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Robust human immune system (HIS) mice are created using human fetal thymus tissue and hematopoietic stem cells (HSCs). A HIS mouse model using neonatal human thymus tissue and umbilical cord blood (CB) HSCs (NeoHu) was recently described. We improved the model by removing the native murine thymus, which can also generate human T cells, and demonstrated definitively the capacity of human T cells to develop in a grafted neonatal human thymus. Human T cells derived from the neonatal thymus tissue appeared in peripheral blood early post-transplantation and CB-derived T cells appeared later. Naïve T cells were demonstrated in peripheral blood but effector memory and T peripheral helper phenotypes predominated later, in association with development of autoimmunity in some animals. Treatment of thymus grafts with 2-deoxyglucose (2-DG) increased the proportion of stem cells derived from injected HSCs, delayed onset of autoimmune disease, reduced early T cell reconstitution, and reduced effector/memory T cell conversion. Younger neonatal human thymus tissue was associated with improved T cell reconstitution. While the NeoHu model bypasses the need for fetal tissue, it has yet to demonstrate equivalent reconstitution to fetal tissue, though 2-DG can improve results by removing native thymocytes prior to transplantation.

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Cytosolic DNA is characteristic of chromosomally unstable metastatic cancer cells, resulting in constitutive activation of the cGAS–STING innate immune pathway. How tumors co-opt inflammatory signaling while evading immune surveillance remains unknown. Here, we show that the ectonucleotidase ENPP1 promotes metastasis by selectively degrading extracellular cGAMP, an immune-stimulatory metabolite whose breakdown products include the immune suppressor adenosine. ENPP1 loss suppresses metastasis, restores tumor immune infiltration, and potentiates response to immune checkpoint blockade in a manner dependent on tumor cGAS and host STING. Conversely, overexpression of wild-type ENPP1, but not an enzymatically weakened mutant, promotes migration and metastasis, in part through the generation of extracellular adenosine, and renders otherwise sensitive tumors completely resistant to immunotherapy. In human cancers, ENPP1 expression correlates with reduced immune cell infiltration, increased metastasis, and resistance to anti–PD-1/PD-L1 treatment. Thus, cGAMP hydrolysis by ENPP1 enables chromosomally unstable tumors to transmute cGAS activation into an immune-suppressive pathway.Significance:Chromosomal instability promotes metastasis by generating chronic tumor inflammation. ENPP1 facilitates metastasis and enables tumor cells to tolerate inflammation by hydrolyzing the immunotransmitter cGAMP, preventing its transfer from cancer cells to immune cells.This article is highlighted in the In This Issue feature, p. 995

Electric Discharge Machining (EDM) working fluid as a medium can control electrical discharges occur, carry away the heat, compress discharge channel and help remove the corrosion products out of the gap. The main working fluids used in EDM are oil-based working fluid, gas-based working fluid, powder mixed working fluid, gas mixed working fluid and water-based working fluid. In order to improve the green and safety of EDM working fluid, an oil-in-water working fluid is proposed. A gap flow field model of EDM is established by using external flushing fluid. The flow field distribution, pressure distribution and corrosion products distribution of the machining gap are analyzed by using computational fluid dynamics. The effects of inlet pressure, processing depth and electrode size on the flow field are studied. The simulated results show that within a certain range, removal effect of the corrosion products will increase with inlet velocity and the size of electrode and decrease with processing depth.

Interactions between B cells and CD4(+) T cells play a central role in the development of Type 1 Diabetes (T1D). Two helper cell subsets, follicular (Tfh) and peripheral (Tph) helper T cells, are increased in patients with T1D but their role in driving B cell autoimmunity is undefined. We used a personalized immune (PI) mouse model to generate human immune systems de novo from hematopoietic stem cells (HSCs) of patients with T1D or from healthy controls (HCs). Both groups developed Tfh and Tph-like cells, and those with T1D-derived immune systems demonstrated increased numbers of Tph-like and Tfh cells compared to HC-derived PI mice. T1D-derived immune systems included increased proportions of unconventional memory CD27(−)IgD(−) B cells and reduced proportions of naïve B cells compared to HC PI mice, resembling changes reported for patients with systemic lupus erythematosus. Our findings suggest that T1D HSCs are genetically programmed to produce increased proportions of T cells that promote the development of unconventional, possibly autoreactive memory B cells. PI mice provide an avenue for further understanding of the immune abnormalities that drive autoantibody pathogenesis and T1D.

