Detection of significant liver fibrosis in Chinese psoriasis patients receiving methotrexate: a comparison between transient elastography and liver histology

INTRODUCTION

Methotrexate (MTX) is effective for treating psoriasis and psoriatic arthritis, but its potential hepatoxicity remains a concern. Liver biopsy, the gold standard for detecting MTX-induced liver injury, is invasive and carries considerable risk. Transient elastography (TE) offers a non-invasive alternative for detecting advanced liver fibrosis. This study investigated the performance of TE in detecting MTX-induced liver fibrosis among Chinese psoriasis patients, compared with liver biopsy.

METHODS

This study included adult patients with clinical psoriasis. Liver stiffness measurement using TE was performed in patients receiving MTX. Exclusion criteria were known liver cirrhosis, positive viral hepatitis carrier status, or conditions influencing TE performance. Liver biopsy was performed when liver stiffness was ≥7.1 kilopascals (kPa) or when the total cumulative dose (TCD) of MTX was ≥3.5 g.

RESULTS

A total of 228 patients were screened; among 34 patients who met the inclusion criteria, nine (26.5%) had significant liver fibrosis (Roenigk grade ≥3a). The area under the receiver operating characteristic curve was 0.76 (95% confidence interval=0.59-0.93; P=0.021), indicating that TE had satisfactory performance in detecting liver fibrosis. A cut-off value of 7.1 kPa of liver stiffness yielded 100% sensitivity and 68% specificity. Liver fibrosis was not correlated with the TCD of MTX or the duration of MTX use; it was significantly correlated with obesity and diabetes status (body mass index ≥30 kg/m2, waist circumference ≥138 cm, and glycated haemoglobin level ≥7.8%).

CONCLUSION

Transient elastography is reliable and superior to the TCD for detecting liver fibrosis in Chinese psoriasis patients receiving MTX. Liver biopsy should be reserved for high-risk patients or patients with liver stiffness ≥11.7 kPa on TE.

Chimeric antigen receptor T cells to target CD79b in B-cell lymphomas

BACKGROUND

Chimeric antigen receptor (CAR) T cells targeting CD19 mediate potent and durable effects in B-cell malignancies. However, antigen loss or downregulation is a frequent cause of resistance. Here, we report development of a novel CAR T-cell therapy product to target CD79b, a pan B-cell antigen, widely expressed in most B-cell lymphomas.

METHODS

We generated a novel anti-CD79b monoclonal antibody by hybridoma method. The specificity of the antibody was determined by testing against isogenic cell lines with human CD79b knock-in or knock-out. A single-chain variable fragment derived from the monoclonal antibody was used to make a panel of CD79b-targeting CAR molecules containing various hinge, transmembrane, and co-stimulatory domains. These were lentivirally transduced into primary T cells and tested for antitumor activity in in vitro and in vivo B-cell lymphoma models.

RESULTS

We found that the novel anti-CD79b monoclonal antibody was highly specific and bound only to human CD79b and no other cell surface protein. In testing the various CD79b-targeting CAR molecules, superior antitumor efficacy in vitro and in vivo was found for a CAR consisting CD8α hinge and transmembrane domains, an OX40 co-stimulatory domain, and a CD3ζ signaling domain. This CD79b CAR specifically recognized human CD79b-expressing lymphoma cell lines but not CD79b knock-out cell lines. CD79b CAR T cells, generated from T cells from either healthy donors or patients with lymphoma, proliferated, produced cytokines, degranulated, and exhibited robust cytotoxic activity in vitro against CD19+ and CD19- lymphoma cell lines and patient-derived lymphoma tumors relapsing after prior CD19 CAR T-cell therapy. Furthermore, CD79b CAR T cells were highly efficient at eradicating pre-established lymphoma tumors in vivo in three aggressive lymphoma xenograft models, including two cell line-derived xenografts and one patient-derived xenograft. Notably, these CAR T cells did not demonstrate any significant tonic signaling activity or markers of exhaustion.

CONCLUSION

Our results indicated that this novel CD79b CAR T-cell therapy product has robust antitumor activity against B-cell lymphomas. These results supported initiation of a phase 1 clinical trial to evaluate this product in patients with relapsed or refractory B-cell lymphomas.

[Study of the predictive role of serum HBV RNA on HBeAg serological conversion in children with chronic hepatitis B]

Objective: To investigate the role of serum hepatitis B virus RNA (HBV RNA) in predicting HBeAg serological conversion in children with chronic hepatitis B. Methods: 175 children aged 1~17 years with chronic hepatitis B who received interferon α (IFNα) for 48 weeks were selected. Patients were divided into HBeAg seroconversion and non-conversion based on whether HBeAg seroconversion occurred at 48 weeks of treatment.T-test and Mann-Whitney U test were used to compare between groups; chisquare test or Fisher exact probability method was used to compare the frequency between groups of classified variables; and Pearson correlation was used to analyze the correlation between indicators. Univariate and multivariate logistic regression analyses were used to identify influencing factors associated with HBeAg serological conversion. The predictive effect of HBV RNA, HBV DNA, and HBsAg on HBeAg serological conversion was compared and analyzed by the receiver operating characteristic curve (ROC). Results: The seroconversion rate of HBeAg at 48 weeks was 36.0% (63/175). The reduction in HBVRNA levels from baseline to the 12th, 24th, 36th, and 48th weeks of antiviral therapy was significantly greater in the HBeAg serological conversion group than that in the non-conversion group, and the difference was statistically significant between the two groups (P < 0.05). Univariate and multivariate regression analyses showed that age and a decline in HBV RNA levels at week 12 were independent predictors of HBeAg serological conversion. The area under the ROC curve (AUROC) of HBV RNA decline at week 12 was 0.677(95% CI∶0.549-0.806, P = 0.012), which was significantly better than the same period of AUROC of HBV DNA (0.657, 95% CI∶0.527-0.788, P = 0.025) and HBsAg (0.660, 95% CI∶0.526-0.795, P = 0.023) decline. HBV RNA levels decreased (>1.385 log10 copies/ml) at week 12, with a positive predictive value of 53.2%, a negative predictive value of 72.2%, a sensitivity of 77.4%, and a specificity of 57.9% for HBeAg seroconversion. Conclusion: HBV RNA level lowering during the 12th week of antiviral therapy can serve as an early predictor marker for HBeAg serological conversion in children with chronic hepatitis B.

Targeting CXCR4 abrogates resistance to trastuzumab by blocking cell cycle progression and synergizes with docetaxel in breast cancer treatment

BACKGROUND

Although trastuzumab and other HER2-targeted therapies have significantly improved survival in patients with HER2 overexpressed or amplified (HER2+) breast cancer, a significant proportion of patients do not respond or eventually develop clinical resistance. Strategies to reverse trastuzumab resistance remain a high clinical priority. We were the first to report the role of CXCR4 in trastuzumab resistance. The present study aims to explore the therapeutic potential of targeting CXCR4 and better understand the associated mechanisms.

