PGE2 Contributes to In vitro MSC‐Mediated Inhibition of Non‐Specific and Antigen‐Specific T Cell Proliferation in MS Patients

Current theories of multiple sclerosis (MS) induction and progression place autoreactive T cells in the focus of the pathogenesis. Mesenchymal/stromal stem cells (MSC) have become a promising alternative approach for pathogenic therapy of MS due to their immunomodulatory properties, underlying mechanisms of which are intensive study. The objective of the research was to investigate the contribution of PGE₂ to MSC‐mediated suppression in patients with MS using in vitro model of mitogen‐ and myelin‐stimulated T cell cocultivation with autologous/allogeneic MSC. We have showed that PGE₂ production depends on cell‐to‐cell contact of MSC and lymphocytes. The antigenic stimulation did not affect PGE₂ production following cocultivation of MSC and PBMC, and it is the presence of MSC in cell culture that significantly increases PGE₂ production irrespective of antigenic cultivation conditions. Simultaneously, PGE₂ synthesis correlated with indexes of MSC‐mediated suppression of mitogen‐ and myelin‐stimulated T cell proliferation in patients with MS. No significant differences in PGE₂ production by autologous and allogeneic MSC have been established. These results have demonstrated that in patients with MS, PGE₂ is one of the possible factors of MSC immunosuppression. The interrelation between PGE₂ concentrations and T cell proliferation suppression mediated by MSC may explain one of the immune mechanisms of cell therapy, which is crucial for the further proper use of MSC in MS research and pathogenic treatment.     

Mesenchymal stem cells control alloreactive CD8+CD28− T cells

CD28/B7 co-stimulation blockade with belatacept prevents alloreactivity in kidney transplant patients. However, cells lacking CD28 are not susceptible to belatacept treatment. As CD8⁺CD28⁻ T-cells have cytotoxic and pathogenic properties, we investigated whether mesenchymal stem cells (MSC) are effective in controlling these cells. In mixed lymphocyte reactions (MLR), MSC and belatacept inhibited peripheral blood mononuclear cell (PBMC) proliferation in a dose-dependent manner. MSC at MSC/effector cell ratios of 1:160 and 1:2·5 reduced proliferation by 38·8 and 92·2%, respectively. Belatacept concentrations of 0·1 μg/ml and 10 μg/ml suppressed proliferation by 20·7 and 80·6%, respectively. Both treatments in combination did not inhibit each other''s function. Allostimulated CD8⁺CD28⁻ T cells were able to proliferate and expressed the cytolytic and cytotoxic effector molecules granzyme B, interferon (IFN)-γ and tumour necrosis factor (TNF)-α. While belatacept did not affect the proliferation of CD8⁺CD28⁻ T cells, MSC reduced the percentage of CD28⁻ T cells in the proliferating CD8⁺ T cell fraction by 45·9% (P = 0·009). CD8⁺CD28⁻ T cells as effector cells in MLR in the presence of CD4⁺ T cell help gained CD28 expression, an effect independent of MSC. In contrast, allostimulated CD28⁺ T cells did not lose CD28 expression in MLR–MSC co-culture, suggesting that MSC control pre-existing CD28⁻ T cells and not newly induced CD28⁻ T cells. In conclusion, alloreactive CD8⁺CD28⁻ T cells that remain unaffected by belatacept treatment are inhibited by MSC. This study indicates the potential of an MSC–belatacept combination therapy to control alloreactivity.     

