A method to define a minimum-phase transfer function within the bounded region of phase-gain specifications

Method to define minimum phase transfer function within bounded region of phase gain specifications at several discrete frequencie

Year-Round Forage Systems for Beef Cows and Calves

Beef cow systems in the USA are based on forages with little or no concentrates fed. Tall fescue (Festuca arundinacea Schreb. L.) is one of the important pasture forages in the lower Northeast and upper South (Allen et al., 2001). Limited research has been conducted on year-round all forage systems based on cool season forages. Stockpiling tall fescue in late summer-early fall provides good quality forage that is usually grazed rather than harvested. Forage systems including tall fescue and clover (Trifolium repens L.) produced excellent performance in beef cows and calves, with minimum inputs (Allen et al., 2001). The present experiment is a component of a larger initiative, Pasture-based Forage Systems for Appalachia. The specific objective of this experiment is to evaluate different forage systems for beef cows and calves

Expression of Foxp3 in colorectal cancer but not in Treg cells correlates with disease progression in patients with colorectal cancer

Background: Regulatory T cells (Treg) expressing the transcription factor forkhead-box protein P3 (Foxp3) have been identified to counteract anti-tumor immune responses during tumor progression. Besides, Foxp3 presentation by cancer cells itself may also allow them to evade from effector T-cell responses, resulting in a survival benefit of the tumor. For colorectal cancer (CRC) the clinical relevance of Foxp3 has not been evaluated in detail. Therefore the aim of this study was to study its impact in colorectal cancer (CRC). Methods and Findings: Gene and protein analysis of tumor tissues from patients with CRC was performed to quantify the expression of Foxp3 in tumor infiltrating Treg and colon cancer cells. The results were correlated with clinicopathological parameters and patients overall survival. Serial morphological analysis demonstrated Foxp3 to be expressed in cancer cells. High Foxp3 expression of the cancer cells was associated with poor prognosis compared to patients with low Foxp3 expression. In contrast, low and high Foxp3 level in tumor infiltrating Treg cells demonstrated no significant differences in overall patient survival. Conclusions: Our findings strongly suggest that Foxp3 expression mediated by cancer cells rather than by Treg cells contribute to disease progression

Methylation matters: binding of Ets-1 to the demethylated Foxp3 gene contributes to the stabilization of Foxp3 expression in regulatory T cells

The forkhead-box protein P3 (Foxp3) is a key transcription factor for the development and suppressive activity of regulatory T cells (Tregs), a T cell subset critically involved in the maintenance of self-tolerance and prevention of over-shooting immune responses. However, the transcriptional regulation of Foxp3 expression remains incompletely understood. We have previously shown that epigenetic modifications in the CpG-rich Treg-specific demethylated region (TSDR) in the Foxp3 locus are associated with stable Foxp3 expression. We now demonstrate that the methylation state of the CpG motifs within the TSDR controls its transcriptional activity rather than a Treg-specific transcription factor network. By systematically mutating every CpG motif within the TSDR, we could identify four CpG motifs, which are critically determining the transcriptional activity of the TSDR and which serve as binding sites for essential transcription factors, such as CREB/ATF and NF-κB, which have previously been shown to bind to this element. The transcription factor Ets-1 was here identified as an additional molecular player that specifically binds to the TSDR in a demethylation-dependent manner in vitro. Disruption of the Ets-1 binding sites within the TSDR drastically reduced its transcriptional enhancer activity. In addition, we found Ets-1 bound to the demethylated TSDR in ex vivo isolated Tregs, but not to the methylated TSDR in conventional CD4+ T cells. We therefore propose that Ets-1 is part of a larger protein complex, which binds to the TSDR only in its demethylated state, thereby restricting stable Foxp3 expression to the Treg lineage

GENN: A GEneral Neural Network for Learning Tabulated Data with Examples from Protein Structure Prediction

