The Stimulatory Potency of T Cell Antigens Is Influenced by the Formation of the Immunological Synapse

SummaryT cell activation is predicated on the interaction between the T cell receptor and peptide-major histocompatibility (pMHC) ligands. The factors that determine the stimulatory potency of a pMHC molecule remain unclear. We describe results showing that a peptide exhibiting many hallmarks of a weak agonist stimulates T cells to proliferate more than the wild-type agonist ligand. An in silico approach suggested that the inability to form the central supramolecular activation cluster (cSMAC) could underlie the increased proliferation. This conclusion was supported by experiments that showed that enhancing cSMAC formation reduced stimulatory capacity of the weak peptide. Our studies highlight the fact that a complex interplay of factors determines the quality of a T cell antigen

SUNSTORM 1/X-ray Flux Monitor for CubeSats (XFM-CS) : Instrument characterization and first results

SUNSTORM 1 CubeSat was launched to Sun-synchronous low Earth orbit on August 17 2021. The primary purpose of the mission is an in-orbit demonstration of X-ray Flux Monitor (XFM) instrument. XFM is an innovative solar X-ray spectrometer for measuring and characterizing solar flares, which are known to be linked to a variety of space weather phenomena. XFM represents a next generation of solar X-ray flux monitors. It is based on silicon drift detector technology, which provides several notable performance improvements over its predecessors, which are based on Si PIN detectors. Transversal electric field and lower output capacitance allow operation at much faster pulse processing shaping times, allowing the system to achieve about 10 times higher throughput without saturation while also making it less sensitive to the increase of leakage current due to high temperature and/or radiation damage. Thus, XFM instruments can cover a very wide dynamic range of solar X-ray emission from the most quiescent conditions to the strongest X-class solar flares, while maintaining good spectral resolution (Peer reviewe

Targeting the MAPK7/MMP9 axis for metastasis in primary bone cancer

Metastasis is the leading cause of cancer related death. This multistage process involves contribution from both tumour cells and the tumour stroma to release metastatic cells into the circulation. Circulating tumour cells (CTCs) survive circulatory cytotoxicity, extravasate and colonise secondary sites effecting metastatic outcome. Reprogramming the transcriptomic landscape is a metastatic hallmark but detecting underlying master regulators that drive pathological gene expression is a key challenge, especially in childhood cancer. Here we used whole tumour plus single cell RNA sequencing in primary bone cancer and CTCs to perform weighted gene co-expression network analysis to systematically detect coordinated changes in metastatic transcript expression. This approach with comparisons applied to data collected from cell line models, clinical samples and xenograft mouse models revealed MAPK7/MMP9 signalling as a driver for primary bone cancer metastasis. RNAi knockdown of MAPK7 reduces proliferation, colony formation, migration, tumour growth, macrophage residency/polarisation and lung metastasis. Parallel to these observations were reduction of activated interleukins IL1B, IL6, IL8 plus mesenchymal markers VIM and VEGF in response to MAPK7 loss. Our results implicate a newly discovered, multidimensional MAPK7/MMP9 signalling hub in primary bone cancer metastasis that is clinically actionable

Distribution of calbindin-D28k immunoreactivity in the deep nuclei of the bottlenose dolphin (Tursiops truncatus).

The amygdala plays a key role in emotional learning and behavior. Calbindin-D28k (CB) is a calcium-binding protein located in a variety of neuronal cell types in many regions of the brain. Despite previous studies in rat (Kemppainen, J. Comp. Neurol. 426, 2000) and Primates (Sorvari, Neuroscience 75, 1996), there are no reports concerning the distribution of CB immunoreactivity in the dolphin amygdala. Thus, we studied the distribution, morphology, and size of CB-immunoreactive (IR) neurons as well as the distribution of CB-IR neuropil in the deep nuclei of the bottlenose dolphin amygdala. The results obtained showed that in the deep nuclei CB-IR neurons were numerous and could be divided into two major cell types: pyramidal and nonpyramidal neurons. Pyramidal cells were large, lightly stained and without an evident immunostained dendritic tree. Nonpyramidal neurons could be subdivided into three types on the basis on the shapes and sizes of their somata and on their dendritic morphology. Type 1 neurons had a small spheroidal somata from which arose thin primary dendrites. Type 2 neurons were large cells with angular somata and evident primary dendrites. Type 3 neurons had a fusiform somata originating the primary dendrites from their opposite pole. These data suggest that in the deep nuclei neuronal microcircuit activity is controlled also by different cell types that contain CB

T cell receptor can be recruited to a subset of plasma membrane rafts, independently of cell signaling and attendantly to raft clustering.

