Influence of PD‐L1 cross‐linking on cell death in PD‐L1‐expressing cell lines and bovine lymphocytes

Programmed death‐ligand 1 (PD‐L1) blockade is accepted as a novel strategy for the reactivation of exhausted T cells that express programmed death‐1 (PD‐1). However, the mechanism of PD‐L1‐mediated inhibitory signalling after PD‐L1 cross‐linking by anti‐PD‐L1 monoclonal antibody (mAb) or PD‐1–immunogloblin fusion protein (PD‐1‐Ig) is still unknown, although it may induce cell death of PD‐L1⁺ cells required for regular immune reactions. In this study, PD‐1‐Ig or anti‐PD‐L1 mAb treatment was tested in cell lines that expressed PD‐L1 and bovine lymphocytes to investigate whether the treatment induces immune reactivation or PD‐L1‐mediated cell death. PD‐L1 cross‐linking by PD‐1‐Ig or anti‐PD‐L1 mAb primarily increased the number of dead cells in PD‐L1^high cells, but not in PD‐L1^low cells; these cells were prepared from Cos‐7 cells in which bovine PD‐L1 expression was induced by transfection. The PD‐L1‐mediated cell death also occurred in Cos‐7 and HeLa cells transfected with vectors only encoding the extracellular region of PD‐L1. In bovine lymphocytes, the anti‐PD‐L1 mAb treatment up‐regulated interferon‐γ (IFN‐γ) production, whereas PD‐1‐Ig treatment decreased this cytokine production and cell proliferation. The IFN‐γ production in B‐cell‐depleted peripheral blood mononuclear cells was not reduced by PD‐1‐Ig treatment and the percentages of dead cells in PD‐L1⁺ B cells were increased by PD‐1‐Ig treatment, indicating that PD‐1‐Ig‐induced immunosuppression in bovine lymphocytes could be caused by PD‐L1‐mediated B‐cell death. This study provides novel information for the understanding of signalling through PD‐L1.     

Increased Expression of Programmed Cell Death‐1 in Regulatory T Cells of Patients with Severe Sepsis and Septic Shock: An Observational Clinical Study

While regulatory T cells (Tregs) constitutively express programmed cell death‐1 (PD‐1), the role of PD‐1 expression in Tregs of patients with sepsis remains unclear. Thus, we determined PD‐1 expression in Tregs from the peripheral blood of patients with severe sepsis and septic shock. Seventy‐eight patients with severe sepsis and 40 with septic shock, as well as 21 healthy subjects, were enrolled in this study. The percentage of peripheral blood PD‐1⁺ Tregs, as well as absolute Treg counts, were compared between these three groups. PD‐1 expression in Tregs and absolute Treg counts were also compared between survivors and non‐survivors in patients with sepsis. PD‐1 expression in Tregs increased in patients with sepsis compared to healthy controls. Conversely, absolute Treg counts were significantly decreased in patients with sepsis compared to healthy controls; patients with septic shock had the lowest absolute Treg counts. Among patients with sepsis, survivors had lower levels of PD‐1 expression in Tregs, as well as higher absolute Treg counts, than non‐survivors. Additionally, the percentage of PD‐1⁺ Tregs correlated positively with lactate levels as well as the Acute Physiology and Chronic Health Evaluation II and Sequential Organ Failure Assessment scores in patients with sepsis. PD‐1 was upregulated in Tregs of patients with sepsis and may indicate a state of immune dysfunction. Overexpression of PD‐1 in Tregs was associated with more severe sepsis as well as poor outcomes.     

