Oxygen supply for ischemic brain tissue during stroke is critical to neuroprotection. Remote ischemic conditioning (RIC) treatment is effective for stroke. However, it is not known whether RIC can improve brain tissue oxygen supply. In current study, we employed a mouse model of stroke created by middle cerebral artery occlusion (MCAO) to investigate the effect of RIC on oxygen supply to the ischemic brain tissue using a hypoxyprobe system. Erythrocyte oxygen-carrying capacity and tissue oxygen exchange were assessed by measuring oxygenated hemoglobin and oxygen dissociation curve. We found that RIC significantly mitigated hypoxic signals and decreased neural cell death, thereby preserving neurological functions. The tissue oxygen exchange was markedly enhanced, along with the elevated hemoglobin P50 and right-shifted oxygen dissociation curve. Intriguingly, RIC markedly elevated 2,3-biphosphoglycerate (2,3-BPG) levels in erythrocyte, and the erythrocyte 2,3-BPG levels were highly negatively correlated with the hypoxia in the ischemic brain tissue. Further, adoptive transfusion of 2,3-BPG-rich erythrocytes prepared from RIC-treated mice significantly enhanced the oxygen supply to the ischemic tissue in MCAO mouse model. Collectively, RIC protects against ischemic stroke through improving oxygen supply to the ischemic brain tissue where the enhanced tissue oxygen delivery and exchange by RIC-induced 2,3-BPG-rich erythrocytes may play a role.

Antigen specificity is a primary goal in developing curative therapies for autoimmune disease. Dendritic cells (DCs), as the most effective antigen presenting cells in the body, represent a key target to mediate restoration of antigen-specific immune regulation. Here, we describe an injectable, dual-sized microparticle (MP) approach that employs phagocytosable ∼1 μm and nonphagocytosable ∼30 μm MPs to deliver tolerance-promoting factors both intracellularly and extracellularly, as well as the type 1 diabetes autoantigen, insulin, to DCs for reprogramming of immune responses and remediation of autoimmunity. This poly(lactic-co-glycolic acid) (PLGA) MP system prevented diabetes onset in 60% of nonobese diabetic (NOD) mice when administered subcutaneously in 8 week old mice. Prevention of disease was dependent upon antigen inclusion and required encapsulation of factors in MPs. Moreover, administration of this "suppressive-vaccine" boosted pancreatic lymph node and splenic regulatory T cells (Tregs), upregulated PD-1 on CD4+ and CD8+ T cells, and reversed hyperglycemia for up to 100 days in recent-onset NOD mice. Our results demonstrate that a MP-based platform can reeducate the immune system in an antigen-specific manner, augment immunomodulation compared to soluble administration of drugs, and provide a promising alternative to systemic immunosuppression for autoimmunity.

Remote ischemic preconditioning (RIPC) is an effective regimen for neuroprotection in ischemic stroke. Exosomes are extracellular vesicles released into the blood, where they can transfer signals throughout the body. Several studies have demonstrated that RIPC leads to many changes in circulating exosomes. However, the role of RIPC-induced exosomes in neuroprotection remains to be determined. In the current study, we demonstrate that infusion of enriched plasma exosomes from RIPC-treated mice significantly attenuates infarction size in a murine model of cerebral ischemia compared to control group receiving infusion of exosomes from non-RIPC-treated mice. Further studies show that infusion of RIPC-exosomes markedly improves neurological functions. In line with the above findings, we find that the level of hypoxia inducible transcription factor (HIF)-1α is significantly higher in plasma exosomes from mice subjected to RIPC than those from control mice, which could have contributed to the RIPC-exosome-induced neuroprotection through HIF-1α-induced signals including the enhanced tolerance to hypoxia. To our knowledge, this is the first to demonstrate RIPC protects against cerebral ischemia through inducing neuroprotective exosomes.

