The importance of Foxp3 antibody and fixation/permeabilization buffer combinations in identifying CD4+CD25+Foxp3+ regulatory T cells

Group 3 innate lymphoid cells secret neutrophil chemoattractants and are insensitive to glucocorticoid via aberrant GR phosphorylation

BACKGROUND

Patients with neutrophil-mediated asthma have poor response to glucocorticoids. The roles and mechanisms of group 3 innate lymphoid cells (ILC3s) in inducing neutrophilic airway inflammation and glucocorticoid resistance in asthma have not been fully clarified.

METHODS

ILC3s in peripheral blood were measured by flow cytometry in patients with eosinophilic asthma (EA) and non-eosinophilic asthma (NEA). ILC3s were sorted and cultured in vitro for RNA sequencing. Cytokines production and signaling pathways in ILC3s after IL-1β stimulation and dexamethasone treatment were determined by real-time PCR, flow cytometry, ELISA and western blot.

RESULTS

The percentage and numbers of ILC3s in peripheral blood was higher in patients with NEA compared with EA, and negatively correlated with blood eosinophils. IL-1β stimulation significantly enhanced CXCL8 and CXCL1 production in ILC3s via activation of p65 NF-κB and p38/JNK MAPK signaling pathways. The expression of neutrophil chemoattractants from ILC3s was insensitive to dexamethasone treatment. Dexamethasone significantly increased phosphorylation of glucocorticoid receptor (GR) at Ser226 but only with a weak induction at Ser211 residues in ILC3s. Compared to human bronchial epithelial cell line (16HBE cells), the ratio of p-GR S226 to p-GR S211 (p-GR S226/S211) was significantly higher in ILC3s at baseline and after dexamethasone treatment. In addition, IL-1β could induce Ser226 phosphorylation and had a crosstalk effect to dexamethasone via NF-κB pathway.

CONCLUSIONS

ILC3s were elevated in patients with NEA, and associated with neutrophil inflammation by release of neutrophil chemoattractants and were glucocorticoid (GC) resistant. This paper provides a novel cellular and molecular mechanisms of neutrophil inflammation and GC-resistance in asthma. Trial registration The study has been prospectively registered in the World Health Organization International Clinical Trials Registry Platform (ChiCTR1900027125).

Intracellular flow cytometry staining of antibody-secreting cells using phycoerythrin-conjugated antibodies: pitfalls and solutions

Background

Antibody-secreting cells are terminally differentiated B cells that play a critical role in humoral immunity through immunoglobulin secretion along with possessing the potential to be long-lived. It is now appreciated that ASCs regulate multiple aspects of biology through the secretion of various cytokines. In this regard, ICFC is a key tool used to assess the presence of intracellular proteins such as cytokines and transcription factors.

Methods

Paraformaldehyde plus saponin or the eBioscience Foxp3/Transcription Factor Staining Buffer Set were used to evaluate the non-specific intracellular retention of phycoerythrin-containing antibody conjugates by ASCs.

Results

We showed that the use of phycoerythrin-containing antibody conjugates led to a false interpretation of ASC intracellular protein expression compared with other cell types. This was mainly due to the inappropriate retention of these antibodies specifically within ASCs. Furthermore, we demonstrated how to reduce this retention which allowed for a more accurate comparison of intracellular protein expression between ASCs and other cell types such as B lymphocytes. Using this methodology, our data revealed that spleen ASCs expressed toll-like receptor 7 as well as the pro-form of the inflammatory cytokine interleukin-1β.

Conclusion

Increasing the number of centrifugation steps performed on ASCs post-fixation leads to inappropriate retention of phycoerythrin-containing antibody conjugates during ICFC.

Guidelines for the use of flow cytometry and cell sorting in immunological studies (third edition)

The third edition of Flow Cytometry Guidelines provides the key aspects to consider when performing flow cytometry experiments and includes comprehensive sections describing phenotypes and functional assays of all major human and murine immune cell subsets. Notably, the Guidelines contain helpful tables highlighting phenotypes and key differences between human and murine cells. Another useful feature of this edition is the flow cytometry analysis of clinical samples with examples of flow cytometry applications in the context of autoimmune diseases, cancers as well as acute and chronic infectious diseases. Furthermore, there are sections detailing tips, tricks and pitfalls to avoid. All sections are written and peer-reviewed by leading flow cytometry experts and immunologists, making this edition an essential and state-of-the-art handbook for basic and clinical researchers.

