Superantigen immune stimulation activates epithelial STAT-1 and PI 3-K: PI 3-K regulation of permeability

2000 ◽  
Vol 279 (5) ◽  
pp. G1094-G1103 ◽  
Author(s):  
Derek M. McKay ◽  
Fernando Botelho ◽  
Peter J. M. Ceponis ◽  
Carl D. Richards

Signal transducers and activators of transcription (STATs) are critical intracellular signaling molecules for many cytokines. We compared the ability of T84 epithelial cells to activate STATs in response to cytokines [interferon-γ (IFN-γ), interleukin (IL)-4, IL-10, and tumor necrosis factor-α (10 ng/ml)] and conditioned medium from superantigen [ Staphylococcus aureus enterotoxin B (SEB)]-activated peripheral blood mononuclear cells (PBMC) using electrophoretic mobility shift assays (EMSA). Of the cytokines tested, only IFN-γ caused a STAT-1 response. Exposure to SEB-PBMC-conditioned medium resulted in STAT-1 or STAT-1/3 activation, and inclusion of anti-IFN-γ antibodies in the conditioned medium abolished the STAT-1 signal. Cells treated with transcription factor decoys, DNA oligonucleotides bearing the STAT-1 recognition motif, and then SEB-PBMC-conditioned medium displayed a reduced STAT-1 signal on EMSA, yet this treatment did not prevent the drop in transepithelial resistance (measured in Ussing chambers) caused by SEB-PBMC-conditioned medium. In contrast, the phosphatidylinositol 3′-kinase (PI 3-K) inhibitor LY-294002 significantly reduced the drop in transepithelial resistance caused by SEB-PBMC-conditioned medium. Thus data are presented showing STAT-1 (±STAT-3) and PI 3-K activation in epithelial cells in response to immune mediators released by superantigen immune activation. Although the involvement of STAT-1/-3 in the control of barrier function remains a possibility, PI-3K has been identified as a regulator of T84 paracellular permeability.

1999 ◽  
Vol 10 (10) ◽  
pp. 2171-2176 ◽  
Author(s):  
BRUNO MEMOLI ◽  
LUIGI MARZANO ◽  
VINCENZO BISESTI ◽  
MICHELE ANDREUCCI ◽  
BRUNA GUIDA

Abstract. Interleukin-12 (IL-12) is a cytokine produced by peripheral blood mononuclear cells (PBMC) that causes interferon-γ (IFN-γ) production and enhancement of cell-mediated cytotoxicity. To clarify the role of hemodialysis biocompatibility on IL-12 production and uremic immunodeficiency, we have studied the IL-12 and IFN-γ release by PBMC harvested from 12 patients dialyzed with cuprophan membrane (CU), eight patients dialyzed with polymethylmethacrylate membrane (PMMA), and eight nondialyzed uremic patients (UR). Ten healthy subjects constituted the control group (CON). PBMC were cultured for 48 h with and without nonspecific mitogen stimulation. In unstimulated conditions, CU showed an IL-12 PBMC production higher than CON, UR, and PMMA (46.67 ± 30.13versus2.56 ± 1.38, 6.16 ± 7.09, and 4.62 ± 4.76 pg/ml, respectively;P< 0.01). IL-12 production was correlated with C3a concentration measured at the outlet of hemodialyzer after 15 min of dialysis (r= 0.69,P< 0.01). IL-12 release in CU remained unchanged under mitogen stimulation (44.34 ± 23.86 pg/ml) and was lower than in CON, UR, and PMMA (66.0 ± 12.41, 68.37 ± 25.78, and 67.75 ± 22.61 pg/ml, respectively;P< 0.05). IFN-γ production was similar, in unstimulated conditions, in all groups. Under stimulation, IFN-γ release was lower in CU (13.42 ± 12.04 IU/ml) than in CON, UR, and PMMA (51.84 ± 30.74, 32.16 ± 13.86, and 32.16 ± 13.86 IU/ml, respectively;P< 0.01). These results demonstrate that hemodialysis with CU induces monocyte activation with an enhanced release of IL-12. On the contrary, stimulated PBMC production of both IL-12 and IFN-γ is lower in these patients than in CON, UR, and PMMA. The altered release of these cytokines could play a role in cell-mediated immunodeficiency of the uremic patients dialyzed with CU.


Gut ◽  
1998 ◽  
Vol 42 (5) ◽  
pp. 643-649 ◽  
Author(s):  
M Carol ◽  
A Lambrechts ◽  
A Van Gossum ◽  
M Libin ◽  
M Goldman ◽  
...  

