MHC class II antigen presentation by intestinal epithelial cells fine-tunes bacteria-reactive CD4 T cell responses.

Although intestinal epithelial cells (IECs) can express major histocompatibility complex class II (MHC II), especially during intestinal inflammation, it remains unclear if antigen presentation by IECs favours pro- or anti-inflammatory CD4+ T cell responses. Using selective gene ablation of MHC II in IECs and IEC organoid cultures, we assessed the impact of MHC II expression by IECs on CD4+ T cell responses and disease outcomes in response to enteric bacterial pathogens. We found that intestinal bacterial infections elicit inflammatory cues that greatly increase expression of MHC II processing and presentation molecules in colonic IECs. Whilst IEC MHC II expression had little impact on disease severity following Citrobacter rodentium or Helicobacter hepaticus infection, using a colonic IEC organoid-CD4+ T cell co-culture system, we demonstrate that IECs can activate antigen-specific CD4+ T cells in an MHC II-dependent manner, modulating both regulatory and effector Th cell subsets. Furthermore, we assessed adoptively transferred H. hepaticus-specific CD4+ T cells during intestinal inflammation in vivo and report that IEC MHC II expression dampens pro-inflammatory effector Th cells. Our findings indicate that IECs can function as non-conventional antigen presenting cells and that IEC MHC II expression fine-tunes local effector CD4+ T cell responses during intestinal inflammation.

The role of toll-like receptor 4 in cisplatin-induced renal injury.

BACKGROUND: Toll-like receptors recognize pattern-associated molecules found in pathogens as well as in endogen cells and in matrix degradation products. Despite the effectiveness of cisplatin against various solid tumors the administered dose is limited by its nephrotoxicity, namely, induction of tubular cell apoptosis. Herein, we investigated whether the cell toxicity of cisplatin was mediated by toll-like receptor 4 signaling. METHODS: C3H/He J (Toll-like receptor 4 deficient) and C3H/HePas (control) were treated with cisplatin (20 mg/kg). We evaluated renal function as well as expression of (HO-1) heme oxygenase 1 and MCP-1 mRNAs. RESULTS: Animals deficient in Toll-like receptor 4 showed less renal dysfunction after cisplatin therapy, which was more evident at later time points. Moreover, MCP-1 mRNA expression in kidneys from these animals were lower than controls, mainly at 96 hours after treatment. No differences were seen in HO-1 mRNA expression. CONCLUSIONS: These results suggested that cisplatin-induced renal toxicity is mediated in part though toll-like receptor 4.

A role for HO-1 in renal function impairment in animals subjected to ischemic and reperfusion injury and treated with immunosuppressive drugs.

INTRODUCTION: Ischemia/reperfusion injury (IRI) represents the single major antigen-independent factor implicated in pathogenesis of chronic graft dysfunction. Tacrolimus is a calcineurin inhibitor, which has been suggested to be helpful in cyclosporine-related chronic toxicity. Rapamycin has antiproliferative properties that may impair renal regeneration after IRI. Therefore, immunosuppressive drugs might impair renal graft outcome in those organs suffering IRI. MATERIAL AND METHODS: C57B1/6 male mice subjected to 45 minutes of renal pedicle ligation were reperfused for 24 hours. Mice were treated with rapamycin, cyclosporine, or tacrolimus. Blood and renal tissue samples were collected at 24 hours after IRI. Urea levels were measured. Heme Oxygenase 1 (HO-1) gene transcript was amplified by a real-time polymerase chain reaction technique. RESULTS: Animals treated with cyclosporine and subjected to IRI showed impaired renal function that peaked at 24 hours. Additional pretreatment with rapamycin produced even more impairment of renal function, when compared with controls. However, tacrolimus pretreatment was associated with a better renal outcome. HO-1 expression was upregulated after IRI by 2.6 arbitrary units at 24 hours. Rapamycin showed worse impairment of renal function. CONCLUSION: Tacrolimus was not associated with worsening renal function when compared with animals just subjected to IRI. Upregulation of HO-1 may be an attractive approach to limit graft injury.

