Peripheral Expansion Research Articles

Augmentation of Hepatitis B Virus-Specific Cellular Immunity with Programmed Death Receptor-1/Programmed Death Receptor-L1 Blockade in Hepatitis B Virus and HIV/Hepatitis B Virus Coinfected Patients Treated with Adefovir

The immunological parameters leading to viral persistence in chronic hepatitis B (CHB) are not clearly established. We analyzed HBV-specific immunoregulatory mechanisms in HIV-infected and HIV-uninfected HBeAg(+) CHB patients to determine (1) the roles of immunoregulatory pathways, (2) the effect of anti-HBV therapy on immunoregulatory pathways, and (3) the role of immunomodulatory therapy to overcome the effect of T regulatory cells (Tregs, CD4(+)CD25(+)FoxP3(+)) in HBV-infected individuals. A prospective, double blind, randomized, placebo-controlled trial treated HBV (HIV(+/-))-infected patients with adefovir 10 mg daily or placebo for 48 weeks. HBV viral load (VL), immunophenotying, and functional studies were performed at multiple time points. Suppression of HBV VL with adefovir leads to decreased peripheral expansion of Tregs. While declining, Tregs significantly inhibit cytokine-secreting HBV-specific CD8(+) T cell responses over 48 weeks of anti-HBV adefovir therapy (p<0.05). A large proportion of these Tregs express programmed death receptor-1 (PD-1), blockade of which in vitro leads to improved cytokine-secreting HBV-specific CD8(+) T cell responses, particularly in HIV/HBV-coinfected patients (p<0.05). Peripheral expansion of Treg levels correlated with HBV viral load and decreased HBV-specific CD8(+) T cells. PD-1 blockade increased survival of HBV-specific CD8(+) T cells, removing the inhibitory effect of PD-1(+) peripheral Tregs. Hence therapies involving PD-1 blockade in combination with directly acting antivirals should be investigated to reduce the need for life-long directly acting antiviral therapy.

Cutting Edge: Type I IFN Drives Emergency Myelopoiesis and Peripheral Myeloid Expansion during Chronic TLR7 Signaling

Mice overexpressing TLR7 (TLR7.1 mice) are a model of systemic lupus erythematosus pathogenesis and exhibit peripheral myeloid expansion. We show that TLR7.1 mice have a dramatic expansion of splenic cells that derive from granulocyte/macrophage progenitors (GMP) compared with wild-type mice. In the bone marrow, TLR7.1 mice exhibited hallmarks of emergency myelopoiesis and contained a discrete population of Sca-1(+) GMP, termed emergency GMP, which are more proliferative and superior myeloid precursors than classical Sca-1(-) GMP. The emergency myelopoiesis and peripheral myeloid expansion in TLR7.1 mice was dependent on type I IFN signaling. TLR7 agonist administration to nontransgenic mice also drove type I IFN-dependent emergency myelopoiesis. TLR7.1 plasmacytoid dendritic cells were cell-intrinsically activated by TLR7 overexpression and constitutively produced type I IFN mRNA. This study shows that type I IFN can act upon myeloid progenitors to promote the development of emergency GMP, which leads to an expansion of their progeny in the periphery.

Geometric Variations of Acetabular Component Design and its Effect on Radiographic Osseointegration

The Reflection uncemented acetabular component (Smith & Nephew, Memphis, Tenn) for total hip arthroplasty is available in 2 geometric variants. The first has a completely hemispherical design; the second has a peripheral rim expansion designed to increase initial press fit and aid osseointegration. The clinical and radiologic outcomes of 527 consecutive primary total hip arthroplasties were reviewed to investigate the differences in component design. Of the components, 95.6% survived at 96 months with revision for aseptic loosening as the end point, with no significant difference between the 2 component designs. Eighty percent of hemispherical and 57% of peripherally expanded components were considered completely osseointegrated at final radiologic review. The midterm radiologic outcome of peripherally expanded acetabular components is inferior to that of a completely hemispherical design.

