Astilbin inhibits Th17 cell differentiation and ameliorates imiquimod-induced psoriasis-like skin lesions in BALB/c mice via Jak3/Stat3 signaling pathway

The flavonoid astilbin is the major active component extracted from the rhizome of Smilax glabra, which has been widely used in China to treat inflammatory and autoimmune diseases, Psoriasis is a common chronic inflammatory disease in which T helper 17 (Th17) cells play an important role, provoking inflammation. We employed an imiquimod (IMQ)-induced psoriasis-like mouse model to investigate the effect of astilbin in inflammation. Mice were administered 25 to 50 mg/kg astilbin. Inflammation of psoriasis-like lesions was assessed by histology, circulating levels of T cells were assessed by flow cytometry and cytokines by bead-based immunoassay. Jak/Stat3 in isolated T cells was assessed by Western blotting and RORγt expression was assessed by RT-PCR. Administration of astilbin ameliorated IMQ-induced keratinocyte proliferation, infiltration of CD3 + cells to psoriatic lesions and ameliorated elevations in circulating CD4 + and CD8 + T cells and inflammatory cytokines (IL-17A, TNF-α, IL-6, IFN-γ and IL-2). In vitro, astilbin inhibited Th17 cell differentiation and IL-17 secretion of isolated T cells, and inhibited Jak/Stat3 signaling in Th17 cells, while up-regulating Stat3 inhibitor SCOSE3 expression in psoriatic lesions. Thus, astilbin likely alleviates psoriasis-like skin lesions by inhibiting Th17 related inflammation. Astilbin represents as an interesting candidate drug for immunoregulation of psoriasis.     

In vitro immunomodulatory effects of an oleanolic acid-enriched extract of Ligustrum lucidum fruit (Ligustrum lucidum supercritical CO2 extract) on piglet immunocytes

This study was conducted to evaluate the in vitro immunomodulatory effects of supercritical CO₂ Ligustrum lucidum extract (LLE) on the immune cells of piglets. The results showed that the LLE enhanced the proliferative activity of piglet blood lymphocytes and up-regulated the CD4⁺ CD8⁺ and CD4⁺ CD8⁻ cell populations. The LLE also regulated the expression of Th1- and Th2-related cytokines; elevated the levels of IL-2, IFN-γ and TNF-α, which were produced by Th1 lymphocytes; and decreased the levels of IL-4 and IL-10, which were produced by Th2 lymphocytes. Furthermore, the LLE stimulated the NO secretion of lymphocytes. These results indicated that LLE might have potential immunomodulatory effects on the immune system of piglets and provided scientific and experimental foundations for the development of a new kind of LLE immune adjuvant in the pig production.     

Formula PSORI-CM01 inhibits the inflammatory cytokine and chemokine release in keratinocytes via NF-κB expression

Psoriasis is a common chronic inflammatory disease in which T-helper 1(Th1) and T-helper 17(Th17) cells play an important role in its pathology. Formula PSORI-CM01 was a novel formulated Chinese medicine used for psoriasis therapy. It had been demonstrated previously that PSORI-CM01 and serum contained Formula PSORI-CM01 (PCM01CS) could improve psoriasis by inhibiting the epithelial hyperplasia, how PSORI-CM01 affects inflammatory cytokine and chemokine in dermis is still unknown. In this study we found PSORI-CM01 pre-treated 3 days before IMQ painting could ameliorated IMQ-induced mice skin lesion as PASI score was apparently reduced. Th1 related cytokine IFN-γ and Th17 related cytokine IL-17/IL-22 was used to induce inflammatory models on human keratinocyte cell line HaCaT in vitro, respectively. PCM01CS significantly reduced IFN-γ induced mRNA expression of IL-6, IL-12 and CXCL-10, reduced IL-6 and CXCL-10 release into HaCaT supernatant. 20 ng/ml IL-17/IL-22 co-stimulation significantly upregulated expression of IL-6, IL-8 and CCL20 mRNA expression in HaCaT cells, PCM01CS significantly inhibit these cytokines expression both in mRNA and in protein levels. Finally, PCM01CS could obviously inhibit nuclear NF-κB p65 expression which activated by IFN-γ and IL-17/IL-22 stimulation. Thus, our new findings reveal that Formula PSORI-CM01 may possess therapeutic action on psoriasis by inhibiting inflammatory within skin environments.     