METHODS

Immunofluorescent staining, confocal microscopy analysis, and immunoblotting were used to analyze CXCR4 expression. BrdU incorporation assays and flow cytometry were used to analyze dynamic CXCR4 expression. Three-dimensional co-culture (tumor cells/breast cancer-associated fibroblasts/human peripheral blood mononuclear cells) or antibody-dependent cellular cytotoxicity assay was used to mimic human tumor microenvironment, which is necessary for testing therapeutic effects of CXCR4 inhibitor or trastuzumab. The FDA-approved CXCR4 antagonist AMD3100, trastuzumab, and docetaxel chemotherapy were used to evaluate therapeutic efficacy in vitro and in vivo. Reverse phase protein array and immunoblotting were used to discern the associated molecular mechanisms.

RESULTS

Using a panel of cell lines and patient breast cancer samples, we confirmed CXCR4 drives trastuzumab resistance in HER2+ breast cancer and further demonstrated the increased CXCR4 expression in trastuzumab-resistant cells is associated with cell cycle progression with a peak in the G2/M phases. Blocking CXCR4 with AMD3100 inhibits cell proliferation by downregulating mediators of G2-M transition, leading to G2/M arrest and abnormal mitosis. Using a panel of trastuzumab-resistant cell lines and an in vivo established trastuzumab-resistant xenograft mouse model, we demonstrated that targeting CXCR4 with AMD3100 suppresses tumor growth in vitro and in vivo, and synergizes with docetaxel.

CONCLUSIONS

Our findings support CXCR4 as a novel therapeutic target and a predictive biomarker for trastuzumab resistance in HER2+ breast cancer.

Multi-camera imaging to characterize jet and liner uniformity on the Plasma Liner Experiment (PLX)

At Plasma Liner Experiment, a set of 36 coaxial plasma guns are deployed quasi-uniformly over a 9 ft diameter spherical chamber and are used to form a high-Z spherically compressive plasma liner. Simulations indicate that for the concept to ultimately achieve optimal target density and temperature, a high degree of timing uniformity is required between all guns. To aid in quantifying and correcting gun-to-gun nonuniformities, a key diagnostic will consist of up to six fisheye-view CCD cameras positioned inside the main chamber such that each has all plasma guns within its view. The individual cameras can be triggered at different times to determine each plasma jet's muzzle velocity and structure for different operating conditions. This camera array is currently under development, and the implementation needs and challenges for this camera array are discussed here. Additionally, we detail the analysis methodology for determining jet-to-jet uniformity deviations and how we can correct them, thereby improving overall liner uniformity.

Experimental Measurements of Ion Diffusion Coefficients and Heating in a Multi-Ion-Species Plasma Shock

Collisional plasma shocks generated from supersonic flows are an important feature in many astrophysical and laboratory high-energy-density plasmas. Compared to single-ion-species plasma shocks, plasma shock fronts with multiple ion species contain additional structure, including interspecies ion separation driven by gradients in species concentration, temperature, pressure, and electric potential. We present time-resolved density and temperature measurements of two ion species in collisional plasma shocks produced by head-on merging of supersonic plasma jets, allowing determination of the ion diffusion coefficients. Our results provide the first experimental validation of the fundamental inter-ion-species transport theory. The temperature separation, a higher-order effect reported here, is valuable for advancements in modeling HED and ICF experiments.

Targeting CXCR4 abrogates resistance to trastuzumab by blocking cell cycle progression and synergizes with docetaxel in breast cancer treatment

Background: Although trastuzumab and other HER2-targeted therapies have significantly improved survival in patients with HER2 overexpressed or amplified (HER2+) breast cancer, a significant proportion of patients do not respond or eventually develop clinical resistance. Strategies to reverse trastuzumab resistance remain a high clinical priority. We were the first to report the role of CXCR4 in trastuzumab resistance. The present study aims to explore the therapeutic potential of targeting CXCR4 and better understand the associated mechanisms. Methods: Immunofluorescent staining, confocal microscopy analysis, and immunoblotting were used to analyze CXCR4 expression. BrdU incorporation assays and flow cytometry were used to analyze dynamic CXCR4expression. Three-dimensional co-culture (tumor cells/ breast cancer-associated fibroblasts / human peripheral blood mononuclear cells) or antibody-dependent cellular cytotoxicity assay was used to mimic human tumor microenvironment, which is necessary for testing therapeutic effect of CXCR4 inhibitor or trastuzumab. The FDA-approved CXCR4 antagonist AMD3100, trastuzumab, and docetaxel chemotherapy were used to evaluate therapeutic efficacy in vitro and in vivo. Reverse phase protein array and immunoblotting were used to discern the associated molecular mechanisms. Results: Using multiple cell lines and patient breast cancer samples we confirmed CXCR4 drives trastuzumab resistance in HER2+ breast cancer and further demonstrated that the increased CXCR4 expression in trastuzumab-resistant cells is associated with cell cycle progression with a peak in the G2/M phases. Blocking CXCR4 with AMD3100 inhibits cell proliferation by downregulating mediators of G2-M transition, leading to G2/M arrest and abnormal mitosis. Using multiple trastuzumab-resistant cell lines and an in vivo established trastuzumab-resistant xenograft mouse model, we demonstrated that targeting CXCR4 with AMD3100 suppresses tumor growth in vitro and in vivo, and synergizes with docetaxel. Conclusions: Our findings support CXCR4 as a novel therapeutic target and a predictive biomarker for trastuzumab resistance in HER2+ breast cancer.

Step-by-step illustrated guide to central neck dissection

BACKGROUND

The incidence of thyroid carcinoma has been increasing worldwide and surgery is the primary treatment. Central compartment dissection of the neck is a very delicate procedure given the risks of recurrent laryngeal nerve injury and hypoparathyroidism.

METHODS

This paper gives a detailed description of this surgical technique in a patient affected by papillary carcinoma of the thyroid gland, supported by highly representative iconographic materials from a tertiary department.

RESULTS

A stepwise description is provided, along with high-quality pictures and specific tips and tricks. Although neck dissection is a well-codified procedure, the fine details of this surgical technique are not currently available and are still the prerogative of the expert surgeon.

CONCLUSION

The central neck compartment contains several vulnerable structures; damage to these structures would affect patients' lives, possibly permanently. Anatomical knowledge and standardisation are needed for all surgeons, particularly new surgeons (such as residents) who cannot rely simply on experience.

Adoptive transfer of immunomodulatory M2 macrophages suppresses experimental autoimmune encephalomyelitis in C57BL/6 mice via blockading NF-κB pathway

Macrophages play important roles in multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE), and M2 macrophage may have anti-inflammatory effects. In this study, we elucidated the roles of M1 and M2 macrophages in the pathogenesis of EAE and the effects of treatment with M2 macrophages that target certain proinflammatory cytokines and with immunomodulatory preparations that beneficially influence the disease course. We found macrophages increased at the onset of clinical signs in the EAE group, consistent with an increased proportion of M1 macrophages and low numbers of M2 macrophages. As the disease progressed and the symptoms worsened, M1 macrophages decreased and M2 macrophages gradually increased until the peak. In the recovery stage, M2 macrophages gradually decreased. Treatment with M2 macrophages inhibited the nuclear factor kappa B (NF-κB) pathway, alleviated the symptoms of EAE, reduced inflammatory cell infiltration and demyelination in the central nervous system and decreased the numbers of macrophages in the spleens. BAY-11-7082, an NF-κB blocking agent, could reduce the total number of macrophages both in vivo and in vitro, effectively prevented EAE development and significantly inhibited EAE symptoms in mice. Our study demonstrates that macrophages may play a crucial role in the pathogenesis of EAE, while M2 macrophages have anti-inflammatory effects. Transfer of M2 macrophages to EAE mice can block the NF-κB pathway successfully and relieve EAE symptoms. Application of NF-κB blockers is useful in the prevention and treatment of EAE.