CD101 inhibits the expansion of colitogenic T cells

CD101 exerts negative-costimulatory effects in vitro, but its function in vivo remains poorly defined. CD101 is abundantly expressed on lymphoid and myeloid cells in intestinal tissues, but absent from naïve splenic T cells. Here, we assessed the impact of CD101 on the course of inflammatory bowel disease (IBD). Using a T-cell transfer model of chronic colitis, we found that in recipients of naïve T cells from CD101^+/+ donors up to 30% of the recovered lymphocytes expressed CD101, correlating with an increased interleukin (IL)-2-mediated FoxP3 expression. Transfer of CD101^−/− T cells caused more severe colitis and was associated with an expansion of IL-17-producing T cells and an enhanced expression of IL-2Rα/β independently of FoxP3. The co-transfer of naïve and regulatory T cells (Treg) protected most effectively from colitis, when both donor and recipient mice expressed CD101. Although the expression of CD101 on T cells was sufficient for Treg-function and the inhibition of T-cell proliferation, sustained IL-10 production required additional CD101 expression by myeloid cells. Finally, in patients with IBD a reduced CD101 expression on peripheral and intestinal monocytes and CD4⁺ T cells correlated with enhanced IL-17 production and disease activity. Thus, CD101 deficiency is a novel marker for progressive colitis and potential target for therapeutic intervention.     

Costimulatory molecules in Wegener's granulomatosis (WG): lack of expression of CD28 and preferential up-regulation of its ligands B7-1 (CD80) and B7-2 (CD86) on T cells

T cells are most likely to play an important role in the pathogenesis of WG, and recently a predominant Th1 pattern of immune response has been demonstrated in granulomatous inflammation. Since the expression of costimulatory molecules has a significant impact on the cytokine profile and proliferation response of T cells, the goal of this study was to characterize the expression of costimulatory molecules (CD28, CTLA-4 (CD152), B7-1 (CD80), B7-2 (CD86)) on T cells, monocytes and B cells in WG, and to correlate the findings with clinical parameters such as disease activity, extent and therapy. WG patients (n = 24) and healthy controls (HC; n = 17) were examined for the expression of costimulatory molecules by fluorescence-activated cell sorter analysis, both in whole peripheral blood and after in vitro activation of T cells and antigen-presenting cells. Results were correlated with clinical data. The expression of CD28 on CD4⁺ and CD8⁺ cells was significantly lower in WG than in HC (CD28⁺ 81.4% in WG versus 97.9% of CD4⁺ cells (P < 0.0001); CD28⁺ 44.6% in WG versus 68.5% of CD8⁺ cells (P < 0.00001)), both in peripheral blood and after in vitro activation. A lower percentage of monocytes was B7-2⁺ in WG than in HC in peripheral blood, whereas no significant differences in the expression of B7-1 and B7-2 were observed after in vitro stimulation of monocytes and B cells. After in vitro activation a significantly higher percentage of B7-1⁺ and B7-2⁺ T cells was seen in WG. There was no significant difference in the CTLA-4 expression pattern between WG and HC. The percentage of CD28⁺ lymphocytes correlated negatively with the Disease Extent Index cumulated over the course of disease (r = ?0.46, P = 0.03), indicating a more severe manifestation in patients with lower CD28 expression. Correlations with other clinical parameters such as activity or therapy were not seen. WG patients show a lack of CD28 expression on T cells and an unusual up-regulation of its ligands B7-1 and B7-2 on T cells after in vitro activation as well as a lower expression of B7-2 on freshly isolated monocytes compared with HC. These features might promote the Th1 cytokine pattern and thereby contribute to persistently high levels of immune activation in WG.     

Endogenous interleukin‐6 amplifies interleukin‐17 production and corticoid‐resistance in peripheral T cells from patients with multiple sclerosis

