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We study a mathematical model of immune response by T cells where the regulatory T cells (Treg) inhibit interleukin 2 (IL‐2) secretion. We model the suppression of the autoimmune line of T cells after a different line of T cells responded to a pathogen infection. In this paper, we show that if the population of the pathogen responding line of T cells becomes large enough, the competition for IL‐2 and the increase in the death rates may lead to a depletion in the concentration of autoimmune T cells. Provided this lasts for a sufficiently long time, the concentration of autoimmune T cells can be brought down to values inside the basin of attraction of the controlled state, and autoimmunity can be suppressed. [ABSTRACT FROM AUTHOR]

We study a mathematical model of immune response by T cells where the regulatory T cells (Treg) inhibit interleukin 2 (IL‐2) secretion. We model the suppression of the autoimmune line of T cells after a different line of T cells responded to a pathogen infection. In this paper, we show that if the population of the pathogen responding line of T cells becomes large enough, the competition for IL‐2 and the increase in the death rates may lead to a depletion in the concentration of autoimmune T cells. Provided this lasts for a sufficiently long time, the concentration of autoimmune T cells can be brought down to values inside the basin of attraction of the controlled state, and autoimmunity can be suppressed. [ABSTRACT FROM AUTHOR]

Abstract: Immune dysregulation, polyendocrinopathy, enteropathy, X‐linked (IPEX) syndrome is a rare disorder that increasingly has gained attention as a model of genetic autoimmunity. Numerous papers documenting the key clinical and molecular characteristics of IPEX have provided a detailed understanding of this devastating disease. IPEX is a primary immunodeficiency caused by mutations in the gene FOXP3, which encodes an essential transcription factor required for maintenance of thymus‐derived regulatory T (tTreg) cells. tTreg cell dysfunction is the main pathogenic event leading to multiorgan autoimmunity in IPEX. In addition to the traditional clinical presentation (i.e., severe enteropathy, type 1 diabetes, and eczema), IPEX may encompass other variable and distinct clinical manifestations. As IPEX awareness and characterization have increased, so has identification of FOXP3 mutations, with at least 70 to date. Thus, while FOXP3 is the unifying gene, IPEX is a complex and diverse clinical continuum of disorders. Despite understanding IPEX pathogenesis, new treatment options have remained elusive, although early diagnosis led to hematopoietic stem cell transplantation (HSCT) and immunosuppression treatment and improved patient outcomes. Here, we review current knowledge about IPEX syndrome and highlight findings that could lead to novel targeted treatments. [ABSTRACT FROM AUTHOR]

This paper argues that multiple sclerosis ( MS) is the result of an autoimmune attack against components of the central nervous system ( CNS). The effector cells involved in the pathogenic process are CNS-autoreactive T cells present in the healthy immune system in a resting state. Upon activation, these cells cross the blood-brain barrier and attack the CNS target tissue. Recent evidence indicates that autoimmune activation may happen in the intestine, following an interaction of bacterial components of the gut flora with local CNS autoreactive T cells. The consequences of this concept are discussed. [ABSTRACT FROM AUTHOR]

As the amount of biomedical information available in the literature continues to increase, databases that aggregate this information continue to grow in importance and scope. The population of databases can occur either through fully automated text mining approaches or through manual curation by human subject experts. We here report our experiences in populating the National Institute of Allergy and Infectious Diseases sponsored Immune Epitope Database and Analysis Resource ( IEDB, http://iedb.org), which was created in 2003, and as of 2012 captures the epitope information from approximately 99% of all papers published to date that describe immune epitopes (with the exception of cancer and HIV data). This was achieved using a hybrid model based on automated document categorization and extensive human expert involvement. This task required automated scanning of over 22 million PubMed abstracts followed by classification and curation of over 13 000 references, including over 7000 infectious disease-related manuscripts, over 1000 allergy-related manuscripts, roughly 4000 related to autoimmunity, and 1000 transplant/alloantigen-related manuscripts. The IEDB curation involves an unprecedented level of detail, capturing for each paper the actual experiments performed for each different epitope structure. Key to enabling this process was the extensive use of ontologies to ensure rigorous and consistent data representation as well as interoperability with other bioinformatics resources, including the Protein Data Bank, Chemical Entities of Biological Interest, and the NIAID Bioinformatics Resource Centers. A growing fraction of the IEDB data derives from direct submissions by research groups engaged in epitope discovery, and is being facilitated by the implementation of novel data submission tools. The present explosion of information contained in biological databases demands effective query and display capabilities to optimize the user experience. Accordingly, the development of original ways to query the database, on the basis of ontologically driven hierarchical trees, and display of epitope data in aggregate in a biologically intuitive yet rigorous fashion is now at the forefront of the IEDB efforts. We also highlight advances made in the realm of epitope analysis and predictive tools available in the IEDB. [ABSTRACT FROM AUTHOR]

Type 1 narcolepsy is a sleep disorder characterized by excessive daytime sleepiness with unintentional sleep attacks and cataplexy. The disorder is caused by a loss of hypocretinergic neurons in the brain. The specific loss of these neurons in narcolepsy is thought to result from an autoimmune attack, and this is supported by evidence of both environmental and genetic factors pointing toward an involvement of the immune system. However, definitive proof of an autoimmune etiology is still missing. Several different immune-mediated disorders targeting neurons are known, and many of these are believed to be caused by autoreactive CD8+ T cells. In this paper, we review the current knowledge on CD8+ T cell-mediated neuronal damage on the basis of our understanding of other autoimmune disorders and experimental studies. We identify major histocompatibility complex class I presentation of autoantigens on neurons as a possiblemechanism in the development of the disease, and propose T cell-mediated pathogenesis, with cytotoxic CD8+ T cells targeting the hypocretinergic neurons, as a central element. [ABSTRACT FROM AUTHOR]