Rheumatoid arthritis: early thymic involution or increased proliferation rate?

Event Abstract Back to Event Rheumatoid arthritis: early thymic involution or increased proliferation rate? Elena A. Blinova1*, Vladimir S. Kozhevnikov1, Alexey E. Sizikov2 and Vladimir A. Kozlov1 1 Research Institute of Clinical Immunology Russian academy of medical science Siberian Branch, Clinical department, Russia 2 Immunology Clinic of Research Institute of Clinical immunology Russian academy of medical science Siberian Branch, department of Rheumatology, Russia It is often observed impaired thymic function in adults with immunopathology, particularly with rheumatoid arthritis (RA). Loss of naive and memory T cell diversity, oligoclonal proliferation, restricted T cell receptor repertoire, emergence of CD28null T cells, and erosion of telomeres in circulating T cells are typical features of the immune disfunction in the eldery and although in RA patients [1,2]. Therefore, it was hypothesized that patient with RA have premature immunosenescence, beginning with early thymic involution. One of the way to asses recent thymic emigrants is a direct analysis of T cell receptor excision circles or TREC level [3]. But TREC number can be influenced by peripheral expansion or cell death. Recently, CD31 has been proposed as a cell surface marker expressed preferentially by naive TREC-rich T cells that have undegone low number of cell divisions [4]. In this study, we determined 2 markers of thymic functional activity (TREC number and amount of CD31+ T cells) to establish the mechanisms for replenishment of the peripheral T cell pool in RA. Absolute and relative TREC number in CD4+ and CD8+ cells was measured in 30 patients with RA (mean age 50±8,2) and 15 healthy age-matched controls using Real-time PCR. Reaction mixture in volume 25μl contained 5μl eluted DNA, 200μM dNTPs, 200 nM each primers and fluorescent probe, and 2 units HotStart Taq DNA polymerase. In each experiment, serial dilutions of a cloned TREC-PCR product were used as a standard for absolute quantification of TREC level. Before DNA purification mononuclear cells from peripheral blood were sorted to CD4+ and CD8+ subsets by cell sorter FACSAria. Reanalysis of the isolated subsets showed that the purities were at least 95%. Proportion of CD4+CD31+ and CD8+CD31+ cells was quantified in 11 patients with RA (mean age 43±14,3) and 5 healthy donors (mean age 43±5,5) using flow cytometry. Statistical analysis was performed using Wilcoxon/Mann-Whitney test for unrelated pairs. A p value of <0,05 was considered significant. Results are shown as median with 25th and 75th percentiles in parenthesis. Relative TREC number was reduced about 2 times in RA compared with control: in CD4+ cells it came to 1650 (range 976-2800) vs 3700 (range 1050-5800) and in CD8+ cells - 1500 (range 838-2400) vs 4200 (range 719-8500). Absolute TREC number in CD4+ population did not differ in patients with RA from donors, whereas it was decreased in CD8+ population in RA. Patients with RA have low levels of serum IL-7, which leads to competition between CD4+ and CD8+ lymphocytes and perhaps, asymmetry in the absolute TREC number in this populations. To determine whether the reduction of TREC number in RA due to insufficient thymic function or increased proliferation rate, it was quantified proportion of CD31+ T cells. Some authors have reported that the proportion of CD31-positive CD4+ and CD8+ cells decreased with age and correlated with thymus volume [5, 6]. Moreover, CD31+CD45RA-CD45RO+ cells, comprising less then 5% CD4+ cells, did not contain TREC. All this makes CD31 as a marker of thymic naive T cells. There were no significant differences in the amount of thymic naïve T cells between patients with RA and healthy donors. CD4+31+ value in RA group was 26 (range 21,6-32,2) vs 27,8 (range 24,9-40,1) in control group, and CD8+CD31+ value – 62 (49,7-70,8) vs 53,8 (50,8-66,5) respectively. Obtained data suggest that replenishment of the peripheral T cell pool in adults with RA occurs more due to the cell proliferation, thymic function is maintained within the normal limits. Acknowledgements The authors are grateful to Evgeniy Khrapov for help in the development of a standard for quantitive measuring TREC.