The eye tracker enables the new applications for consumer electronics. By estimating the human gaze direction in real-time as a human-machine interface (HMI), various novel computer games or remote learning systems for education purpose could be developed. In this paper, a new HMI system, which integrates a visible-spectrum gaze tracker, a fixation/saccade analyzer, an object tracking, and a score evaluation module, has been proposed. This system aims at guiding the design the computer game as well as the examination of human visual reaction for various consumer electronics.

We developed a rapid method to remove the native mouse thymus from NSG mice, which allowed us to compare the behavior of human immune cells in the presence or absence of human T cells in human immune system mice. Removing the native mouse thymus is critical for studies of human thymopiesis in grafted thymic tissue in humanized mice.

Background A major obstacle to the success of organ transplantation from pigs to humans, necessitated by the shortage of human organs, is robust humoral immune rejection by pig-reactive human antibodies. Mixed xenogeneic hematopoietic chimerism induces xenoreactive B cell tolerance in rodents, but whether mixed pig/human chimerism could induce tolerance of human B cells to pig xenoantigens is unknown. Methods We investigated this question using a humanized mouse model in which durable mixed (pig-human) xenogeneic chimerism can be established. Results Human natural anti-pig cytotoxic antibodies, predominantly IgM, are detectable in non-chimeric humanized mouse serum, and pig-reactive antibodies were reduced in mixed chimeric versus non-chimeric humanized mice. This difference required persistent mixed chimerism and was not due to the adsorption of antibodies on pig cells in vivo. Furthermore, human B cells from spleens of mixed chimeric mice produced lower levels of anti-pig antibodies when stimulated in vitro compared with those from non-chimeric mice. Conclusions Our findings demonstrate that mixed chimerism reduces human natural antibodies to pig xenoantigens, providing the first in vivo evidence of human B cell tolerance induction by mixed xenogeneic chimerism and supporting further evaluation of this approach for inducing human B cell tolerance to xenografts.

We evaluated the role of the thymus in development of multi-organ autoimmunity in human immune system (HIS) mice. T cells were essential for disease development and the same T cell clones with varying phenotypes infiltrated multiple tissues. De novo-generated hematopoietic stem cell (HSC)-derived T cells were the major disease drivers, though thymocytes pre-existing in grafted human thymi contributed if not first depleted. HIS mice with a native mouse thymus developed disease earlier than thymectomized mice with a thymocyte-depleted human thymus graft. Defective structure in the native mouse thymus was associated with impaired negative selection of thymocytes expressing a transgenic TCR recognizing a self-antigen. Disease developed without direct recognition of antigens on recipient mouse MHC. While human thymus grafts had normal structure and negative selection, failure to tolerize human T cells recognizing mouse antigens presented on HLA molecules may explain eventual disease development. These new insights have implications for human autoimmunity and suggest methods of avoiding autoimmunity in next-generation HIS mice.

Cytosolic DNA is characteristic of chromosomally unstable metastatic cancer cells, resulting in constitutive activation of the cGAS–STING innate immune pathway. How tumors co-opt inflammatory signaling while evading immune surveillance remains unknown. Here, we show that the ectonucleotidase ENPP1 promotes metastasis by selectively degrading extracellular cGAMP, an immune-stimulatory metabolite whose breakdown products include the immune suppressor adenosine. ENPP1 loss suppresses metastasis, restores tumor immune infiltration, and potentiates response to immune checkpoint blockade in a manner dependent on tumor cGAS and host STING. Conversely, overexpression of wild-type ENPP1, but not an enzymatically weakened mutant, promotes migration and metastasis, in part through the generation of extracellular adenosine, and renders otherwise sensitive tumors completely resistant to immunotherapy. In human cancers, ENPP1 expression correlates with reduced immune cell infiltration, increased metastasis, and resistance to anti–PD-1/PD-L1 treatment. Thus, cGAMP hydrolysis by ENPP1 enables chromosomally unstable tumors to transmute cGAS activation into an immune-suppressive pathway. Significance: Chromosomal instability promotes metastasis by generating chronic tumor inflammation. ENPP1 facilitates metastasis and enables tumor cells to tolerate inflammation by hydrolyzing the immunotransmitter cGAMP, preventing its transfer from cancer cells to immune cells. This article is highlighted in the In This Issue feature, p. 995

