells to differentiate into CD4⁺CD25⁺Foxp3⁺ T cells in vitro, and they acquired suppressive function. In a rat orthotopic tracheal transplantation OB model, the adoptive transfer of the induced Tregs reduced symptoms of airway obliteration and fibrication of grafts when compared with adoptive transfer of control cells without suppressive property. Moreover, recipients treated with the induced Tregs secreted high level of immunosuppressive cytokine TGF-β and IL-10, and low level of pro-inflammatory cytokines IL-17, IFN-γ, IL-6, and MCP-1, and had fewer effector T cells including Th17 cells and Th1 cells in the graft. Taken together, these findings suggest that in vitro induced Tregs by the combination of TGF-β, IL-2, and atRA are effective in protecting rat trachea allograft rejection through the inhibition of effector T cells and their function. These datas implicate new therapies to prevent OB and allograft rejection in human lung transplantation.     

Rapamycin inhibits differentiation of Th17 cells and promotes generation of FoxP3+ T regulatory cells

Reciprocal differentiation of immunosuppressive CD4⁺CD25⁺FoxP3⁺ T regulatory cells (Tregs) and proinflammatory IL-17-producing cells (Th17) from naïve CD4 cells is contingent upon the cytokine environment. Using MACS-purified CD4 cells, we found that rapamycin and cyclosporine A (CsA) potently inhibited the TGFβ and IL-6-induced generation of IL-17-producing cells. Intriguingly, rapamycin promoted, while CsA markedly inhibited, TGFβ-mediated generation of Tregs. The aforementioned effects of rapamycin and CsA were also observed for Flow-sorted CD4⁺CD25⁻ T cells, indicating that the effect of these two immunosuppressive agents was based on their action on de novo generation of Tregs and Th17 cells from naïve CD4 cells. Our observation suggests a distinct mode of immunosuppressive action and tolerance induction by rapamycin and CsA. The capacity of rapamycin to generate immunosuppressive Tregs and to suppress differentiation of pathogenic Th17 cells furthers our understanding of the basis for the therapeutic immunosuppressive effects of rapamycin in patients with autoimmune diseases and allo-transplantation reactions.     

T2 enhances in situ level of Foxp3+ regulatory cells and modulates inflammatory cytokines in Crohn's disease

BackgroundActing via IL-10 and transforming growth factor-β (TGF-β), t regulatory cells (Tregs) that express the Forkhead Box P3 (Foxp3) play a vital role in maintaining intestinal immune homeostasis. Many studies have found correlation between Foxp3⁺ Treg cells and Crohn's disease (CD). T2, extracted from the medicinal plant Tripterygium wilfordii Hook F, has already been proved to be therapeutically effective in inducing the remission of CD. However, the mechanisms in human studies remain largely unknown.AimWe aimed to explore the effect of T2 on the in situ levels of inflammatory cytokines and the number of Foxp3⁺ Tregs in inflamed mucosa of CD.MethodsMucosal biopsies from 20 patients treated with T2 were taken by colonoscopy. The changes of Foxp3⁺ Tregs as well as TNF-α and IL-10 in diseased tissue were visualized by immunochemistry. Western blot and ELISA were used to quantify levels of Foxp3 protein expression and inflammatory cytokines.ResultsT2 treatment ameliorated the pathological inflammation of CD. We observed that the significantly elevated Foxp3⁺ Tregs and IL-10 levels in the mucosa of CD patients after T2 treatment concurred with the down-regulation of proinflammatory TNF-α.ConclusionWe confirmed the efficacy of T2 treatment in CD and showed that microscopic inflammation was attenuated by the modulation of in situ levels of inflammatory cytokines. The therapeutic mechanisms might involve the up-regulation of Foxp3⁺ Tregs.     