The Impact of Aging on Regulatory T-Cells

Age-related deviations of the immune system contribute to a higher likelihood of infections, cancer, and autoimmunity in the elderly. Senescence of T-lymphocytes is characterized by phenotypical and functional changes including the loss of characteristic T-cell surface markers, while an increase of stimulatory receptors, cytotoxicity as well as resistance against apoptosis is observed. One of the key mediators of immune regulation are naturally occurring regulatory T-cells (Tregs). Tregs express high levels of CD25 and the intracellular protein forkhead box P3; they exert their suppressive functions in contact-dependent as well as contact-independent manners. Quantitative and qualitative defects of Tregs were observed in patients with autoimmune diseases. Increased Treg activity was shown to suppress anti-tumor and anti-infection immunity. The effect of aging on Tregs, and the possible contribution of age-related changes of the Treg pool to the pathophysiology of diseases in the elderly are still poorly understood. Treg homeostasis depends on an intact thymic function and current data suggest that conversion of non-regulatory T-cells into Tregs as well as peripheral expansion of existing Tregs compensates for thymic involution after puberty to maintain constant Treg numbers. In the conventional T-cell subset, peripheral proliferation of T-cells is associated with replicative senescence leading to phenotypical and functional changes. For Tregs, different developmental stages were also described; however, replicative senescence of Tregs has not been observed yet.

Abstract P4-04-02: Tumor-initiated peripheral myeloid cell expansion is reversed by radiation therapy

Abstract Myeloid lineage cells, particularly monocytes and macrophages, have an important role in the development and progression of cancer. Within established tumors, macrophages are critical for angiogenesis, invasion, metastasis, immunosuppression and response to therapy. In addition, both transplantable and transgenic mouse models of mammary cancer are associated with myeloid expansions detectible in the tumor, spleen and peripheral blood, and these myeloid cells are able to suppress T cell activation in vitro. Reducing the tumor burden through chemotherapy and resection has been shown to control the myeloid expansion. However, chemotherapies that reduce tumor burden also have direct effects on myeloid cells, and surgical trauma has been shown to mobilize myeloid cells. Radiation therapy is the third major option to treat cancer, but the consequence of radiation therapy to systemic myeloid populations has not been described. We applied tumor-specific radiation therapy to test the hypothesis that the frequency of myeloid lineage cells correlates with the primary tumor burden. We demonstrate in the MMTV-PyMT model of mammary cancer that myeloid expansion in the blood closely correlates with myeloid involvement in the tumor and with tumor progression. We demonstrate that radiation therapy of 4T1 mammary tumors leads to a decline in myeloid cell numbers in the blood and a decrease in spleen size. The frequency of myeloid cells does not decline to the level seen in tumor-free mice: we demonstrate that metastatic disease can prevent myeloid cell numbers from returning to baseline, and that tumor recurrence from residual disease correlates with re-expansion of myeloid lineage cells. Despite these changes in the frequency of myeloid lineage cells, T cell numbers in the blood and spleen remains constant. However, radiation therapy improves the myeloid cell:CD8+ T cell ratio and results in increased proliferation of T cells in the spleen. Finally, we demonstrate that T cell responses to foreign antigens are not altered by tumor burden or myeloid cell expansion, while T cell responses to tumor-associated antigens are increased after radiation therapy of the tumor. These data demonstrate that myeloid cell numbers are directly linked to primary tumor burden, that this population contracts following radiation therapy, and that radiation therapy may open a therapeutic window for immunotherapy of residual disease. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-04-02.