Type 1 narcolepsy is a sleep disorder characterized by excessive daytime sleepiness with unintentional sleep attacks and cataplexy. The disorder is caused by a loss of hypocretinergic neurons in the brain. The specific loss of these neurons in narcolepsy is thought to result from an autoimmune attack, and this is supported by evidence of both environmental and genetic factors pointing toward an involvement of the immune system. However, definitive proof of an autoimmune etiology is still missing. Several different immune-mediated disorders targeting neurons are known, and many of these are believed to be caused by autoreactive CD8+ T cells. In this paper, we review the current knowledge on CD8+ T cell-mediated neuronal damage on the basis of our understanding of other autoimmune disorders and experimental studies. We identify major histocompatibility complex class I presentation of autoantigens on neurons as a possible mechanism in the development of the disease, and propose T cell-mediated pathogenesis, with cytotoxic CD8+ T cells targeting the hypocretinergic neurons, as a central element. [ABSTRACT FROM AUTHOR]

Any discussion of the regulation of effector class must include feedback control on the magnitude of the response. The induced effector activities are biodestructive and ridding. They are, in and of themselves, unspecific with respect to self and nonself. Consequently all responses include some level of innocent bystander pathology. The regulation of magnitude is essential to keeping this level of pathology at an evolutionarily acceptable level. This is my postulated role of suppressor T-cells, more popularly referred to as Treg. In order to perform this function they must be somatically selected to be anti-nonself like all other T/B-cells. If correct, any role that they might play in determining normal tolerance is excluded. As the commentary of Ellestad illustrates, their function to regulate autoimmunity is the consensus view today and, therefore, this competing concept and my analysis of suggested papers should invite a wide ranging debate. [ABSTRACT FROM AUTHOR]

Programmed death-1 (PD-1) is a surface receptor critical for the regulation of T cell function during immunity and tolerance. PD-1 interactions with its ligands PD-L1 and PD-L2 inhibit T cell effector functions in an antigen-specific manner. This paper examines the role of PD-1 in limiting autoreactivity and establishing self-tolerance and discusses the hypothesis that PD-1 ligand (PD-L) expression both spatially and temporally dictates the fate of self-reactive T cells during the breakdown of peripheral tolerance and development of autoimmunity. We focus our discussion on the role of PD-1/PD-L interactions during peripheral tolerance, the differential role for PD-L1 and PD-L2 in response to environmental or self-antigens, and the impact of PD-1 signaling on dynamic T cell motility and the T cell receptor (TCR) stop signal. Finally, we discuss the potential to selectively target the PD-1 pathway therapeutically to alter T cell function during autoimmunity. [ABSTRACT FROM AUTHOR]

MHC class II molecules function by selective binding of antigenic peptides, thereby both shaping the T-cell receptor (TCR) repertoire in the thymus and influencing presentation of immunogenic peptides to CD4[sup+] T cells in the periphery. The strong association between a number of human autoimmune diseases (type 1 diabetes, rheumatoid arthritis, and multiple sclerosis) and certain HLA-DR/DQ alleles suggests that it may be possible to alter pathological autoimmune responses by deliberate introduction of autoantigenic peptides in a "tolerogenic" manner. Since there are likely to be differences in epitope selection and epitope spreading in different patients over time, this approach requires identification of all the immunogenic CD4[sup+]T-cell epitopes (dominant, subdominant, or cryptic) DR/DQ alleles predisposing to these autoimmune disease. This paper describes a new approach for the identification of immunogenic peptide epitopes of human autoantigenic proteins using HLA-DR and DQ transgenic mice. These mice are engineered to select a full TCR repertoire which can identify immunogenic peptide epitopes similar or identical to human subjects of the same HLA-DR/DQ genotype. This experimental system also allows comparison of autoantigenic immune response restricted to disease-susceptible and disease-resistant HLA-DR/DQ alleles. [ABSTRACT FROM AUTHOR]

In this paper we describe the first in vitro response to the liver alloantigen F. The anti-F response serves as a valuable model for autoimmune phenomena since priming appropriate strains of mice (responders) with allogeneic but not syngeneic type F leads to autoantibody production. The in vitro system is based on the proliferation of T cells, from mice primed in vivo with F, when coincubated with splenic adherent cells (SAC) prepulsed with F in vivo. The system displays two important correlates of the in vivo antibody response to F:1.T cells from mice primed with syngeneic F do not proliferate when incubated with SAC prepulsed with syngeneic F and 2. Mice that do not make antibody responses to allo F in vivo (DBA/2) do not show in vitro proliferative responses. These findings indicate that the proliferative assay is a good in vitro model for the F response. [ABSTRACT FROM AUTHOR]

HLA-G non classical class I locus shows a comparatively low polymorphism. It encodes for tolerogenic HLA molecules that may be important in autoimmunity and transplant (and foetal) rejection control. HLA-G molecules give negative signals to Natural Killer and T lymphocytes. In the present paper, a new allele, HLA-G*08, is described, which may be useful for monitoring transplants and for HLA and disease studies. [ABSTRACT FROM AUTHOR]