Dendritic cell (DC) immunotherapy has been effective for prevention of type 1 diabetes (T1D) in NOD mice but fails to protect if initiated after active autoimmunity. As autoreactivity expands inter- and intramolecularly during disease progression, we investigated whether DCs unpulsed or pulsed with β cell antigenic dominant determinants (DD), subdominant determinants (SD), and ignored determinants (ID) could prevent T1D in mice with advanced insulitis. We found that diabetes was significantly delayed by DC therapy. Of interest, DCs pulsed with SD or ID appeared to provide better protection. T lymphocytes from DC-treated mice acquired spontaneous proliferating capability during in vitro culture, which could be largely eliminated by IL-2 neutralizing antibodies. This trend maintained even 29 weeks after discontinuing DC therapy and appeared antigen-independent. Furthermore, CD4+Foxp3+ T regulatory cells (Tregs) from DC-treated mice proliferated more actively in vitro compared to the controls, and Tregs from DC-treated mice showed significantly enhanced immunosuppressive activities in contrast to those from the controls. Our study demonstrates that DC therapy leads to long-lasting immunomodulatory effects in an antigen-dependent and antigen-independent manner and provides evidence for peptide-based intervention during a clinically relevant window to guide DC-based immunotherapy for autoimmune diabetes.

Myeloid-derived suppressor cells (MDSCs) are identified as a heterogeneous population of cells with the function to suppress innate as well as adaptive immune responses. The initial studies of MDSCs were primarily focused on the field of animal tumor models or cancer patients. In cancer, MDSCs play the deleterious role to inhibit tumor immunity and to promote tumor development. Over the past few years, an increasing number of studies have investigated the role of MDSCs in autoimmune diseases. The beneficial effects of MDSCs in autoimmunity have been reported by some studies, and thus, immunosuppressive MDSCs may be a novel therapeutic target in autoimmune diseases. There are some controversial findings as well. Many questions such as the activation, differentiation, and suppressive functions of MDSCs and their roles in autoimmune diseases remain unclear. In this review, we have discussed the current understanding of MDSCs in autoimmune diseases.

The major metabolic feature of diabetes is hyperglycemia which has been linked to the diabetes inflammatory processes, and diabetes-related vulnerability to infection. In the present study, we assessed how glucose affected PBMCs in type I interferon (IFN) production and subsequent signaling. We found that the moderately elevated glucose promoted, and high glucose suppressed type I IFN production, respectively. Pre-exposure to high glucose rendered monocytes more sensitive to IFN-α stimulation with heightened signaling, whereas, instantaneous addition of high glucose did not exhibit such effect. Consistent with this finding, the mRNA levels of IFN-α-induced IRF-7 in PBMCs were positively correlated with HbA1c levels of diabetes patients. Additionally, we found that high glucose promoted the production of other proinflammatory cytokines/chemokines. This study suggests that hyperglycemia may affect the inflammatory process in diabetes via promoting proinflammatory cytokines, as well as the host defense against microbial infections through impeding type I IFN production and signaling.

Objective To induce alloantigen immune tolerance between C3H mice and Balb/c mice by infusing the ultraviolet B(UVB)radiation immature dendritic cells (imDC) and and study the immunological mechanisms of this process.Methods (①) The authors induced alloantigen tolerance in C3H mice (H-2k) by intravenous injecting ultraviolet B (UVB) irradiated Balb/c immature dendritic cells (UVB-Balb/c imDC) derived from the cultures of Balb/c bone marrow cells.(②)Detection of immune tolerance induced regulatory T cells,interleukin-10 (IL-10) and interferon-γ(IFN-γ) in mice in order to study the tolerance mechanism.Results (①)C3H mice immunized with UVB-Balb/c imDC can produce immune tolerance to Balb/c antigens and can not produce anti-Balb/c antibody.(②)C3H mice immunized with UVB-Balb/c imDC can not clear the Balb/c spleen cells in vivo.(③)The T cells of C3H mice immunized with UVB-Balb/c imDC can secrete more IL-10 and produce more FOX-P3 + regulatory T cells than the control group in vitro.Conclusion (①)Immunization of C3H mice with UVB-Balb/c imDC allows C3H mice to fully tolerate Balb/c antigen.(②)The possible cause of immune tolerance to Balb/c antigens in C3H mice is due to the increased secretion of IL-10 from T cells and the production of more FOX-P3 + regulatory T cells.

