Amniotic Epithelial Cells from the Human Placenta Potently Suppress a Mouse Model of Multiple Sclerosis

Human amniotic epithelial cells (hAEC) have stem cell-like features and immunomodulatory properties. Here we show that hAEC significantly suppressed splenocyte proliferation in vitro and potently attenuated a mouse model of multiple sclerosis (MS). Central nervous system (CNS) CD3+ T cell and F4/80+ monocyte/macrophage infiltration and demyelination were significantly reduced with hAEC treatment. Besides the known secretion of prostaglandin E2 (PGE2), we report the novel finding that hAEC utilize transforming growth factor-β (TGF-β) for immunosuppression. Neutralization of TGF-β or PGE2 in splenocyte proliferation assays significantly reduced hAEC-induced suppression. Splenocytes from hAEC-treated mice showed a Th2 cytokine shift with significantly elevated IL-5 production. While transferred CFSE-labeled hAEC could be detected in the lung, none were identified in the CNS or in lymphoid organs. This is the first report documenting the therapeutic effect of hAEC in a MS-like model and suggest that hAEC may have potential for use as therapy for MS

Maturation-Dependent Licensing of Naive T Cells for Rapid TNF Production

The peripheral naïve T cell pool is comprised of a heterogeneous population of cells at various stages of development, which is a process that begins in the thymus and is completed after a post-thymic maturation phase in the periphery. One hallmark of naïve T cells in secondary lymphoid organs is their unique ability to produce TNF rapidly after activation and prior to acquiring other effector functions. To determine how maturation influences the licensing of naïve T cells to produce TNF, we compared cytokine profiles of CD4+ and CD8+ single positive (SP) thymocytes, recent thymic emigrants (RTEs) and mature-naïve (MN) T cells during TCR activation. SP thymocytes exhibited a poor ability to produce TNF when compared to splenic T cells despite expressing similar TCR levels and possessing comparable activation kinetics (upregulation of CD25 and CD69). Provision of optimal antigen presenting cells from the spleen did not fully enable SP thymocytes to produce TNF, suggesting an intrinsic defect in their ability to produce TNF efficiently. Using a thymocyte adoptive transfer model, we demonstrate that the ability of T cells to produce TNF increases progressively with time in the periphery as a function of their maturation state. RTEs that were identified in NG-BAC transgenic mice by the expression of GFP showed a significantly enhanced ability to express TNF relative to SP thymocytes but not to the extent of fully MN T cells. Together, these findings suggest that TNF expression by naïve T cells is regulated via a gradual licensing process that requires functional maturation in peripheral lymphoid organs

Highly selective chemical vapor deposition of tin diselenide thin films onto patterned substrates via single source diselenoether precursors

The distorted octahedral complexes [SnCl4{nBuSe(CH2)nSenBu}]  (n = 2 or 3), (1) and (2), obtained from reaction of SnCl4 with the neutral bidentate ligands and characterized by IR/Raman and multinuclear (1H, 77Se{1H} and 119Sn) NMR spectroscopy and X-ray crystallography, serve as very effective single source precursors for low pressure chemical vapor deposition (LPCVD) of microcrystalline, single phase tin diselenide films onto SiO2, Si and TiN substrates. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) imaging show hexagonal plate crystallites which grow perpendicular to the substrate surface in the thicker films, but align mostly parallel to the surface when the quantity of reagent is reduced to limit the film thickness. X-ray diffraction (XRD) and Raman spectroscopy on the deposited films are consistent with hexagonal SnSe2 (P3m1; a = b = 3.81 Å; c = 6.13 Å), with strong evidence for preferred orientation of the crystallites in thinner (0.5–2 µm) samples, consistent with crystal plate growth parallel to the substrate surface. Hall measurements show the deposited SnSe2 is a n-type semiconductor. The resistivity of the crystalline films is 210 (±10) mΩ cm and carrier density is 5.0 × 1018 cm–3. Very highly selective film growth from these reagents onto photolithographically patterned substrates is observed, with deposition strongly preferred onto the (conducting) TiN surfaces of SiO2/TiN patterned substrates, and onto the SiO2 surfaces of Si/SiO2 patterned substrates. A correlation between the high selectivity and high contact angle of a water droplet on the substrate surfaces is observed

Evaluation of group 4 metal bis-cyclopentadienyl complexes with selenolate and tellurolate ligands for CVD of ME2Films (E = Se or Te)

The selenolate and tellurolate complexes [Cp2M(SeR)2] (M = Ti, Zr, or Hf; R = Me or But) and [Cp2M(TeBut)2] (M = Zr or Hf) have been prepared and characterized by 1H, 13C{1H}, 77Se{1H} and 125Te{1H} NMR spectroscopy and microanalysis. Crystal structures of representative examples are reported, together with the structure of the oxo-bridged species [{Cp2Zr(SeMe)}2(?-O)] formed by partial hydrolysis. Trends in the NMR parameters are discussed. These molecular [Cp2M(SeBut)2] complexes are shown to be suitable as precursors for the single source LPCVD of intensely colored MSe2 thin films for each of the Group 4 elements, confirmed by SEM/EDX and PXD. These are the first examples of single source CVD of ZrSe2 and HfSe2 thin films. The corresponding [Cp2M(TeBut)2] species (M = Zr or Hf) deposit elemental Te under similar LPCVD conditions