Background—Cytokines secreted by intestinal T lymphocytes probably play a critical role in regulation of the gut associated immune responses.Aims—To quantify interferon γ (IFN-γ) and interleukin 4 (IL-4) secreting cells (SC) among human intraepithelial (IEL) and lamina propria (LPL) lymphocytes from the duodenum and right colon in non-pathological situations and in the absence of in vitro stimulation.Patients—Duodenal and right colonic biopsy specimens were obtained from patients with no inflammation of the intestinal mucosa.Methods—Intraepithelial and lamina propria cell suspensions were assayed for numbers of cells spontaneously secreting IFN-γ and IL-4 by a two site reverse enzyme linked immunospot technique (ELISPOT).Results—The relatively high proportion of duodenal lymphocytes spontaneously secreting IFN-γ (IEL 3.6%; LPL 1.9%) and IL-4 (IEL 1.3%; LPL 0.7%) contrasted with the very low numbers of spontaneously IFN-γ SC and the absence of spontaneously IL-4 SC among peripheral blood mononuclear cells. In the basal state, both IFN-γ and IL-4 were mainly produced by CD4+ cells. Within the colon, only 0.2% of IEL and LPL secreted IFN-γ in the basal state, and 0.1% secreted IL-4.Conclusions—Compared with peripheral lymphocytes substantial proportions of intestinal epithelial and lamina propria lymphocytes spontaneously secrete IFN-γ and/or IL-4. These cytokines are probably involved in the normal homoeostasis of the human intestinal mucosa. Disturbances in their secretion could play a role in the pathogenesis of gastrointestinal diseases.


2019 ◽  
Author(s):  
Maryana Stephany Ferreira Branquinho ◽  
Maysa Braga Barros Silva ◽  
Renan Orsati Clara ◽  
Ariane Rivellis Julio ◽  
Silvya Stuchi Maria Engler ◽  
...  

AbstractThe inhibition of the enzyme indoleamine-2,3-dioxygenase (IDO), that catalyzes the oxidation of the amino acid tryptophan to kynurenine (KYN), is considered a good target for immunoadjuvants in antineoplastic therapy. 1-Methyl-tryptophan (1-MT) is the most studied molecule for this purpose. Although L-1-MT is better than D-1-MT in inhibiting IDO, for an unknown reason the D-enantiomer has higher clinical efficacy. Here we took advantage of co-cultures of tumor cells (SK-Mel 19 melanoma line; 1×105 cells/well) with peripheral blood mononuclear cells (PBMC; 5×106 cells/well) to verify the effect of 1-MT enantiomers on cytokine production and tumoricidal activity. At a concentration that did not affect KYN production, 1-MT (50 µM) affected the production of TNF-α, IL-10, and IFN-γ measured in co-cultures supernatants. Stereospecificity was only observed for IFN-γ production. D-1-MT inhibited more than 30% of IFN-γ production, while L-1-MT had no effect. Stereospecific effect was also seen in PBMC tumoricidal activity, estimated by tumor cell viability (Trypan assay). The racemic mixture DL- and D-1-MT almost doubled the tumoricidal activity of PBMCs, while L-1-MT had no effect. These are previous unknown off-target effects of D-1-MT. Our data suggest the modulation of IFN-γ and the activation of tumor recognition and killing processes by immune cells as important features for the in vivo effects of the D-1-MT. These findings should be considered in future studies of immunoadjuvants for cancer treatment.


2016 ◽  
Vol 25 (12) ◽  
pp. 2259-2268 ◽  
Author(s):  
Vaihere Delaune ◽  
Christian Toso ◽  
Pierre-Yves Benhamou ◽  
Anne Wojtusciszyn ◽  
Laurence Kessler ◽  
...  