The constitutive/inducible association of the T cell receptor (TCR) with isolated detergent-resistant, lipid raft-derived membranes has been studied in Jurkat T lymphocytes. Membranes resistant to 1% Triton X-100 contained virtually no CD3epsilon, part of the TCR complex, irrespective of cell stimulation. On the other hand, membranes resistant either to a lower Triton X-100 concentration (i.e. 0.2%) or to the less hydrophobic detergent Brij 58 (1%) contained (i) a low CD3epsilon amount (approximate 2.7% of total) in resting cells and (ii) a several times higher amount of the TCR component, after T cell stimulation with either antigen-presenting cells or with phytohemagglutinin. It appeared that CD3/TCR was constitutively associated with and recruited to a raft-derived membrane subset because (i) all three membrane preparations contained a similar amount of the raft marker tyrosine kinase Lck but no detectable amounts of the conventional membrane markers, CD45 phosphatase and transferrin receptor; (ii) a larger amount of particulate membranes were resistant to solubilization with 0.2% Triton X-100 and Brij 58 than to solubilization with 1% Triton X-100; and (iii) higher cholesterol levels were present in membranes resistant to either the lower Triton X-100 concentration or to Brij 58, as compared with those resistant to 1% Triton X-100. The recruitment of CD3 to the raft-derived membrane subset appeared (i) to occur independently of cell signaling events, such as protein-tyrosine phosphorylation and Ca(2+) mobilization/influx, and (ii) to be associated with clustering of plasma membrane rafts induced by multiple cross-linking of either TCR or the raft component, ganglioside GM(1). We suggest that during T cell stimulation a lateral reorganization of rafts into polarized larger domains can determine the recruitment of TCR into these domains, which favors a polarization of the signaling cascade

Bone marrow stromal cell antigen 2 is a specific marker of type I IFN-producing cells in the naive mouse, but a promiscuous cell surface antigen following IFN stimulation.

Type I IFN-producing cells (IPC) are sentinels of viral infections. Identification and functional characterization of these cells have been difficult because of their small numbers in blood and tissues and their complex cell surface phenotype. To overcome this problem in mice, mAbs recognizing IPC-specific cell surface molecules have been generated. In this study, we report the identification of new Abs specific for mouse IPC, which recognize the bone marrow stromal cell Ag 2 (BST2). Interestingly, previously reported IPC-specific Abs 120G8 and plasmacytoid dendritic cell Ag-1 also recognize BST2. BST2 is predominantly specific for mouse IPC in naive mice, but is up-regulated on most cell types following stimulation with type I IFNs and IFN-gamma. The activation-induced promiscuous expression of BST2 described in this study has important implications for the use of anti-BST2 Abs in identification and depletion of IPC. Finally, we show that BST2 resides within an intracellular compartment corresponding to the Golgi apparatus, and may be involved in trafficking secreted cytokines in IPC

Immunohistochemical Localization of Substance P And Cholecystokinin in the Dorsal Root Ganglia and Spinal Cord of the Bottlenose Dolphin (Tursiops truncatus).

The presence of substance P (SP) and cholecystokinin (CCK) immunoreactive neurons was examined in the bottlenose dolphin dorsal root ganglia (DRGs) and spinal cord by immunohistochemical techniques. SP-positive and CCK-immunoreactive neurons were respectively approximately 50% and 1% of the total number of ganglion cells examined and especially belonged to small and medium-sized cell populations. Using double labeling techniques we observed that SP- and CCK-immunoreactivity coexisted in a very low number of primary afferent neurons (2.7%). Few SP-immunoreactive (IR) neurons (2.7%) were also CCK-positive. On the contrary, 65% of CCK-immunoreactive neurons contained SP. Interestingly, we observed CCK-immunoreactive satellite glial cells located around large cell class somata. Virtually no SP-IR and CCK-positive neurons were surrounded by peripheral CCK-immunoreactive satellite glial cells. The SP-IR and CCK-positive nerve fibers were particularly conspicuous in the superficial layers of the spinal cord. The present study indicates that SP and CCK only partially overlap in the thoracic, lumbar, and caudal DRGs of the bottlenose dolphin, suggesting that the majority of SP-IR ganglion neurons are lacking in CCK-immunoreactivity. The role of SP-containing DRG neurons is discussed also in relation to the huge vascular spinal retia mirabilia typical of cetaceans