Plasmacytoid dendritic cells (pDCs) are known mainly for their secretion of type I IFN upon viral encounter. We describe a CD2 hi CD5 + CD81 + pDC subset, distinguished by prominent dendrites and a mature phenotype, in human blood, bone marrow, and tonsil, which can be generated from CD34 + progenitors. These CD2 hi CD5 + CD81 + cells express classical pDC markers, as well as the toll-like receptors that enable conventional pDCs to respond to viral infection. However, their gene expression profile is distinct, and they produce little or no type I IFN upon stimulation with CpG oligonucleotides, likely due to their diminished expression of IFN regulatory factor 7. A similar population of CD5 + CD81 + pDCs is present in mice and also does not produce type I IFN after CpG stimulation. In contrast to conventional CD5 − CD81 − pDCs, human CD5 + CD81 + pDCs are potent stimulators of B-cell activation and antibody production and strong inducers of T-cell proliferation and Treg formation. These findings reveal the presence of a discrete pDC population that does not produce type I IFN and yet mediates important immune functions previously attributed to all pDCs.P lasmacytoid dendritic cells (pDCs) are a distinct lineage of bone-marrow-derived cells that reside mainly in blood and lymphoid organs in the steady state, but can also be found in sites of infection, inflammation, and cancer (1). As one of the two principal lineages of dendritic cells, pDCs diverge from conventional DCs (cDCs) during maturation in the bone marrow and are recognized mainly for their rapid and massive production of type I IFN (IFNα/β) in response to viral infection (2). Although generally viewed as weak antigen-presenting cells by comparison with cDCs, pDCs interact with many types of cells, such as NK cells, cDCs, T cells, and B cells through their secretion of cytokines and chemokines in addition to type I IFN, as well as through their expression of various costimulatory molecules (3, 4). Thus, pDCs are capable of activating CD4 + helper and regulatory T cells and CD8 + cytotoxic T cells (5-16). They can also stimulate B-cell activation, differentiation into plasma cells, and antibody production through mechanisms that are not yet completely understood (17)(18)(19)(20)(21)(22).Whether the diverse functions of pDCs are mediated by the same cells responding to different environmental cues or by distinct preprogrammed subsets or lineages is not clear, although several reports suggest the existence of phenotypically distinct subpopulations of pDCs in mice (23-25) and humans (26-30). Surface expression of CD2 divides human pDCs into two distinct subsets. Whereas both CD2 lo and CD2 hi pDCs produce type I IFN, the CD2 hi subset secretes more IL12p40, triggers more T-cell proliferation (26), and is relatively resistant to apoptosis on the basis of higher BCL2 expression (28). Here we show that CD2 hi pDCs contain a unique subpopulation that expresses CD5 and CD81. Unlike CD2 hi CD5 − CD81 − pDCs, CD2 hi CD5 + CD81 + pDCs fail to produce type 1 IFN but ...

For the purpose of oxidation decomposition control of the polyether-based solid polymer electrolyte (SPE) in the high-voltage state, lithium phosphate (Li3PO4)-coated cathode (LiCoO2) powder was prepared via a mechanical coating technique. An all-solid-state lithium polymer secondary battery that used Li3PO4-coated LiCoO2 was prepared. By the oxidation suppression enabled by the Li3PO4 that was intervened between SPE and LiCoO2, charging up to a high voltage (4.6 V vs Li/Li+) was made possible and the discharge capacity was observed to be over 200 mAh g-1. Detailed electrochemical analysis was enabled by a combination of constant current−constant voltage charging measurements and electrochemical impedance spectroscopy (EIS). As a result, it became clear that the oxidation decomposition that takes place at the SPE/cathode interface can be controlled by a coating of Li3PO4 on LiCoO2.

The thermal behavior of a lithium-ion cell during charge and discharge was determined using an isothermal calorimeter. In order to assign the thermal characteristics of the lithium-ion cell to the cathode false(LiCoO2false) and the anode (graphite) material, a LiCoO2/normalLi cell and a graphite/Li cell were prepared. The thermal behaviors were compared with that of a lithium-ion false(LiCoO2 /graphite) cell. The notable thermal characteristics could be attributed to the individual electrode materials. In particular, the discontinuous thermal profiles showed good agreement with the phase change of the host structure of each electrode material. The degradation factor of commercially available lithium-ion cells was determined using these discontinuous thermal profiles as an indicator of the electrode reactions. We found that the decrease in the effective active material of the graphite is the main cause of capacity fading after cycling. © 2002 The Electrochemical Society. All rights reserved.

A 5 V class ceramic/polymer composite all-solid-state lithium battery was prepared. The cell configuration was ͓Li 3 PO 4 coated LiNi 0.5 Mn 1.5 O 4 ͉solid polymer electrolyte͉ Li͔. The total cell impedance was 4 k⍀ at 333 K and the discharge capacity was 100 mAh g Ϫ1 with a discharge voltage plateau in both 4.7 and 4.1 V regions. X-ray absorption near-edge structure results indicated that both transition metal ions, Ni and Mn, involved in the oxidation/reduction processes. The cell without Li 3 PO 4 showed a lower discharge voltage plateau ͑Ͻ3.5 V͒ than the composite one. Although the Li 3 PO 4 film was so thin that it could be nearly removed with only 2 min of Ar etching in X-ray photoelectron spectroscopy, Li 3 PO 4 is thought to have a function as a solid electrolyte interface between LiNi 0.5 Mn 1.5 O 4 and SPE to prevent the degradation of solid polymer electrolyte.Lithium-ion cells, which consist of lithium transition-metaloxide positive electrodes and carbon negative electrodes, are widely used in portable electric devices. 1 However, the issue of the genuine safety of the cell must be resolved in scaling up of the cell for use in load leveling ͑LL͒ and zero-emission vehicles ͑ZEV͒. 2 Namely, the combination of a flammable organic electrolyte with a highly oxidized positive electrode can explode easily if sufficient care is not taken. Some safety systems have already been applied in commercialized cells, which have worked well in small-scale cells. However, not all of these safety systems may work well in the large-scale cell. Therefore, a solvent-free all-solid-state battery, which is the most suitable for a large-scale battery system, is needed. There are two types of lithium conductive solid electrolyte, the polymer type and the inorganic type. The polymer type was mainly developed for large-scale batteries because it easily tolerates volume change of the electrode materials during charge and discharge. However, combinating a high voltage positive electrode with the polymer electrolyte is difficult because of the poor oxidation resistivity of the ethylene oxide units, and therefore a 3 V class positive electrode, such as vanadium oxide, V 2 O 5 , was applied to the polymer-type system. 3 On the other hand, an inorganic electrolyte has high oxidation resistivity; for example, a lithium phosphorous oxynitride electrolyte ͑Li-PON͒ showed resistivity at over 5 V. 4,5 However, the ceramic electrolyte cannot tolerate the volume change of electrodes, particularly in large scale batteries, during charge and discharge. Thus, we proposed the concept of a composite in which an inorganic electrolyte is placed at the positive electrode surface and a polymer electrolyte is placed at the negative electrode surface. In this setup, a high voltage positive material can be utilized with a lithium metal negative electrode in an all-solid-state battery. Furthermore, the composite system has the potential to permit scaling of the cell due to the contribution of the polymer flexibility. We previously demonstrated the combina...

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