Paeoniflorin inhibits skin lesions in imiquimod-induced psoriasis-like mice by downregulating inflammation

Psoriasis is a common chronic immune-mediated inflammatory disease. It is well known that macrophages, neutrophils and T-helper 1 (Th1)/T-helper 17 (Th17) cells play important roles in skin lesions by provoking inflammation. Paeoniflorin (PF) is the major effective component extracted from the root of Paeonia lactiflora, which has been widely used in China to treat inflammatory and autoimmune diseases, including psoriasis. Although PF shows a clinical therapeutic effect on psoriasis patients, how PF affects infiltrated immune cells in psoriasis skin lesions is still unknown. In this study, using a generated imiquimod (IMQ)-induced psoriasis-like mouse model, we found that PF ameliorates inflammation and skin lesions. Subsequent analyses showed that PF decreases the number of F4/80⁺CD68⁺ macrophages and their related cytokine production (TNF-α, IL-1β, IL-6, IL-12 and inducible nitric oxide synthase (iNOS)) in the skin of IMQ-challenged mice. Moreover, PF suppresses the number of CD11b⁺Gr-1⁺ neutrophils and the expression of macrophage inflammatory protein-2 (MIP-2; a counterpart of human IL-8, which is responsible for the recruitment of neutrophils in mice). Finally, PF also down-regulates Th1- and Th17-related cytokine expression. Therefore, our new findings reveal that PF alleviates psoriatic skin lesions by inhibiting inflammation, which provides new insights into the immunomodulatory effect of PF in psoriasis treatment.     

Oral administration of acarbose ameliorates imiquimod-induced psoriasis-like dermatitis in a mouse model

Psoriasis is a chronic autoimmune disease of undefined etiology that involves dysregulated interplay between immune cells and keratinocytes. Acarbose was found to decrease inflammatory parameters in diabetic patients in addition to its anti-diabetic effects. Here, we report that imiquimod (IMQ)-induced epidermal hyperplasia and psoriasis like-inflammation were significantly inhibited by acarbose treatment. Real-time PCR showed that mRNA levels of the cytokines TNF-α, IL-6, IL-1β IL-17A, and IL-22 in skin were also decreased significantly by acarbose. In addition, we found that acarbose reduced infiltration of CD3⁺ T cells and GR-1⁺ neutrophils in lesional skin and also reduced the percentage of IL-17-producing CD4⁺ T cells (Th17) and IL-17- and IL-22-producing γδ T cells in the spleen. In contrast, acarbose increased the frequency of IL-10-producing CD4⁺ regulator Tr1 T cells in the spleen and small intestine. These results indicate that oral administration of acarbose can attenuate the severity of imiquimod-induced psoriasis with local and systemic anti-inflammatory and immune modulation effects, thus suggesting that acarbose is an effective therapeutic strategy for psoriasis regulation.     

Functional modulation of CD8+ T cell by approved novel immune enhancer: Nocardia rubra Cell-Wall Skeletons (Nr-CWS)

Nocardia rubra cell wall skeleton (Nr-CWS) has been reported to have innate immunostimulating and anti-tumor activities. However, the immunomodulatory effects of Nr-CWS on CD8+ T cells and their related mechanisms are still unknown. In this work, our team purified CD8⁺T cells from spleen cells and explored the phenotype and function of NR-CWS in vitro on CD8⁺T cells. We observed that Nr-CWS can significantly up-regulate the expression of CD69 and CD25 on CD8⁺T cells, with no significant effect on apoptosis or cell death of CD8⁺T cells that occurs in vitro during culture. In addition, the effect of perforin and granzyme B was increased after Nr-CWS treatment, but did not substantially alter the expression of TRAIL and FasL. A variety of cytokine analyses have shown that of the cytokines examined (IFN-γ, TNF-α, IL-2, IL-4, IL-5, IL-6 and IL-10), only IFN-γ and TNF The increase in -α was more pronounced, and the effect of Nr-CWS in CD8⁺T cell culture medium on CD8+ T cells was independent of Th cells. Our results demonstrated that Nr-CWS could up-regulate CD69 and CD25 expression on CD8⁺T cells, promoting IFN-γ and TNF-α secretion, and enhancing perforin and granzyme B production. Thus Nr-CWS may have Immunoaugmenting therapeutic activity via an increase in CD8⁺T cells response.     