Policy on Characterization of Antibodies Used in Immunochemical Methods of Analysis for Mycotoxins and Phycotoxins

The purpose of this document is to provide a policy on antibody characterization for conducting AOAC collaborative studies for immunochemical methods submitted for AOAC®Official MethodsSM Program status. The policy defines recommended information and characteristics to be provided by the Study Director, in the protocol of the collaborative study, for approval by AOAC. The document specifies parameters for characterization of antibodies used as biological reagent in the protocol of validation of immunochemical methods for the determination of mycotoxins and phycotoxins. These recommendations are applicable to the validation of any method, whether proprietary or non-proprietary, that is submitted to AOAC for Official Methods of AnalysisSM status recognition.

CXCR5+CD8+ T cells are a distinct functional subset with an antitumor activity

CXCR5 mediates homing of both B and follicular helper T (TFH) cells into follicles of secondary lymphoid organs. We found that CXCR5+CD8+ T cells are present in human tonsils and follicular lymphoma, inhibit TFH-mediated B cell differentiation, and exhibit strong cytotoxic activity. Consistent with these findings, adoptive transfer of CXCR5+CD8+ T cells into an animal model of lymphoma resulted in significantly greater antitumor activity than CXCR5-CD8+ T cells. Furthermore, RNA-Seq-based transcriptional profiling revealed 77 differentially expressed genes unique to CXCR5+CD8+ T cells. Among these, a signature comprised of 33 upregulated genes correlated with improved survival in follicular lymphoma patients. We also showed that CXCR5+CD8+ T cells could be induced and expanded ex vivo using IL-23 plus TGF-β, suggesting a possible strategy to generate these cells for clinical application. In summary, our study identified CXCR5+CD8+ T cells as a distinct T cell subset with ability to suppress TFH-mediated B cell differentiation, exert strong antitumor activity, and confer favorable prognosis in follicular lymphoma patients.

Determining Metastable Ion Lifetime and History through Wave-Particle Interaction

Laser-induced fluorescence (LIF) performed on metastable ions is frequently used to probe the dynamics of ground-state ion motions in many laboratory plasmas. However, these measurements place restrictions on the metastable ion lifetime. Metastable states are produced from direct ionization of neutral atoms as well as ions in other electronic states, of which the former will only faithfully represent processes that act on the ion dynamics in a time shorter than the metastable lifetime. We present here the first experimental study of this type of systematic effect using wave-particle interaction in an argon multidipole plasma. The metastable lifetime and relative fraction of metastables produced from preexisting ions, necessary for correcting the LIF measurement errors, can be determined by fitting the experimental results with the theory we propose.

Evaluating the effectiveness of a preclinical practice of tooth preparation using digital training system: A randomised controlled trial

PURPOSE

This study aimed to evaluate the effectiveness of preclinical training on ceramic crown preparation using digital training system compared with traditional training method.

MATERIALS AND METHODS

A sample of 66 participating fourth-year undergraduate dental students were randomly assigned to one of two groups for ceramic crown preparation: experimental group as trained using digital method with Online Peer-Review System (OPRS) and Real-time Dental Training and Evaluation System (RDTES); control group as trained using traditional method with instructor demonstration and evaluation. At the completion of training periods, both groups performed the preparation of ceramic crown of upper left central incisor, which were blindly scored by the experienced instructors under the pre-defined assessment criteria. The results of both were compared using Student's t-test or Wilcoxon signed rank test. The level of significance was P < .05. The questionnaires regarding the benefits or drawbacks of digital training system were answered by the students of experimental group.

RESULTS

Five of 15 items in the assessment outcome of the digital group were significantly better than the traditional group. The questionnaire results from the students of the experimental group indicated 96.97% of the students agreed or strongly agreed that using digital training system could better improve the practical ability than traditional method. The total scores of practical results were significantly positively correlated with the points of the questionnaires.

CONCLUSION

The digital training system with OPRS and RDTES might be a good alternative to the traditional training method in the preclinical course of dental practice.

Abstract 2566: A TCL1-specific T-cell receptor redirects T cells against B-cell lymphomas and non-hematological tumors

T-cell leukemia/lymphoma Antigen1 (TCL1) is a B-cell oncoprotein that is overexpressed in multiple forms of B-cell lymphoma. In our previous study, we identified a HLA*A0201-restricted T cell epitope from TCL1 that stimulated CD8+ T cells to specifically lyse lymphoma cells. In this study, we have cloned the TCL170-79 peptide-specific T-cell receptor (TCR) gene that after lentivirus transduction into donor T cells can redirect the specificity of T cells to lyse T2 cells pulsed with TCL170-79 but not control peptide. The TCR-transduced CD8+ T cells efficiently lysed HLA-0201+, TCL1-expressing human lymphoma cell lines and primary lymphoma cells, but not normal B cells. Adoptive transfer of TCR-transduced T cells into a mantle cell lymphoma xenograft mouse model inhibited the tumor growth and significantly extended the survival of mice. In addition, we found that TCL1 is expressed in multiple solid tumors. The TCR-transduced T cells lysed colon and liver tumor cells but not normal human cells in vitro as well as in a mouse xenograft model. Collectively, our data demonstrate that TCL1-specific TCR-based immunotherapy is highly effective against human B-cell lymphomas and non-hematological tumors.

Citation Format: Jinsheng Weng, Kelsey E. Moriarty, Yong Pan, Flavio Egidio Baio, Hua Wang, Hiroki Torikai, Sourindra N. Maiti, Fuliang Chu, Xiaoyun Cheng, Swathi Karri, Deepshika Medapalli, Laurence J. N. Cooper, Sattva S. Neelapu. A TCL1-specific T-cell receptor redirects T cells against B-cell lymphomas and non-hematological tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2566.

Appropriate cyclic tensile strain promotes biological changes of cranial base synchondrosis chondrocytes

OBJECTIVES

This study was designed to clarify biological changes of cranial base synchondrosis chondrocytes (CBSCs) upon cyclic tensile strain (CTS) loading which simulated orthopaedic mechanical protraction on cranial base synchondroses (CBS).

MATERIAL AND METHODS

A two-step digestion method was used to isolate CBSCs obtained from 1-week-old Sprague Dawley rats. Immunohistochemical staining of type II collagen and Sox9 was conducted to identify chondrocytes. A CTS of 1 Hz and 10% elongation was applied to the second passage of CBSCs by FX-5000™ Tension System for 24 hours. The control group kept static at the same time. The expression levels of extracellular matrix (Acan, Col1a1, Col2a1 and Col10a1) and key regulatory factors (Sox9, Ihh and PTHrP) were detected by quantitative real-time RT-PCR.