Dysfunction of IL-10-producing type 1 regulatory T cells and CD4+CD25+ regulatory T cells in a mimic model of human multiple sclerosis in Cynomolgus monkeys

CD4⁺CD25⁺ Treg and IL-10⁺ Tr1 cells play a major role in controlling autoimmunity by suppressing self-reactive T cells. Dysfunction of Tregs appears to be a critical factor in the pathogenesis of autoimmune diseases. Multiple sclerosis (MS) is an inflammatory demyelinating disorder of CNS, where CD4⁺ T cells result in nervous tissue damage. The aim of this study was to investigate the protective role of Treg and Tr1 cells in a mimic model of human MS in Cynomolgus monkeys.This study indicated the suppressive capacity of Tregs from MS monkeys was impaired compared with naive controls. The population of CD4⁺CD25⁺ Tregs was decreased in acute stage of MS. However, they showed a restored function and percentage in remitting monkeys. In stable phase, CD4⁺CD25⁺ Tregs differentially expressed elevated level of CD62P cell adhesion molecule which contributes to the mechanism by which Treg cells inhibit CD4⁺ T cell responses. On the other hand, the percentage of CD4⁺IL-10⁺ Tr1 and suppressive function of Tr1 cells were found reduced in MS monkeys. IL-10 secretion was diminished almost 9-fold in active MS, and recovered in active MS. This deficit in IL-10 secretion was specific to CD3/CD46, but not to CD3/CD28 stimulation. The concentrations of IFN-γ secreted by CD3/CD46-activated T cells were also not affected.These results demonstrate that Tregs are dysfunctional in Cynomolgus monkey with MS. Loss of regulatory function appears to be an important factor in the pathogenesis of MS. Hence, to develop new approaches for induction of Tregs in vivo may be beneficial for the clinical treatment in autoimmune diseases.     

In vitro induced CD4+CD25+Foxp3+ Tregs attenuate hepatic ischemia–reperfusion injury

Reperfusion injury causes liver dysfunction after warm or cold ischemia. Emerging data suggest a role of T cells as mediators in this ischemia/reperfusion (I/R) injury. In the T cells, a part of CD4⁺CD25⁺FoxP3⁺ T regulatory cells (Tregs) were reported to facilitate recovery from I/R injury. These Tregs can be induced by TGF-β in vitro. Interestingly, rapamycin was reported to selectively expand these Tregs in vitro. In the present study, addition of rapamycin to cultures containing TGF-β further increased the frequency and absolute number of functional CD4⁺ Tregs. Using a partial (70%) hepatic warm ischemia model, we investigated the effects of liver function recovery under the treatment of Tregs induced by rapamycin and TGF-β. The treatment of Tregs significantly reduced serum alanine aminotransferase and aspartate aminotransferase compared to I/R control animals at 24 h after reperfusion (P < 0.05). They also significantly attenuated the up-regulation of IFN-γ and IL-17 compared to the I/R control animals (P < 0.05). In conclusion, Tregs ameliorate the biochemical of hepatic I/R injury by preventing proinflammatory cytokines following a warm I/R insult. These data may pave the way to use Tregs as cell therapy to prevent hepatic I/R injury.     

Orally administered lactoperoxidase ameliorates dextran sulfate sodium-induced colitis in mice by up-regulating colonic interleukin-10 and maintaining peripheral regulatory T cells

We previously demonstrated orally administered bovine lactoperoxidase (LPO) ameliorated dextran sulfate sodium-induced colitis in mice. Here, we examine the mechanism of action of LPO. Three days after colitis induction, expression of interferon-γ mRNA in colonic tissue was significantly decreased in mice administered LPO; while mRNA expression of interleukin (IL)-10 and regulatory T cell (Treg) marker, Foxp3, were significantly increased. The proportion of CD4⁺CD25⁺ Tregs in peripheral CD4⁺ T cells was also significantly elevated when LPO was administered. Nine days after colitis induction, the severity of colitis symptoms, including body weight loss and colon shortening, was reduced and expression of IL-10 mRNA was increased in mice administered LPO. The proportion of CD4⁺CD25⁺ Tregs in peripheral leukocytes was also significantly elevated when LPO was administered. These results suggest LPO ameliorates colitis by up-regulating colonic anti-inflammatory cytokines and maintaining peripheral regulatory T cells.     