The effects of rapamycin in the progression of renal fibrosis.

UNLABELLED: Renal fibrosis is a hallmark of end-stage renal diseases and of chronic allograft nephropathy (CAN). Rapamycin, besides its action through blockade of lymphocyte proliferation, also has antiproliferative, antiviral, and antitumor actions. Its use in clinical in patients with CAN has recently been advocated. OBJECTIVES: Our goal was to evaluate the effect of rapamycin in an established model of renal fibrosis, unilateral ureteral obstruction. MATERIALS AND METHODS: C57BL/6 mice were divided into two groups, treated or not with daily doses of rapamycin (0.2 mg/kg) beginning on day-1. The obstruction was performed as day 0. Blood and kidney tissues were collected at 1, 4, 7, and 14 days after the surgery to quantify bone morphogenic protein (BMP)-7 and transforming growth factor (TGF)-beta mRNA by real time PCR. RESULTS: Daily treatment with rapamycin caused a significant reduction in serum creatinine at day 1 (0.57 +/- 0.03 vs 0.95 +/- 0.15 mg/dL, P = .002) and at day 14 (0.56 +/- 0.04 vs 0.73 +/- 0.07 mg/dL, P = .040). This profile was corroborated by histological morphometric analyses showing less fibrosis at day 14. However, rapamycin surprisingly induced an upregulation of TGF-beta at day 4 (3.05 +/- 0.46 vs 1.85 +/- 0.41, P = .006) and at day 7 (6.33 +/- 0.55 vs 4.97 +/- 0.38, P = .024) with a reduced expression by day 14 (4.03 +/- 1.07 vs 7.89 +/- 0.83, P < .001). Surprisingly, rapamycin also promoted an increment in BMP-7, completely reversing the ratio of TGF-beta to BMP-7, allowing a more protective phenotype. CONCLUSION: Rapamycin slightly ameliorated the renal dysfunction and, at later time points, induced less fibrosis and less decrease in the TGF-beta to BMP-7 ratio.

Validation of ELISA methods for quantification of the major birch allergen Bet v 1 (BSP090).

To date, the potency of allergen products in Europe is expressed in manufacturer-specific units relative to a product-specific in-house reference. Consequently, cross-product comparability of allergen products from different manufacturers with respect to strength and efficacy is impossible. The Biological Standardisation Programme (BSP) project BSP090 addresses this issue via the establishment of reference standards in conjunction with ELISA methods for the quantification of major allergens in allergen products. Since the initiation of BSP090, the recombinant major allergen Bet v 1 has been adopted by the European Pharmacopoeia Commission as a Chemical Reference Substance (CRS). In parallel, two sandwich ELISA systems for quantification of Bet v 1 were found suitable in preliminary phases of BSP090 to be validated in a large collaborative study. In this study, the candidate ELISA systems were compared with respect to accuracy, precision and variability. Thirteen participating laboratories tested model samples containing the CRS as well as spiked and unspiked birch pollen extracts. Both in pre-testing and in the collaborative study, the 2 candidate ELISA systems confirmed their suitability to quantify recombinant and native Bet v 1. As no clear-cut decision for one of the ELISA systems could be made based on the results of the collaborative study, a post-study testing was performed. Bet v 1 content of 30 birch pollen allergen products was determined in parallel in both ELISA systems. Consequently, 1 candidate ELISA system was selected to be proposed as the future European Pharmacopoeia standard method for Bet v 1 quantification.

Protective effect of trifluoperazine on the mitochondrial damage induced by Ca2+ plus prooxidants.