Th22 Cells as Well as Th17 Cells Expand Differentially in Patients with Early-Stage and Late-Stage Myelodysplastic Syndrome

BackgroundImmunological mechanisms are increasingly recognized in the progression of myelodysplastic syndrome (MDS). Early-stage MDS (E-MDS) is characterized by autoimmune-mediated myelosuppression whereas late-stage MDS (L-MDS) involves immune evasion, giving dysplastic cells growth potential to progress into acute myeloid leukemia. T-helper (Th) 22 is involved in the pathogenesis of inflammatory autoimmunity and tumorigenesis. The roles of Th22 cells in the pathophysiology of E-MDS and L-MDS remain unsettled.Design and MethodsWe studied 37 MDS patients (E-MDS, n = 17; L-MDS, n = 20) and 20 healthy controls to characterize their peripheral blood (PB), as well as 25 MDS patients and 10 healthy controls to characterize their bone marrow(BM). The expression of Interleukin-22 (IL-22), IL-17 or interferon gamma (IFN-γ) was examined in E-MDS, L-MDS patients and controls by flow cytometry. The mRNA expression levels of RAR-related orphan receptor C (RORC), IL-6, tumor necrosis factor alpha (TNF-α) and IL-23 in peripheral blood mononuclear cells (PBMCs) were determined by real-time quantitative polymerase chain reaction. The levels of IL-22 and IL-17 both in PB and BM plasma were examined by enzyme-linked immunosorbent assay.ResultsIn E-MDS, peripheral Th17 cells were significantly elevated and correlated with peripheral Th22 cells compared with healthy controls and L-MDS. Significantly higher levels of peripheral Th22 expansion, mRNA expression of IL-6, TNF-α and lower level of RORC mRNA expression were observed in L-MDS compared with E-MDS. No statistical difference was found in IL-23 mRNA expression or plasma IL-22, IL-17 levels among E-MDS, L-MDS and controls.ConclusionsOur data demonstrated that L-MDS cohort had increased frequencies of peripheral Th22 cells and higher mRNA expression levels of IL-6 and TNF-α, indicating that Th22 cells along with Th17 cells or not are involved in the dynamic immune responses of MDS.

Peripheral Blood γδ T Cell Response to High-Grade Glioma: Implications for Localized Adoptive Immunotherapy

Abstract 4114Glioblastoma multiforme (GBM) remains impervious to existing therapy. We have recently established that GBM is vulnerable to recognition and lysis by γδ T cells using in vitro cytotoxicity testing and in a treatment model based on human γδ T cell therapy of intracranial xenografted human glioma cell line tumors in immunodeficient mice. We have also shown that circulating γδ T cell counts and function are significantly reduced in GBM patients at the time of diagnosis. In this study, we sought to resolve the paradox between these findings with a working hypothesis that γδ T cells are depleted by activation-induced cell death following an unsuccessful immune response to GBM. We monitored peripheral and tumor immune responses over time in a C57BL/6 mouse model after intracranial placement of 1 × 105 syngeneic GL261 glioma cells, methylcellulose carrier alone, or no treatment (n=10/group). Tumor-bearing mice uniformly develop aggressive infiltrating gliomas with pseudopalisading morphology and necrotic centers that are uniformly fatal within 30 days. At 11 days following tumor placement, mice were asymptomatic. Brain sections revealed the presence of small infiltrating gliomas in 100% of mice. Peripheral blood expansion of γδ T cells was significantly increased compared to mice that received only the methylcellulose vehicle (p=0.0003). T cell proliferation was specific only to the γδ T cell compartment and did not involve other T cell subtypes, A significant proportion of γδ T cells expressed Annexin-V (20%-45%) in contrast to 2–5% in controls (p<0.0001) indicative of progression to apoptotic death. Mice that received intracranial injection of methylcellulose alone showed no changess relative to untreated mice. Although GL261 gliomas expressed γδ T cell-recognized NKG2D ligands H60, MULT-1 and RAE-1, peripheral γδ T cells did not infiltrate the intracranial tumors nor confer a survival advantage when compared to identical experiments conducted in tumor-bearing γδ T cell-deficient (C57BL/6δ−/−) mice. Placement of extra-cranial GL261 flank tumors resulted in accumulation of T cells around the periphery of the tumor but no significant T cell invasion into the tumor parenchyma. However, when mice were treated with adoptive transfer of 1.5 × 106ex vivo expanded/activated syngeneic γδ T cells by stereotactic intracranial injection on the same day as GL261 tumor placement, local tumor development was inhibited. Mice that were injected only with saline following tumor placement developed large tumors at the injection site. These data suggest that depletion of γδ T cells previously seen in GBM patients is likely due to activation-induced cell death. Although glioma-reactive γδ T cell effectors are stimulated in the early phase of tumor formation, they are unable to successfully invade and thereby impede tumor progression. Finally, these findings suggest that treatment strategies directed toward both reduction of tumor-derived immunosuppression and localized post-resection adoptive γδ T cell-based therapy may provide an approach to minimal residual GBM. Disclosures:No relevant conflicts of interest to declare.