Expression and prognostic significance of programmed death protein 1 and programmed death ligand‐1, and cytotoxic T lymphocyte‐associated molecule‐4 in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignancies and causes of death worldwide. In this study, we assessed the correlation between clinicopathologic factors with programmed cell death protein 1 (PD‐1) and programmed cell death ligand‐1 (PD‐L1), and cytotoxic T lymphocyte‐associated molecule‐4 (CTLA‐4) expressions. Furthermore, we analyzed the prognostic significance of these proteins in a subgroup of patients. We retrospectively evaluated the PD‐1, PD‐L1, and CTLA‐4 expressions in 294 HCC tissue microarray samples using immunohistochemistry. PD‐1 and PD‐L1 expressions were significant related to high CD8+ tumor‐infiltrating lymphocytes (TILs) (r = 0.664, p < 0.001 and r = 0.149, p = 0.012). Only high Edmondson–Steiner grade was statistically related to high PD‐1 expression. High PD‐L1 expression was demonstrated as an independent poor prognostic factor for disease‐free survival in addition to previous known factors, size >5 cm and serum albumin ≤3.5 g/dL in high CD8+ TILs group. We have demonstrated that the combined high expression of PD‐L1 and CD8+ TIL is an important prognostic factor related to the immune checkpoint pathway in HCC and furthermore, there is a possibility that it could be used as a predictor of therapeutic response. Also, this result would be helpful in evaluating the applicable group of PD‐1/PD‐L1 blocking agent for HCC patients.     

细胞因子信号转导抑制因子1和3在脓毒症小鼠脾脏中表达量的变化

目的探讨细胞因子信号转导抑制因子-1和3（SOCS1和SOCS3）的含量在脓毒症小鼠脾脏中的变化情况以及可能的作用机制。方法采用盲肠结扎并穿刺术（CLP）制作脓毒症模型,提取脾脏组织的RNA及蛋白质,采用RT-PCR测定组织中SOCS1和SOCS3 mRNA的相对含量,用免疫印迹方法测定组织中SOCS1和SOCS3相对蛋白含量,用SPSS统计软件测定上述指标之间的变化关系。结果脓毒症手术后SOCS1在脾脏中仅检测到基因表达,随时间逐渐上升,并一直保持高位;SOCS3在脾脏内的基因表达和蛋白表达在术后2h迅速升高,至12h达峰值（P〈0.05）;统计分析发现SOCS1和SOCS3的基因表达呈明显正相关性（P〈0.05）。结论 CLP导致的脓毒症可以诱导SOCS1和SOCS3在脾脏中表达增多,提示SOCS1和SOCS3在脓毒症出现后的免疫变化中有重要作用,可能可利用它们对脓毒症进行干预,以改善脓毒症的预后。     

Anti‐CD3 treatment up‐regulates programmed cell death protein‐1 expression on activated effector T cells and severely impairs their inflammatory capacity

T cells play a key role in the pathogenesis of type 1 diabetes, and targeting the CD3 component of the T‐cell receptor complex provides one therapeutic approach. Anti‐CD3 treatment can reverse overt disease in spontaneously diabetic non‐obese diabetic mice, an effect proposed to, at least in part, be caused by a selective depletion of pathogenic cells. We have used a transfer model to further investigate the effects of anti‐CD3 treatment on green fluorescent protein (GFP)⁺ islet‐specific effector T cells in vivo. The GFP expression allowed us to isolate the known effectors at different time‐points during treatment to assess cell presence in various organs as well as gene expression and cytokine production. We find, in this model, that anti‐CD3 treatment does not preferentially deplete the transferred effector cells, but instead inhibits their metabolic function and their production of interferon‐γ. Programmed cell death protein 1 (PD‐1) expression was up‐regulated on the effector cells from anti‐CD3‐treated mice, and diabetes induced through anti‐PD‐L1 antibody could only be reversed with anti‐CD3 antibody if the anti‐CD3 treatment lasted beyond the point when the anti‐PD‐L1 antibody was washed out of the system. This suggests that PD‐1/PD‐L1 interaction plays an important role in the anti‐CD3 antibody mediated protection. Our data demonstrate an additional mechanism by which anti‐CD3 therapy can reverse diabetogenesis.     