Interleukin‐6 (IL‐6) has been implicated in the induction of pathogenic IL‐17‐producing T cells in autoimmune diseases, and studies evaluating the role of this cytokine in T‐cell function in patients with multiple sclerosis (MS) are lacking. Our objective was to evaluate the role of IL‐6 receptor (IL‐6R) signalling on in vitro functional status of T cells from patients with relapsing–remitting MS during clinical remission. Our results demonstrated that, even during the remission phase, activated T cells from patients produce higher levels of IL‐17, and this cytokine was positively correlated with disease severity, as determined by Expanded Disability Status Scale score. In the MS group, the blockade of IL‐6R signalling by anti‐IL‐6R monoclonal antibody reduced IL‐17 production and elevated IL‐10 release by activated CD4⁺ T cells, but it did not alter the production of these cytokines by activated CD8⁺ T cells. Blockade of IL‐6R signalling also reduced the ability of monocytes to up‐regulate T helper type 17 phenotype in patients with MS. Finally, both cell proliferation and IL‐17 release by CD4⁺ and, mainly, CD8⁺ T cells from patients with MS were less sensitive to hydrocortisone inhibition than control group. Interestingly, IL‐6R signalling blockade restored the ability of hydrocortisone to inhibit both T‐cell proliferation and IL‐17 production. Collectively, these results suggest that IL‐6 might be involved in MS pathogenesis by enhancing IL‐17 production and reducing corticoid inhibitory effects on activated T cells.     

Adenosine metabolism of human mesenchymal stromal cells isolated from patients with head and neck squamous cell carcinoma

BackgroundMesenchymal stromal cells (MSC) are a major component of the tumor microenvironment in patients with head and neck squamous cell carcinoma (HNSCC). MSC display innate and regulatory immunologic functions, very similar to many hematopoietic ‘classical’ immune cells. Conversion of ATP to immunosuppressive adenosine is an immunosuppressive mechanism utilized by other hematopoietic immune cells. The present study explores the adenosine metabolism of tumor derived MSC in comparison to autologous MSC from non-malignant tissue.MethodsFrom HNSCC patients (n = 10), paired MSC were generated from tumor tissue (tMSC) and autologous healthy control tissue (cMSC). Differentiation properties and phenotype (CD105, CD73, CD39, CD90, CD26, CD29) were compared by flow cytometry. Production of immunosuppressive adenosine (ADO) by functionally active ectonucleotidases, CD39 and CD73, was determined by luminescence and mass spectrometry. Suppressive activity of ADO was tested in CFSE proliferation assays of isolated T-cells. Plasticity of cMSC was explored after incubation with tumor-cell conditioned media.ResultsDifferentiation into osteogenic, chondrogenic and adipogenic directions was comparable in tMSC and cMSC. Expression of ectonucleotidases, CD39 and CD73, was decreased in tMSC as compared to corresponding cMSC, which correlated with decreased ATP metabolism in mass spectrometry. Proliferation of CD4⁺ T-cells was significantly suppressed by exogenous ADO. Tumor-conditioned medium was unable to down-regulate ADO production in cMSC.ConclusionWe identified MSC of the oropharyngeal mucosa as an important producer of exogenous ADO. In patients with HNSCC, reduced expression of ADO may contribute to excessive inflammation and tumor growth.     

Mesenchymal stem cell inhibition of T-helper 17 cell- differentiation is triggered by cell-cell contact and mediated by prostaglandin E2 via the EP4 receptor

Mesenchymal stem cells (MSCs) inhibit T‐cell activation and proliferation but their effects on individual T‐cell‐effector pathways and on memory versus naïve T cells remain unclear. MSC influence on the differentiation of naïve and memory CD4⁺ T cells toward the Th17 phenotype was examined. CD4⁺ T cells exposed to Th17‐skewing conditions exhibited reduced CD25 and IL‐17A expression following MSC co‐culture. Inhibition of IL‐17A production persisted upon re‐stimulation in the absence of MSCs. These effects were attenuated when cell–cell contact was prevented. Th17 cultures from highly purified naïve‐ and memory‐phenotype responders were similarly inhibited. Th17 inhibition by MSCs was reversed by indomethacin and a selective COX‐2 inhibitor. Media from MSC/Th17 co‐cultures contained increased prostaglandin E2 (PGE2) levels and potently suppressed Th17 differentiation in fresh cultures. MSC‐mediated Th17 inhibition was reversed by a selective EP4 antagonist and was mimicked by synthetic PGE2 and a selective EP4 agonist. Activation‐induced IL‐17A secretion by naturally occurring, effector‐memory Th17 cells from a urinary obstruction model was also inhibited by MSC co‐culture in a COX‐dependent manner. Overall, MSCs potently inhibit Th17 differentiation from naïve and memory T‐cell precursors and inhibit naturally‐occurring Th17 cells derived from a site of inflammation. Suppression entails cell‐contact‐dependent COX‐2 induction resulting in direct Th17 inhibition by PGE2 via EP4.     