During T cell development in mice, thymic negative selection deletes cells with the potential to recognize and react to self-antigens. In human T cell-dependent autoimmune diseases such as Type 1 diabetes, multiple sclerosis, and rheumatoid arthritis, T cells reactive to autoantigens are thought to escape negative selection, traffic to the periphery and attack self-tissues. However, physiological thymic negative selection of autoreactive human T cells has not been previously studied. We now describe a human T-cell receptor-transgenic humanized mouse model that permits the study of autoreactive T-cell development in a human thymus. Our studies demonstrate that thymocytes expressing the autoreactive Clone 5 TCR, which recognizes insulin B:9–23 presented by HLA-DQ8, are efficiently negatively selected at the double and single positive stage in human immune systems derived from HLA-DQ8+ HSCs. In the absence of hematopoietic expression of the HLA restriction element, negative selection of Clone 5 is less efficient and restricted to the single positive stage. To our knowledge, these data provide the first demonstration of negative selection of human T cells recognizing a naturally-expressed tissue-restricted antigen. Intrathymic antigen presenting cells are required to delete less mature thymocytes, while presentation by medullary thymic epithelial cells may be sufficient to delete more mature single positive cells. These observations set the stage for investigation of putative defects in negative selection in human autoimmune diseases., Highlights • In the presence of the HLA-restriction element on hematopoietic stem cells (HSCs) and thymus.•Thymocytes bearing insulin peptide-reactive TCRs express markers of thymic negative selection.•Insulin peptide-reactive T cells are efficiently negatively selected in the human thymus.•The few transgenic T cells that escape negative selection largely express endogenous TCRs. • HLA-restriction element on HSCs is required for efficient negative selection.

Non-Hermitian descriptions of quantum matter have seen impressive progress recently, with major advances in understanding central aspects such as their topological properties or the physics of exceptional points, the non-Hermitian counterpart of critical points. Here, we use single-photon interferometry to reconstruct the non-Hermitian Kibble-Zurek mechanism and its distinct scaling behavior for exceptional points, by simulating the defect production upon performing slow parameter ramps. Importantly, we are able to realise also higher-order exceptional points, providing experimental access to their theoretically predicted characteristic Kibble-Zurek scaling behaviour. Our work represents a crucial step in increasing the experimental complexity of non-Hermitian quantum time-evolution. It thus also furthers the quest to move the frontier from purely single-particle physics towards increasingly complex settings in the many-body realm., Comment: 8 pages, 6 figures

Background Tolerance-inducing approaches to xenotransplantation would be optimal and may be necessary for long-term survival of transplanted pig organs in human patients. The ideal approach would generate donor-specific unresponsiveness to the pig organ without suppressing the patient's normal immune function. Porcine thymus transplantation has shown efficacy in promoting xenotolerance in humanized mice and large animal models. However, murine studies demonstrate that T cells selected in a swine thymus are positively selected only by swine thymic epithelial cells, and therefore, cells expressing human HLA-restricted TCRs may not be selected efficiently in a transplanted pig thymus. This may lead to suboptimal patient immune function. Methods To assess human thymocyte selection in a pig thymus, we used a TCR transgenic humanized mouse model to study positive selection of cells expressing the MART1 TCR, a well-characterized human HLA-A2-restricted TCR, in a grafted pig thymus. Results Positive selection of T cells expressing the MART1 TCR was inefficient in both a non-selecting human HLA-A2- or swine thymus compared with an HLA-A2+ thymus. Additionally, CD8 MART1 TCRbright T cells were detected in the spleens of mice transplanted with HLA-A2+ thymi but were significantly reduced in the spleens of mice transplanted with swine or HLA-A2- thymi. [Correction added on October 15, 2019, after first online publication: The missing superscript values +, -, and bright have been included in the Results section.] CONCLUSIONS: Positive selection of cells expressing a human-restricted TCR in a transplanted pig thymus is inefficient, suggesting that modifications to improve positive selection of cells expressing human-restricted TCRs in a pig thymus may be necessary to support development of a protective human T-cell pool in future patients.