RESULTS

Positive staining of type II collagen and Sox9 was detected in the isolated CBSCs. The relative expression level of Acan, Col2a1, Col10a1, Sox9 and Ihh in the CTS-loading group was 1.85-fold, 2.19-fold, 1.53-fold, 6.62-fold, and 1.39-fold, respectively, as much as that in the control group, which had statistical significance (P<.05). There was no statistical difference (P>.05) in the expression of Col1a1 and PTHrP.

CONCLUSIONS

A CTS of 1 Hz and 10% elongation for 24 hours had positive effects on chondrocyte proliferation, phenotype maintenance and cartilage matrix synthesis.

MicroRNA-126 deficiency enhanced the activation and function of CD4+ T cells by elevating IRS-1 pathway

Recent evidence has shown that microRNA-126 (miR-126) has been involved in the development and function of immune cells, which contributed to the pathogenesis of related clinical diseases. However, the potential role of miR-126 in the development and function of CD4+ T cells remains largely unknown. Here we first found that the activation and proliferation, as well as the expression of interferon (IFN)-γ, of CD4+ T cells from miR-126 knock-down (KD) mice using the miRNA-sponge technique were enhanced significantly in vitro, compared with those in CD4+ T cells from wild-type (WT) mice. To monitor further the possible effect of miR-126 deficiency on the function of CD4+ T cells in vivo, we used dextran sulphate sodium (DSS)-induced murine model of acute autoimmune colitis and found that miR-126 deficiency could elevate the pathology of colitis. Importantly, the proportion of CD4+ T cells in splenocytes increased significantly in miR-126KD mice. Moreover, the expression levels of CD69 and CD44 on CD4+ T cells increased significantly and the expression level of CD62L decreased significantly. Of note, adoptive cell transfer assay showed that the pathology of colitis was more serious in carboxyfluorescein succinimidyl ester (CFSE)-labelled miR-126KD CD4+ T cell-transferred group, compared with that in the CFSE-labelled WT CD4+ T cells transferred group. Consistently, the expression levels of CD69 and CD44 on CFSE+ cells increased significantly. Furthermore, both the proliferation and IFN-γ secretion of CFSE+ cells also increased significantly in the CFSE-labelled miR-126KD CD4+ T cell-transferred group. Mechanistic evidence showed that the expression of insulin receptor substrate 1 (IRS-1), as a functional target of miR-126, was elevated in CD4+ T cells from miR-126KD mice, accompanied by altered transduction of the extracellular regulated kinase, protein B (AKT) and nuclear factor kappa B (NF-κB) pathway. Our data revealed a novel role in which miR-126 was an intrinsic regulator in the function of CD4+ T cells, which provided preliminary basis for exploring further the role of miR-126 in the development, function of CD4+ T cells and related clinical diseases.

Germline transformation of the western corn rootworm, Diabrotica virgifera virgifera

The western corn rootworm (WCR), a major pest of maize, is notorious for rapidly adapting biochemically, behaviourally and developmentally to a variety of control methods. Despite much effort, the genetic basis of WCR adaptation remains a mystery. Since transformation-based applications such as transposon tagging and enhancer trapping have facilitated genetic dissection of model species such as Drosophila melanogaster, we developed a germline-transformation system for WCR in an effort to gain a greater understanding of the basic biology of this economically important insect. Here we report the use of a fluorescent-marked Minos element to create transgenic WCR. We demonstrate that the transgenic strains express both an eye-specific fluorescent marker and piggyBac transposase. We identified insertion-site junction sequences via inverse PCR and assessed insertion copy number using digital droplet PCR (ddPCR). Interestingly, most WCR identified as transgenic via visual screening for DsRed fluorescence proved to carry multiple Minos insertions when tested via ddPCR. A total of eight unique insertion strains were created by outcrossing the initial transgenic strains to nontransgenic WCR mates. Establishing transgenic technologies for this beetle is the first step towards bringing a wide range of transformation-based tools to bear on understanding WCR biology.

Mesenchymal stem cells and their therapeutic applications in inflammatory bowel disease

Mesenchymal stem or stromal cells (MSCs) are non-hematopoietic stem cells that facilitate tissue regeneration through mechanisms involving self-renewal and differentiation, supporting angiogenesis and tissue cell survival, and limiting inflammation. MSCs were originally identified and expanded in long-term cultures of cells from bone marrow and other organs; and their native identity was recently confined into pericytes and adventitial cells in vascularized tissue. The multipotency, as well as the trophic and immunosuppressive effects, of MSCs have prompted the rapid development of clinical applications for many diseases involving tissue inflammation and immune disorders, including inflammatory bowel disease. Although standard criteria have been established to define MSCs, their therapeutic efficacy has varied significantly among studies due to their natural heterogenicity. Thus, understanding the biological and immunological features of MSCs is critical to standardize and optimize MSCs-based therapy. In this review, we highlight the cellular and molecular mechanisms involved in MSCs-mediated tissue repair and immunosuppression. We also provide an update on the current development of MSCs-based clinical trials, with a detailed discussion of MSC-based cell therapy in inflammatory bowel disease.

Response rates with pembrolizumab in combination with rituximab in patients with relapsed follicular lymphoma: Interim results of an on open-label, phase II study

7519

Background: Follicular lymphoma (FL) tumors are infiltrated with antitumor T cells, however, their function is impaired by immune checkpoints such as PD-1/PD-ligand pathway. Blocking PD-1 enhances the function of antitumor T cells in FL. In addition, blocking PD-1 on NK cells has been shown to enhance the ADCC effect of NK cells. We reasoned that the combination of pembrolizumab (P), an anti-PD-1 antibody (ab), and rituximab (R), an anti-CD20 ab that induces ADCC, is likely to be synergistic through activation of both the innate and adaptive immune systems and result in enhanced clinical activity in FL. Methods: We evaluated P and R in an open-label, non-randomized, single institution, phase II trial (N=30). Key inclusion criteria included adult (age ≥ 18 years), FL grade 1-3a, ECOG 0-1, in relapse after ≥1 prior therapy (tx) and R sensitive disease, defined as a complete (CR) or partial response lasting at least 6 months (mos) after most recent R-containing therapy. Pts received R (375 mg/m2 IV) on days 1, 8, 15, and 22 of cycle 1 and P (200mg IV) q 3 weeks for up to 16 cycles starting on day 2 of cycle 1. Primary endpoint was overall response rate (ORR). Results: 27 pts have initiated therapy, median age 65 (range 42-79), 52% male, 76% had intermediate or high risk FLIPI, 56% met GELF criteria. Median prior tx =1 (range 1-4). Adverse events (AE) regardless of causality were mild, most grade 1-2. Grade 3 AE’s included nausea (N=2), infusion reaction (N=2), aseptic meningitis (N=1), pneumonia (N=1). Immune-related AEs included grade 2 diarrhea (N=2), grade 2 pneumonitis (N=1), grade 2 skin rash (N=1). At the pre-planned interim analysis (N=15), ORR was 80%, CR rate was 60%. With a median follow up of 7 mos (range 0.5-17), median DOR, PFS, and OS has not been reached. PD-L1 expression was tested in 8 baseline tumor samples using PD-L1 22C3 IHC pharmDx and was detected in histiocytes in all 8 tumors, present in only 1-8% of tumor cells in 5 tumors. Additional biomarker analyses are ongoing. Conclusions: The combination of P and R is well tolerated in relapsed FL and is associated with high overall and CR rate. These interim results warrant further investigation of this combination in FL. Clinical trial information: NCT02446457.