细胞因子信号转导抑制因子3在脓毒症小鼠肝脏和脾脏中的表达

目的 探讨细胞因子信号转导抑制因子3(SOCS3)在脓毒症小鼠肝脏和脾脏中的表达情况及其可能的作用机制.方法 采用盲肠结扎并穿刺术(CLP)制作小鼠脓毒症模型.检测肝脏和脾脏组织的SOCS3 mRNA及蛋门表达,采用RT-PCR检测组织中SOCS3 mRNA的相对含量,用免疫印迹方法测定组织中SOCS3相对蛋白含量.用SPSS统计软件对上述指标间的变化关系进行分析.结果 脓毒症手术后SOCS3在肝脏内基因和蛋白表达量有升高趋势,但与对照组比较筹异无统计学意义(P>0.05).SOCS3在脾脏内的基因和蛋白表达在术后2 h迅速升高.至12 h达峰值.在肝脏和脾脏中SOCS3的基因表达和蛋白表达均正相关(r=0.353、0.731,P均<0.05).结论 CLP导致的脓毒症可以诱导SOCS3在小鼠肝脏和脾脏中表达增多,提示SOCS3在脓毒症后的免疫变化中有重要作用.     

Modulating sphingosine 1‐phosphate signaling with DOP or FTY720 alleviates vascular and immune defects in mouse sepsis

Sepsis is a systemic inflammatory response to pathogens and a leading cause of hospital related mortality worldwide. Sphingosine 1‐phosphate (S1P) regulates multiple cellular processes potentially involved in the pathogenesis of sepsis, including antigen presentation, lymphocyte egress, and maintenance of vascular integrity. We thus explored the impact of manipulating S1P signaling in experimental polymicrobial sepsis in mice. Administration of 4‐deoxypyridoxine (DOP), an inhibitor of the S1P‐degrading enzyme S1P‐lyase, or of the sphingosine analog FTY720 that serves as an S1P receptor agonist after phosphorylation ameliorated morbidity, improved recovery from sepsis in surviving mice, and reduced sepsis‐elicited hypothermia and body weight loss. Treated mice developed lymphopenia, leading to an accumulation of lymphocytes in peripheral lymph nodes, and reduced bacterial burden in liver, but not in blood. Sepsis‐induced upregulation of mRNA expression of cytokines in spleen remained unchanged, but reduction of IL‐6, TNF‐α, MCP‐1, and IL‐10 in plasma was evident. DOP and FTY720 treatment significantly reduced levels of Evans blue leakage from blood into liver and lung, decreased hematocrit values, and lowered plasma levels of VEGF‐A in septic mice. Collectively, our results indicate that modulation of S1P signaling showed a protective phenotype in experimental sepsis by modulating vascular and immune functions.     

The use of the soluble adhesion molecules sE‐selectin,sICAM‐1, sVCAM‐1, sPECAM‐1 and their ligands CD11a and CD49d as diagnostic and prognostic biomarkers in septic and critically ill non‐septic ICU patients

Endothelial activation is pivotal in the development and escalation of sepsis. Central to endothelial activation is the endothelial up‐regulation of cellular adhesion molecules (CAMs) including E‐selectin, ICAM‐1, VCAM‐1, and PECAM‐1. Shed CAMs are also found in circulating soluble forms (sCAMs). We investigated whether sCAMs can be used as biomarkers for the differentiation between septic and non‐septic patients. Furthermore, we investigated lymphocyte and monocyte expression of LFA‐1 (CD11a/CD18) and VLA‐4 (CD49d/CD29) ligands for ICAM‐1 and VCAM‐1, respectively. Twenty‐one septic and 15 critically ill non‐septic patients were included. All patients had an APACHE II score above 13 at ICU admission. Fifteen healthy volunteers served as controls. Flow cytometry was used to estimate levels of sE‐selectin, sICAM‐1, sVCAM‐1, sPECAM‐1, and the cellular expression of CD11a and CD49d. Levels of sE‐selectin, sICAM‐1 and sPECAM‐1 were higher in the septic patients compared with the non‐septic patients and controls at admission and during the observation period. Lymphocyte and monocyte expression of CD11a and CD49d was suppressed or unaltered in the septic patients compared with the non‐septic patients and controls. Levels of sE‐selectin, sICAM‐1, and sPECAM‐1 were able to discriminate between septic and non‐septic patients, indicating that sCAMs may be potential diagnostic biomarkers of sepsis.     