Islet transplantation is an effective treatment for selected patients with type 1 diabetes. However, an accurate test still lacks for the early detection of graft rejection. Blood samples were prospectively collected in four university centers (Geneva, Grenoble, Montpellier, and Strasbourg). Peripheral blood mononuclear cells were stimulated with donor splenocytes in the presence of interleukin-2. After 24 h of incubation, interferon-γ (IFN-γ) ELISpot analysis was performed. After a total of 5 days of incubation, cell proliferation was assessed by fluorescence-activated cell sorting (FACS) analysis for Ki-67. Immunological events were correlated with adverse metabolic events determined by loss of ≥1 point of β-score and/or an increased insulin intake ≥10%. Twenty-five patients were analyzed; 14 were recipients of islets alone, and 11 combined with kidney. Overall, 76% (19/25) reached insulin independence at one point during a mean follow-up of 30.7 months. IFN-γ ELISpot showed no detectable correlation with adverse metabolic events [area under the curve (AUC) = 0.57]. Similarly, cell proliferation analysis showed no detectable correlation with adverse metabolic events (CD3+/ CD4+ AUC = 0.54; CD3+/CD8+ AUC = 0.55; CD3-/CD56+ AUC = 0.50). CD3-/CD56+ cell proliferation was significantly higher in patients with combined kidney transplantation versus islet alone (6 months, p = 0.010; 12 months, p = 0.016; and 24 months, p = 0.018). Donor antigen-stimulated IFN-γ production and cell proliferation do not predict adverse metabolic events after islet transplantation. This suggests that the volume of transplanted islets is too small to produce a detectable systemic immune response and/or that alloimmune rejection is not the sole reason for the loss of islet graft function.


Blood ◽  
2009 ◽  
Vol 113 (4) ◽  
pp. 827-836 ◽  
Author(s):  
Markus Kleinewietfeld ◽  
Mireille Starke ◽  
Diletta Di Mitri ◽  
Giovanna Borsellino ◽  
Luca Battistini ◽  
...  

Abstract The adoptive transfer of regulatory Foxp3+ T (Treg) cells has been shown in various animal models to prevent inflammatory immune and autoimmune diseases. Translation into therapeutic applications, however, is hindered by the lack of suitable techniques and markers. CD25, commonly used to isolate Treg cells from mice, has only limited value in humans as it is also present on proinflammatory CD4+ effector cells. Here we show that clean populations of human Foxp3+ Treg cells can be obtained with antibodies directed against CD49d. The marker is present on proinflammatory peripheral blood mononuclear cells but is absent on immune-suppressive Treg cells. Depletion with α-CD49d removes contaminating interferon-γ (IFN-γ)– and interleukin-17 (IL-17)–secreting cells from Treg preparations of CD4+CD25high cells. More importantly, in combination with α-CD127 it allows the isolation of “untouched” Foxp3+ Treg (ie, cells that have not been targeted by an antibody during purification). The removal of CD49d+/CD127+ cells leaves a population of Foxp3+ Treg virtually free of contaminating CD25+ effector cells. The cells can be expanded in vitro and are effective suppressors both in vitro and in vivo. Thus, CD49d provides access to highly pure populations of untouched Foxp3+ Treg cells conferring maximal safety for future clinical applications.


2005 ◽  
Vol 33 (04) ◽  
pp. 559-571 ◽  
Author(s):  
Andy Sun ◽  
Jean-San Chia ◽  
Won-Bo Wang ◽  
Chun-Pin Chiang

Recurrent aphthous ulcerations (RAU) represent a common oral mucosal disease with altered humoral and cellular immunities. Tien-Hsien liquid (THL) is an extract of Chinese medicinal herbs with immunomodulating effects. Our previous study found that THL can modulate the antigen-stimulated proliferative response of peripheral blood mononuclear cells and T-cells isolated from RAU patients. In this study, we further tested whether THL can modulate the antigen-stimulated cytokine production by T-cells isolated from RAU patients. To achieve this goal, T-cells isolated from 19 RAU patients were incubated with phytohemagglutinin (PHA), glutaraldehyde-inactivated tetanus toxoid (TT), glucosyltransferase D (GtfD), or antigens of Streptococcus mutans in the presence or absence of THL. The levels of interleukin (IL)-2, interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), IL-6, or IL-10 in the supernatants of T-cell cultures were measured by cytokine enzyme-linked immunosorbent assay (ELISA) kits. We found that THL significantly increased the PHA- or TT-stimulated TNF-α, IL-6, and IL-10 production by T-cells isolated from RAU patients. However, THL could also significantly decrease the TT-stimulated IL-2 production, the GtfD-stimulated IL-2, TNF-α, IL-6 and IL-10 production, and the S. mutans-stimulated IFN-γ, TNF-α, and IL-10 production by T-cells isolated from RAU patients. These results indicate that THL can modulate the antigen-stimulated cytokine production by T-cells isolated from RAU patients. Because RAU is probably a Thl-mediated disease with elevated levels of IL-2, IFN-γ, TNF-α and IL-6 in either the patient's sera or oral lesions and these increased levels of cytokines can be reduced by THL, we suggest that THL may be a potential immunoceutical agent for treatment of RAU.