Andrographolide sulfonate ameliorates chronic colitis induced by TNBS in mice via decreasing inflammation and fibrosis

Inflammatory bowel disease could result in diarrhea and abdominal pain, as well as potential complications such as tissue fibrosis. The therapeutic effect of andrographolide sulfonate on acute murine experimental colitis induced by 2, 4, 6-trinitrobenzene sulfonic acid (TNBS) has been confirmed. In the study here, chronic colitis triggered by repeated intrarectal administration of TNBS was established and the effect of andrographolide sulfonate was examined. Repeated TNBS administration induced substantial mice death, which was significantly decreased by andrographolide sulfonate treatment. The elevation of inflammatory cytokines including IL-6, IL-17A, TNF-α as well as IFN-γ in colonic tissues levels were decreased after administration of andrographolide sulfonate. Next, CD4⁺ T cell and macrophage infiltration was found to descend. The subset of pathogenic CD4⁺ T cell subset including CD4⁺IFN-γ⁺ (Th1) and CD4⁺IL-17A⁺ (Th17) were also suppressed by andrographolide sulfonate. Further, the restrain of p38 and p65 activation were also observed after andrographolide sulfonate administration. Finally, TNBS-induced colonic epithelial damage as well as fibrosis were significantly mitigated by andrographolide sulfonate. Based on the results got here, we can make a conclusion that andrographolide sulfonate could decrease inflammation and epithelial damage as well as fibrosis thus ameliorating chronic colitis in mice. Our study suggest the possible use of andrographolide sulfonate for chronic colitis treatment in clinical.     

Obaculactone suppresses Th1 effector cell function through down-regulation of T-bet and prolongs skin graft survival in mice

Allograft rejection is a predominantly Th1 immune response. In this study, we showed that obaculactone, a natural compound derived from citrus fruit, prolonged skin graft survival in mice when treated after but not before transplantation. Furthermore, obaculactone inhibited alloantigen-specific production of Th1 cytokine IFN-γ as well as proinflammatory cytokine IL-2, TNFα and IL-6. In parallel, IL-10 production was markedly up-regulated. Obaculactone significantly enhanced the percentage of CD4⁺CD25⁺Foxp3⁺ Treg cells in the CD4⁺ splenocytes without any effect on their inhibitory function. In vitro and in vivo tests showed obaculactone down-regulated T-bet expression in Th1 effector cells. Taken together, the unique immunomodulatory properties might qualify obaculactone as a putative, therapeutic compound for the treatment of Th1-driven diseases, including transplant rejection.     

Dendritic cell immunotherapy combined with cytokine-induced killer cells promotes skewing toward Th2 cytokine profile in patients with metastatic non-small cell lung cancer

Dendritic cell (DC) vaccination and cytokine-induced killer (CIK) cell therapy (DC/CIK) have shown limited success in the treatment of advanced non-small cell lung cancer (NSCLC). To investigate the reason for this limited success, the effects of DC/CIK cell therapy on the immune responses of tumor-bearing patients and patients with resected NSCLC were evaluated. In the total 50 patients studied, the serum concentrations of the Th2 cytokines (IL-4 and IL-10) in tumor-bearing patients were significantly higher than those with resected NSCLC before immunotherapy. The post-therapy Th1 cytokine (IFN-γ) level in patients with resected NSCLC significantly increased from the pre-therapy level. In contrast, significantly enhanced post-therapy Th2 cytokine (IL-4 and IL-10) levels were found in tumor-bearing patients. The intracellular staining assay revealed that DC/CIK cell therapy increased the IFN-γ-producing T lymphocyte (CD8⁺IFN-γ⁺) frequency in patients with resected NSCLC, but these lymphocytes were not found in tumor-bearing patients. Furthermore, overproduction of vascular endothelial growth factor (VEGF) in tumor-bearing patients showed a statistically positive correlation with IL-4, suggesting that VEGF might be responsible for the predominance of serum Th2 cytokines. In a word, tumor-bearing patients developed a Th2-dominant status that could not be reversed toward Th1 following immunotherapy. A combined regiment of DC vaccination and CIK cell therapy with other treatments to overcome systemic Th2-dominant immune response might improve the current clinical benefit.     

