Microstructure and Ablation Behavior of C/C-SiC-(ZrxHf1-x)C Composites Prepared by Reactive Melt Infiltration Method.

C/C-SiC-(ZrxHf1-x)C composites were prepared by the reactive melt infiltration method. The microstructure of the porous C/C skeleton and the C/C-SiC-(ZrxHf1-x)C composites, as well as the structural evolution and ablation behavior of the C/C-SiC-(ZrxHf1-x)C composites, were systematically investigated. The results show that the C/C-SiC-(ZrxHf1-x)C composites were mainly composed of carbon fiber, carbon matrix, SiC ceramic, (ZrxHf1-x)C and (ZrxHf1-x)Si2 solid solutions. The refinement of the pore structure is beneficial to promote the formation of (ZrxHf1-x)C ceramic. The C/C-SiC-(ZrxHf1-x)C composites exhibited outstanding ablation resistance under an air-plasma environment at around 2000 °C. After ablation for 60 s, CMC-1 appeared to possess the minimum mass and linear ablation rates of only 2.696 mg/s and -0.814 µm/s, respectively, which are lower than those of CMC-2 and CMC-3. During the ablation process, a Bi-liquid phase and a liquid-solid two-phase structure were formed on the ablation surface which could act as an oxygen diffusion barrier to retard further ablation, which is responsible for the excellent ablation resistance of the C/C-SiC-(ZrxHf1-x)C composites.

Effective Killing of Acute Myeloid Leukemia by TIM-3 Targeted Chimeric Antigen Receptor T Cells.

Acute myeloid leukemia (AML) is an aggressive disease with poor outcomes, overwhelmingly due to relapse. Minimal residual disease (MRD), defined as the persistence of leukemic cells after chemotherapy treatment, is thought to be the major cause of relapse. The origins of relapse in AML have been traced to rare therapy-resistant leukemic stem cells (LSCs) that are already present at diagnosis. Effective treatment strategies for long-term remission are lacking, as it has been difficult to eliminate LSCs with conventional therapy. Here, we proposed a new approach based on the chimeric antigen receptor (CAR)-directed T lymphocytes, targeting T-cell immunoglobulin, and mucin domain 3 (TIM-3) to treat MRD in patients with AML. TIM-3 is selected as the target because it is highly expressed on AML blasts and LSCs in most subtypes regardless of the patient's genetic characteristics and treatment course. Moreover, it is absent in the normal hematopoietic stem cells, granulocytes, naïve lymphocytes, and most normal nonhematopoietic tissues. Using a naïve human Fab phage display library, we isolated an anti-human TIM-3 antibody and designed a second-generation anti-TIM-3. Our anti-TIM-3 CAR T cells exhibit potent antileukemic activity against AML cell lines and primary AML blasts, and in the mouse models. More importantly, we demonstrate efficient killing of the primary LSCs directly isolated from the patients. Hence, eradication of the LSCs present in the MRD by anti-TIM-3 CAR T-cell therapy following the first-line treatment may improve the clinical outcomes of patients with AML.

Influenza A Virus Facilitates Its Infectivity by Activating p53 to Inhibit the Expression of Interferon-Induced Transmembrane Proteins.

Human influenza virus (IAV) are among the most common pathogens to cause human respiratory infections. A better understanding on interplay between IAV and host factors may provide clues for disease prevention and control. While many viruses are known to downregulate p53 upon entering the cell to reduce the innate host antiviral response, IAV infection is unusual in that it activates p53. However, it has not been clear whether this process has proviral or antiviral effects. In this study, using human isogenic p53 wild-type and p53null A549 cells generated from the CRISPR/Cas9 technology, we observed that p53null cells exhibit significantly reduced viral propagation when infected with influenza A virus (strain A/Puerto Rico/8/1934 H1N1). Genome-wide microarray analysis revealed that p53 regulates the expression of a large set of interferon-inducible genes, among which the interferon-induced transmembrane family members IFITM1, IFITM2, and IFITM3 were most significantly downregulated by the expression of p53. Knockdown of interferon-induced transmembrane proteins (IFITMs) by short interfering RNAs enhanced influenza virus infectivity in p53null A549 cells, while overexpressed IFITMs in A549 cells blocked virus entry. Intriguingly, regulation of IFITMs by p53 is independent of its transcriptional activity, as the p53 short isoform Δ40p53 recapitulates IFITM regulation. Taken together, these data reveal that p53 activation by IAV is an essential step in maintaining its infectivity. This novel association between human p53 and the broad spectrum antiviral proteins, the IFITMs, demonstrates a previous mechanism employed by influenza virus to enhance its propagation via p53 inhibition of IFITMs.