Transcription Factor Evaluation by Flow Cytometry

The development of T helper (Th) cell subsets requires activated T cells that respond to a polarizing cytokine environment, resulting in the activation and expression of specific transcription factors. The subset-specific transcription factors are located either in the cytoplasm or in the nucleus, which determine the functional profile of Th populations, inducing the production of specific effector cytokines and functions. Flow cytometry analysis of transcription factors has become very common not only in research but also in immunologic follow-up protocols of patients recruited in clinical trials (as evaluation of CD4+CD25+ FOXP3+ T regulatory cells). Here, we propose and describe one-step protocols to evaluate the expression of transcription factors in mouse and human CD4+ lymphocytes, focusing the critical points of this cytometric approach.

Lower Functional and Proportional Characteristics of Cord Blood Treg of Male Newborns Compared with Female Newborns

Understanding the early events involved in the induction of immune tolerance to harmless environmental antigens and microbiota compounds could reveal potential targets for allergic disease therapy or prevention. Regulatory T cells (Treg), particularly induced Treg (iTreg), are crucial for the induction and maintenance of tolerance against environmental antigens including allergens. A decrease in the number and/or function of Treg or iTreg could represent an early predictor of allergy development. We analyzed proportional and functional properties of Treg in the cord blood of children of allergic mothers (neonates at high risk of allergy development) and healthy mothers (neonates with relatively low risk of allergy development). We observed a higher number of induced Treg in the cord blood of females compared to males, suggesting an impaired capacity of male immunity to set up tolerance to allergens, which could contribute to the higher incidence of allergy observed in male infants. The decreased proportion of iTreg in cord blood compared with maternal peripheral blood documents the general immaturity of the neonatal immune system. We observed a positive correlation in the demethylation of the Treg-specific demethylated region (TSDR) and the proportion of Treg in cord blood. Our data suggest that immaturity of the neonatal immune system is more severe in males, predisposing them to increased risk of allergy development.

Value of cord blood Treg population properties and function-associated characteristics for predicting allergy development in childhood

Allergic diseases represent some of the most common immunological disorders with high clinical and economic impact. Despite intensive research, there are still few universally accepted and reliable biomarkers capable of predicting their development at an early age. There is therefore a pressing need for identification of potential predictive factors and validation of their prognostic value by correlating them with allergy development. Dysbalance of the branches of immune response, most often excessive Th2 polarization, is the principal cause of allergic diseases. Regulatory T cells (Treg) are a crucial population for the timely establishment of physiological immune polarization and induction and maintenance of tolerance against environmental antigens. This makes them a potentially promising candidate for an early marker predicting allergy development. In our study, we analysed samples of cord blood of children of allergic mothers and children of healthy mothers by flow cytometry and retrospectively correlated the data with clinical allergy status of the children at the age of 6 to 10 years. Studied parameters included cord blood Treg population proportions and functional properties - intracellular presence of IL-10 and TGF-b, MFI of FoxP3. We observed higher percentage of Tregs in cord blood of children who did not develop allergy compared with allergic children. Further, we found higher numbers of IL-10+ Tregs in cord blood of healthy children of healthy mothers than in cord blood of children of allergic mothers and decreased TGF-b+ cord blood Tregs in the group of allergic children of allergic mothers compared to all other groups.

T-regulatory cell/T helper 17 cell imbalance functions as prognostic biomarker of oral squamous cell carcinoma - CONSORT

BACKGROUND

The role of T cells in the pathogenesis of oral squamous cell carcinoma (OSCC) was clarified by examining the levels of differentiated CD4CD25FOXP3 T-regulatory cells (Treg cells) and CD4+IL17+ T helper 17 (Th17) cells in OSCC patients.

METHODS

Flow cytometry was conducted to measure the proportions of Treg/Th17 cells in different sample groups to identify a proper maker indicative of the progression and prognosis of OSCC.