Type 1 diabetes (T1D) has been associated with both genetic and environmental factors. Increasing incidence of T1D worldwide is prompting researchers to adopt different approaches to explain the biology of T1D, beyond the presence and activity of autoreactive lymphocytes. In this review, we propose inflammatory pathways as triggers for T1D. Within the scope of those inflammatory pathways and in understanding the pathogenesis of disease, we suggest that viruses, in particular Coxsackieviruses, act by causing a type 1 interferonopathy within the pancreas and the microenvironment of the islet. As such, this connection and common thread represents an exciting platform for the development of new diagnostic, treatment and/or prevention options.

Hepatocellular carcinoma (HCC) has a high morbidity and mortality rate worldwide, with limited treatment options. Glypican-3 (GPC3) is a glycosylphosphatidylinositol-anchored glycoprotein that is overexpressed in most HCC tissues but not in normal tissues. GPC3-targeting antibody therapy shows limited response in a clinical trial due to the lack of a tumor specific cytotoxic T lymphocyte (CTL) response. Here, in C57/B6 mice, we demonstrated that intravenous infusion of GPC3-coupled lymphocytes (LC/GPC3(+)) elicited robust GPC3-specific antibody and CTL responses, which effectively restricted proliferation and lysed cultured-HCC cells. Treatment with LC/GPC3(+) induced durable tumor regression in HCC-bearing C57/B6 mice. Administration of LC/GPC3(+) induced elevated levels of the cytotoxic T cell bioactive factors tumor necrosis factor alpha (TNF-alpha), interferon-gamma (IFN-gamma), granzyme B, and perforin, and substantially increased the number of infiltrating CD8(+) T cells in tumor tissues. Moreover, immune responses elicited by LC/GPC3(+) selectively suppressed GPC3(+) tumors, but didn't affect the GPC3(-) tumors in BALB/c mice. Our findings provide the first preclinical evidence that intravenous infusion of the LC/GPC3(+) complex can induce a strong anti-HCC effect through regulating systemic and local immune responses. These results indicate that the LC/GPC3(+) complex could be developed as precision therapeutics for HCC patients in the future.

T cells engineered with chimeric antigen receptor (CAR) have been successfully applied to treat advanced refractory B cell malignancy. However, many challenges remain in extending its application toward the treatment of solid tumors. The immunosuppressive nature of tumor microenvironment is considered one of the key factors limiting CAR-T efficacy. One negative regulator of T cell activity is lymphocyte activation gene-3 (LAG-3). We successfully generated LAG-3 knockout T and CAR-T cells with high efficiency using CRISPR-Cas9 mediated gene editing and found that the viability and immune phenotype were not dramatically changed during in vitro culture. LAG-3 knockout CAR-T cells displayed robust antigen-specific antitumor activity in cell culture and in murine xenograft model, which is comparable to standard CAR-T cells. Our study demonstrates an efficient approach to silence immune checkpoint in CAR-T cells via gene editing.

Significance Glycan binding proteins (GBPs) play an important and ever-emerging role in decoding the structural diversity of cell surface glycans into function. New GBPs provide useful tools to probe and manipulate biological processes. Here we describe the characterization of the Y3 protein from the mushroom Coprinus comatus as a unique GBP that shows selective cytotoxicity toward human T-cell leukemia Jurkat cells through caspase-associated apoptosis. Structural analysis along with glycan array screening of Y3 reveals a unique tertiary structure and a specific interaction with GalNAcβ1-4(Fucα1-3)GlcNAc, a glycan abundant in invertebrates but uncommon in humans. This work expands on promising novel GBPs available in less-explored sources for biomedical and research applications.