Peripheral Blood Lymphocyte and Platelet STEM CELL Expansion in Autologous Platelet-Derived Growth Factor-RICH Plasma

AbstractAbstract 4717Research on stimulatory and inhibitory factors present in the hematopoietic microenvironment promoted development of ex-vivo cell culture methods. Recent investigations strive to select natural and novel mitogenic substances within defined conditions to culture and harvest specific progenitor cells and cell lines. Optimal large scale cell expansion of HSCs remains to be developed. The present study documents ex-vivo human lymphocytes and platelet culture in autologous human blood plasma (BP) complemented with a novel ionic metal polysulphide. Resulting plasma is growth-factor rich (FRP) with a high platelet count (HPC) containing > 4.5×10E6 plts/ul. Co-culture expansion for 3-days of normal peripheral blood cells from n=20 healthy individuals in FRP promotes lymphoid and platelet series stem cell lineage growth and differentiation. Cultured cells characterized using conventional hematology and flow cytometry methods on CD3, CD4, CD8, CD34, CD38, CD41, CD61 antigen bearing cells; and average values reported. Result analysis of CD3 and CD4 bearing cells before-after a 3-day culture indicates a 4 % and 18 % respective increase, while CD8 cell population decrease 7%. A stimulation response obtained on CD34 and CD38 cells with a 67.30% and 53.89 % respective increase. Cell growth of CD41 and CD61 antigen bearing cells increased 50.89 % and 69.22 %, respectively. Functional platelet counts (before-after culture) correspond with a 3–5 fold increase of original concentration, and presence of recently reported proto-platelets. Minimum and maximum values varied among studied population. Discrete elevation in Neutrophils and Granulocytes counts observed. Potential applications thought for immunosuppression, cancer and organ transplant. Disclosures:No relevant conflicts of interest to declare.

Rapid T‐cell chimerism switch and memory T‐cell expansion are associated with pre‐engraftment immune reaction early after cord blood transplantation

Rapid <scp>T</scp>‐cell chimerism switch and memory <scp>T</scp>‐cell expansion are associated with pre‐engraftment immune reaction early after cord blood transplantation

NKT cell adjuvant-based tumor vaccine for treatment of myc oncogene-driven mouse B-cell lymphoma