Dual non-contiguous peptide occupancy of HLA class I evoke antiviral human CD8 T cell response and form neo-epitopes with self-antigens.

Host CD8 T cell response to viral infections involves recognition of 8-10-mer peptides presented by MHC-I molecules. However, proteasomes generate predominantly 2-7-mer peptides, but the role of these peptides is largely unknown. Here, we show that single short peptides of <8-mer from Latent Membrane Protein 2 (LMP2) of Epstein Barr Virus (EBV) can bind HLA-A*11:01 and stimulate CD8+ cells. Surprisingly, two peptide fragments between 4-7-mer derived from LMP2(340-349) were able to complement each other, forming combination epitopes that can stimulate specific CD8+ T cell responses. Moreover, peptides from self-antigens can complement non-self peptides within the HLA binding cleft, forming neoepitopes. Solved structures of a tetra-complex comprising two peptides, HLA and ß2-microglobulin revealed the free terminals of the two peptides to adopt an upward conformation directed towards the T cell receptor. Our results demonstrate a previously unknown mix-and-match combination of dual peptide occupancy in HLA that can generate vast combinatorial complexity.

[Biological characteristics of mesenchymal stem cell and hematopoietic stem cell in the co-culture system].

The aim of the present study was to obtain the qualified hematopoietic stem/progenitor cells (HSC/HPC) and human umbilical cord-mesenchymal stem cells (MSC) in vitro in the co-culture system. Cord blood mononuclear cells were separated from umbilical cord blood by Ficoll lymphocyte separation medium, and then CD34+ HSC was collected by MACS immunomagnetic beads. The selected CD34+ HSC/HPC and MSC were transferred into culture flask. IMDM culture medium with 15% AB-type cord plasma supplemented with interleukin-3 (IL-3), IL-6, thrombopoietin (TPO), stem cell factor (SCF) and FMS-like tyrosine kinase 3 ligand (Flt-3L) factors were used as the co-culture system for the amplification of HSC/HPC and MSC. The cellular growth status and proliferation on day 6 and 10 after co-culture were observed by using inverted microscope. The percentage of positive expression of CD34 in HSC/HPC, as well as the percentages of positive expressions of CD105, CD90, CD73, CD45, CD34 and HLA-DR in the 4th generation MSC, was tested by flow cytometry. Semisolid colony culture was used to test the HSC/HPC colony forming ability. The osteogenic, chondrogenesis and adipogenic ability of the 4th generation MSC were assessed. The karyotype analysis of MSC was conducted by colchicines. The results demonstrated that the HSC/HPC of co-culture group showed higher ability of amplification, CFU-GM and higher CD34+ percentage compared with the control group. The co-cultured MSC maintained the ability to differentiate into bone cells, fat cells and chondrocytes. And the karyotype stability of MSC remained normal. These results reveal that the appropriate co-culture system for MSC and HSC is developed, and via this co-culture system we could gain both two kinds of these cells. The MSCs under the co-culture system maintain the biological characteristics. The CFU-GM ability, cell counting and the flow cytometry results of HSC/HPC under the co-culture system are conform to the criterion, showing that the biological functions of HSC/HPC are maintained.