RESULTS

The results showed that a higher Treg/Th17 ratio led to poorer prognosis. Also, the proportions of both Treg cells and Th17 cells were significantly elevated in OSCC patients compared with those in the control groups, suggesting a correlation between Treg/Th17 imbalance and the prognosis of OSCC. Furthermore, the ratios of Treg/Th17 cells in OSCC patients differed at different time points of cancer progression. For example, stage III-IV patients showed the most evident increase in the Treg/Th17 ratio, while the Treg/Th17 ratio in control subjects was the lowest.

CONCLUSIONS

Therefore, a higher ratio of Treg/Th17 indicated the progression of OSCC and a larger tumor size. Therefore, Treg and Th17 imbalance was implicated in OSCC progression.

Immune changes in peripheral blood and hematoma of patients with intracerebral hemorrhage

Immunologic changes in the hematoma of patients with intracerebral hemorrhage (ICH) and the contribution of these changes to prognosis are unknown. We collected the blood samples and hematoma fluid from 35 patients with acute ICH (<30 hours from symptom onset) and 55 age-matched healthy controls. Using flow cytometry and ELISA, we found that the percentages of granulocytes, regulatory T cells, helper T (Th) 17 cells, and dendritic cells were higher in the peripheral blood of patients with ICH than in healthy controls, whereas the percentages of lymphocytes, M1-like macrophages, and M2-like macrophages were lower. Levels of IL-6, IL-17, IL-23, TNF-α, IL-4, IL-10, and TGF-β were higher in the peripheral blood of patients with ICH. The absolute counts of white blood cells, lymphocytes, monocytes, and granulocytes in the hematoma tended to be greater at 12-30 hours than they were within 12 hours after ICH, but the percentage of Th cells decreased in peripheral blood. Increased levels of IL-10 in the serum and hematoma, and a reduction in M1-like macrophages in hematoma were independently associated with favorable outcome on day 90. These results indicate that immunocytes present in the hematoma may participate in the acute-phase inflammatory response after ICH.

Guidelines for the use of flow cytometry and cell sorting in immunological studies (second edition)

These guidelines are a consensus work of a considerable number of members of the immunology and flow cytometry community. They provide the theory and key practical aspects of flow cytometry enabling immunologists to avoid the common errors that often undermine immunological data. Notably, there are comprehensive sections of all major immune cell types with helpful Tables detailing phenotypes in murine and human cells. The latest flow cytometry techniques and applications are also described, featuring examples of the data that can be generated and, importantly, how the data can be analysed. Furthermore, there are sections detailing tips, tricks and pitfalls to avoid, all written and peer-reviewed by leading experts in the field, making this an essential research companion.

Increased infiltration of CCR4-positive regulatory T cells in prostate cancer tissue is associated with a poor prognosis

BACKGROUND

Regulatory T cells (Tregs) play important roles in the suppression of immune responses, including antitumor immune responses. C-C chemokine receptor 4 (CCR4) is highly expressed on effector Tregs, and anti-CCR4 antibody is attracting attention as a novel immunotherapeutic agent for solid tumors. This study aimed to evaluate the expression of CCR4-positive Tregs (CCR4+Tregs) in prostate cancer and estimate the clinical potential of CCR4-targeting therapy for prostate cancer.

METHODS

A total of 15 radical prostatectomy (RP) specimens and 60 biopsy specimens from individuals diagnosed with prostate cancer were analyzed to evaluate the infiltration of CCR4+Tregs in prostate cancer. The relationships between the number of CCR4+Tregs and clinical parameters were investigated in RP and biopsy specimens. Moreover, the total number of Tregs, CCR4+Tregs, and T cells and the ratio of CCR4+Tregs to Tregs and T cells in biopsy specimens were compared between patients with poor prognosis who progressed to castration-resistant prostate cancer (CRPC) within 12 months (n = 13) and those with good prognosis who were stable with hormone-sensitive prostate cancer over 12 months (n = 47). Furthermore, biopsy specimens were divided into two groups: low and high CCR4+Treg expression groups and the prognosis was compared between them.

RESULTS

There was a higher expression of CCR4+Tregs in RP specimens with a higher (≥8) Gleason score than in those with a lower (<8) Gleason score (P = .041). In biopsy specimens, 65.9% Tregs were positive for CCR4. The number of CCR4+Tregs positively correlated with clinical stage (P < .001) and Gleason score (P = .006). The total number of Tregs and CCR4+Tregs significantly increased in the poor prognosis group compared with that in the good prognosis group (P = .024 and .01, respectively). Furthermore, patients with lower CCR4+Treg expression levels showed a significantly longer time to progression to CRPC (not reached vs 27.3 months; P < .001) and median survival time (not reached vs 69.0 months; P = .014) than those with higher expression levels.