AbstractImmunomodulators are effective in controlling hematologic malignancy by initiating or reactivating host antitumor immunity to otherwise poorly immunogenic and immune suppressive cancers. We aimed to boost antitumor immunity in B-cell lymphoma by developing a tumor cell vaccine incorporating α-galactosylceramide (α-GalCer) that targets the immune adjuvant properties of NKT cells. In the Eμ-myc transgenic mouse model, single therapeutic vaccination of irradiated, α-GalCer–loaded autologous tumor cells was sufficient to significantly inhibit growth of established tumors and prolong survival. Vaccine-induced antilymphoma immunity required NKT cells, NK cells, and CD8 T cells, and early IL-12–dependent production of IFN-γ. CD4 T cells, gamma/delta T cells, and IL-18 were not critical. Vaccine treatment induced a large systemic spike of IFN-γ and transient peripheral expansion of both NKT cells and NK cells, the major sources of IFN-γ. Furthermore, this vaccine approach was assessed in several other hematopoietic tumor models and was also therapeutically effective against AML-ETO9a acute myeloid leukemia. Replacing α-GalCer with β-mannosylceramide resulted in prolonged protection against Eμ-myc lymphoma. Overall, our results demonstrate a potent immune adjuvant effect of NKT cell ligands in therapeutic anticancer vaccination against oncogene-driven lymphomas, and this work supports clinical investigation of NKT cell–based immunotherapy in patients with hematologic malignancies.

Enhancing Immune Reconstitution: From Bench to Bedside

INTRODUCTION Slow and incomplete reconstitution of cellular and humoral immunity has long been recognized as a weak link limiting the success of allogeneic hematopoietic stem cell transplantation (allo-HSCT). Delayed posttransplantation reconstitution of the adaptive immune system is associated with increased infection, relapse, secondary malignancies, and overall mortality in recipients of an allo-HSCT [1,2]. In particular, reconstitution of the T cell compartment can take 1-2 years, and deficiencies in the T cell repertoire can persist even longer. Deficiencies in T cell reconstitution are dependent on patient age, conditioning regimen, use of in vitro or in vivo T cell depletion to decrease graft-versus-host disease (GVHD), HLA disparity between donor and recipient, and GVHD prophylaxis, as well as the occurrence of GVHD. T cell recovery after allo-HSCT occurs through 2 unrelated mechanisms: (1) peripheral expansion of infused donor T cells and, to a lesser extent, residual host T cells, and (2) de novo T cell development in the thymus. Peripheral expansion is associated with a narrow repertoire, whereas de novo T cell development can reconstitute a full T cell repertoire. However, damage from conditioning and GVHD, in combination with age-associated involution, results in poor posttransplantation thymic function. Consequently, this review takes a “bench-to-bedside” approach, evaluating strategies aimed at enhancing not only the peripheral expansion of the tumor and virus-specific immune response, but also the recovery of thymic function (Figure 1).

Double Umbilical Cord Blood Transplantation: A Study of Early Engraftment Kinetics in Leukocyte Subsets using HLA-Specific Monoclonal Antibodies

Single cord blood unit (CBU) predominance is usually established within the first month after double umbilical cord blood transplantation (UCBT). However, the kinetics of engraftment of the different leukocyte subsets and the mechanism of graft predominance is largely unknown. To investigate whether a differential engraftment might reveal a specific subset that could play a key role in the mechanism of graft predominance, we studied early engraftment kinetics of different leukocyte subpopulations by flow cytometry using human monoclonal antigen–specific human leukocyte antigen antibodies, directed against mismatched human leukocyte antigen-A or –B antigens between recipient and CBUs. Twenty-two patients, who had received a double UCBT preceded by a reduced-intensity conditioning regimen, were evaluated at days +11, +18, +25, and +32 posttransplantation. Single CBU predominance in the various leukocyte subsets was established within 18 days posttransplantation. CD4+ T cells of the dominant CBU showed early peripheral blood expansion. Moreover, chimerism in CD4+ and CD8+ T cell and natural killer cell subsets at day +11 was predictive of ultimate graft predominance. These findings show that engraftment kinetics of the various leukocyte subsets vary considerably after double UCBT and may suggest an important role for CD4+ T cells in a presumed alloreactive graft-versus-graft rejection.