Expression of Programmed Death-1 (PD-1) on CD4+ and CD8+ T cells in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is characterized by chronic inflammatory process that targets the synovial lining of diarthrodial joints. Programmed death 1 (PD-1) plays a key role in the negative regulation of the immune response. In the current study, we investigated the expression of PD-1 on peripheral CD4+ and CD8+ T cells in RA patients. Percentage of PD-1+ cells was measured by flow cytometry in 82 RA cases and 90 healthy controls. Results showed that PD-1 expression was significantly decreased in both peripheral CD4+ and CD8+ T cells in RA (p?=?0.002 and p?<?0.001, respectively). Similarly, serum levels of soluble PD-1 were also downregulated in RA cases. When comparing PD-1 level in RA patients with different clinical parameters, patients with positive C-reactive protein (CRP) revealed lower proportion of PD-1 on CD4+ and CD8+ T cells than those with negative CRP. Also, disease activity score of RA patients was inversely correlated with PD-1 expression on peripheral CD4+ and CD8+ T cells. These data suggested that PD-1 may act as a negative regulator in the pathogenesis and progression of RA.     

Serotonin decreases the production of Th1/Th17 cytokines and elevates the frequency of regulatory CD4+ T‐cell subsets in multiple sclerosis patients

Excessive levels of proinflammatory cytokines in the CNS are associated with reduced serotonin (5‐HT) synthesis, a neurotransmitter with diverse immune effects. In this study, we evaluated the ability of exogenous 5‐HT to modulate the T‐cell behavior of patients with MS, a demyelinating autoimmune disease mediated by Th1 and Th17 cytokines. Here, 5‐HT attenuated, in vitro, T‐cell proliferation and Th1 and Th17 cytokines production in cell cultures from MS patients. Additionally, 5‐HT reduced IFN‐γ and IL‐17 release by CD8⁺ T cells. By contrast, 5‐HT increased IL‐10 production by CD4⁺ T cells from MS patients. A more accurate analysis of these IL‐10‐secreting CD4⁺ T cells revealed that 5‐HT favors the expansion of FoxP3⁺CD39⁺ regulatory T cells (Tregs) and type 1 regulatory T cells. Notably, this neurotransmitter also elevated the frequency of Treg17 cells, a novel regulatory T‐cell subset. The effect of 5‐HT in upregulating CD39⁺ Treg and Treg17 cells was inversely correlated with the number of active brain lesions. Finally, in addition to directly reducing cytokine production by purified Th1 and Th17 cells, 5‐HT enhanced in vitro Treg function. In summary, our data suggest that serotonin may play a protective role in the pathogenesis of MS.     

Inverse correlation between CD4+ regulatory T-cell population and autoantibody levels in paediatric patients with systemic lupus erythematosus