CONCLUSIONS

CCR4+Tregs are highly infiltrated in the prostate tissue of patients with poor prognosis with potential to progress to CRPC. Furthermore, the degree of infiltration of CCR4+Tregs is related to the prognosis of prostate cancer.

Immunophenotyping of Human Regulatory T Cells

Regulatory T cells, also known as Tregs, play a pivotal role in maintaining homeostasis of the immune system and self-tolerance. Tregs express CD3, CD4, CD25, and FOXP3 but lack CD127. CD4 and CD3 identify helper T lymphocytes, of which Tregs are a subset. CD25 is IL-2Rα, an essential activation marker that is expressed in high levels on Tregs. FOXP3 is the canonical transcription factor, important in the development, maintenance, and identification of Tregs. CD127 is IL-7 receptor, expressed inversely with suppression, and is therefore downregulated on Tregs. Flow cytometry is a powerful tool that is capable of simultaneously measuring Tregs along with several markers associated with subpopulations of Tregs, activation, maturation, proliferation, and surrogates of functional suppression. This chapter describes a multicolor flow cytometry-based approach to measure human Tregs, including details for surface staining, fixation/permeabilization, intracellular/intranuclear staining, acquisition of samples on a flow cytometer, plus analysis and interpretation of resulting FCS files.

The Clinical Significance of Programmed Death-1, Regulatory T Cells and Myeloid Derived Suppressor Cells in Patients with Nontuberculous Mycobacteria-Lung Disease

Background: Increasing expression of programmed death-1 (PD-1) in patients with nontuberculous mycobacteria lung disease (NTM-LD) has been reported, but its role in clinical characteristics and outcomes remains unclear. Methods: We enrolled 96 participants, including 46 with Mycobacterium avium complex (MAC)-LD, 23 with M. abscessus (MAB)-LD, and 27 controls. We measured expressions of PD-1, cytotoxic T-lymphocyte antigen-4 (CTLA-4) and regulatory T (Treg) cells on CD4⁺ lymphocytes and myeloid-derived suppressor cells (MDSCs) and analyzed their association with clinical features and radiographic outcomes. Results: The percentage of PD-1 on CD4⁺(PD-1⁺CD4⁺) lymphocytes and MDSCs were higher in the MAC-LD group than the controls. There were no intergroup differences regarding CTLA-4⁺CD4⁺ lymphocytes. Higher PD-1⁺CD4⁺ lymphocytes were found in M. intracellulare- and M. avium-LD than in other MAC-LD. Positive sputum acid-fast stains and fibrocavitary radiographic lesions were correlated with elevated PD-1⁺CD4⁺ lymphocytes and Treg cells. The percentage of PD-1⁺CD4⁺ lymphocytes at the initial and 2 months of follow-up significantly predicted subsequent radiographic progression. Conclusion: As markers of immune tolerance, PD-1⁺CD4⁺ lymphocytes and MDSCs were higher in MAC-LD patients. The levels of PD-1⁺CD4⁺ and Treg cells were correlated with high mycobacteria bacilli burden in NTM-LD. Monitoring the expressions of PD-1⁺CD4⁺ lymphocytes may predict radiographic progression.

Standardisation of flow cytometry for whole blood immunophenotyping of islet transplant and transplant clinical trial recipients