CTLA4-Ig Restores Rejection of MHC Class-II Mismatched Allografts by Disabling IL-2-Expanded Regulatory T Cells

Allograft acceptance and tolerance can be achieved by different approaches including inhibition of effector T cell responses through CD28-dependent costimulatory blockade and induction of peripheral regulatory T cells (Tregs). The observation that Tregs rely upon CD28-dependent signals for development and peripheral expansion, raises the intriguing possibility of a counterproductive consequence of CTLA4-Ig administration on tolerance induction. We have investigated the possible negative effect of CTLA4-Ig on Treg-mediated tolerance induction using a mouse model of single MHC class II-mismatched skin grafts in which long-term acceptance was achieved by short-term administration of IL-2/anti-IL-2 complex. CTLA4-Ig treatment was found to abolish Treg-dependent acceptance in this model, restoring skin allograft rejection and Th1 alloreactivity. CTLA4-Ig inhibited IL-2-driven Treg expansion, and prevented in particular the occurrence of ICOS(+) Tregs endowed with potent suppressive capacities. Restoring CD28 signaling was sufficient to counteract the deleterious effect of CTLA4-Ig on Treg expansion and functionality, in keeping with the hypothesis that costimulatory blockade inhibits Treg expansion and function by limiting the delivery of essential CD28-dependent signals. Inhibition of regulatory T cell function should therefore be taken into account when designing tolerance protocols based on costimulatory blockade.

Low-Dose IL-2 for In Vivo Expansion of CD4+ and CD8+ Regulatory T Cells in Nonhuman Primates

IL-2 is a known potent T cell growth factor that amplifies lymphocyte responses in vivo. This capacity has led to the use of high-dose IL-2 to enhance T cell immunity in patients with AIDS or cancer. However, more recent studies have indicated that IL-2 is also critical for the development and peripheral expansion of regulatory T cells (Tregs). In the current study, low-dose IL-2 (1 million IU/m(2) BSA/day) was administered to expand Tregs in vivo in naïve nonhuman primates. Our study demonstrated that low-dose IL-2 therapy significantly expanded peripheral blood CD4(+) and CD8(+) Tregs in vivo with limited expansion of non-Treg cells. These expanded Tregs are mainly CD45RA(-) Foxp3(high) activated Tregs and demonstrated potent immunosuppressive function in vitro. The results of this preclinical study can serve as a basis to develop Treg immunotherapy, which has significant therapeutic potential in organ/cellular transplantation.

Transglutaminase 2 exacerbates experimental autoimmune encephalomyelitis through positive regulation of encephalitogenic T cell differentiation and inflammation

The increased activity of transglutaminase 2 (TG2) in various inflammatory and fibrotic conditions results in the development of numerous disease processes. Experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis, is an inflammatory and demyelinating disease of the central nervous system and is mediated by many inflammatory cytokines and mediators. We examined the role of TG2 in encephalitogenic CD4(+) T cell responses and EAE development using mice lacking TG2 (TG2(-/-)). TG2(-/-) mice showed decreased disease severity as compared with wild-type (WT) mice. Treatment with cysteamine, a TG2 inhibitor, ameliorated disease severity in WT mice. Exacerbated disability in WT mice resulted from the increased infiltration of cytokine-producing CD4(+) T cells and sustained expression of inflammatory cytokines and mediators in the lesion. The increased number of IL-17- and IFN-γ-producing cells in the spinal cord resulted from peripheral expansion of these cells after immunization with myelin-derived antigen. In vitro differentiation of WT and TG2(-/-) splenocytes revealed that proliferation and activation-induced cell death did not differ, but differentiation into IL-17- or IFN-γ-producing cells was increased in WT mice. Adoptive transfer experiments revealed that pathogenic CD4(+) T cell differentiation and disease progression were caused by both the T cell-intrinsic and -extrinsic effects of TG2. This study is the first to report a pathogenic role for TG2 in the EAE progress and suggests that therapeutic targeting of TG2 may be effective against multiple sclerosis.