Pathogenic fungi regulate immunity by inducing neutrophilic myeloid-derived suppressor cells.

Despite continuous contact with fungi, immunocompetent individuals rarely develop pro-inflammatory antifungal immune responses. The underlying tolerogenic mechanisms are incompletely understood. Using both mouse models and human patients, we show that infection with the human pathogenic fungi Aspergillus fumigatus and Candida albicans induces a distinct subset of neutrophilic myeloid-derived suppressor cells (MDSCs), which functionally suppress T and NK cell responses. Mechanistically, pathogenic fungi induce neutrophilic MDSCs through the pattern recognition receptor Dectin-1 and its downstream adaptor protein CARD9. Fungal MDSC induction is further dependent on pathways downstream of Dectin-1 signaling, notably reactive oxygen species (ROS) generation as well as caspase-8 activity and interleukin-1 (IL-1) production. Additionally, exogenous IL-1ß induces MDSCs to comparable levels observed during C. albicans infection. Adoptive transfer and survival experiments show that MDSCs are protective during invasive C. albicans infection, but not A. fumigatus infection. These studies define an innate immune mechanism by which pathogenic fungi regulate host defense.

[Condition optimization for bio-oxidation of high-S and high-As gold concentrate].

OBJECTIVE: To study the effects of temperature and lixivium return on the concentrate bio-oxidation and rate of gold cyanide leaching. METHODS: The bioleaching of a high-sulphur (S) and high-arsenic (As) refractory gold concentrate was conducted, and we studied the effects of different temperature (40 ° and 45 °C) and lixivium return (0 and 600 mL) on the bio-oxidation efficiency. The bacterial community structure also was investigated by 16S rRNA gene clone library. RESULTS: The results showed that both the temperature and lixivium return significantly influenced the oxidation system. The temperature rising elevated the oxidation level, while the addition of lixivium depressed the oxidation. Dissimilarity and DCA (detrended correspondence analysis) indicated the effect of temperature on oxidation system was much greater than lixivium. The bacterial community was comprised by Acidithiocacillus caldu (71%) Leptospirillum ferriphilum (23%) and Sulfobacillus thermosulfidooxidans (6%) indicated by the clone library, and the OTU coverage based on 97% sequence similarity was as high as 93.67%. CONCLUSION: Temperature rising to 45 T would improve the oxidation efficiency while lixivium return would decrease it. This study is helpful to provide an important guiding value for the industry cost optimization of mesophile bacterial oxidation and reduction process.

Burkholderia pseudomallei infection of T cells leads to T-cell costimulation partially provided by flagellin.

Burkholderia pseudomallei is the causative agent of melioidosis. While adaptive immunity has been shown to be important for host resistance to B. pseudomallei, the direct interaction of the bacteria with adaptive immune cells such as T and B cells is not well known. To address this question, we infected Jurkat T cells, as well as human primary CD4(+) and CD8(+) T cells, with live B. pseudomallei. We found that live bacterial infection could costimulate T cells to produce interleukin-2 (IL-2) and gamma interferon (IFN-gamma) in the presence of anti-CD3 cross-linking antibodies. Bacterial supernatant could also costimulate T cells, and this was due to the presence of flagellin in the supernatant. However, T cells infected with bacterial mutants lacking flagellin showed strong impairment in IL-2 but only a slight impairment in IFN-gamma production. When cross-linking of CD3 is replaced by IL-2, live bacterial infection was still able to costimulate human primary T cells to produce IFN-gamma and flagellin is only a minor ligand contributing to this costimulation. Thus, live B. pseudomallei could potentially costimulate T cells not only in an antigen-specific manner but also in a nonspecific manner through bystander activation via IL-2.

Distinct mechanisms involving diverse histone deacetylases repress expression of the two gonadotropin beta-subunit genes in immature gonadotropes, and their actions are overcome by gonadotropin-releasing hormone.