CD4(+) CD25(+) regulatory T cells (Tregs) are critical in maintaining self-tolerance and preventing organ-specific autoimmunity. Their role in paediatric systemic lupus erythematosus (SLE), an autoimmune disease characterized by inappropriate regulation of hyperactivated B and T cells, has not been clearly defined. Using flow cytometry to determine cell populations and real-time polymerase chain reaction to assay mRNA expression for FOXP3, CTLA-4, and GITR, we characterized CD4(+) CD25(+) T cells in paediatric SLE patients and healthy subjects. The frequency of CD4(+) CD25(+) Tregs was significantly decreased in patients with active SLE compared with patients with inactive SLE and with controls (7.27% +/- 2.50%, 9.59% +/- 2.80% and 9.78% +/- 2.11%, respectively; P = 0.027 and P < 0.001, respectively), and was inversely correlated with disease activity, as assessed with the Systemic Lupus Erythematosus Disease Activity Index 2000 scores (r = -0.59, P = 0.001) and serum anti-double-stranded DNA levels (r = -0.65, P < 0.001). Our preliminary investigations found elevated surface expression of GITR in CD4(+) CD25(+) T cells, elevated mRNA expression of CTLA-4 in CD4(+) T cells and higher amounts of mRNA expression for FOXP3 in CD4(+) cells in patients with active SLE compared with patients with inactive disease and controls. We demonstrated reduced CD4(+) CD25(+) Treg levels were inversely correlated with disease activity, indicating a defective Treg population in paediatric SLE patients. The differences in the expression of FOXP3, CTLA-4 and GITR imply the possible role of CD4(+) Tregs in the pathogenesis of SLE.     

Programmed death-1 (PD-1)-dependent functional impairment of CD4+ T cells in recurrent genital papilloma

Genital papilloma is caused by human papilloma virus (HPV) infection and recurs frequently. Although T cells are known to play a critical role in the control of HPV infection and papilloma development, the function and phenotype of these cells in the lesion remain to be elucidated. In the present study, we examined the function and phenotype of CD4⁺ T cells isolated from the lesions of primary (n = 9) and recurrent (n = 11) genital papillomas. In recurrent papillomas, the frequency of proliferating (Ki-67⁺) CD4⁺ T cells was significantly reduced compared with primary papillomas. Cytokine production was evaluated by intracellular cytokine staining in anti-CD3/anti-CD28-stimulated CD4⁺ T cells. CD4⁺ T cells from recurrent lesions showed impaired production of IL-2, IFN-γ, and TNF-α. Of interest, the frequency of cytokine-producing CD4⁺ T cells significantly correlated with the frequency of Ki-67⁺CD4⁺ T cells. We also studied expression of programmed death-1 (PD-1), a T-cell exhaustion marker. The frequency of PD-1⁺CD4⁺ T cells was significantly increased in recurrent lesions and inversely correlated with the frequency of cytokine-producing CD4⁺ T cells. The functional significance of PD-1 expression was determined in blocking assays with anti-PD-L1, which restored cytokine production of CD4⁺ T cells from recurrent lesions. Taken together, in recurrent genital papilloma lesions, proliferation, and cytokine production by CD4⁺ T cells are impaired and the PD-1/PD-L1 interaction is responsible for the functional impairment of CD4⁺ T cells.     

Association of kinesin family member 2A with increased disease risk,deteriorative clinical characteristics,and shorter survival profiles in acute myeloid leukemia

This study aimed to explore the correlation of kinesin family member 2A (KIF2A) expression with disease risk, clinical characteristics, and prognosis of acute myeloid leukemia (AML), and investigate the effect of KIF2A knockdown on AML cell activities in vitro. Bone marrow samples were collected from 176 AML patients and 40 healthy donors, and KIF2A expression was measured by real-time quantitative polymerase chain reaction. Treatment response, event-free survival (EFS), and overall survival (OS) were assessed in AML patients. In vitro, KIF2A expression in AML cell lines and CD34⁺ cells (from healthy donors) was measured, and the effect of KIF2A knockdown on AML cell proliferation and apoptosis in HL-60 and KG-1 cells was detected. KIF2A expression was greater in AML patients compared to healthy donors, and receiver operating characteristic curve indicated that KIF2A expression predicted increased AML risk (area under curve: 0.793 (95%CI: 0.724-0.826)). In AML patients, KIF2A expression positively correlated with white blood cells, monosomal karyotype, and high risk stratification. Furthermore, no correlation of KIF2A expression with complete remission or hematopoietic stem cell transplantation was found. Kaplan-Meier curves showed that KIF2A expression was negatively correlated with EFS and OS. In vitro experiments showed that KIF2A was overexpressed in AML cell lines (KG-1, HL-60, ME-1, and HT-93) compared to CD34⁺ cells, moreover, cell proliferation was reduced but apoptosis was increased by KIF2A knockdown in HL-60 and KG-1 cells. In conclusion, KIF2A showed potential to be a biomarker and treatment target in AML.     