A two-hit model of autoimmunity: lymphopenia and unresponsiveness to TGF-β signaling

A two-hit model of autoimmunity: lymphopenia and unresponsiveness to TGF-β signaling

SOCIAL AND ENVIRONMENTAL PROBLEMS AND INSTITUTIONAL ASPECTS OF URBAN MANAGEMENT IN PALMAS (TO)

This work aims to meet the urban environmental management in Palmas and establish consistency with the socio-environmental problems and needs and their efficiency in monitoring and controlling the environment. Palmas, the newest planned city in Brazil is facing conflicts that urban planning could not prevent the peripheral expansion and separation of social classes determined the absence or little coverage of basic infrastructure services like water supply, sewerage, collection and disposal of garbage and the deficiency in the management and maintenance of green areas. From this backdrop, we carried out analysis on the institutions and the environmental reality of the city and proposed a model for the municipal environment, based on the Statute of the city, and also suggestions to formulate public policies and proposals for immediate action, aimed at improve the quality of life of Palmas.

α-MSH-Stimulated Tolerogenic Dendritic Cells Induce Functional Regulatory T Cells and Ameliorate Ongoing Skin Inflammation

The neuropeptide α-melanocyte-stimulating hormone (α-MSH) is a well-known mediator of skin pigmentation. More recently, it has been shown that α-MSH also exerts a strong anti-inflammatory and immunosuppressive activity. To elucidate the mechanisms underlying α-MSH-induced immunosuppression, we investigated whether α-MSH affects dendritic cell/T cell communication, as especially this interaction has an important role in the regulation of immune responses. Here, we show that α-MSH, by binding to MC-1R, induced tolerogenic dendritic cells, which were capable of expanding CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs) in vitro, as well as in vivo. Notably, those α-MSH-induced Tregs were functional as they efficiently inhibited cutaneous contact allergy and ongoing psoriasis-like skin inflammation in mice. Furthermore, α-MSH induced tolerogenic dendritic cells capable of generating functional Tregs in human blood. Interestingly, human Tregs expanded via α-MSH-stimulated dendritic cells suppressed the proliferation and cytokine secretion of pathogenic T-helper-17 (Th17) cells from individuals with psoriasis. Taken together, these data indicate that α-MSH induced immunosuppressive Tregs in vitro and in vivo, which inhibited disease progression in a mouse model of psoriasis-like skin inflammation and suppressed the activation and proliferation of effector T cells from subjects with psoriasis.

Glioblastoma: Biology, Genetics, and Behavior

Glioblastoma (GBM) is a highly malignant, rapidly progressive astrocytoma that is distinguished pathologically from lower-grade tumors by necrosis and microvascular hyperplasia. The global pattern of growth changes dramatically with the development of GBM histology and is characterized by hypoxia-driven peripheral expansion from a growing necrotic core. Necrotic foci present centrally in GBM and are typically surrounded by "pseudopalisading" cells-a configuration that is relatively unique and long recognized as an ominous prognostic feature. Theses pseudopalisades are severely hypoxic, overexpress hypoxia inducible factor-1 (HIF-1), and secrete proangiogenic factors, such as vascular endothelial growth factor (VEGF) and interleukin 8 (IL-8). The microvascular hyperplasia that emerges in response promotes peripheral tumor expansion. Recent evidence suggests that pseudopalisades represent a wave of tumor cells actively migrating away from central hypoxia that arises following a vascular insult. Vaso-occlusive and prothrombotic mechanisms in GBM could readily explain the presence of pseudopalisading necrosis in tissue sections, the rapid peripheral expansion on neuroimaging, and the dramatic shift to an accelerated rate of clinical progression as a result of hypoxia-induced angiogenesis. The genetic alterations that coincide with progression to GBM include amplification of epidermal growth factor receptor (EGFR), deletion of CDKN2A, and mutation or deletion of PTEN. Other diagnostic and prognostic tests used in neuro-oncology include assessment of 1p/19q, MGMT promoter methylation, IDH1, and p53. More recently, the Cancer Genome Atlas data have indicated that there are four robust transcriptional classes of GBM, referred to as proneural, neural, classical, and mesenchymal. These classes have genetic associations and may pave the road for future development of targeted therapies.