We present a GEneral Neural Network (GENN) for learning trends from existing data and making predictions of unknown information. The main novelty of GENN is in its generality, simplicity of use, and its specific handling of windowed input/output. Its main strength is its efficient handling of the input data, enabling learning from large datasets. GENN is built on a two-layered neural network and has the option to use separate inputs–output pairs or window-based data using data structures to efficiently represent input–output pairs. The program was tested on predicting the accessible surface area of globular proteins, scoring proteins according to similarity to native, predicting protein disorder, and has performed remarkably well. In this paper we describe the program and its use. Specifically, we give as an example the construction of a similarity to native protein scoring function that was constructed using GENN. The source code and Linux executables for GENN are available from Research and Information Systems at http://mamiris.com and from the Battelle Center for Mathematical Medicine at http://mathmed.org. Bugs and problems with the GENN program should be reported to EF

Helios Expression Is a Marker of T Cell Activation and Proliferation

Foxp3+ T-regulatory cells (Tregs) normally serve to attenuate immune responses and are key to maintenance of immune homeostasis. Over the past decade, Treg cells have become a major focus of research for many groups, and various functional subsets have been characterized. Recently, the Ikaros family member, Helios, was reported as a marker to discriminate naturally occurring, thymic-derived Tregs from those peripherally induced from naïve CD4+ T cells. We investigated Helios expression in murine and human T cells under resting or activating conditions, using well-characterized molecules of naïve/effector/memory phenotypes, as well as a set of Treg-associated markers. We found that Helios-negative T cells are enriched for naïve T cell phenotypes and vice versa. Moreover, Helios can be induced during T cell activation and proliferation, but regresses in the same cells under resting conditions. We demonstrated comparable findings using human and murine CD4+Foxp3+ Tregs, as well as in CD4+ and CD8+ T cells. Since Helios expression is associated with T cell activation and cellular division, regardless of the cell subset involved, it does not appear suitable as a marker to distinguish natural and induced Treg cells

Phenotypic and Functional Properties of Helios+ Regulatory T Cells

Helios, an Ikaros family transcription factor, is preferentially expressed at the mRNA and protein level in regulatory T cells. Helios expression previously appeared to be restricted to thymic-derived Treg. Consistent with recent data, we show here that Helios expression is inducible in vitro under certain conditions. To understand phenotypic and functional differences between Helios+ and Helios− Treg, we profiled cell-surface markers of FoxP3+ Treg using unmanipulated splenocytes. We found that CD103 and GITR are expressed at high levels on a subset of Helios+ Treg and that a Helios+ Treg population could be significantly enriched by FACS sorting using these two markers. Quantitative real-time PCR (qPCR) analysis revealed increased TGF-β message in Helios+ Treg, consistent with the possibility that this population possesses enhanced regulatory potential. In tumor-bearing mice, we found that Helios+ Treg were relatively over-represented in the tumor-mass, and BrdU studies showed that, in vivo, Helios+ Treg proliferated more than Helios− Treg. We hypothesized that Helios-enriched Treg might exert increased suppressive effects. Using in vitro suppression assays, we show that Treg function correlates with the absolute number of Helios+ cells in culture. Taken together, these data show that Helios+ Treg represent a functional subset with associated CD103 and GITR expression

Partial Depletion of Natural CD4+CD25+ Regulatory T Cells with Anti-CD25 Antibody Does Not Alter the Course of Acute Influenza A Virus Infection

Foxp3+ CD4+ regulatory T cells represent a T cell subset with well-characterized immunosuppressive effects during immune homeostasis and chronic infections, and there is emerging evidence to suggest these cells temper pulmonary inflammation in response to acute viral infection. Recent studies have demonstrated treatment with PC61 CD25-depleting antibody potentiates inflammation in a murine model of RSV infection, while paradoxically delaying recruitment of CD8+ T cells to the site of inflammation. The present study therefore sought to examine the role of these cells in a murine model of acute influenza A virus infection through the administration of PC61 CD25-depleting antibody. PC61 antibody is able to partially deplete CD25+Foxp3+ regulatory T cells to a comparable degree as seen within previous work examining RSV, however this does not alter influenza A-virus induced mortality, weight loss, viral clearance and cellularity within the lung. Collectively, these data demonstrate that partial depletion of CD4+CD25+ regulatory T cells with PC61 antibody does not alter the course of influenza A virus infection