Understanding the immunological phenotype of transplant recipients is important to improve outcomes and develop new therapies. Immunophenotyping of whole peripheral blood (WPB) by flow cytometry is a rapid method to obtain large amounts of data relating to the outcomes of different transplant treatments with limited patient impact. Healthy individuals and patients with type 1 diabetes (T1D) enrolled in islet transplantation were recruited and WPB was collected. 46 fluorochrome-conjugated mouse-anti-human antibodies were used (43 of 46 antibodies were titrated). BD cytometer setup and tracking beads were used to characterize and adjust for cytometer performance. Antibody cocktails were pre-mixed <60 minutes before staining. Multicolour panels were designed based on fluorochrome brightness, antigen density, co-expression, and fluorochrome spillover into non-primary detectors in each panel on a 5 laser flow cytometer. WPB sample staining used 50–300 μl WPB for each panel and was performed within 2 hours of blood sample collection. Samples were acquired on a BD-LSRFortessa. The operating procedures, including specimen collection, antibody cocktails, staining protocol, flow-cytometer setup and data analysis, were standardized. The staining index of 43 antibodies and the spillover spreading matrix for each panel was calculated. The final concentrations for the 46 antibodies used was determined for staining of WPB samples. Absolute cell-count and 7 leukocyte profiling panels consisting of subsets and/or status of granulocytes, monocytes, dendritic, B, NK, and T cells including regulatory T cells (Tregs) and NKT were designed and established on a 5 laser BD-LSR Fortessa. 13 T1D patients, including 4 islet transplant recipients and 8 healthy controls, were evaluated. The ability to reproducibly measure immune subsets and immune-profiles of islet transplant patients up to 18 months post transplantation has been established as a tool to measure immune cell reconstitution after transplantation.

Distinct characteristics of Tregs of newborns of healthy and allergic mothers

Allergic diseases represent a major issue in clinical and experimental immunology due to their high and increasing incidence worldwide. Allergy status of the mother remains the best predictor of an individual's increased risk of allergy development. Dysregulation of the balance between different branches of immune response, chiefly excessive polarization towards Th2, is the underlying cause of allergic diseases. Regulatory T cells (Tregs) play a pivotal role in the timely establishment of physiological immune polarization and are crucial for control of allergy. In our study we used flow cytometry to assess Tregs in cord blood of newborns of healthy (n = 121) and allergic (n = 108) mothers. We observed a higher percentage of Tregs (CD4+CD25+CD127lowFoxP3+) in cord blood of children of allergic mothers. However, the percentage of cells expressing extracellular (PD-1, CTLA-4, GITR) and intracellular (IL-10, TGF-β) markers of function was lower (significantly for PD-1 and IL-10) within Tregs of these children. Furthermore, Helios- induced Tregs in the cord blood of children of allergic mothers were decreased. These results were supported by a decrease in plasma levels of IL-10 and TGF-β in cord blood of newborns of allergic mothers, implying lower tolerogenic capacity on the systemic level. Taken together, these findings reflect deficient function of Tregs in the group with higher risk of allergy development. This may be caused by a lower maturation status of the immune system, specifically Tregs, at birth. Such immaturity may represent an important mechanism involved in the increased risk of allergy in children of allergic mothers.

Decreased allergy incidence in children supplemented with E. coli O83:K24:H31 and its possible modes of action

The growing knowledge of the key role of microbiota in the maturation of neonatal immune system suggests that manipulation of microbiota could be exploited in hampering allergy development. In this study, Escherichia coli O83:K24:H31 (EcO83) was administered to newborns that were followed prospectively. Several immunological characteristics (cytokines, specific IgE, total T regulatory cells (Treg) and subpopulation of natural Treg (nTreg) and induced Treg (iTreg)) were tested in peripheral blood of 8-year-old children. Incidence of allergic disease was decreased in EcO83 supplemented children and significantly elevated levels of IL-10 and IFN-ɣ were detected in serum of EcO83 supplemented children. Probiotic supplementation did not influence the numbers of the total Treg population but their functional capacity (intracellular expression of IL-10) was significantly increased in children supplemented with EcO83 in comparison to non-supplemented children. Morover, decreased proportion of iTreg was present in peripheral blood of non-supplemented in comparison to EcO83 supplemented children. Finally, stimulation of cord blood cells with EcO83 promoted both gene expression and secretion of IL-10 and IFN-ɣ suggesting that beneficial effect of EcO83 in prevention of allergy development could be mediated by promotion of regulatory responses (by IL-10) and Th1 immune response (by IFN-ɣ).