Programmed death (PD)‐1 molecule and its ligand PD‐L1 distribution among memory CD4 and CD8 T cell subsets in human immunodeficiency virus‐1‐infected individuals

Human immunodeficiency virus (HIV)‐1 causes T cell anergy and affects T cell maturation. Various mechanisms are responsible for impaired anti‐HIV‐1‐specific responses: programmed death (PD)‐1 molecule and its ligand PD‐L1 are negative regulators of T cell activity and their expression is increased during HIV‐1 infection. This study examines correlations between T cell maturation, expression of PD‐1 and PD‐L1, and the effects of their blockade. Peripheral blood mononuclear cells (PBMC) from 24 HIV‐1⁺ and 17 uninfected individuals were phenotyped for PD‐1 and PD‐L1 expression on CD4⁺ and CD8⁺ T cell subsets. The effect of PD‐1 and PD‐L1 blockade on proliferation and interferon (IFN)‐γ production was tested on eight HIV‐1⁺ patients. Naive (CCR7⁺CD45RA⁺) CD8⁺ T cells were reduced in HIV‐1 aviraemic (P = 0·0065) and viraemic patients (P = 0·0130); CD8 T effector memory subsets [CCR7^‐CD45RA^–(T_EM)] were increased in HIV‐1⁺ aviraemic (P = 0·0122) and viraemic (P = 0·0023) individuals versus controls. PD‐1 expression was increased in CD4 naive (P = 0·0496), central memory [CCR7⁺CD45RA^– (T_CM); P = 0·0116], T_EM (P = 0·0037) and CD8 naive T cells (P = 0·0133) of aviraemic HIV‐1⁺versus controls. PD‐L1 was increased in CD4 T_EMRA (CCR7^‐CD45RA⁺, P = 0·0119), CD8 T_EM (P = 0·0494) and CD8 T_EMRA (P = 0·0282) of aviraemic HIV‐1⁺versus controls. PD‐1 blockade increased HIV‐1‐specific proliferative responses in one of eight patients, whereas PD‐L1 blockade restored responses in four of eight patients, but did not increase IFN‐γ‐production. Alteration of T cell subsets, accompanied by increased PD‐1 and PD‐L1 expression in HIV‐1 infection contributes to anergy and impaired anti‐HIV‐1‐specific responses which are not rescued when PD‐1 is blocked, in contrast to when PD‐L1 is blocked, due possibly to an ability to bind to receptors other than PD‐1.     

Impaired antigen‐specific lymphocyte priming in mice after Toll‐like receptor 4 activation via induction of monocytic myeloid‐derived suppressor cells

In sepsis, the pathology involves a shift from a proinflammatory state toward an immunosuppressive phase. We previously showed that an agonistic anti‐TLR4 antibody induced long‐term endotoxin tolerance and suppressed antigen‐specific secondary IgG production when primed prior to immunization with antigen. These findings led us to speculate that TLR4‐induced innate tolerance due to primary infection causes an immunosuppressive pathology in sepsis. Therefore, the mechanism underlying impaired antigen‐specific humoral immunity by the TLR4 antibody was investigated. We showed, in a mouse model, that primary antigen‐specific IgG responses were impaired in TLR4 antibody‐induced tolerized mice, which was the result of reduced numbers of antigen‐specific GC B cells and plasma cells. Ovalbumin‐specific CD4 and CD8 T‐cell responses were impaired in TLR4 antibody‐injected OT‐I and ‐II transgenic mice ex vivo. Adoptive transfer studies demonstrated suppression of OVA‐specific CD4 and CD8 T‐cell responses by the TLR4 antibody in vivo. The TLR4 antibody induced Gr1⁺CD11b⁺ myeloid‐derived suppressor cell (MDSC) expansion with suppression of T‐cell activation. Monocytic MDSCs were more suppressive and exhibited higher expression of PD‐L1 and inducible nitric oxidase compared with granulocytic MDSCs. In conclusion, immune tolerance conferred by TLR4 activation induces the expansion of monocytic MDSCs, which impairs antigen‐specific T‐cell priming and IgG production.     