IL-15 enhances the antitumor effect of human antigen-specific CD8+ T cells by cellular senescence delay

Optimal expansion protocols for adoptive human T-cell therapy often include interleukin (IL)-15; however, the mechanism by which IL-15 improves the in vivo antitumor effect of T cells remains to be elucidated. Using human T cells generated from HLA-A2+ donors against novel T-cell epitopes derived from the human U266 myeloma cell line Ig light chain V-region (idiotype) as a model, we found that T cells cultured with IL-15 provided superior resistance to tumor growth in vivo, compared with IL-2, after adoptive transfer into immunodeficient hosts. This effect of IL-15 was associated with delayed/reversed senescence in tumor antigen-specific memory CD8⁺ T cells mediated through downregulation of P21^WAF1, P16^INK4a, and P53 expression. Compared to IL-2, IL-15 stimulation dramatically activated JAK3-STAT5 signaling and inhibited the expression of DNA damage genes. Thus, our study elucidates a new mechanism for IL-15 in the regulation of STAT signaling pathways and CD8⁺ T-cell senescence.

Bypassing STAT3-mediated inhibition of the transcriptional regulator ID2 improves the antitumor efficacy of dendritic cells

Despite the potent ability of dendritic cells (DCs) to stimulate lymphocyte responses and host immunity, granulocyte-macrophage colony-stimulating factor-derived DCs (GM-DCs) used as antitumor vaccines have demonstrated relatively modest success in cancer immunotherapy. We found that injecting GM-DCs into melanoma tumors in mice, or culturing GM-DCs with melanoma-secreted cytokines or melanoma-conditioned medium, rapidly suppressed DC-intrinsic expression of the gene encoding inhibitor of differentiation 2 (ID2), a transcriptional regulator. Melanoma-associated cytokines repressed Id2 transcription in murine DCs through the activation of signal transducer and activator of transcription 3 (STAT3). Enforced expression of ID2 in GM-DCs (ID2-GM-DCs) suppressed their production of the proinflammatory cytokine tumor necrosis factor-α (TNF-α). Vaccination with ID2-GM-DCs slowed the progression of melanoma tumors and enhanced animal survival, which was associated with an increased abundance of tumor-infiltrating interferon-γ-positive CD4(+) effector and CD8(+) cytotoxic T cells and a decreased number of tumor-infiltrating regulatory CD4(+) T cells. The efficacy of the ID2-GM-DC vaccine was improved by combinatorial treatment with a blocking antibody to programmed cell death protein-1 (PD-1), a current immunotherapy that overcomes suppressive immune checkpoint signaling. Collectively, our data reveal a previously unrecognized STAT3-mediated immunosuppressive mechanism in DCs and indicate that DC-intrinsic ID2 promotes tumor immunity by modulating tumor-associated CD4(+) T cell responses. Thus, inhibiting STAT3 or overexpressing ID2 selectively in DCs may improve the efficiency of DC vaccines in cancer therapy.

Determination of an optimal dosing schedule for combining Irinophore C™ and temozolomide in an orthotopic model of glioblastoma

Our laboratory reported that Irinophore C™ (IrC™; a lipid-based nanoparticulate formulation of irinotecan) is effective against an orthotopic model of glioblastoma (GBM) and that treatment with IrC™ was associated with vascular normalization within the tumor. Here, the therapeutic effects of IrC™ when used in combination with temozolomide (TMZ) in concurrent and sequential treatment schedules were tested. It was anticipated that IrC™ engendered vascular normalization would increase the delivery of TMZ to the tumor and that this would be reflected by improved treatment outcomes. The approach compared equally efficacious doses of irinotecan (IRN; 50 mg/kg) and IrC™ (25 mg/kg) in order to determine if there was a unique advantage achieved when combining TMZ with IrC™. The TMZ sensitive U251MG(O) cell line (null expression of O-6-methylguanine-DNA methyltransferase (MGMT)) modified to express the fluorescent protein mKate2 was inoculated orthotopically into NOD.CB17-SCID mice and treatment was initiated 14 days later. Our results demonstrated that IrC™ and TMZ administered concurrently resulted in optimal treatment outcomes, with 50% long term survivors (>180 days) in comparison to 17% long term survivors in animals treated with IRN and TMZ or TMZ alone. Indeed, the different treatments resulted in a 353%, 222% and 280% increase in median survival time (MST) compared to untreated animals for, respectively, IrC™ combined with TMZ, IRN combined with TMZ, and TMZ alone. When TMZ was administered after completion of IRN or IrC™ dosing, an increase in median survival time of 167-174% was observed compared to untreated animals and of 67% and 74%, respectively, when IRN (50 mg/kg) and IrC™ (25mg/kg) were given as single agents. We confirmed in these studies that after completion of the Q7D×3 dosing of IrC™, but not IRN, the tumor-associated vascular was normalized as compared to untreated tumors. Specifically, reductions in the fraction of collagen IV-free CD31 staining (p<0.05) and reductions in tumor vessel diameter were observed in tumors from IrC™-treated animals when compared to tumors from untreated or IRN treated animals. Analysis by transmission electron microscopy of the ultra-structure of tumors from IrC™-treated and untreated animals revealed that tumor-associated vessels from treated animals were smaller, more organized and exhibited a morphology comparable to normal blood vessels. In conclusion, optimal treatment outcomes were achieved when IrC™ and TMZ were administered concurrently, whereas IrC™ followed by TMZ treatment given sequentially did not confer any therapeutic advantage.

Abstract 4094: Identification of co-inhibitory receptor expression on T cells from gastric cancer patients

The critical role of tumour antigen-specific immune responses to restrain tumour growth in patients with gastric cancer furthers the need to dissect the co-inhibitory pathways involved in tumour infiltrating lymphocyte (TIL) exhaustion/dysfunction. It was previously reported that PD-1 expression was significantly increased on CD4+ and CD8+ T cells from patients with gastric cancer and in gastric cancer tissues, compared to normal donors. In this study, we observed up-regulation of TIM-3 and PD-1 expression on peripheral T cells and up-regulation of CTLA-4, TIGIT, TIM-3 and PD-1 expression on TILs from gastric cancer patients; however TIGIT was down-regulated on CD8+ TILs and TIM-3 up-regulation on CD8+ TILs was not statistically significant. Furthermore, the percentages of PD-1+/TIM-3+ and PD-1+/TIM-3- peripheral T cells was significantly higher in gastric cancer patients than normal donors, and the percentage of PD-1+/TIM-3+ TILs was significantly higher than the percentage of PD-1+/TIM-3+ peripheral T cells in gastric cancer patients. PD-1+/TIM-3+ cells represent the predominant fraction of TILs. PD-1 blockade enhanced cytokine production and the cytotoxicity of TILs and exhibited a synergistic effect with TIM-3 blockade. Collectively, our results suggest that the use of anti-PD-1 blockade in combination with anti-TIM-3 blockade could restore the cytotoxic activity of TILs in patients with gastric cancer.