Thymol as a reciprocal regulator of T cell differentiation: Promotion of regulatory T cells and suppression of Th1/Th17 cells

Regulatory T cells (Tregs) are critical for maintaining immune response and enhancing their differentiation has therapeutic implications for autoimmune diseases. In this study, we investigated the effects of thymol a well-known monoterpene from Thyme on differentiation and function of Tregs. In vitro generation of Tregs from purified naïve CD4⁺CD25⁻ T cells in the presence of thymol was carried out. Suppressor activity of generated Tregs was examined by changes in the proliferation of CFSE-labeled conventional T cells. Thymol promotes differentiation of naïve CD4⁺CD25⁻ T cells to CD4⁺CD25⁺Foxp3⁺ Tregs [66.9–71.8% vs. control (47%)] and increased intensity of Foxp3 expression on Tregs (p < 0.01). In functional assay, an increased immune suppression by thymol-induced Tregs (≈2.5 times of untreated Tregs) was detected. For in vivo study, thymol was intraperitoneally administered to ovalbumin (Ova)-immunized mice. Flow cytometry assessment of spleens from thymol-treated Ova-immunized mice showed increased number of CD4⁺ Foxp3⁺ Tregs (>8%, p < 0.01(and decreased levels of CD4⁺T-bet⁺ Th1 and CD4⁺RORγt⁺ Th17 cells resulted in significant decreased Th1/Treg and Th17/Treg ratios. In ex vivo Ova challenge of splenocytes from thymol-treated Ova-immunized mice, similarly higher levels of CD4⁺ Foxp3⁺ Tregs, and also elevated TGF-β expression in CD4⁺Foxp3⁺ population (48.1% vs. 18.9% in untreated Ova-immunized group) and reduced IFN-γ-producing CD4⁺T-bet⁺ T cells and IL-17-producing CD4⁺RORγt⁺ T cells were detected. This led to marked decreased ratios of IFNγ/TGF-β and IL-17/TGF-β expressions. In conclusion, this study revealed thymol as a compound with enhancing effects on Treg differentiation and function, which may have potential benefits in treatment of immune-mediated diseases with Th1/Th17 over-activation.     

Fasudil regulates T cell responses through polarization of BV-2 cells in mice experimental autoimmune encephalomyelitis

Aim:

Fasudil, a selective Rho kinase (ROCK) inhibitor, has been shown to alleviate the severity of experimental autoimmune encephalomyelitis (EAE) via attenuating demyelination and neuroinflammation. The aim of this study was to investigate the effects of fasudil on interactions between macrophages/microglia and T cells in a mice EAE model.

Methods:

Mouse BV-2 microglia were treated with IFN-γ and fasudil. Cell viability was detected with MTT assay. BV-2 microglia polarization was analyzed using flow cytometry. Cytokines and other proteins were detected with ELISA and Western blotting, respectively. Mice were immunized with MOG_35–55 to induce EAE, and then treated with fasudil (40 mg/kg, ip) every other day from d 3 to d 27 pi. Encephalomyelitic T cells were prepared from the spleen of mice immunized with MOG_35–55 on d 9 pi.

Results:

Treatment of mouse BV-2 microglia with fasudil (15 μg/mL) induced significant phenotype polarization and functional plasticity, shifting M1 to M2 polarization. When co-cultured with the encephalomyelitic T cells, fasudil-treated BV-2 microglia significantly inhibited the proliferation of antigen-reactive T cells, and down-regulated IL-17-expressing CD4⁺ T cells and IL-17 production. Furthermore, fasudil-treated BV-2 microglia significantly up-regulated CD4⁺CD25^high and CD4⁺IL-10⁺ regulatory T cells (Tregs) and IL-10 production, suggesting that the encephalomyelitic T cells had converted to Tregs. In EAE mice, fasudil administration significantly decreased both CD11b⁺iNOS⁺ and CD11b⁺TNF-α⁺ M1 microglia, and increased CD11b⁺IL-10⁺ M2 microglia.