Our previous study demonstrated that transfusion of ultraviolet B-irradiated immature dendritic cells (UVB-iDCs) induced alloantigen-specific tolerance between two different strains of mice. Programmed death-1 (PD-1) and programmed death ligand-1 (PD-L1) have been suggested to play an important role in maintaining immune tolerance. In the present study, we seek to address whether PD-1/PD-L1 plays a role in the maintenance of UVB-iDC-induced tolerance. We first observe that the UVB-iDC-induced alloantigen-specific tolerance can be maintained for over 6 weeks. Supporting this, at 6 weeks after tolerance induction completion, alloantigen-specific tolerance is still able to be transferred to syngeneic naïve mice through adoptive transfer of CD4+ T cells. Furthermore, skin transplantation study shows that the survival of allogeneic grafts is prolonged in those tolerant recipients. Further studies show that PD-1/PD-L1 interaction is essential for maintaining the induced tolerance as blockade of PD-1/PD-L1 by anti-PD-L1 antibodies largely breaks the tolerance at both cellular and humoral immunological levels. Importantly, we show that PD-1/PD-L1 interaction in tolerant mice is also essential for controlling alloantigen-responding T cells, which have never experienced alloantigens. The above findings suggest that PD-1/PD-L1 plays a crucial role in maintaining immune tolerance induced by UVB-iDCs, as well as in actively controlling effector T cells specific to alloantigens.

In the present study, we report our recently developed new approach to inducing antigen-specific immune response. We use two nucleophilic substitution “click” chemistry processes to successfully couple protein antigens or peptides to mouse spleen cells or T cells by a heterobifunctional crosslinker, succinimidyl-4-(N-maleimidomethyl cyclohexane)-1-carboxylate (SMCC) or sulfo-SMCC. SMCC and its water-soluble analog sulfo-SMCC contain N-hydroxysuccinimide (NHS) ester and maleimide groups, which allow stable covalent conjugation of amine- and sulfhydryl-containing molecules in trans. Protein coupling to cells relies on the free sulfhydryls (thiols) on cell surfaces and the free amines on protein antigens. Although the amount of protein coupled to cells is limited due to the limited number of cell surface thiols, the injection of spleen cells coupled with antigenic proteins, such as keyhole limpet hemocyanin (KLH) or ovalbumin (OVA), induces a potent antigen-specific immune response in vivo, which is even stronger than that induced by the injection of a large dose of protein plus adjuvants. In addition, short peptides coupled to purified splenic T cells also potently elicit peptide-specific T cell proliferation in vivo after injection. Further studies show that antigen-coupled spleen cell treatment leads to augmented IFN-γ-producing T cells. Our study provides a unique antigen delivery method that efficiently distributes antigen to the entire immune system, subsequently eliciting a potent antigen-specific immune response with enhanced IFN-γ production. The findings in the present study suggest that this antigen-cell coupling strategy could be employed in immunotherapy for cancers, infectious diseases as well as immune-mediated disorders.

Recent evidence has highlighted the role of the innate immune system in type 1 diabetes (T1D) pathogenesis. Specifically, aberrant activation of the interferon response prior to seroconversion of T1D-associated autoantibodies supports a role for the interferon response as a precipitating event toward activation of autoimmunity. Melanoma differentiation-associated protein 5 (MDA5), encoded by IFIH1, mediates the innate immune system's interferon response to certain viral species that form double-stranded RNA (dsRNA), the MDA5 ligand, during their life cycle. Extensive research has associated single nucleotide polymorphisms (SNPs) within the coding region of IFIH1 with T1D. This review discusses the different risk and protective IFIH1 alleles in the context of recent structural and functional analysis that relate to MDA5 regulation of interferon responses. These studies have provided a functional hypothesis for IFIH1 T1D-associated SNPs' effects on MDA5-mediated interferon responses as well as supporting the genome-wide association (GWA) studies that first associated IFIH1 with T1D.

Nonobese diabetic mouse exhibits heightened type I IFN signaling in dendritic cells and it has been demonstrated that type I IFN signaling drastically influences hematopoiesis. In this study, we seek to determine whether heightened type I IFN signaling takes place in NOD hematopoietic stem cells (HSC) and whether HSC functioning alters after onset of diabetes. Lin-Sca-1+c-kit+ (LSK) was used to define HSC within which CD48-CD34- cells were defined as dormant HSCs. In contrast to B6 mice, NOD LSKs was much higher, but the Sca-1 levels on HSCs were significantly lower. No significant difference was found between the two strains in terms of dormant HSCs. Notably, there were much higher numbers of CD34+CD48+ HSCs in NOD mice than in B6 mice. NOD HSCs responded to type I IFN-inducing agent, poly I:C at much higher levels than those of B6 mice, showing higher expression levels of Sca-1. The effect of Poly I:C on Sca-1 up-regulation in HSCs was inhibited by anti-IFNR antibodies in both the NOD and B6 mice. Interestingly, NOD HSCs lose their type I IFN-responding capability after onset of diabetes, which could be recovered after normalization of blood glucose, suggesting that hyperglycemia may impact on HSCs in diabetic animals. Our study demonstrates that heightened type I IFN signaling takes place in HSCs of autoimmune diabetes mouse model NOD mice, and hyperglycemia in diabetes may alter HSC functioning.