Citation Format: Yunhui Zong, Fuliang Chu, Songbing He, Yu Jing, Sally A Hunsucker, Tina Yang, Ming Zhang, Sisi Ye, Yafen Li, Bin Liu, Jinle Tang, Huimin Meng, Gangli An, Lin Yang. Identification of co-inhibitory receptor expression on T cells from gastric cancer patients. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4094. doi:10.1158/1538-7445.AM2014-4094

Selective targeting of Toll-like receptors and OX40 inhibit regulatory T-cell function in follicular lymphoma

Immunotherapeutic strategies are promising approaches for the treatment of follicular lymphoma (FL). However, their efficacy may be limited by immunosuppressive elements in the immune system and tumor microenvironment. Therefore, strategies to reverse the effects of the immunosuppressive elements are needed. We observed that regulatory T cells (Tregs) were increased in the peripheral blood at diagnosis and persisted in high numbers after induction of clinical remission with a cyclophosphamide and doxorubicin-containing chemotherapy regimen in FL patients. High levels of peripheral blood Tregs prior to therapy were associated with decreased progression-free survival in FL patients treated with either chemotherapy or combination immunotherapy that targeted CD20 and PD-1 with monoclonal antibodies rituximab and pidilizumab, respectively. Intratumoral and peripheral blood Tregs potently suppressed autologous antitumor effector T cells in FL. However, the effects of FL Tregs could be reversed by triggering Toll-like receptors (TLR) with TLR ligands Pam3 CSK4 (TLR 1/2), flagellin (TLR 5), and CpG-B (TLR 9), and/or OX40. The TLR ligands synergized with each other as well as OX40 signaling to inhibit Tregs. Furthermore, they restored the function of FL tumor-specific effector T cells. Our results suggest that a state of tolerance exists in FL patients at diagnosis and after induction of clinical remission, and agents that activate TLRs 1/2, 5, and 9, and OX40 may serve as adjuvants to enhance the efficacy of antitumor immunotherapeutic strategies and preventive vaccines against infectious diseases in these patients.

IL-15 enhances the anti-tumor effect of human tumor antigen-specific T cells by cellular senescence delay (TUM2P.880)

Optimal expansion protocol for adoptive T-cell therapy often include interleukin (IL)-15, however, the mechanism by which IL-15 improves the in vivo anti-tumor effect of T cells remains to be elucidated. Using T cells generated from HLA-A2+ normal donors against novel T-cell epitopes derived from the U266 myeloma Ig light chain V-region (idiotype) as a model, we confirmed that T cells cultured with IL-15 provide more potent anti-tumor effects than IL-2-cultured T cells, after adoptive transfer in vivo into immunodeficient hosts. This effect was associated with delayed/reversed senescence in IL-15 expanded idiotype-specific memory CD8 T cells. In vitro experiments revealed IL-15 mediated senescence delay/reversal through JAK3-STAT5 and IL-2 receptor βγ signaling pathway. Specifically, we found DNA damage molecules MDC1, 53BP1, and ATM are the direct targets of IL-15 signaling and STAT5 represses the promoter activity of these genes through the competition with STAT3 to bind to the STATs sites. Thus, our study provides the first evidence for IL-15-inducing the repression of transcription of DNA damage molecules and senescence delay in human memory CD8 T cells.

Anti-PD-1 antibodies for the treatment of B-cell lymphoma: Importance of PD-1+ T-cell subsets

Monoclonal antibodies specific for programmed cell death 1 (PDCD1, best known as PD-1) have been shown to mediate antineoplastic effects in follicular lymphoma patients. However, the relative proportion of intratumoral PD-1⁺ T-cell subsets, in particular follicular helper T cells (which exert pro-tumor functions) and effector T cells (which have anticancer activity), may impact clinical outcome, and should therefore be carefully considered for patient selection in this setting.

Abstract P5-08-09: Synergistic cytotoxicity of digoxin and 5-fluorouracil in doxorubicin-resistant breast cancer cell lines

BACKGROUND: Metastatic breast cancer is the leading cause of cancer death for women in the US. Cytotoxic chemotherapy remains one of the most important systemic treatment options for breast cancer patients. To enhance the tumor response to chemotherapy, attention has been focused on agents that reverse multidrug resistance (MDR) and increase the sensitivity of tumor cells to chemical drugs. Although many reversal drugs have been identified in vitro, their clinical application has been limited due to their own toxicity. It was reported that 5 years after mastectomy, the recurrence rate of breast cancer among patients on cardiac glycoside therapy, namely digoxin or digitoxin, was almost 10 times lower as compared with those who were not on cardiac glycoside therapy. Digoxin has also been shown to inhibit hypoxia-inducible factors (HIF) and block lung metastasis in a breast cancer model. Interestingly, digoxin was demonstrated to stimulate cell death in various cell lines including breast cancer. Therefore the aim of this study was to examine the reversal effect of combined digoxin and 5-fluorouracil (5-FU) on MDR resistance in human breast cell lines MCF-7 and MDA-MB-231 in vitro, as well as its mechanism of action.

METHODS: Wild-type and doxorubicin-resistant ER-positive (MCF-7 and MCF-7/DoxR) and triple negative (MDA-MB-231 and MDA-231/DoxR) breast cancer lines were used for this study. We have previously shown that both doxorubicin-resistant cell lines are also cross-resistant to 5-FU. Cell viability of both resistant cancer cell lines to 5-FU, digoxin, and both 5-FU with digoxin were compared to control at 96 hours of incubation both in normoxia and hypoxia using MTT assay. Western blot was used to quantify the level of HIF-1α and p-glycoprotein (P-gP).

RESULTS: In both doxorubicin-resistant cell lines, sub-IC50 concentration of digoxin together with 5-FU significantly decreased the cell viabilities at 96 hours compared to single agent digoxin and 5-FU. Under both normoxic and hypoxic conditions, the same synergistic cytotoxic effects were demonstrated. Western blot revealed that HIF-1α and P-gP were decreased in both doxorubicin-resistant breast cancer cells treated with the digoxin and 5-FU combination compared to single agent digoxin or 5-FU.

CONCLUSION: The combination of digoxin and 5-FU demonstrates a synergistic cytotoxic effect in doxorubicin-resistant breast cancer cell lines that is maintained under hypoxic conditions. This is, at least in part, via the inhibitory effects on both HIF-1α and P-gP. The combination of digoxin and 5-FU could be an effective clinical treatment strategy to overcome MDR in breast cancer. A phase II clinical trial is ongoing to test this hypothesis in patients with doxorubicin-resistant metastatic breast cancer.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-08-09.