Isolated rat liver mitochondria undergo extensive swelling and disruption of membrane potential when they accumulate Ca2+ in the presence of a prooxidant such as diamide or t-butylhydroperoxide. The phenothiazinic drug trifluoperazine, at concentrations (15-35 microM) which do not inhibit respiration or the influx of Ca2+ into mitochondria, significantly protected mitochondria against the deleterious effects of Ca2+ plus a prooxidant. In contrast, at concentrations higher than 100 microM the drug potentiated these deleterious effects of Ca2+ and prooxidants and had a damaging effect per se on the inner mitochondrial membrane. It is proposed that the protection conferred by the drug is mediated by changes in membrane protein structure that decrease the production of protein thiol cross-linkings which occur when mitochondria accumulate calcium under oxidant stress conditions.

The role of heme oxygenase 1 in rapamycin-induced renal dysfunction after ischemia and reperfusion injury.

Ischemia and reperfusion injury (IRI) is the main etiology of acute renal failure in native and transplanted kidneys. In the transplantation field, immunosuppressive drugs may play an additional role in acute graft dysfunction. Rapamycin may impair renal regeneration post IRI. Heme oxygenase 1 (HO-1) is a protective gene with anti-inflammatory and anti-apoptotic actions. We investigated whether HO-1 played a role in rapamycin-induced renal dysfunction in an established model of IRI. Rapamycin (3 mg/kg) was administered to mice before being subjected to 45 min of ischemia. Animals subjected to IRI presented with impaired renal function that peaked at 24 h (2.05+/-0.23 mg/dl), decreasing thereafter. Treatment with rapamycin caused even more renal dysfunctions (2.30+/-0.33 mg/dl), sustained up to 120 h after reperfusion (1.54+/-0.4 mg/dl), when compared to the control (0.63+/-0.09 mg/dl, P<0.05). Rapamycin delayed tubular regeneration that was normally higher in the control group at day 5 (68.53+/-2.30 vs 43.63+/-3.11%, P<0.05). HO-1 was markedly upregulated after IRI and its expression was even enhanced by rapamycin (1.32-fold). However, prior induction of HO-1 by cobalt protoporphyrin improved the renal dysfunction imposed by rapamycin, mostly at later time points. These results demonstrated that rapamycin used in ischemic-injured organs could also negatively affect post-transplantation recovery. Modulation of HO-1 expression may represent a feasible approach to limit rapamycin acute toxicity.

[Non-polio enterovirus in France from 1974 to 1985. Data collected from a system of 30 hospital virology laboratories]. / Les enterovirus non poliomyélitiques en France de 1974 à 1985. Données recueillies à partir d'un réseau de trente laboratories hospitaliers de virologie.

A total of 12,097 isolates of NPEV was reported in France from 1974 through 1985 by 30 volunteers laboratories (71% of all virology laboratories). The 14 most common types which accounted for 75% of all isolates are echoviruses 4, 6, 7, 9, 11, 14, 30 and 33, coxsackieviruses A9, B1 to B5. Among them, 12 are equally reported as the most common types isolated in the United States from 1970 through 1983. Echoviruses 14 and 33 are specially found in France; Echoviruses 3 and 5 in the United States. We can estimate that those 16 types are the most common EVNP in human pathology. The pattern of each type is different in the United States and in France: it seems not possible to assign an epidemic character specific to each of them. Yet epidemic types accounted for 13 to 27% of isolates in March, April, May. Among clinical manifestations, aseptic meningitis are the most frequently reported: 37% of 3,619 cases. Echoviruses are significantly most often associated with meningitis than coxsackieviruses (p less than 0.001) and coxsackieviruses more often associated with other neurological manifestations, myocarditis and pericarditis. From these results wa can suggest to simplify the typing procedures of NPEV for routine diagnosis.

Dynamics of tearing modes during strong electron cyclotron heating on the FTU tokamak.

The localized electron cyclotron resonance heating power that can suppress sawteeth reconnection often drives m = 2 tearing modes in a tokamak operating at constant current. The dynamics of mode onset and coupled mode evolution is described in detail and compared with a nonlinear theoretical model that identifies the effects of mode coupling, finite inertia of the rotating islands, and wall braking.