Analysis of CD8+ Treg cells in patients with ovarian cancer: a possible mechanism for immune impairment

Regulatory T (Treg) cells may participate in mediating a suppressive microenvironment that blunts successful anti-tumor immunotherapy. Recent studies show that CD8⁺ Treg cells might impede effective immune responses to established tumors. However, there is limited research regarding CD8⁺ Treg cells in ovarian cancer (OC) patients. Here, we investigated CD8⁺ Treg cells in OC patients and their in vitro induction. The immunohistochemistry of tumor-infiltrating lymphocytes revealed a significant correlation between the intratumoral CD8⁺ T cells and the forkhead box p3 (Foxp3)⁺ cells in the intraepithelial and stromal areas of advanced OC tissues. We examined the expression of Treg markers in CD8⁺ T cells from the peripheral blood and fresh tumor tissues of OC patients using flow cytometry. Our results indicated an increase in the CD8⁺ Treg cell subsets of OC patients compared with those in patients with benign ovarian tumors and healthy controls, including an increased expression of CD25, cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), and Foxp3 and decreased CD28 expression. To demonstrate whether the tumor microenvironment could convert CD8⁺ effector T cells into suppressor cells, we used an in vitro transwell culturing system. Compared with the CD8⁺ T cells cultured alone, the CD8⁺ Treg cells induced in vitro by coculture with SK-OV-3/A2780 showed increased CTLA-4 and Foxp3 expression and decreased CD28 expression. In addition, the in vitro-induced CD8⁺ Treg cells inhibited naïve CD4⁺ T-cell proliferation, which was partially mediated through TGF-β1 and IFN-γ. Our study suggests that CD8⁺ Treg cells were increased in OC patients and could be induced in vitro, which may be the way that tumors limit antitumor immunity and evade immune surveillance.     

Dysregulation of regulatory CD56bright NK cells/T cells interactions in multiple sclerosis

Recent evidence has shown that CD56^bright NK cells, a subset of NK cells abundant in lymph nodes, may have an immunoregulatory function. In multiple sclerosis (MS), expansion of CD56^bright NK cells has been associated to successful response to different treatments and to remission of disease during pregnancy; how whether they exert immunoregulation in physiologic conditions and whether this is impaired in MS is not known. We dissected the immunoregulatory role of CD56^bright NK cells function in healthy subjects (HS) and compared it with that of untreated MS subjects or patients with clinically isolated syndrome suggestive of MS (CIS). We found that CD56^bright NK cells from HS acquire, upon inflammatory cues, the capability of suppressing autologous CD4+T cell proliferation through direct cytotoxicity requiring engagement of natural cytotoxicity receptors (NCRs) and secretion of granzyme B. CD56^bright NK cells from patients with MS/CIS did not differ in frequency and share a similar phenotype but displayed a significantly lower ability to inhibit autologous T cell proliferation. This impairment was not related to deficient expression of NCRs or granzyme B by CD56^bright NK cells, but to increased HLA-E expression on T cells from MS/CIS subjects, which could enhance the inhibitory effect mediated by NKG2A that is homogeneously expressed on CD56^bright NK cells. The defect in controlling autologous T cells by CD56^bright NK cells in MS/CIS might contribute to the excess of autoimmune response that is associated to disease development.     