Safety and activity of PD1 blockade by pidilizumab in combination with rituximab in patients with relapsed follicular lymphoma: a single group, open-label, phase 2 trial

BACKGROUND

Endogenous or iatrogenic antitumour immune responses can improve the course of follicular lymphoma, but might be diminished by immune checkpoints in the tumour microenvironment. These checkpoints might include effects of programmed cell death 1 (PD1), a co-inhibitory receptor that impairs T-cell function and is highly expressed on intratumoral T cells. We did this phase 2 trial to investigate the activity of pidilizumab, a humanised anti-PD1 monoclonal antibody, with rituximab in patients with relapsed follicular lymphoma.

METHODS

We did this open-label, non-randomised trial at the University of Texas MD Anderson Cancer Center (Houston, TX, USA). Adult (≥18 years) patients with rituximab-sensitive follicular lymphoma relapsing after one to four previous therapies were eligible. Pidilizumab was administered at 3 mg/kg intravenously every 4 weeks for four infusions, plus eight optional infusions every 4 weeks for patients with stable disease or better. Starting 17 days after the first infusion of pidilizumab, rituximab was given at 375 mg/m(2) intravenously weekly for 4 weeks. The primary endpoint was the proportion of patients who achieved an objective response (complete response plus partial response according to Revised Response Criteria for Malignant Lymphoma). Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00904722.

FINDINGS

We enrolled 32 patients between Jan 13, 2010, and Jan 20, 2012. Median follow-up was 15.4 months (IQR 10.1-21.0). The combination of pidilizumab and rituximab was well tolerated, with no autoimmune or treatment-related adverse events of grade 3 or 4. The most common adverse events of grade 1 were anaemia (14 patients) and fatigue (13 patients), and the most common adverse event of grade 2 was respiratory infection (five patients). Of the 29 patients evaluable for activity, 19 (66%) achieved an objective response: complete responses were noted in 15 (52%) patients and partial responses in four (14%).

INTERPRETATION

The combination of pidilizumab plus rituximab is well tolerated and active in patients with relapsed follicular lymphoma. Our results suggest that immune checkpoint blockade is worthy of further study in follicular lymphoma.

FUNDING

National Institutes of Health, Leukemia and Lymphoma Society, Cure Tech, and University of Texas MD Anderson Cancer Center.

Preparation and Characterization of Melamine Modified Urea-Formaldehyde Foam

Melamine-urea-formaldehyde (MUF) foam was prepared using melamine modified urea formaldehyde resin. The effects of blowing agent, curing agent and surfactant on the properties of MUF foam such as apparent densities, compression strength, microstructure, fragility, limited oxygen index, thermal conductivity and formaldehyde emission were investigated. The best performance of MUF was obtained as the composition of blowing agent, curing agent and surfactant were 2.5%, 18% and 12% respectively. The water resistance of MUF foam, contents of foam's burning gas, curing mechanism and physical properties were also studied by Contact angle analyzer, TGA-FT-IR, FT-IR and 13C NMR.

Differential effect of long-term drug selection with doxorubicin and vorinostat on neuroblastoma cells with cancer stem cell characteristics

Numerous studies have confirmed that cancer stem cells (CSCs) are more resistant to chemotherapy; however, there is a paucity of data exploring the effect of long-term drug treatment on the CSC sub-population. The purpose of this study was to investigate whether long-term doxorubicin treatment could expand the neuroblastoma cells with CSC characteristics and histone acetylation could affect stemness gene expression during the development of drug resistance. Using n-myc amplified SK-N-Be(2)C and non-n-myc amplified SK-N-SH human neuroblastoma cells, our laboratory generated doxorubicin-resistant cell lines in parallel over 1 year; one cell line intermittently treated with the histone deacetylase inhibitor (HDACi) vorinostat and the other without exposure to HDACi. Cells' sensitivity to chemotherapeutic drugs, the ability to form tumorspheres, and capacity for in vitro invasion were examined. Cell-surface markers and side populations (SPs) were analyzed using flow cytometry. Differentially expressed stemness genes were identified through whole genome analysis and confirmed with real-time PCR. Our results indicated that vorinostat increased the sensitivity of only SK-N-Be(2)C-resistant cells to chemotherapy, made cells lose the ability to form tumorspheres, and reduced in vitro invasion and the SP percentage. CD133 was not enriched in doxorubicin-resistant or vorinostat-treated doxorubicin-resistant cells. Nine stemness-linked genes (ABCB1, ABCC4, LMO2, SOX2, ERCC5, S100A10, IGFBP3, TCF3, and VIM) were downregulated in vorinostat-treated doxorubicin-resistant SK-N-Be(2)C cells relative to doxorubicin-resistant cells. A sub-population of cells with CSC characteristics is enriched during prolonged drug selection of n-myc amplified SK-N-Be(2)C neuroblastoma cells. Vorinostat treatment affects the reversal of drug resistance in SK-N-Be(2)C cells and may be associated with downregulation of stemness gene expression. This work may be valuable for clinicians to design treatment protocols specific for different neuroblastoma patients.

Cross talk between follicular Th cells and tumor cells in human follicular lymphoma promotes immune evasion in the tumor microenvironment

The microenvironment of human follicular lymphoma (FL), an incurable B cell non-Hodgkin's lymphoma, is thought to play a major role in its pathogenesis and course. Microenvironmental cells of likely importance include follicular Th cells (TFH) and regulatory T cells (Tregs), and understanding their interactions with FL tumor cells is necessary to develop novel therapeutic strategies. We found that IL-4 and CD40L are expressed by intratumoral TFH and induce production of CCL17 and CCL22 by FL tumor cells. IL-4 alone induces only CCL17 but enhances stimulation by CD40L of both CCL17 and CCL22. Consistent with our in vitro results, mRNA transcripts of IL-4 correlated with CCL17, but not CCL22, in gene expression profiling studies of FL biopsies, whereas CD40L correlated with both CCL17 and CCL22. Tumor supernatants induced preferential migration of Tregs and IL-4-producing T cells rather than IFN-γ-producing T cells, and Abs to CCR4 significantly abrogated the migration of Tregs. Our results suggest that through two distinct mechanisms, intratumoral TFH induce production of CCL17 and CCL22 by FL tumor cells and facilitate active recruitment of Tregs and IL-4-producing T cells, which, in turn, may stimulate more chemokine production in a feed-forward cycle. Thus, TFH appear to play a major role in generating an immunosuppressive tumor microenvironment that promotes immune escape and tumor survival and growth. Our results provide novel insights into the cross talk among TFH, tumor cells, and Tregs in FL, and offer potential targets for development of therapeutic strategies to overcome immune evasion.