Changes in the cellular immune system and circulating inflammatory markers of stroke patients

This study was designed to investigate dynamic changes in the cellular immune system and circulating inflammatory markers after ischemic stroke. Blood was collected from 96 patients and 99 age-matched control subjects for detection of lymphocyte subpopulations and inflammatory markers. We observed decreases in B cells, Th cells, cytotoxic T cells, and NK cells and an increase in regulatory T (Treg) cells in stroke patients on days 1, 3, and 7. Serum levels of TNF-α, C-reactive protein (CRP), IL-4, IL-6, IL-10, IL-17, IL-23, and TGF-β increased, whereas serum level of IFN-γ decreased at all time points after stroke. Stroke patients with infection exhibited a similar tendency toward changes in some lymphocyte subpopulations and inflammatory markers as stroke patients without infection. After controlling for NIH Stroke Scale (NIHSS), we observed no differences in lymphocyte subpopulations between patients with anterior circulation stroke and those with posterior circulation stroke at any time point. The splenic volume correlated positively with the percentages of B cells, Th cells, and cytotoxic T cells, but negatively with Treg cells on day 3 after stroke. Infections were associated with splenic volume, leukocyte counts, percentage of Treg cells, and serum levels of CRP, IL-10, and IFN-γ on day 3. Lesion volume correlated positively with CRP, IL-6, and IL-23, but negatively with IFN-γ on day 3. The NIHSS showed a positive relation with IL-6 and IL-10 on day 3. Ischemic stroke has a profound effect on the systemic immune system that might explain the increased susceptibility of stroke patients to infection.

Oncolytic virotherapy as an immunotherapeutic strategy for multiple myeloma

Multiple Myeloma (MM), a clonal malignancy of antibody-producing plasma cells, is the second most common hematologic malignancy and results in significant patient morbidity and mortality. The high degree of immune dysregulation in MM, including T cell imbalances and up-regulation of immunosuppressive checkpoint proteins and myeloid derived suppressor cells, allows this malignancy to escape from host immune control. Despite advances in the therapeutic landscape of MM over the last decade, including the introduction of immunomodulatory drugs, the prognosis for this disease is poor, with less than 50% of patients surviving 5 years. Thus, novel treatment strategies are required. Oncolytic viruses (OV) are a promising new class of therapeutics that rely on tumour specific oncolysis and the generation of a potent adaptive anti-tumour immune response for efficacy. To date, a number of OV have shown efficacy in pre-clinical studies of MM with three reaching early phase clinical trials. OVs represent a rational therapeutic strategy for MM based on (1) their tumour tropism, (2) their ability to potentiate anti-tumour immunity and (3) their ability to be rationally combined with other immunotherapeutic agents to achieve a more robust clinical response.

Mucosal and systemic immune modulation by Trichuris trichiura in a self-infected individual

Helminthic therapy of immune-mediated diseases has gained attention in recent years, but we know little of how helminths modulate human immunity. In this study, we investigated how self-infection with Trichuris (T.) trichiura in an adult man without intestinal disease affected mucosal and systemic immunity. Colonic mucosal biopsies were obtained at baseline, during T. trichiura infection, and after its clearance following mebendazole treatment. Unexpectedly, the volunteer experienced a Campylobacter colitis following T. trichiura clearance, and this served as a positive infectious control. Trichuris trichiura colonization induced equally increased expressions of T-helper (h)1-, Th2-, Th17- and Treg-associated cytokines and transcription factors, measured by quantitative polymerase chain reaction. We observed several indicators of modulation of systemic immunity during the T. trichiura infection. Plasma eosinophils and anti-Trichuris antibodies rose markedly during the inoculation phase, and a shift towards a Th2-dominated T cell response at the expense of the Th1-response was observed in circulating T cells. Taken together, our findings corroborate that helminths modulate regional and systemic human immunity.

Phenotypic and Functional Analysis of the Suppressive Function of Human Regulatory T Cells

Regulatory T cells (Tregs) are defined as immunosuppressive cells playing crucial roles in the establishment and maintenance of immune homeostasis. During the course of immune responses, Tregs control the balance between host defense from pathogens and the prevention of excessive immunity. Here, we describe the phenotypic analysis of Tregs, evaluated in peripheral blood mononuclear cells of healthy adults, by multiparameter flow cytometry, which allows examining the expression of peculiar markers of Treg subpopulations with different features, and provides efficient discrimination of multiple characteristics at the single-cell level. The same technique may be applied to characterize mononuclear cells extracted from different specimens, including whole blood, biological fluids or solid tissues. The immunoregulatory identity of a certain Treg subpopulation may be functionally verified by performing an in vitro suppression assay described here, testing the capability of Tregs to suppress the activation of responder cells.