Mesenchymal stem cell therapy induces glucocorticoid synthesis in colonic mucosa and suppresses radiation-activated T cells: new insights into MSC immunomodulation

Non-neoplastic tissues around an abdomino-pelvic tumor can be damaged by the radiotherapy protocol, leading to chronic gastrointestinal complications that affect the quality of life with substantial mortality. Stem cell-based approaches using immunosuppressive bone marrow mesenchymal stem cells (MSCs) are promising cell therapy tools. In a rat model of radiation proctitis, we evidenced that a single MSC injection reduces colonic mucosa damages induced by ionizing radiation with improvement of the re-epithelization process for up to 21 days. Immune cell infiltrate and inflammatory molecule expressions in the colonic mucosa were investigated. We report that MSC therapy specifically reduces T-cell infiltration and proliferation, and increases apoptosis of radiation-activated T cells. We assessed the underlying molecular mechanisms and found that interleukin-10 and regulatory T lymphocytes are not involved in the immunosuppressive process in this model. However, an increased level of corticosterone secretion and HSD11b1 (11β-hydroxysteroid dehydrogenase type 1)-steroidogenic enzyme expression was detected in colonic mucosa 21 days after MSC treatment. Moreover, blocking the glucocorticoid (GC) receptor using the RU486 molecule statistically enhances the allogenic lymphocyte proliferation inhibited by MSCs in vitro and abrogates the mucosal protection induced by MSC treatment in vivo. Using the irradiation model, we found evidence for a new MSC immunosuppressive mechanism involving GCs.     

Decreased 4-1BB expression on CD4+CD25 high regulatory T cells in peripheral blood of patients with multiple sclerosis

As a tumour necrosis factor receptor superfamily member, 4-1BB (CD137) is preferentially expressed in CD4+CD25+ regulatory T cells (Tregs) and has been suggested to play an important role in regulating the generation or function of Tregs. Recent studies of human Tregs have shown that blood CD4+CD25(high) T cells were much closer to Tregs in terms of their functionality. Furthermore, CD4+CD25(high) Tregs have been found to have a decreased effector function in patients with multiple sclerosis (MS). In this study, we examined the expression of 4-1BB and soluble 4-1BB (s4-1BB) protein levels in the peripheral blood of MS patients. Compared with healthy controls, MS patients had decreased 4-1BB expression in their CD4+C25(high) Tregs and increased plasma s4-1BB protein levels. Moreover, the plasma s4-1BB levels of MS patients were shown to be inversely correlated with the 4-1BB surface expression of CD4+CD25(high) Tregs. The down-regulated 4-1BB expression on CD4+CD25(high) Tregs of MS patients may be involved in the impaired immunoactivity of these Tregs. The elevated s4-1BB levels may, at least in part, function as a self-regulatory attempt to inhibit antigen-driven proliferation of Tregs or their immunosuppressive activity.     

Both in vitro T cell proliferation and telomere length are decreased,but CD25 expression and IL-2 production are not affected in aged men

IntroductionAging is a natural process involving dysfunction of multiple organs and is characterized by increased susceptibility to infections, cancer and autoimmune diseases. The functionality of the immune system depends on the capacity of lymphocytes to proliferate in response to antigenic challenges, and telomere length has an important role regulating the number of cell divisions. The aim of this study was to determine the possible relationship between telomere length, interleukin 2 (IL-2) production, CD25 expression and proliferation of peripheral blood mononuclear cells (PBMCs) in aged men.Material and methodsTelomere length was measured by RT-PCR in PBMCs from young and aged men. IL-2 production and CD25 expression were determined by ELISA and flow cytometry, respectively. Cell proliferation was measured by CFSE dilution assays upon in vitro stimulation with concanavalin A (Con A).ResultsPBMCs from aged men showed a shorter telomere length and a reduced capacity to proliferate in vitro, compared to young men. In contrast, no significant differences in the level of CD25 expression on T lymphocytes, and in vitro production of IL-2 were detected in both groups. In addition, no significant correlation was detected between levels of CD25 expression, IL-2 production, cell proliferation, and telomere length in aged men.ConclusionsIn aged men the telomere length shortening and the reduced T cell proliferation are not related to the capacity of IL-2 production and CD25 expression on T lymphocytes.     