Adenoid assessment in paediatric patients: the role of flexible nasal endoscopy

Adenoid hypertrophy is the most common cause of nasal obstruction in paediatric patients. Over the years, various methods to assess the adenoid size were proposed such as the posterior rhinoscopy and the radiological examination of the nasopharynx. Nasal endoscopy was introduced for children in the 80&#x0027;s, and nowadays this is a known and diffuse method in routine practice. The purpose of this article is to describe the personal experience in the assessment of the adenoid size in children, with a particular regard to the flexible nasal endoscopy, and to analyse the literature reports. The personal technique is described in performing nasal endoscopy in paediatric patients, reporting advantages and possible disadvantages of the procedure. A retrospective analysis was conducted on 6036 children since 1999 to 2010. In most cases children fully collaborated to complete the exam. No major or minor complications (such as nose bleedings or other traumatic injuries) were observed. No topical intranasal decongestant, local or general anaesthesia were used in our series. In our opinion, nasal endoscopy in children is a reliable, safe, accurate, easily tolerated and dynamic diagnostic method to assess the adenoid size.

Follicular regulatory T cells expressing Foxp3 and Bcl-6 suppress germinal center reactions

Foxp3(+) regulatory T (T(reg)) cells suppress different types of immune responses to help maintain homeostasis in the body. How T(reg) cells regulate humoral immunity, including germinal center reactions, is unclear. Here we identify a subset of T(reg) cells expressing CXCR5 and Bcl-6 that localize to the germinal centers in mice and humans. The expression of CXCR5 on T(reg) cells depends on Bcl-6. These CXCR5(+)Bcl-6(+) T(reg) cells are absent in the thymus but can be generated de novo from CXCR5(-)Foxp3(+) natural T(reg) precursors. A lack of CXCR5(+) T(reg) cells leads to greater germinal center reactions including germinal center B cells, affinity maturation of antibodies and the differentiation of plasma cells. These results unveil a Bcl-6-CXCR5 axis in T(reg) cells that drives the development of follicular regulatory T (T(FR)) cells that function to inhibit the germinal center reactions.

Comparison of NbCr2 and HfV2 C15 Laves Phases

The elastic properties, phase stability, and alloying behavior of NbCr2 and HfV2 C15 Laves phases have been investigated with a combined experimental and theoretical approach. Experimental results indicate that HfV2 has anomalous elastic properties as well as a structural instability, but NbCr2 does not. In addition, ternary phase fields of NbCr2 with V and HfV2 with Nb were examined experimentally, and they have substantially different alloying behavior. In order to understand these experimental phenomena, the total energy and electronic structure of C15 NbCr2 and HfV2 were calculated using the linear muffin-tin orbital method with the atomic sphere approximation. Calculation results suggest that the phase instability of HfV2 is induced by phonon softening, and the anomalous elastic properties of HfV2 appear to be attributed to a doubly degenerate electronic energy level with a linear dispersion relation very close to the Fermi level. Finally, density of states plots indicate that for HfV2, some bonding d-states are unoccupied while for NbCr2, all bonding and some anti-bonding d-states are occupied. The bonding difference may be responsible for the alloying behavior in the two Laves phase alloys. As a result, alloy design schemes are suggested for enhanced deformability in Laves phases.

The Effects of Film Thickness and Texture on the high and Low-Field stress Response of Lead Zirconate Titanate Thin Films

Lead zirconate titanate (PZT) thin films are currently employed in non-volatile ferroelectric memories (FRAM's) and are intended to be used as the active material in a number of microelectromechanical systems (MEMS). Several groups have reported that both the piezoelectric and dielectric characteristics of ferroelectric thin films improve with an increase of film thickness, though the reasons for those improvements are unclear. Previous investigations on the effects of biaxial mechanical stress indicate that non-180° domain wall motion is limited in PZT 52/48 films less than 0.5 μm thick. It is possible that some of the improvements of the dielectric and piezoelectric characteristics reported for thicker films (i.e. films thicker than 0.5 μm) are associated with an increase of extrinsic contributions to the properties. To evaluate domain wall mobility in thicker films, the high and low-field stress response of sol-gel PZT fabricated with either rapid thermal processing or conventional furnace annealing were investigated. Films with thicknesses ranging from 0.6 to 5.0 μm thick were measured as a function of applied biaxial stress (±110 MPa). It was found that for all films tested the changes of capacitance were on the order of 2–3%. High-field measurements showed: (1) the coercive field to be insensitive to applied stress, (2) remanent polarizations to decrease about 20% at the maximum applied tension, (3) remanent polarizations to increase less than 10% with applied compression, and (4) all changes to be reversible over the stress range investigated. These results suggest that extrinsic contributions are limited for the films tested.

Measurement of Effective Longitudinal Piezoelectric Coefficient of thin Films by Direct Piezoelectric Effect

This paper presents a new method for the measurement of the longitudinal piezoelectric coefficient of piezoelectric thin films using the direct piezoelectric effect. A uniform uniaxial stress was applied to the piezoelectric thin film by high-pressure gas and the induced charge was collected and measured by a charge integrator. The effective longitudinal piezoelectric coefficient of lead zirconate titanate (PZT) 52/48 thin films made by sol-gel processing was measured by this method. Undoped films typically have d33 values of ∼ 5 pC/N, while poled films have values up to 220 pC/N.

Processing and Properties of Mo5Si3 Single Crystals and Alloys

Among the high-temperature intermetallic systems, transition-metal silicides are attractive because of their high melting temperatures (many greater than 2273 K) and potential oxidation resistance. In particular, Mo5Si3 exhibits a very high melting point (2453 K) and also has a solubility range of 2 – 3 atomic percent, which can aid in processing and alloy design strategies. The focus of this study is to evaluate the processing and properties of Mo5Si3 and Mo5Si3-base ntermetallics. For the optimal baseline comparison, high-purity single crystals have been fabricated, and thermal and elastic properties have been experimentally measured. Although Mo5Si3 has a strong thermal expansion anisotropy, ts elastic anisotropy factors and the Poisson's ratios indicate that Mo5Si3 is less anisotropic in elasticity. The combination of the thermal and elastic properties has been employed to calculate the thermal residual stress and to explain the potential for grain boundary cracking during processing. Room temperature Vickers indentation tests of Mo5Si3 have been performed. The orientation dependence of hardness and fracture toughness of Mo5Si3 single crystals have been obtained. The corresponding deformation and fracture modes have been revealed by microscopy studies. Finally, micro- and macroalloyed Mo5Si3 with aluminum and boron will be briefly explored with property assessments.

Thickness Dependence of the Electrical Properties of Sol-Gel Derived Lead Zirconate Titanate Thin Films with (111) and (100) Texture

Crack-free (111) and (100)-textured Pb(Zr0.52Ti0.48)O3 films with thicknesses ranging from 0.25 to 2.5 μm were prepared using a methoxyethanol-based precursor solution, multiple spin-coating and multiple crystallization steps. The thickness dependence of the dielectric, ferroelectric and piezoelectric properties were investigated on both (111) and (100) oriented PZT films. In both cases, the degree of preferred orientation did not change with thickness. It is found that the dielectric constant, remanent polarization and piezoelectric coefficients (d33 and d31) increase with increasing film thickness. The (100)-textured film showed higher dielectric constant but lower remanent polarization relative to (111) textured film. 1 μm was identified to be a critical thickness that marks the change of dielectric, ferroelectric and piezoelectric behaviors as a function of thickness.