Role of interplay between IL-4 and IFN-γ in the in regulating M1 macrophage polarization induced by Nattectin

Recently our group described that Nattectin, a C-type lectin of the venom of Thalassophryne nattereri shows a potent pro-inflammatory capacity. Here, we demonstrated that Nattectin is able to induce M1 macrophage marker iNOS, and up-regulate the expression of MHC class II, CD80, CD86 and CD40 molecules. The increase in MHC class II and CD49a integrin expression with MMP-9 production and endocytic capacity depend on lectin function of Nattectin. Moreover, the polarization of peritoneal and bone marrow-derived macrophages induced by Nattectin to M1 profile is dependent on Th1 cytokines (IL-12 and IFN-γ), and negatively regulated by Th2 cytokines (IL-4, IL-10 and IL-13). Also we reveal that IL-4 play a dual role in this polarization: a regular action of IL-4 was seen in the negative regulation of the CD40 expression, but an unexpected positive regulation was seen in the expression of CCR7 and MHC class II. Finally, our in vivo studies showed that the influx of neutrophils and small peritoneal macrophage - F4/80^lowMHCII^hi induced by Nattectin is totally dependent on IL-4 and IFN-γ cytokines. Furthermore, the induction of IL-6 release is negatively regulated by IL-4 and positively regulated by IL-12 and IFN-γ. Together, the results allowed us to expand the knowledge about the regulation of macrophage activation, as well as confirmed the ability of Nattectin, a fish C-type lectin, as an important immunomodulatory agent.     

Targeting IL-17 in autoimmunity and inflammation

The discovery of two distinct subsets of helper T cells, IFN-γ-producing Th1 cells and IL-4-producing Th2 cells, about three decades ago enabled us to understand the immunopathology of cell-mediated and allergic inflammatory diseases in humans. The observation that T cell-mediated experimental autoimmune diseases can be induced in mice lacking Th1 and Th2 cell responses prompted many immunologists to hypothesize that there might be additional subsets in helper T cell population which mediate autoimmunity in the absence of Th1 and Th2 cells. Consequently, multiple independent research groups identified IL-17-expressing RORγt⁺CD4⁺ T cell population as a distinct subset of helper T cells which promotes autoimmune tissue inflammation. Subsequent studies have revealed that innate immune cells, including γδ T cells, NKT cells and innate lymphoid cells, also produce type 17 cytokines and contribute to tissue inflammation. In this review, we discuss our current understanding on the biology of IL-17 and the therapeutic potential of targeting IL-17 for the treatment of immune disorders in humans.     

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.     

HIV infection confers distinct mechanisms in severe drug eruption: Endogenous virus activation with aberrant Th2/Th1 and CD8+ T cells function

