SYK expression endows human ZAP70-deficient CD8 T cells with residual TCR signaling.

Autosomal recessive human ZAP70 deficiency is a rare cause of combined immunodeficiency (CID) characterized by defective CD4 T cells and profound CD8 T cell lymphopenia. Herein, we report two novel patients that extend the molecular genetics, the clinical and functional phenotypes associated with the ZAP70 deficiency. The patients presented as infant-onset CID with severe infections caused by varicella zoster virus and live vaccines.

T cell expansion is the limiting factor of virus control in mice with attenuated TCR signaling: implications for human immunodeficiency.

Defining the minimal thresholds for effective antiviral T cell immunity is important for clinical decisions in immunodeficient patients. TCR signaling is critical for T cell development, activation, and effector functions. In this article, we analyzed which of these TCR-mediated processes is limiting for antiviral immunity in a mouse strain with reduced expression of SLP-76 (twp mice).

Pre-clustering of the B cell antigen receptor demonstrated by mathematically extended electron microscopy.

The B cell antigen receptor (BCR) plays a crucial role in adaptive immunity, since antigen-induced signaling by the BCR leads to the activation of the B cell and production of antibodies during an immune response. However, the spatial nano-scale organization of the BCR on the cell surface prior to antigen encounter is still controversial. Here, we fixed murine B cells, stained the BCRs on the cell surface with immuno-gold and visualized the distribution of the gold particles by transmission electron microscopy.

Activation of the TCR complex by peptide-MHC and superantigens.

Drug hypersensitivity reactions are immune mediated, with T lymphocytes being stimulated by the drugs via their T-cell antigen receptor (TCR). In the nonpathogenic state, the TCR is activated by foreign peptides presented by major histocompatibility complex molecules (pMHC). Foreign pMHC binds with sufficient affinity to TCRαβ and thereby elicits phosphorylation of the cytoplasmic tails of the TCRαβ-associated CD3 subunits.

Semi-automatic determination of cell surface areas used in systems biology.

Quantitative biology requires high precision measurement of cellular parameters such as surface areas or volumes. Here, we have developed an integrated approach in which the data from 3D confocal microscopy and 2D high-resolution transmission electron microscopy were combined. The volumes and diameters of the cells within one population were automatically measured from the confocal data sets.

Scaffold-based transplantation of vascular endothelial growth factor-overexpressing stem cells leads to neovascularization in ischemic myocardium but did not show a functional regenerative effect.

The transplantation of skeletal myoblasts (SkM) might improve cardiac function after myocardial infarction via paracrine action. We used scaffold-based cell transfer by using vascular endothelial growth factor (VEGF)-overexpressing myoblasts. Skeletal myoblasts were isolated and expanded from newborn Lewis rats.

Hepatocyte growth factor-transfected skeletal myoblasts to limit the development of postinfarction heart failure.

Stem cells transplanted to an injured heart affect the host myocardium indirectly. The cytokine hepatocyte growth factor (HGF) may play a key role in this paracrine activity. We hypothesized that HGF-overexpressing stem cells would restore cardiac function after myocardial infarction (MI).

Functional regeneration of ischemic myocardium by transplanted cells overexpressing stromal cell-derived factor-1 (SDF-1): intramyocardial injection versus scaffold-based application.

Objective: Stromal cell-derived factor-1 (SDF-1) is a potent chemotaxin. Increased SDF-1 levels can be found in ischemic myocardium and might protect against ischemia-reperfusion injury. We hypothesized that transplantation of stem cells overexpressing SDF-1 might improve cardiac function after myocardial infarction (MI).

Blue native polyacrylamide gel electrophoresis (BN-PAGE) for analysis of multiprotein complexes from cellular lysates.

Multiprotein complexes (MPCs) play a crucial role in cell signalling, since most proteins can be found in functional or regulatory complexes with other proteins (Sali, Glaeser et al. 2003). Thus, the study of protein-protein interaction networks requires the detailed characterization of MPCs to gain an integrative understanding of protein function and regulation.

Scaffold-based transplantation of akt1-overexpressing skeletal myoblasts: functional regeneration is associated with angiogenesis and reduced infarction size.

Myoblast-based therapy can improve cardiac function after infarction and is conventionally performed by direct injection. A scaffold-based transfer could overcome injection-associated problems. In upgrading this approach we transplanted skeletal myoblasts (SkM) overexpressing the prosurvival gene Akt1.

A potential role for P2X7R in allergic airway inflammation in mice and humans.

P2X₇R deficiency is associated with a less severe outcome in acute and chronic inflammatory disorders. Recently, we demonstrated that extracellular adenosine triphosphate is involved in the pathogenesis of asthma by modulating the function of dendritic cells (DCs). However, the role of the purinergic receptor subtype P2X₇ is unknown.

Polyurethane scaffolds seeded with genetically engineered skeletal myoblasts: a promising tool to regenerate myocardial function.

In animal models, intramyocardial injection of primary skeletal myoblasts is supposed to promote tissue regeneration and to improve cardiac function after myocardial infarction. The usage of genetically engineered myoblasts overexpressing the paracrine factors involved in tissue repair is believed to enhance these effects. However, cell therapy via injection is always accompanied by a high death rate of the injected cells.

Detection of phosphorylated T and B cell antigen receptor species by Phos-tag SDS- and Blue Native-PAGE.

Detection of phospho-proteins and differently phosphorylated forms of the same protein are important in understanding cell behaviour. One novel method is Phos-tag SDS-PAGE. A dinuclear Mn(2+) complex that binds to phosphate groups (the Phos-tag) is covalently attached to the polyacrylamide gel matrix.

5-hydroxytryptamine modulates migration, cytokine and chemokine release and T-cell priming capacity of dendritic cells in vitro and in vivo.

Beside its well described role in the central and peripheral nervous system 5-hydroxytryptamine (5-HT), commonly known as serotonin, is also a potent immuno-modulator. Serotoninergic receptors (5-HTR) are expressed by a broad range of inflammatory cell types, including dendritic cells (DCs). In this study, we aimed to further characterize the immuno-biological properties of serotoninergic receptors on human monocyte-derived DCs.

Cleavage of Escherichia coli cytotoxic necrotizing factor 1 is required for full biologic activity.

Cytotoxic necrotizing factor 1 (CNF1) is a protein toxin produced by pathogenic Escherichia coli strains. CNF1 constitutively activates small GTPases of the Rho family by deamidation of a glutamine, which is crucial for GTP hydrolysis. The toxin is taken up into mammalian cells by receptor-mediated endocytosis and is delivered from late endosomes into the cytosol.

The cytotoxic necrotizing factors from Yersinia pseudotuberculosis and from Escherichia coli bind to different cellular receptors but take the same route to the cytosol.

The cytotoxic necrotizing factors CNF1 and CNF2 produced by pathogenic Escherichia coli strains and CNF(Y) of Yersinia pseudotuberculosis constitutively activate small GTPases of the Rho family. They deamidate a glutamine (Gln63 in RhoA), which is crucial for GTP hydrolysis. CNF1 and CNF(Y) exhibit 61% identity on the amino acid level, with equal distribution over the whole molecule.