Ubiquitous Self Research Articles

Organoboron luminophores with extremely strong dual–phase emissions

Developing efficient dual–phase emission emitters upon organoboron luminophores remains a formidable challenge due to the ubiquitous self–absorption and deleterious π-π interactions from aromatic structure. Here, a new family of benzothiazole–enolate–based organoboron luminophores (HN1–4) with effective dual–phase emission was constructed. HN4 showed almost the highest quantum yield (QY) among this type of compound so far. The three-ring–fused rigid skeleton and moderate intramolecular charge transfer (ICT) effect ensured that HN4 could give rise to extremely strong emission in any solution (QY up to 99%). X-ray crystallographic analysis showed that the twisted core structure constructed by the boronic coordination of two penta-fluorobenzene of HN4 was responsible for intense emission in the solid state (QY up to 68%). Besides, HN4 exhibited a unique response to mechanical force accompanied by a reversible change of the QY. We believe that this strategy provides beneficial inspiration and methodology to design materials with high emissive quantum yield that can be used in a variety of luminescent events.

Opposing peripheral fates of tissue-restricted self antigen-specific conventional and regulatory CD4+ T cells.

The development of self antigen-specific T cells is influenced by how the self antigen is expressed. Here, we created a mouse in which a model self antigen is conditionally expressed in different tissue environments. Using peptide:MHCII tetramer-based cell enrichment methods, we examined the development of corresponding endogenous self antigen-specific CD4+ T cell populations. While ubiquitous self antigen expression resulted in efficient deletion of self antigen-specific T cells in the thymus, some tissue-restricted expression patterns resulted in partial deletion of the population in peripheral lymphoid organs. Deletion specifically affected Foxp3- conventional T cells (Tconv) with a bias towards high avidity TCR expressing cells in the case of thymic, but not peripheral deletion. In contrast, Foxp3+ Treg exhibited elevated frequencies with increased TCR avidity. T cells surviving deletion were functionally impaired, with Tconv cells exhibiting more impairment than Tregs. Collectively, our results illustrate how postthymic recognition of tissue-restricted self antigens results in opposing developmental fates for Tconv and Treg cell subsets.

Analysis of a token density metric for concern detection in Matlab sources using UbiSOM

AbstractMatrix and data manipulation programming languages are an essential tool for data analysts. However, these languages are often unstructured and lack modularity mechanisms. This article presents a knowledge discovery approach for studying manifestations of the lack of modularity support in that sort of languages. The study is focused on Matlab, as a well‐established representative of those languages. We present a technique for the automatic detection and quantification of concerns in Matlab and their exploration in a code base. The Ubiquitous Self Organizing Map (UbiSOM) is used to perform exploratory data analysis over concerns detected in a, possibly changing, repository of Matlab files. The UbiSOM is quite effective in detecting patterns of co‐occurrence of multiple concerns. To illustrate the technique, a repository comprising over 35,000 Matlab files is analysed. The results show that the use of Token Density metrics in conjunction with UbiSOM enables the detection of patterns of co‐occurrence of multiple concerns in m‐files.

The ubiquitous self: what the properties of self-bias tell us about the self.

People show systematic biases in perception, memory, and attention to favor information related to themselves over information related to other people. Researchers have examined these biases in order to throw light on the nature of the self. We review this evidence in memory, face recognition, and simple perceptual matching tasks through objective measures of self-biases. We argue that the self serves as a stable anchor across different forms of judgment and that referring a stimulus to ourselves enhances the binding of stimulus features at different stages of processing (e.g., in perception and in memory) and also the binding between processing stages. There is neural evidence that self-biases reflect an underlying neural network that interacts with but is independent of attentional control networks in the brain, and that damage to the self-related network disrupts the bias effects. We discuss the implications for understanding the nature of the self.

Beta-testing NKT cell self-reactivity

Natural killer T cells (NKT cells) recognize lipid-based antigens presented by CD1d. The mammalian glycolipid β-glucosylceramide, a ubiquitous self antigen for NKT cells, is upregulated by microbial danger signals, which leads to activation of NKT cells in the absence of foreign glycolipid antigen.