Severe drug eruption (SDE), a common skin disease, becomes dangerous when it occurs in patients with human immunodeficiency virus (HIV). However, the molecular mechanisms are poorly understood. Forty patients including HIV⁺ SDE⁺ (n = 15), HIV⁻ SDE⁺ (n = 15) and HIV⁺ SDE⁻ (n = 10) subjects were enrolled in our study. All HIV⁺ patients were at acquired immune deficiency syndrome (AIDS) stage. Serum levels of TNF-α, IFN-γ, IL-4, IL-13, IL-6, CXCL9, and CCL17 were quantified by ELISA. Epstein–Barr virus (EBV) and cytomegalovirus (CMV) loads were quantified by RT-qPCR. CD4, CD8, Th1, Th2, TNF-α-CD8, and IFN-γ-CD8 T cell populations were measured by flow cytometry. Levels of biochemical indexes in HIV⁺ SDE⁺ patients were significantly different from in HIV⁻ SDE⁺ patients (P < .05). EBV and CMV viral loads were significantly higher in HIV⁺ SDE⁺ patients, but not in HIV⁻ SDE⁺ patients (P < .05). Inflammatory cytokines TNF-α and IFN-γ were significantly elevated in HIV⁺ SDE⁺ patients (P < .05). Th2/Th1 populations and TNF-α secreting or IFN-γ secreting CD8⁺ T cells, were significantly up-regulated in HIV⁺ SDE⁺ patients compared to HIV⁻ SDE⁺ patients (P < .05). Conversely, the CD4/CD8 ratio was significantly down-regulated in HIV⁺ SDE⁺ patients compared to HIV⁻ SDE⁺ patients (P < .05). HIV infection confers distinct clinical phenotypes and immune inflammatory mechanisms in SDE. Sustained EBV and CMV activation, unbalanced Th2/Th1 and overactive CD8⁺ T cells mediating a pro-inflammatory response could act as distinct mechanisms in the aggravation of SDE in HIV⁺ SDE⁺ patients.     

Decreased severity of experimental autoimmune encephalomyelitis during resveratrol administration is associated with increased IL-17+IL-10+ T cells,CD4− IFN-γ+ cells,and decreased macrophage IL-6 expression

Experimental autoimmune encephalomyelitis (EAE), an animal model of Multiple Sclerosis, is induced after injection of PLP_139–151 myelin peptide in complete Freund's adjuvant into SJL/J mice. During EAE, T cells and macrophages infiltrate the brain, produce cytokines IL-17, IFN-γ, TNF-α, or IL-6, and bring about autoimmune neuroinflammation. However, infiltrating T cells which simultaneously produce IL-17 and IL-10 or infiltrating CD4⁻ NKT cells that produce IFN-γ protect against EAE. Resveratrol, a plant polyphenol, exhibits anti-inflammatory properties. To determine if resveratrol can relieve EAE, SJL/J mice were administered diets enriched in resveratrol at EAE injection. EAE symptoms were significantly less compared with controls in mice fed resveratrol. At day 56 of EAE, splenic T cells from mice fed 0%, 0.04% or 0.08% resveratrol that were restimulated with PLP_139–151 produced similar levels while splenic T cells from mice fed 0.02% resveratrol produced significantly higher levels of IL-17, IFN-γ, and TNF-α. At peak EAE (day 14), mice fed resveratrol had higher numbers of IL-17⁺ T cells, IL-17⁺/IL-10⁺ T cells, and CD4⁻IFN-γ ⁺ cells in the brain and spleen compared with controls. Adoptive transfer of day 14 EAE encephalogenic T cells into mice fed resveratrol reduced the severity of EAE. In addition, resveratrol directly suppressed expression of IL-6 and IL-12/23 p40 but increased expression of IL-12 p35 and IL-23 p19 from macrophages. Therefore resveratrol protection against EAE is not associated with declines in IL-17⁺ T cells but is associated with rises in IL-17⁺/IL-10⁺ T cells and CD4^-IFN-γ⁺ and with repressed macrophage IL-6 and IL-12/23 p40 expression.     

2′-fucosyllactose inhibits imiquimod-induced psoriasis in mice by regulating Th17 cell response via the STAT3 signaling pathway

Psoriasis is a chronic immune-mediated inflammatory cutaneous disorder with Th17 cells and Th17-related cytokines playing an important role in its development. 2′-FL (2′-fucosyllactose), which makes up about 30% of all HMOs (human milk oligosaccharides) in blood type secretor positive maternal milk, plays an essential role in supporting aspects of immune development and regulation. To explore the immunomodulatory effect of 2′-FL in psoriasis, we employed the imiquimod (IMQ)-induced psoriasis-like mouse model. Our data showed that mice administered with 2′-FL exhibited attenuated skin damage and inflammation, characterized by significantly decreased erythema and thickness and reduced recruitment of pro-inflammatory cytokines, when compared to control mice. The alleviated skin inflammation in 2′-FL treated mice was associated with a reduced proportion of Th17 cells and decreased production of Th17-related cytokines. Furthermore, we have demonstrated that 2′-FL reduced the phosphorylation of STAT3 in the skin tissue from mice with IMQ stimulation, which could account for the decreasing recruitment of Th17 cells. In vitro studies showed that 2′-FL inhibited differentiation of Th17 cells, phosphorylation of STAT3, and RORγt mRNA levels in T cells under Th17 polarization. Our results indicate that 2′-FL ameliorates IMQ-induced psoriasis by inhibiting Th17 cell immune response and Th17-related cytokine secretion via modulation of the STAT3 signaling pathway.     