The gonadotropins luteinizing hormone (LH) and follicle-stimulating hormone (FSH) are produced in the embryonic pituitary in response to delivery of the hypothalamic gonadotropin releasing hormone (GnRH). GnRH has a pivotal role in reestablishing gonadotropin levels at puberty in primates, and for many species with extended reproductive cycles, these are reinitiated in response to central nervous system-induced GnRH release. Thus, a clear role is evident for GnRH in overcoming repression of these genes. Although the mechanisms through which GnRH actively stimulates LH and FSH beta-subunit (FSHbeta) gene transcription have been described in some detail, there is currently no information on how GnRH overcomes repression in order to terminate reproductively inactive stages. We show here that GnRH overcomes histone deacetylase (HDAC)-mediated repression of the gonadotropin beta-subunit genes in immature gonadotropes. The repressive factors associated with each of these genes comprise distinct sets of HDACs and corepressors which allow for differentially regulated derepression of these two genes, produced in the same cell by the same regulatory hormone. We find that GnRH activation of calcium/calmodulin-dependent protein kinase I (CaMKI) plays a crucial role in the derepression of the FSHbeta gene involving phosphorylation of several class IIa HDACs associated with both the FSHbeta and Nur77 genes, and we propose a model for the mechanisms involved. In contrast, derepression of the LH beta-subunit gene is not CaMK dependent. This demonstration of HDAC-mediated repression of these genes could explain the temporal shut-down of reproductive function at certain periods of the life cycle, which can easily be reversed by the actions of the hypothalamic regulatory hormone.

Flagellin contamination of recombinant heat shock protein 70 is responsible for its activity on T cells.

Heat shock proteins (Hsp) 60 and 70 have been intensively studied for their ability to activate innate immunity. Heat shock proteins had been shown to induce the activation of dendritic cells, T cells, and B cells. However, the possible contamination of endotoxin in heat shock protein preparations makes their function as an activator of immune system ambiguous. Here, we examined the ability of bacterial Hsp60 and Hsp70 to activate Jurkat T cells and primary T cells. We found that Burkholderia pseudomallei Hsp70 and Mycobacterium tuberculosis Hsp70 could costimulate Jurkat T cells to make IL-2 and signal through TLR5. This costimulatory activity is not due to endotoxin or contaminants signaling via TLR2 nor TLR4. However, recombinant Hsp70 expressed in Escherichia coli DeltafliC strain completely lost its ability to costimulate T cells. Thus, the activation of T cells by recombinant Hsp70 is ascribed to flagellin contamination.

Composition and oligosaccharides of a milk sample of the giant panda, Ailuropoda melanoleuca.

A milk sample from a captive giant panda (Ailuropoda melanoleuca), obtained at 13 days postpartum, contained 7.1% protein, 1.6% carbohydrate, 10.4% lipid and 0.9% ash. The ratio of casein to whey proteins was 5.0:2.1. Sodium dodecyl sulfate polyacrylamide electrophoresis (SDS-PAGE) of the whey protein fraction showed the presence of at least two major proteins other than alpha-lactalbumin and beta-lactoglobulin. SDS-PAGE and urea-gel electrophoresis showed that alphas-casein is not a major component. The proportions of triacylglycerol, cholesterol, cholesterol esters and phospholipid were 90.5, 5.3, 0.96 and 3.1%, of the total lipid, respectively. The dominant saccharide in the panda milk was Gal(alpha1-3)Gal(beta1-4)Glc (isoglobotriose). The milk contained, in addition, lesser amounts of lactose, Gal(alpha1-3)Gal(beta1-4)[Fuc(alpha1-3)]Glc (fucosyl isoglobotriose), Neu5Ac(alpha2-3)Gal(beta1-4)Glc (3'-N-acetylneuraminyl-lactose), Neu5Ac(alpha2-6)Gal(beta1-4)Glc (6'-N-acetylneuraminyl-lactose) and Neu5Ac(alpha2-3)Gal(beta1-4)[Fuc(alpha1-3)]Glc.