Conclusion:

Fasudil polarizes BV-2 microglia into M2 cells, which convert the encephalomyelitic T cells into Tregs in the mice EAE model.     

Tim3/Gal9 interactions between T cells and monocytes result in an immunosuppressive feedback loop that inhibits Th1 responses in osteosarcoma patients

The Tim3/Gal9 pathway is associated with immunosuppression and worse clinical outcome in multiple cancers. To illustrate the specific mechanism of Tim3/Gal9 interaction in osteosarcoma, we examined expression, function, and regulation of Tim3/Gal9 in various cells from osteosarcoma patients. Data showed that CD4⁺ T cells, CD8⁺ T cells, and monocytes from both peripheral blood and tumor of osteosarcoma patients contained high frequencies of Tim3⁺ cells, while the Gal9 expression was primarily found in regulatory T cells (Tregs) from osteosarcoma patients and was elevated compared to that in non-cancer controls. The Tim3⁺ CD4⁺ and CD8⁺ T cells presented lower proliferation capacity compared to their Tim3⁻ counterparts, which could be reverted by blocking Tim3 or Gal9. Interestingly, purified Tim3⁺ CD4⁺ T cells secreted more interferon gamma (IFNγ) than purified Tim3⁻ CD4⁺ T cells, but IFNγ production by Tim3⁺ CD4⁺ T cells was vulnerable to Gal9-mediated suppression. In monocytes, Tim3 expression was associated with high interleukin (IL)-10 and low IL-12 cytokine secretion profile. Exogenous recombinant Gal9, as well as CD4⁺ CD25⁺ Treg supernatant, further decreased IL-12 expression in monocytes. In CD4⁺ T cell-monocyte coculture experiments, Tim3⁺ monocytes inhibited IFNγ expression from total CD4⁺ T cells and the development of IFNγ response in naive CD4⁺ T cells. Blocking the Tim3/Gal9 pathway reverted these effects. Together, these results suggested that in osteosarcoma patients, Tim3 expression did not directly mediate immune suppression, but the interaction between Tim3⁺ T cells and monocytes, naive CD4⁺ T cells, and Gal9-expressing CD4⁺ CD25⁺ Tregs could resulting in progressive suppression of Th1 responses.     

Astragaloside IV attenuates inflammatory reaction via activating immune function of regulatory T-cells inhibited by HMGB1 in mice

Context: High-mobility group box 1 (HMGB1) protein is a highly abundant protein that can promote the pathogenesis of inflammatory. Some experiments have demonstrated a vital role for HMGB1 to modulate the immune function of regulatory T-cells (Tregs). Astragaloside IV (AST IV), an extract from Astragalus membranaceus Moench (Leguminosae), has been shown to exert potent cardioprotective and anti-inflammatory effects. It is still unclear whether AST IV has a latent effect on the proinflammatory ability of HMGB1 with subsequent activation of Tregs in vivo.

Objective: This research explores the antagonism of different doses of AST IV on the immunologic function of Tregs mediated by HMGB1.

Materials and methods: Mouse models (BALB/c) were constructed by which normal saline or AST IV was administered i.p. at 2, 4 and 6 days after the administration i.p. of 20?μg recombinate HMGB1. Spleen was used to procure Treg and CD4?⁺?CD25^? T-cells which were co-cultured with Treg. Cell phenotypes of Tregs(Foxp3) were examined, and the cytokine levels in supernatants and the proliferation of T-cells were assayed. Gene expression was measured by RT-PCR.

Results: (1) The expression levels of Foxp3 in Treg on post-stimulus days (PSD) 1–7 were significantly decreased in the HMGB1 group in comparison to those in the control group mice (p?<?0.01). The Foxp3 expression was markedly increased in a dose-dependent manner in the AST group as compared with those in the HMGB1 group (p?<?0.0 1–0.05). The same results were found in the contents of cytokines (IL-10 and TGF-β) released into supernatants by Treg. (2) When CD4?⁺?CD25^? T-cells were co-cultured with Treg stimulated by HMGB1, the cell proliferation and the levels of cytokines (IL-2 and IFN-γ) in supernatant were markedly increased as compared with those in the HMGB1 group. The level of IL-4 was markedly decreased as compared with that in the HMGB1 group. The same results were found when CD4?⁺?CD25^? T-cells were co-cultured with Treg in the NS group. Compared with those in the NS group, the contrary results were shown in a dose-dependent manner in the AST group.