We studied human T cell repertoire formation using high-throughput T cell receptor β (TCRβ) complementarity-determining region 3 (CDR3) sequencing in immunodeficient mice receiving human hematopoietic stem cells (HSCs) and human thymus grafts. Replicate humanized mice generated diverse and highly divergent repertoires. We observed repertoire narrowing and increased CDR3β sharing during thymocyte selection. Whereas hydrophobicity analysis implicated self-peptides in positive selection of the overall repertoire, positive selection favored shorter shared sequences that had reduced hydrophobicity at positions 6 and 7 of CDR3βs, suggesting weaker interactions with self-peptides than were observed with unshared sequences, possibly allowing escape from negative selection. Sharing was similar between autologous and allogeneic thymi and occurred between different cell subsets. Shared sequences were enriched for allo–cross-reactive CDR3βs and for type 1 diabetes–associated autoreactive CDR3βs. Single-cell TCR sequencing showed increased sharing of CDR3αs compared with CDR3βs between mice. Our data collectively implicate preferential positive selection for shared human CDR3βs that are highly cross-reactive. Although previous studies suggested a role for recombination bias in producing “public” sequences in mice, our study is the first to our knowledge to demonstrate a role for thymic selection. Our results implicate positive selection for promiscuous TCRβ sequences that probably evade negative selection, given their low affinity for self-ligands, in the abundance of “public” human TCRβ sequences.

We study the properties of Bose–Einstein condensates under a non-Hermitian spin–orbit coupling (SOC), induced by a dissipative two-photon Raman process. We focus on the dynamics of the condensate at short times, when the impact of decoherence induced by quantum jumps is negligible and the dynamics is coherently driven by a non-Hermitian Hamiltonian. Given the significantly modified single-particle physics by dissipative SOC, the interplay of non-Hermiticity and interaction leads to a quasi-steady-state phase diagram different from its Hermitian counterpart. In particular, we find that dissipation can induce a phase transition from the stripe phase to the plane-wave phase. We further map out the phase diagram with respect to the dissipation and interaction strengths, and finally investigate the stability of quasi-steady states through the time-dependent dissipative Gross–Pitaevskii equation. Our results are readily accessible based on standard experiments with synthetic spin–orbit couplings.

The immunosuppressive capacity of human mesenchymal stromal cells (MSCs) renders them promising candidates for treating diverse immune disorders. However, after hundreds of clinical trials, there are still no MSC therapies approved in the United States. MSCs require specific cues to adopt their immunosuppressive phenotype, and yet most clinical trials use cells expanded in basic culture medium and growth conditions. We propose that priming MSCs prior to administration will improve their therapeutic efficacy. Interferon-gamma (IFN-γ) priming are cues common to situations of immune escape that have individually shown promise as MSC priming cues but have not been systematically compared. Using mixed lymphocyte reactions, we show that priming MSCs with either cue alone improves T-cell inhibition. However, combining the two cues results in additive effects and markedly enhances the immunosuppressive phenotype of MSCs. We demonstrate that IFN-γ induces expression of numerous immunosuppressive proteins (IDO, PD-L1, HLA-E, HLA-G), whereas hypoxia switches MSCs to glycolysis, causing rapid glucose consumption and production of T-cell inhibitory lactate levels. Dual IFN-γ/hypoxia primed MSCs display both attributes and have even higher induction of immunosuppressive proteins over IFN-γ priming alone (IDO and HLA-G), which may reflect another benefit of metabolic reconfiguration.

Background: Spontaneous intracerebral hemorrhage (sICH) is a serious condition that incurs a high medical expenditure. The most frequent cause of sICH in young adults and children is arteriovenous malformation (AVM). Most cases of AVM are congenital, and there is 4% per year who have sICH attacked since birth. There are two primary methods of treatment: craniotomy with removal of AVM and radiosurgery; in addition, some patients undergo general head surgery with removal of the sICH only.Methods: A dataset consisting of inpatient expenditure by admission and a registry of beneficiaries was derived from the Taiwan National Health Insurance Research Database (NHIRD). AVM patients were separated into groups according to the type of surgery they received, which included no surgery, craniotomy, arteriovenous surgery and radiosurgery. In this study, we recorded the characteristics of the AVM patients, including age, medical expenditure and total length of stay, in the different treatment groups, and analyzed the occurrence of first-attack arteriovenous malformation in each age group.Results: In total, 710 person-times were included in this study; 380 person-times were male and 330 were female patients, and 438, 35, 169, 141 person-times were classified into the no surgery, craniotomy, arteriovenous surgery and radiosurgery groups, respectively. The results showed that craniotomy attracted a higher medical expenditure than the other treatments due to room fees. Age, medical expenditure and total length of stay differed significantly between the groups of patients undergoing different types of surgery.Conclusions: This study demonstrated that AVM surgery differs significantly from general head surgery, craniotomy with removal of AVM, and radiosurgery in various ways. Decision-making regarding treatment depends on the condition of the patient. General head surgery incurs the highest medical expenditure, and the patients who underwent radiosurgery were younger than the others.

