αβ T-cell receptors from multiple sclerosis brain lesions show MAIT cell-related features.

Objectives: To characterize phenotypes of T cells that accumulated in multiple sclerosis (MS) lesions, to compare the lesional T-cell receptor (TCR) repertoire of T-cell subsets to peripheral blood, and to identify paired α and β chains from single CD8(+) T cells from an index patient who we followed for 18 years.

Methods: We combined immunohistochemistry, laser microdissection, and single-cell multiplex PCR to characterize T-cell subtypes and identify paired TCRα and TCRβ chains from individual brain-infiltrating T cells in frozen brain sections. The lesional and peripheral TCR repertoires were analyzed by pyrosequencing.

T cells become licensed in the lung to enter the central nervous system.

The blood–brain barrier (BBB) and the environment of the central nervous system (CNS) guard the nervous tissue from peripheral immune cells. In the autoimmune disease multiple sclerosis, myelin-reactive T-cell blasts are thought to transgress the BBB and create a pro-inflammatory environment in the CNS, thereby making possible a second autoimmune attack that starts from the leptomeningeal vessels and progresses into the parenchyma. Using a Lewis rat model of experimental autoimmune encephalomyelitis, we show here that contrary to the expectations of this concept, T-cell blasts do not efficiently enter the CNS and are not required to prepare the BBB for immune-cell recruitment.

Nicotinic acid adenine dinucleotide phosphate-mediated calcium signalling in effector T cells regulates autoimmunity of the central nervous system.

Nicotinic acid adenine dinucleotide phosphate represents a newly identified second messenger in T cells involved in antigen receptor-mediated calcium signalling. Its function in vivo is, however, unknown due to the lack of biocompatible inhibitors. Using a recently developed inhibitor, we explored the role of nicotinic acid adenine dinucleotide phosphate in autoreactive effector T cells during experimental autoimmune encephalomyelitis, the animal model for multiple sclerosis.

Real-time imaging reveals the single steps of brain metastasis formation.

Brain metastasis frequently occurs in individuals with cancer and is often fatal. We used multiphoton laser scanning microscopy to image the single steps of metastasis formation in real time. Thus, it was possible to track the fate of individual metastasizing cancer cells in vivo in relation to blood vessels deep in the mouse brain over minutes to months.

Effector T cell interactions with meningeal vascular structures in nascent autoimmune CNS lesions.

The tissues of the central nervous system are effectively shielded from the blood circulation by specialized vessels that are impermeable not only to cells, but also to most macromolecules circulating in the blood. Despite this seemingly absolute seclusion, central nervous system tissues are subject to immune surveillance and are vulnerable to autoimmune attacks. Using intravital two-photon imaging in a Lewis rat model of experimental autoimmune encephalomyelitis, here we present in real-time the interactive processes between effector T cells and cerebral structures from their first arrival to manifest autoimmune disease.

Np95 interacts with de novo DNA methyltransferases, Dnmt3a and Dnmt3b, and mediates epigenetic silencing of the viral CMV promoter in embryonic stem cells.

Recent studies have indicated that nuclear protein of 95 kDa (Np95) is essential for maintaining genomic methylation by recruiting DNA methyltransferase (Dnmt) 1 to hemi-methylated sites. Here, we show that Np95 interacts more strongly with regulatory domains of the de novo methyltransferases Dnmt3a and Dnmt3b. To investigate possible functions, we developed an epigenetic silencing assay using fluorescent reporters in embryonic stem cells (ESCs).

Instant effect of soluble antigen on effector T cells in peripheral immune organs during immunotherapy of autoimmune encephalomyelitis.

i.v. infusion of native autoantigen or its altered peptide variants is an important therapeutic option for the treatment of autoimmune diseases, because it selectively targets the disease-inducing T cells.

RhoH is important for positive thymocyte selection and T-cell receptor signaling.

RhoH is a small GTPase expressed only in the hematopoietic system. With the use of mice with targeted disruption of the RhoH gene, we demonstrated that RhoH is crucial for thymocyte maturation during DN3 to DN4 transition and during positive selection. Furthermore, the differentiation and expansion of DN3 and DN4 thymocytes in vitro were severely impaired.

Secretion of brain-derived neurotrophic factor by glatiramer acetate-reactive T-helper cell lines: Implications for multiple sclerosis therapy.

Treatment with glatiramer acetate (GA) is thought to induce an in vivo change of the cytokine secretion pattern and the effector function of GA-reactive T helper (TH) cells (TH1-TH2-shift). Current theories propose that GA-reactive TH2 cells can penetrate the CNS, since they are activated by daily immunization. Inside the CNS, GA-reactive T cells may cross-react with products of the local myelin turnover presented by local antigen-presenting cells (APCs).

The activation status of neuroantigen-specific T cells in the target organ determines the clinical outcome of autoimmune encephalomyelitis.

The clinical picture of experimental autoimmune encephalomyelitis (EAE) is critically dependent on the nature of the target autoantigen and the genetic background of the experimental animals. Potentially lethal EAE is mediated by myelin basic protein (MBP)-specific T cells in Lewis rats, whereas transfer of S100beta- or myelin oligodendrocyte glycoprotein (MOG)-specific T cells causes intense inflammatory response in the central nervous system (CNS) with minimal disease. However, in Dark Agouti rats, the pathogenicity of MOG-specific T cells resembles the one of MBP-specific T cells in the Lewis rat.

Neuronal or glial progeny: regional differences in radial glia fate.

The precursor function of the ubiquitous glial cell type in the developing central nervous system (CNS), the radial glia, is largely unknown. Using Cre/loxP in vivo fate mapping studies, we found that radial glia generate virtually all cortical projection neurons but not the interneurons originating in the ventral telencephalon. In contrast to the cerebral cortex, few neurons in the basal ganglia originate from radial glia, and in vitro lineage analysis revealed intrinsic differences in the potential of radial glia from the dorsal and ventral telencephalon.

Glatiramer acetate-specific T-helper 1- and 2-type cell lines produce BDNF: implications for multiple sclerosis therapy. Brain-derived neurotrophic factor.

The clinical effects of glatiramer acetate (GA), an approved therapy for multiple sclerosis, are thought to be largely mediated by a T-helper 1 (TH1) to T-helper 2 (TH2) shift of GA-reactive T-lymphocytes. Current theories propose that activated GA-reactive TH2 cells penetrate the CNS, release anti-inflammatory cytokines such as interleukin (IL)-4, IL-5 and IL-10, and thus inhibit neighbouring inflammatory cells by a mechanism termed 'bystander suppression'. We demonstrate that both GA-specific TH2 and TH1 cells produce the neurotrophin brain-derived neurotrophic factor (BDNF).

The 2.2-A crystal structure of human pro-granzyme K reveals a rigid zymogen with unusual features.

Granzyme K (GzmK) belongs to a family of trypsin-like serine proteases localized in electron dense cytoplasmic granules of activated natural killer and cytotoxic T-cells. Like the related granzymes A and B, GzmK can trigger DNA fragmentation and is involved in apoptosis. We expressed the Ser(195) --> Ala variant of human pro-GzmK in Escherichia coli, crystallized it, and determined its 2.