Discussion and conclusion: These results showed that AST IV has a therapeutic effect on inflammation promoted by HMGB1, and it should be studied as a new drug for the treatment of sepsis.     

The shiitake mushroom-derived immuno-stimulant lentinan protects against murine malaria blood-stage infection by evoking adaptive immune-responses

Lentinan, a (1-3)-beta glucan from Lentinus edodes, is an effective immunostimulatory drug. We tested the effects of lentinan during blood-stage infection by Plasmodium yoelii 17XL (P.y17XL). Pre-treatment of mice with lentinan significantly decreased the parasitemia and increased their survival after infection. Enhanced IL-12, IFN-γ and NO production induced by lentinan in spleen cells of infected mice revealed that the Th1 immune response was stimulated against malaria infection. In vitro and in vivo, lentinan can result in enhanced expression of MHC II, CD80/CD86, and Toll-like receptors (TLR2/TLR4), and increased production of IL-12 in spleen dendritic cells (DCs) co-cultured with parasitized red blood cells (pRBCs). Moreover, both the number of CD4⁺CD25⁺ regulatory T cells (Tregs) and the levels of IL-10 secreted by Tregs were reduced by pre-treatment with lentinan in the spleen of malaria-infected mice. Meanwhile, apoptosis of CD4⁺ T cell in spleens of mice pretreated with lentinan was significantly reduced. In summary, lentinan can induce protective Th1 immune responses to control the proliferation of malaria parasites during the blood-stage of P.y17XL infection by stimulating maturation of DCs to inhibit negative regulation of the Th1 immune response by Tregs. Taken together, our findings suggest that lentinan has prophylactic potential for the treatment of malaria.     

Interleukin-7 promotes lung-resident CD14+ monocytes activity in patients with lung squamous carcinoma

Interleukin (IL)-7 enhances cytokines secretion by CD14⁺ monocytes, and induces recruitment of monocytes to endothelium. As an important regulator to different types of immune cells, the role of IL-7 in modulation of CD14⁺ monocytes is still not fully elucidated. Thus, the aim of current study was to investigate the immunoregulatory activity of IL-7 to peripheral and lung-resident CD14⁺ monocytes in lung squamous carcinoma patients. Thirty-seven lung squamous carcinoma patients and eighteen healthy individuals were enrolled. CD14⁺ monocytes and CD4⁺ T cells were purified from both peripheral bloods and bronchoalveolar lavage fluids (BALF). IL-7 expression in plasma and BALF was measured by ELISA, and CD127 expression in peripheral and lung-resident CD14⁺ monocytes was investigated by real-time PCR and flow cytometry, respectively. Cellular proliferation, cytokine production, and molecules in IL-7 signaling pathway was assessed in CD14⁺ monocytes in response to IL-7 stimulation. IL-7-induced CD14⁺ monocytes activity to CD4⁺ T cells was also assessed in direct and indirect contact co-culture system. There were no remarkable differences of plasma IL-7 concentration or CD127 level between healthy individuals and lung squamous carcinoma patients. However, IL-7 expression was significantly reduced in BALF from tumor site in squamous carcinoma patients, especially in stage III and IV. IL-7 stimulation not only promoted proliferation, cytokines secretion, and STAT-5 phosphorylation in lung-resident CD14⁺ monocytes, but also enhanced CD14⁺ monocytes-induced Th1 and T follicular helper cells activation, which presented as elevated interferon-γ and IL-21 secretion by CD4⁺ T cells. This process required direct cell-to-cell contact, and was dependent on IL-6 secretion. The current data revealed a potential immunopromotive property of IL-7 to lung-resident CD14⁺ monocytes in lung squamous carcinoma.