A crucial player in immune regulation, FoxP3+ regulatory T cells (Tregs) are drawing attention for their heterogeneity and noncanonical functions. Here, we describe a Treg subpopulation that controls hematopoietic stem cell (HSC) quiescence and engraftment. These Tregs highly expressed an HSC marker, CD150, and localized within the HSC niche in the bone marrow (BM). Specific reduction of BM Tregs achieved by conditional deletion of CXCR4 in Tregs, increased HSC numbers in the BM. Adenosine generated via the CD39 cell surface ectoenzyme on niche Tregs protected HSCs from oxidative stress and maintained HSC quiescence. In transplantation settings, niche Tregs prevented allogeneic (allo-) HSC rejection through adenosine and facilitated allo-HSC engraftment. Furthermore, transfer of niche Tregs promoted allo-HSC engraftment to a much greater extent than transfer of other Tregs. These results identify a unique niche-associated Treg subset and adenosine as regulators of HSC quiescence, abundance, and engraftment, further highlighting their therapeutic utility.

Mixed chimerism is a promising approach to inducing allograft and xenograft tolerance. Mixed allogeneic and xenogeneic chimerism in mouse models induced specific tolerance and global hyporesponsiveness, respectively, of host mouse natural killer (NK) cells. In this study, we investigated whether pig/human mixed chimerism could tolerize human NK cells in a humanized mouse model. Our results showed no impact of induced human NK cell reconstitution on porcine chimerism. NK cells from most pig/human mixed chimeric mice showed either specifically decreased cytotoxicity to pig cells or global hyporesponsiveness in an in vitro cytotoxicity assay. Mixed xenogeneic chimerism did not hamper the maturation of human NK cells but was associated with an alteration in NK cell subset distribution and interferon gamma (IFN-gamma) production in the bone marrow. In summary, we demonstrate that mixed xenogeneic chimerism induces human NK cell hyporesponsiveness to pig cells. Our results support the use of this approach to inducing xenogeneic tolerance in the clinical setting. However, additional approaches are required to improve the efficacy of tolerance induction while ensuring adequate NK cell functions.

A digital mask microlithography system is designed and constructed, which employs a 405nm semiconductor laser diode as light source, and uses a DMD (Digital Micro-mirror Device) as high-precision digital mask. The microstructure array with logo and optical grating has been obtained successfully on this system. Lithography results have been evaluated carefully with the aid of microscope and white light scanning profiler. The feasibility of the microlithography system has been further proved.

In mice, graft-versus-host reactions, associated with powerful graft-versus-tumor effects, can be achieved without graft-versus-host disease (GVHD) by delayed administration of donor lymphocyte infusions (DLI) to established mixed chimeras. However, GVHD sometimes occurs after DLI in established mixed chimeric patients. In contrast to mice, in which T cell recovery from the thymus occurs prior to DLI administration, human T cell reconstitution following T cell–depleted hematopoietic cell transplantation is slow, resulting in lymphopenia at the time of DLI. We demonstrate in this study that T cell lymphopenia is an independent risk factor for GVHD following DLI in the absence of known inflammatory stimuli. DLI-induced GVHD was prevented in lymphopenic recipients by prior administration of a small number of nonalloreactive polyclonal T cells, insufficient to prevent lymphopenia-associated expansion of subsequently administered T cells, through a regulatory T cell–independent mechanism. GVHD was not inhibited by T cells with irrelevant specificity. Moreover, administration of antibiotics reduced the severity of GVHD in lymphopenic hosts. Accumulation of DLI-derived effector T cells and host hematopoietic cell elimination were markedly diminished by regulatory T cell–depleted, nonalloreactive T cells. Finally, thymectomized mixed chimeras showed increased GVHD following delayed DLI. Collectively, our data demonstrate that in the absence of known conditioning-induced inflammatory stimuli, T cell lymphopenia is a risk factor for GVHD in mixed chimeras receiving delayed DLI. Our data suggest that the predisposition to GVHD can at least in part be explained by the presence of occult inflammatory stimuli due to the absence of T cells to control microbial infections.