Conservation of characteristics and functions of CD4 positive lymphocytes in a teleost fish

The presence of helper and cytotoxic T cells in fish has been suggested, although T cell subsets have yet to be identified at the cellular level. In order to investigate the functions of CD4 and CD8α positive T cells we attempted to produce and characterize monoclonal antibodies (mAbs) against teleost CD4 and CD8α. Here we report the successful production of mAbs against CD4 and CD8α in clonal ginbuna crucian carp Carassius auratus langsdorfii and the function of CD4 positive T cells. In this study we demonstrate the presence of teleost CD4- and CD8α-positive T cell subsets with morphology, tissue distribution and gene expression similar to those of mammalian CD4- and CD8-positive T lymphocytes. Using mAbs we found that CD4/CD8 double positive T cells are only present in the thymus, suggesting that it is the site of T cell development. We further demonstrated in vitro proliferation of CD4 positive T cells by allogeneic combination of mixed leukocyte culture and antigen-specific proliferation of CD4 positive T cells after in vitro sensitization with OVA. In our previous study we showed that CD8α-positive lymphocytes are the primary cell type showing specific cytotoxicity against allogeneic targets. Collectively, these findings suggest that CD4 and CD8α positive T cells in ginbuna are equivalent to helper and cytotoxic T lymphocytes (CTL) in mammals, respectively. This is the first report to show the characteristics and functions of CD4 positive T cells in fish and these findings shed light into the evolutionary origins and primordial functions of helper T cells.     

Effects of the NK Cell Recovery on Outcomes of Unmanipulated Haploidentical Blood and Marrow Transplantation for Patients with Hematologic Malignancies

The goal of this study was to investigate the association of natural killer (NK) cell recovery with clinical outcomes after unmanipulated haploidentical blood and marrow transplantation. We sequentially monitored the reconstitution kinetics of circulating NK cells, CD56^bright and CD56^dim, in 43 patients by flow cytometry, and the functionality recovery of cytokine or cytotoxicity of NK cells by flow cytometry or lactate dehydrogenase release assay after transplantation. Reconstitution of NK cells was rapid but accompanied by skewing of cell subsets mainly in CD56^bright, which recovered earlier. Linear regression analysis demonstrated that dose of CD34⁺ cells in the allografts was inversely correlated with the ratio of T/NK cells (β = −0.506, P = .003) and CD56^dim/CD56^bright cell (β = −.403, P = .018) by day 14 after hematopoietic stem cell transplantation (HSCT), and the dose of CD3⁺ T cells in the allografts was also inversely correlated with the ratio CD56^dim/CD56^bright cells by day 14 after HSCT (β = −0.474, P = .005). Moreover, the dose of CD56^dim NK cells in the allograft was positively associated with the day 14 CD56^brigh NK cells (β = 0.494, P = .032) and inversely correlated with the day 14 ratio of CD56^dim/CD56^bright cells (β = −0.617, P = .005). Compared with nonacute graft-versus-host disease (GVHD) patients, patients with acute GVHD (aGVHD) had a higher level of NK subsets during week 2 posttransplantation. Cox regression analysis revealed that the patients with more CD56^bright NK cells in the recovery stage had a higher survival rate (hazard risk [HR], 0.406; P = .017) and the patients with a higher ratio of T/NK (>1.0) had a higher chance of getting aGVHD (HR, 3.436; P = .059) and chronic GVHD (HR, 3.925; P = .028). Our results suggest that the recovery of NK cells is and can be used as an indicator to predicate the clinical outcomes after unmanipulated haploidentical transplantation.