Double Positive CD4CD8 αβ T Cells: A New Tumor-Reactive Population in Human Melanomas

BackgroundDouble positive (DP) CD4CD8 Tαβ cells have been reported in normal individuals as well as in different pathological conditions including inflammatory diseases, viral infections and cancer, but their function remains to be elucidated. We recently reported the increased frequency of DP Tαβ cells in human breast pleural effusions. This manuscript addresses the question of the existence and above all the role of this non-conventional DP sub-population among tumor associated lymphocytes in melanomas.Methodology/Principal FindingsWe analyzed the intratumoral cell infiltrate in solid metastasis (n = 6) and tumor invaded lymph nodes (n = 26) samples from melanomas patients by multiparametric cytometry. Here we documented for the first time significant increased frequency of DP T cells in about 60% of melanoma tumors compared to blood samples. Interestingly, a high proportion of these cells produced TNF-α in response to autologous melanoma cell lines. Besides, they are characterized by a unique cytokine profile corresponding to higher secretion of IL-13, IL-4 and IL-5 than simple positive T cells. In deep analysis, we derived a representative tumor-reactive DP T cell clone from a melanoma patient's invaded lymph node. This clone was restricted by HLA-A*2402 and recognized both autologous and allogeneic tumor cells of various origins as well as normal cells, suggesting that the target antigen was a ubiquitous self antigen. However, this DP T cell clone failed to kill HLA-A*2402 EBV-transformed B cells, probably due to the constitutive expression of immunoproteasome by these cells.Conclusions/SignificanceIn conclusion, we can postulate that, according to their broad tumor reactivity and to their original cytokine profile, the tumor associated DP T cells could participate in immune responses to tumors in vivo. Therefore, the presence of these cells and their role will be crucial to address in cancer patients, especially in the context of immunotherapies.

Recognition of a Ubiquitous Self Antigen by Prostate Cancer-Infiltrating CD8 + T Lymphocytes

Substantial evidence exists that many tumors can be specifically recognized by CD8+ T lymphocytes. The definition of antigens targeted by these cells is paramount for the development of effective immunotherapeutic strategies for treating human cancers. In a screen for endogenous tumor-associated T cell responses in a primary mouse model of prostatic adenocarcinoma, we identified a naturally arising CD8+ T cell response that is reactive to a peptide derived from histone H4. Despite the ubiquitous nature of histones, T cell recognition of histone H4 peptide was specifically associated with the presence of prostate cancer in these mice. Thus, the repertoire of antigens recognized by tumor-infiltrating T cells is broader than previously thought and includes peptides derived from ubiquitous self antigens that are normally sequestered from immune detection.

Cancer Antigens Uncovered

The potential of T cells to invade and attack tumors forms the basis for some very promising avenues of cancer immunotherapy. However, progress is often hampered by poor characterization of the antigens that killer T lymphocytes use to target tumor cells. Savage et al. (see the Perspective by Schreiber and Rowley) describe a broadly recognized antigen in a mouse model of prostate cancer. Unusually, the antigen was derived from a ubiquitous histone protein that is normally compartmentalized away from detection by the immune system. However, in the context of the tumor, the antigen was revealed to potentially reactive T cells, which suggests that the tumor environment somehow bends the rules of antigen processing and engagement by the immune system. Because features of this model are similar to those seen in human cancers, the system may also be useful in exploring tumor detection and therapeutic immune intervention. P. A. Savage, K. Vosseller, C. Kang, K. Larimore, E. Riedel, K. Wojnoonski, A. A. Jungbluth, J. P. Allison, Recognition of a ubiquitous self antigen by prostate cancer-infiltrating CD8 + T lymphocytes. Science 319 , 215-220 (2008). [Abstract] [Full Text] H. Schreiber, D. A. Rowley, Quo vadis, specificity? Science 319 , 164-165 (2008). [Summary] [Full Text]

Conserved TCR beta chain usage in reactive arthritis; evidence for selection by a putative HLA-B27-associated autoantigen.