2011 ◽  
Vol 106 (8) ◽  
pp. 1216-1223 ◽  
Author(s):  
T. Pozo-Rubio ◽  
J. R. Mujico ◽  
A. Marcos ◽  
E. Puertollano ◽  
I. Nadal ◽  
...  

Bifidobacterium spp. typical of the human intestinal microbiota are believed to influence the balance of immune responses in the intestinal mucosa. The aim of the present study was to investigate the effect of different bifidobacterial species and their mixtures in in vitro experiments with peripheral blood mononuclear cells (PBMC) and Caco-2 cells. Bifidobacterium adolescentis, B. angulatum, B. breve, B. catenulatum, B. infantis, B. longum and two combinations of these bifidobacteria simulating the species composition found in faecal samples from breast-fed (BF) and formula-fed (FF) infants were used. The levels of several cytokines were measured by direct stimulation of PBMC and by stimulation of a Caco-2/PBMC co-culture with bifidobacteria. B. catenulatum and B. breve were the strongest enhancers of interferon-γ (IFN-γ) production by direct stimulation of PBMC. B. longum was the highest inducer of IL-10 and the lowest TNF-α stimulus. In the Caco-2/PBMC system, B. breve was the highest inducer of IL-8 production by Caco-2 cells, significantly different from B. infantis, B. adolescentis and the FF mixture (P < 0·05). IFN-γ produced by PBMC stimulated with the BF mixture (containing 22 % B. breve, compared with 7 % in the FF mixture) was significantly higher compared with B. adolescentis, B. infantis and B. longum. B. adolescentis also inhibited IFN-γ production compared with the FF mixture and B. longum. The proportion of different Bifidobacterium strains seems to be an important determinant of the cytokine balance in the simulated intestinal environment studied. B. breve and the combination of the Bifidobacterium species typically found in the microbiota of BF infants have shown the most significant effects.


2020 ◽  
Vol 11 (1) ◽  
pp. 76-85
Author(s):  
Gunjan Kak ◽  
Brijendra K Tiwari ◽  
Yogendra Singh ◽  
Krishnamurthy Natarajan

AbstractInterferon-gamma (IFN-γ) is a key cytokine that mediates immunity to tuberculosis (TB). Mycobacterium tuberculosis (M. tb) is known to downregulate the surface expression of IFN-γ receptor (IFN-γR) on macrophages and peripheral blood mononuclear cells (PBMCs) of patients with active TB disease. Many M. tb antigens also downmodulate IFN-γR levels in macrophages when compared with healthy controls. In the current study, we aimed at deciphering key factors involved in M. tb mediated downregulation of IFN-γR levels on macrophage surface. Our data showed that both M. tb H37Rv and M. bovis BCG infections mediate downmodulation of IFN-γR on human macrophages. This downmodulation is regulated at the level of TLR signaling pathway, second messengers such as calcium and cellular kinases i.e. PKC and ERK-MAPK, indicating that fine tuning of calcium response is critical to maintaining IFN-γR levels on macrophage surface. In addition, genes in the calcium and cysteine protease pathways which were previously identified by us to play a negative role during M. tb infection, also regulated IFN-γR expression. Thus, modulations in IFN-γR levels by utilizing host machinery may be a key immune suppressive strategy adopted by the TB pathogen to ensure its persistence and thwart host defense.


2000 ◽  
Vol 192 (9) ◽  
pp. 1373-1380 ◽  
Author(s):  
Masafumi Nakayama ◽  
Nobuhiko Kayagaki ◽  
Noriko Yamaguchi ◽  
Ko Okumura ◽  
Hideo Yagita

TWEAK, a new member of the tumor necrosis factor (TNF) family, induces cell death in some tumor cell lines, but its physiological functions are largely unknown. In this study, we investigated the expression and function of TWEAK in human peripheral blood mononuclear cells (PBMCs) by using newly generated anti–human TWEAK mAbs. Although freshly isolated PBMCs expressed no detectable level of TWEAK on their surfaces, a remarkable TWEAK expression was rapidly observed on monocytes upon stimulation with interferon (IFN)-γ but not with IFN-α or lipopolysaccharide. Cytotoxic activity of IFN-γ–stimulated monocytes against human squamous carcinoma cell line HSC3 was inhibited partially by anti-TWEAK mAb alone and almost completely by combination with anti-TRAIL (TNF-related apoptosis-inducing ligand) mAb. These results revealed a novel pathway of monocyte cytotoxicity against tumor cells that is mediated by TWEAK and potentiated by IFN-γ.


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