Effect of recombinant serine protease from adult stage of Trichinella spiralis on TNBS-induced experimental colitis in mice

Inflammatory bowel disease (IBD), which includes ulcerative colitis (UC) and Crohn’s disease (CD), is a chronic autoimmune disease. At present, worms and their products has been shown to have protective effects on immune-mediated diseases. Therefore, we aimed to investigate the effect of the recombination Trichinella spiralis (T. spiralis, Ts) adult serine protease-like protein rTs-ADSp-7 on a 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced CD mouse model. Colitis was induced by intrarectal administration of a TNBS solution. The disease activity index (DAI), which included weight loss, diarrhoea, and bloody stool, was measured. Colon segments were stained with haematoxylin and eosin (H.E.) for histopathological score. Cytokine release in the serum was analysed by meso scale discovery (MSD). Cytokine release in the colon was detected by ELISA. Splenocytes were separated, and the cytokine profiles of Th1 (IFN-γ), Th2 (IL-4), Th17 (IL-17A) and Treg cells were analysed by flow cytometry. Our result showed that rTs-ADSp-7 reduced the clinical disease activity of TNBS-induced colitis in mice. In addition, we found that rTs-ADSp-7 reduced the production of Th1- and Th17-related cytokines while upregulating the expression of Th2- and Treg-related cytokines in TNBS-induced colitis mice. rTs-ADSp-7 also increased the population of Th2 and Treg cells in TNBS-induced colitis mice. rTs-ADSp-7 alleviated the severity of TNBS-induced colitis while balancing the CD4⁺ T cell immune response. rTs-ADSp-7 has therapeutic potential for colitis treatment and can be used as a helminth-derived protein therapy for CD or other Th1 immunity-mediated diseases.     

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.     

Circulating follicular helper T cells presented distinctively different responses toward bacterial antigens in primary biliary cholangitis

Primary biliary cholangitis (PBC) is a chronic and progressive cholestatic liver disease with unknown causes. The initiation of PBC is associated with bacterial infections and abnormal immune correlates, such as the presence of self-reactive anti-mitochondrial antibodies and shifted balance of T cell subsets. In particular, the CD4⁺ CXCR5⁺ follicular helper T (Tfh) cells are highly activated in PBC patients and are significantly associated with PBC severity, but the underlying reasons are unknown. In this study, we found that the circulating CD4⁺ CXCR5⁺ T cells were enriched with the interferon (IFN)-γ-secreting Th1-subtype and the interleukin (IL)-17-secreting Th17-subtype, but not the IL-4-secreting Th2 subtype. We further demonstrated that a host of microbial motifs, including Pam3CSK4, poly(I:C), LPS, imiquimod, and CpG, could significantly stimulate IFN-γ, IL-17, and/or IL-21 from circulating CD4⁺ CXCR5⁺ T cells in PBC patients, especially in the presence of monocytes and B cells. Whole bacterial cells of Escherichia coli, Novosphingobium aromaticivorans, and Mycobacterium gordonae, could also potently stimulate IFN-γ, IL-17, and/or IL-21 production from circulating CD4⁺ CXCR5⁺ T cells. But interestingly, while the whole cell could potently stimulate circulating CD4⁺ CXCR5⁺ T cells from both healthy controls and PBC patients, the cell protein lysate could only potently stimulate circulating CD4⁺ CXCR5⁺ T cells from PBC patients, but not those from healthy controls, suggesting that circulating CD4⁺ CXCR5⁺ T cells in PBC patients had distinctive antigen-specificity from those in healthy individuals. Together, these data demonstrated that bacterial antigen stimulation is a potential source of aberrant Tfh cell activation in PBC patients.