Recent Insight into the Role of the PD‐1/PD‐L1 Pathway in Feto‐Maternal Tolerance and Pregnancy

Pregnancy presents a great challenge to the maternal immune system. Given that maternal alloreactive lymphocytes are not depleted during pregnancy, local and/or systemic mechanisms have to serve a central function in altering the maternal immune responses. Regulatory T cells (Tregs) and the PD‐1/PD‐L1 pathway are both critical in controlling the immune responses. Recent studies have proved the critical function of the PD‐1/PD‐L1 pathway in regulating the T‐cell homeostasis and the peripheral tolerance through promoting the development and function of Tregs, and inhibiting the activation of effector T cells. The function of the PD‐1/PD‐L1 pathway in feto‐maternal interface and pregnancy has been investigated in human and animal models of pregnancy. In this review, we provide recent insight into the role of the PD‐1/PD‐L1 pathway in regulating T‐cell homeostasis, maternal tolerance, and pregnancy‐related complications as well as its possible applicability in clinical immunotherapy.     

Japanese encephalitis virus expands regulatory T cells by increasing the expression of PD‐L1 on dendritic cells

The mechanisms underlying Japanese encephalitis virus (JEV) pathogenesis need to be thoroughly explored to delineate therapeutic approaches. It is believed that JEV manipulates the innate and adaptive compartments of the host's immune system to evade immune response and cross the blood–brain barrier. The present study was thus designed to investigate the functional modulation of DCs after exposure to JEV and to assess the consequences on CD4⁺ T‐lymphocyte functions. Human monocyte‐derived DCs were either infected with 1 MOI of live virus, UV‐inactivated virus, or were mock‐infected. Replication‐competent JEV induced a significant increase in the expression of maturation markers 48 h postinfection, along with that of programmed cell death 1 ligand 1 (PD‐L1; also called B7‐H1 and CD274). JEV‐infected DCs expanded the Treg cells in allogenic mixed lymphocyte reactions. The expansion of Treg cells by JEV‐infected DCs was significantly reduced upon blocking PD‐L1 using an antagonist. In addition, JEV‐infected DCs significantly altered the proliferation and reduced the polarization of Th cells toward the Th1‐cell phenotype. The results, for the first time, suggest that JEV evades the host's immune system by modulating the crosstalk between DCs and T lymphocytes via the PD‐L1 axis.     

Exposure to anti‐PD‐1 causes functional differences in tumor‐infiltrating lymphocytes in rare solid tumors

The pervasive use of therapeutic antibodies targeting programmed cell death protein 1 (PD‐1) to boost anti‐tumor immunity has positioned this approach to become the standard‐of‐care for some solid tumor malignancies. However, little is known as to how blockade of PD‐1 may alter the function or phenotype of tumor‐infiltrating lymphocytes (TIL). We used our ongoing Phase II clinical trial of pembrolizumab for patients with rare solid tumors from various types (NCT02721732) with matched core biopsies taken at baseline and after initial dose of anti‐PD‐1 (15–21 days post‐dose) to elucidate this question. One fresh core needle biopsy was used to propagate TIL ex vivo to analyze phenotype and function using flow cytometry in both CD8⁺ and CD4⁺ TIL populations. An enriched CTLA‐4 expression in the CD4⁺ TIL population was observed in TIL expanded from the on‐treatment samples compared to TIL expanded from the matched baseline (n = 22, p = 0.0007) but was not observed in patients who experienced tumor regression. Impact on functionality was evaluated by measuring secretion of 65 soluble factors by expanded TIL from 26 patients at baseline and on‐treatment. The CD8⁺ TIL population demonstrated a diminished cytokine secretion profile post‐pembrolizumab. Overall, our study assesses the ramifications of one dose of anti‐PD‐1 on TIL in rare solid tumor types.     