Previous work suggested that expanded CD8+ T-cell clones in the synovial fluid (SF) of HLA-B27+ patients with reactive arthritis (ReA) preferentially use the T-cell receptor variable region (TCRBV) 1, similar CDR3 sequences, and joining region (BJ) 2S3. To determine the range of conservation and disease-specificity of CDR3-sequences, we analyzed the TCRBV1-J2S3 repertoire from 33 healthy HLA-B27+ individuals, patients with various types of spondyloarthropathies (SpA), and with rheumatoid arthritis (RA) by CDR3-spectratyping. After collection and database submission of all available TCRB-CDR3 from HLA-B27-restricted or SpA-derived T cells, we systematically screened the entire human sequence database for sequences similar to the B27/SpA-related CDR3. Spectratyping revealed expanded T cell clones using conserved TCRBV1J2S3 in the SF from 5/6 of the patients with acute ReA but not among the controls. In database searches, 50 HLA-B27 or SpA-related CDR3-sequences generated similar clusters of matched sequences, and matched reciprocally. Identical or closely related sequences were identified in 15 different individuals and a canonical ReA-associated TCRB was defined [BV1-CASSVG(V/I/L)(Y/F)STDTQYF-J2S3]. All but one patient-derived conserved sequences originated from acute stage ReA-patients, and were not present among approximately 3800 other human TCRB sequences in the database. Five of the conserved sequences originated from T cell clones that recognized uninfected cells in an HLA-B27-restricted fashion, implying a role of HLA-B27-restricted CD8+ T cells specific for a ubiquitous self- or cross-reactive microbial determinant in the early phase of ReA. Related sequences were independently identified in four different laboratories. The consensus TCRB motif could be a helpful diagnostic marker in HLA-B27-associated 'undifferentiated arthritis'.

Disruption of T cell tolerance by directing a self antigen to macrophage-specific scavenger receptors.

Breakdown of immune self tolerance is speculated to cause autoimmune diseases, but most studies on tolerance use foreign molecules as targets. In this study, we show another approach using delivery of a maleylated self protein to macrophage-specific scavenger receptors. Mice generate Abs against the maleylated form of a ubiquitous self Ag, mouse serum albumin (MSA), although native MSA is nonimmunogenic. This generation of anti-maleyl MSA Abs depends on binding of maleyl MSA to scavenger receptors in vivo, since coinjection of a serologically unrelated scavenger receptor ligand inhibits it, suggesting that the Ab response is T cell dependent. Spleen cells as well as nylon adherence-purified splenic T cells from maleyl MSA-immune mice proliferate in response to both maleyl MSA and MSA; this response is blocked by anti-MHC class II mAbs, and the autoimmune cells can recognize at least five 15-mer peptides from the MSA sequence, establishing that T cell tolerance to MSA has been broken in these mice. Maleyl MSA and MSA are recognized equally well, provided the scavenger receptor-specific delivery of maleyl MSA is blocked during stimulation in vitro, indicating that maleyl MSA-specific non-self peptides are unlikely to play a major role in the observed disruption of T cell tolerance. Thus, delivery of some self molecules to scavenger receptors may lead to disruption of immune tolerance. These results are relevant to mechanisms of immune tolerance and the etiopathogenesis of autoimmunity.

A ubiquitous protein is the source of naturally occurring peptides that are recognized by a CD8+ T-cell clone.

We previously isolated from mouse spleen an octapeptide (LSPFPFDL) that in association with the class I major histocompatibility complex protein Ld is recognized by the antigen-specific receptor of an alloreactive CD8+ T-cell clone (2C). Guided by an assay dependent upon the same 2C T-cell receptor, we have now isolated from the same source another naturally occurring peptide. The second peptide (VAITRIEQLSPFPFDL) includes the entire octapeptide sequence and preliminary evidence suggests that it may be a natural precursor of the octapeptide. On finding extensive sequence homology between the 16-mer and part of human 2-oxoglutarate dehydrogenase, we determined the cDNA sequence of mouse 2-oxoglutarate dehydrogenase and found that the deduced amino acid sequence matches precisely the two naturally occurring peptides, indicating their origin by cellular processing of this ubiquitous self protein.