Objective To explore the meaning of midkine (MK) levels in serum in different development stage of acute leukemia,and to explore the relationship between MK and WT1.Methods The levels of the MK in serum of 86 cases of acute leukemia and 30 cases of normal people were detected by ELISA.Real-time quantitative PCR (RQ-PCR) method was used to determine the expression of WT1 at mRNA level in 15 AML patients.Results The MK level in serum in the new diagnosed group was higher than that in the complete remission group and the normal control group [7.52 (5.44,10.55) ng/ml vs 3.52 (1.56,5.20) ng/ml vs 2.44 (1.89,3.12) ng/ml].There' s no statistical difference between midkine level in new diagnosed acute B cell leukemia (B-ALL) group and acute myeloid leukemia (AML) group [7.88 (5.78,15.78) ng/ml vs 6.25 (4.59,16.33) ng/ml].The clear correlation was found between the level of serum MK and quantities of marrow WT1 gene (r =0.529,P =0.043).Conclusions The level of MK in serum of acute leukemia patients is increased at the time of new diagnosis and decreased at complete remission.ELISA may be a way to measure the status of AL.The location of MK gene is adjacent to WT1 gene and MK' s clinical significance is similar to WT1' s,furthermore,there is a clear correlation between MK in serum and WT1 of marrow in quantities.

DLI is an effective strategy for patients with recurrent hematological malignancies after allogeneic hematopoietic SCT (allo-HSCT). DLI has been widely applied to boost the graft vs tumor (GVT) or GVL effects. However, given the potentially severe complications associated with conventional DLI and transient GVL effect, new strategies for DLI are emerging. In this review, we have discussed the recent important studies on DLI as a prophylactic or therapeutic modality for relapsed hematological disorders after allo-HSCT. The strategies to separate GVL from GVHD have also been discussed. Leukemia-targeting therapy and lymphodepletion combined with DLI, and prophylactic DLI after allo-HSCT are often employed for patients with high risk of relapse, which has been reviewed as well. In addition, we have also discussed the issues on DLI to be further addressed, such as the doses, timing and frequency of DLI in different clinical settings, leukemic antigen-specific DLI as well as how to augment GVL effect while attenuating GVHD.

It remains a top research priority to develop immunotherapeutic approaches to induce potent antigen-specific immune responses against tumors. However, in spite of some promising results, most strategies are ineffective because they generate low numbers of tumor-reactive cytotoxic T lymphocytes (CTLs). Here we designed a strategy to enhance antigen-specific immune response via administering sulfosuccinimidy1-4-[N-maleimidomethyl] cyclohexane-1-carboxylate (sulfo-SMCC)-conjugated melanoma tumor antigen GP100(25-33) peptide-coupled syngeneic spleen cells in a mouse model of melanoma. We found that infusion of GP100(25-33) peptide-coupled spleen cells significantly attenuated the growth of melanoma in prophylactic and therapeutic immunizations. Consistent with these findings, the adoptive transfer of spleen cells from immunized mice to naive syngeneic mice was able to transfer anti-tumor effect, suggesting that GP100(25-33) peptide-specific immune response was induced. Further studies showed that, CDS+ T cell proliferation and the frequency of interferon (IFN)-gamma-producing CD8+ T cells upon ex vivo stimulation by GP100(25-33) were significantly increased compared to control groups. Tumor antigen, GP100(25-33) specific immune response was also confirmed by ELISpot and GP100-tetramer assays. This approach is simple, easy-handled, and efficiently delivering antigens to lymphoid tissues. Our study offers an opportunity for clinically translating this approach into tumor immunotherapy. (C) 2015 Elsevier Inc. All rights reserved.