Malt1 self‐cleavage is critical for regulatory T cell homeostasis and anti‐tumor immunity in mice

Mucosa‐associated lymphoid tissue 1 (Malt1) regulates immune cell function by mediating the activation of nuclear factor κB (NF‐κB) signaling through both its adaptor and proteolytic function. Malt1 is also a target of its own protease activity and this self‐cleavage further contributes to NF‐κB activity. Until now, the functional distinction between Malt1 self‐cleavage and its general protease function in regulating NF‐κB signaling and immune activation remained unclear. Here we demonstrate, using a new mouse model, the importance of Malt1 self‐cleavage in regulating expression of NF‐κB target genes and subsequent T cell activation. Significantly, we further establish that Treg homeostasis is critically linked to Malt1 function via a Treg intrinsic and extrinsic mechanism. TCR‐mediated Malt1 proteolytic activity and self‐cleavage was found to drive Il2 expression in conventional CD4⁺ T cells, thereby regulating Il2 availability for Treg homeostasis. Remarkably, the loss of Malt1‐mediated self‐cleavage alone was sufficient to cause a significant Treg deficit resulting in increased anti‐tumor immune reactivity without associated autoimmunity complications. These results establish for the first time that inhibition of MALT1 proteolytic activity could be a viable therapeutic strategy to augment anti‐tumor immunity.     

PD‐1/PD‐L1 inhibitors in haematological malignancies: update 2017

The introduction of PD‐1/PD‐L1 pathway inhibitors is an important landmark in solid oncology with unprecedented practice‐changing activity in various types of solid tumours. Among haematological malignancies, PD‐1/PD‐L1 inhibitors have been successful, so far, only in the treatment of classical Hodgkin lymphoma, which typically exhibits an over‐expression of PD‐1 ligands (PD‐L1, PD‐L2) due to alterations in chromosome 9p24.1. Such positive outcomes led to the US Food and Drug Administration approval of nivolumab use in relapsed Hodgkin lymphoma in 2016 as the first haematological indication. Although the results in other lymphoid malignancies have not been so striking, blockade of the PD‐1/PD‐L1 axis has led to meaningful responses in other lymphoma types such as diffuse large B‐cell lymphoma, follicular lymphoma or several T‐cell lymphomas. Monotherapy with PD‐1/PD‐L1 inhibitors in chronic lymphocytic leukaemia and multiple myeloma has been unsatisfactory, suggesting that a combinational approach with other synergistic drugs is needed. In the case of multiple myeloma, immunomodulatory agents together with corticosteroids represent the most promising combinations. Among myeloid malignancies, the anti‐PD‐1 monoclonal antibodies are examined dominantly in acute myeloid leukaemia and myelodysplastic syndromes in combination with potentially synergistic hypomethylating drugs such as 5‐azacitidine, resulting in promising outcomes that warrant further investigation. We have described all available clinical results of PD‐1/PD‐L1 inhibitors in haematological malignancies and discussed related toxicities, as well as highlighted crucial preclinical studies in this review.     

In‐vitro effect of pembrolizumab on different T regulatory cell subsets

Programmed death‐1 (PD‐1) and interactions with PD‐ligand 1 (PD‐L1) play critical roles in the tumour evasion of immune responses through different mechanisms, including inhibition of effector T cell proliferation, reducing cytotoxic activity, induction of apoptosis in tumour‐infiltrating T cells and regulatory T cell (T_reg) expansion. Effective blockade of immune checkpoints can therefore potentially eliminate these detrimental effects. The aim of this study was to investigate the effect of anti‐PD‐1 antibody, pembrolizumab, on various T_reg subpopulations. Peripheral blood mononuclear cells (PBMC) from healthy donors (HD) and primary breast cancer patients (PBC) were treated in vitro with pembrolizumab, which effectively reduced PD‐1 expression in both cohorts. We found that PD‐1 was expressed mainly on CD4⁺CD25⁺ T cells and pembrolizumab had a greater effect on PD‐1 expression in CD4⁺CD25^? T cells, compared to CD4⁺CD25⁺ cells. In addition, pembrolizumab did not affect the expression levels of T_reg‐related markers, including cytotoxic T lymphocyte antigen‐4 (CTLA‐4), CD15s, latency‐associated peptide (LAP) and Ki‐67. Moreover, we report that CD15s is expressed mainly on forkhead box P3 (FoxP3)^?Helios⁺ T_reg in HD, but it is expressed on FoxP3⁺Helios^? T_reg subset in addition to FoxP3^?Helios⁺ T_reg in PBC. Pembrolizumab did not affect the levels of FoxP3^+/?Helios^+/? T_reg subsets in both cohorts. Taken together, our study suggests that pembrolizumab does not affect T_reg or change their phenotype or function but rather blocks signalling via the PD‐1/PD‐L1 axis in activated T cells.     

PD‐L1 expression on tumor or stromal cells of nodal cytotoxic T‐cell lymphoma: A clinicopathological study of 50 cases

Inhibitors of programmed cell‐death 1 (PD‐1) and programmed cell‐death ligand 1 (PD‐L1) have revolutionized cancer therapy. Nodal cytotoxic T‐cell lymphoma (CTL) is characterized by a poorer prognosis compared to nodal non‐CTLs. Here we investigated PD‐L1 expression in 50 nodal CTL patients, with and without EBV association (25 of each). We identified seven patients (14%) with neoplastic PD‐L1 (nPD‐L1) expression on tumor cells, including three males and four females, with a median age of 66 years. One of the seven cases was TCRαβ type, three were TCRγδ type and three were TCR‐silent type. Six of the seven cases exhibited a lethal clinical course despite multi‐agent chemotherapy, of whom four patients died within one year of diagnosis. Morphological findings were uniform, with six cases showing centroblastoid appearance. Among nPD‐L1⁺ cases, two of three examined had structural variations of PD‐L1 disrupting 3′‐UTR region. Notably, all of the TCRγδ‐type nodal CTL cases showed nPD‐L1 or miPD‐L1 positivity (3 and 10 cases, respectively). TCRγδ‐type cases comprised 42% of nPD‐L1⁺ cases (P = 0.043 vs. PD‐L1^?), and 35% of miPD‐L1⁺ cases (P = 0.037 vs. PD‐L1^?). The results indicate that PD‐L1⁺ nodal CTL cases, especially of the TCRγδ type, are potential candidates for anti‐PD‐1/PD‐L1 therapies.     

小檗碱与育亨宾对脓毒症小鼠脾细胞凋亡的影响及其机制研究

 目的:探讨小檗碱与育亨宾对脓毒症小鼠脾细胞凋亡的影响及其作用机制。方法: 采用盲肠结扎穿孔（CLP）构建小鼠脓毒症模型,分为假手术（sham）组、CLP组、CLP+小檗碱组、CLP+育亨宾组、CLP+小檗碱与育亨宾合剂组。CLP术后2 h灌胃给予相应药物,20 h后取脾脏,用TUNEL和流式细胞术检测小鼠脾细胞凋亡,酶荧光法检测caspase-3、caspase-8和caspase-9的活性变化,Western blotting检测凋亡相关蛋白Fas、Bim、Bcl-2和Bax的表达。结果: (1) CLP组脾脏TUNEL阳性细胞百分率显著高于sham组（P＜0.05）,CLP+育亨宾与小檗碱合剂组、CLP+育亨宾组凋亡细胞百分率显著低于CLP组（P＜0.05）。(2) 流式细胞仪检测显示CLP组凋亡的脾细胞及T淋巴细胞明显多于sham组(P＜0.05),CLP+育亨宾与小檗碱合剂组、CLP+育亨宾组凋亡的脾细胞及T淋巴细胞明显少于CLP组 (P＜0.05) 。(3) CLP+育亨宾与小檗碱合剂组、CLP+育亨宾组脾细胞caspase-3、caspase-8、caspase-9的活性均低于CLP组(P＜0.05);而CLP+小檗碱组脾细胞caspase-9活性也低于CLP组 (P＜0.05)。(4) CLP+育亨宾与小檗碱合剂组胞浆Fas、Bim、Bax表达均低于CLP组,CLP+育亨宾组胞浆Fas表达低于CLP组,CLP+小檗碱治疗组胞浆Bim、线粒体Bax表达均低于CLP组。结论: (1) 小檗碱与育亨宾合用可通过阻断内、外源性凋亡途径抑制脓毒症小鼠脾细胞凋亡,特别是T淋巴细胞凋亡。(2) 育亨宾主要通过抑制Fas的表达、进而阻断内、外源性凋亡途径减少脓毒症诱导的脾细胞凋亡。(3) 小檗碱可抑制脓毒症小鼠脾细胞线粒体凋亡途径,但对脓毒症小鼠脾细胞凋亡的抑制作用并不明显。