Determining Immune System Suppression versus CNS Protection for Pharmacological Interventions in Autoimmune Demyelination

A major hallmark of the autoimmune demyelinating disease multiple sclerosis (MS) is immune cell infiltration into the brain and spinal cord resulting in myelin destruction, which not only slows conduction of nerve impulses, but causes axonal injury resulting in motor and cognitive decline. Current treatments for MS focus on attenuating immune cell infiltration into the central nervous system (CNS). These treatments decrease the number of relapses, improving quality of life, but do not completely eliminate relapses so long-term disability is not improved. Therefore, therapeutic agents that protect the CNS are warranted. In both animal models as well as human patients with MS, T cell entry into the CNS is generally considered the initiating inflammatory event. In order to assess if a drug protects the CNS, any potential effects on immune cell infiltration or proliferation in the periphery must be ruled out. This protocol describes how to determine whether CNS protection observed after drug intervention is a consequence of attenuating CNS-infiltrating immune cells or blocking death of CNS cells during inflammatory insults. The ability to examine MS treatments that are protective to the CNS during inflammatory insults is highly critical for the advancement of therapeutic strategies since current treatments reduce, but do not completely eliminate, relapses (i.e., immune cell infiltration), leaving the CNS vulnerable to degeneration.

Phenotypical characterization of regulatory T cells in humans and rodents

Regulatory T cells (Tregs ) constitute a fascinating subpopulation of CD4(+) T cells due to their ability to limit the immune response against self and non-self antigens. Murine models and antibodies directed against surface and intracellular molecules have allowed elucidation of the mechanisms that govern their development and function. However, these markers used to their classification lack of specificity, as they can be expressed by activated T cells. Similarly, there are slight differences between animal models, in steady state and pathological conditions, anatomical localization and strategy of analysis by flow cytometry. Here, we revised the most common markers utilized for Treg typification by flow cytometry such as CD25, forkhead box protein 3 (FoxP3) and CD127, along with our data obtained in different body compartments of humans, mice and rats. Furthermore, we revised and determined the expression of other molecules important for the phenotypical characterization of Treg cells. We draw attention to the drawbacks of those markers used in chronic states of inflammation. However, until a specific marker for the identification of Tregs is discovered, the best combination of markers will depend upon the tissue or the degree of inflammation from which Tregs derive.

Pretransplant Recipient Circulating CD4+CD127lo/- Tumor Necrosis Factor Receptor 2+ Regulatory T Cells: A Surrogate of Regulatory T Cell-Suppressive Function and Predictor of Delayed and Slow Graft Function After Kidney Transplantation

BACKGROUND

Delayed graft function (DGF) and slow graft function (SGF) are ischemia-reperfusion-associated acute kidney injuries (AKI) that decrease long-term graft survival after kidney transplantation. Regulatory T (Treg) cells are protective in murine AKI, and their suppressive function predictive of AKI in kidney transplantation. The conventional Treg cell function coculture assay is however time-consuming and labor intensive. We sought a simpler alternative to measure Treg cell function and predict AKI.

METHODS

In this prospective observational cohort study, pretransplant recipient circulating CD4+CD25+CD127lo/- and CD4+CD127lo/- tumor necrosis factor receptor 2 (TNFR2)+ Treg cells were measured by flow cytometry in 76 deceased donor kidney transplant recipients (DGF, n = 18; SGF, n = 34; immediate graft function [IGF], n = 24). In a subset of 37 recipients, pretransplant circulating Treg cell-suppressive function was also quantified by measuring the suppression of autologous effector T-cell proliferation by Treg cell in coculture.

RESULTS

The TNFR2+ expression on CD4+CD127lo/- T cells correlated with Treg cell-suppressive function (r = 0.63, P < 0.01). In receiver operating characteristic curves, percentage and absolute number of CD4+CD127lo/-TNFR2+ Treg cell predicted DGF from non-DGF (IGF + SGF) with area under the curves of 0.75 and 0.77, respectively, and also AKI (DGF + SGF) from IGF with area under the curves of 0.76 and 0.72, respectively (P < 0.01). Prediction of AKI (DGF + SGF) from IGF remained significant in multivariate logistic regression accounting for cold ischemic time, donor age, previous transplant, and pretransplant dialysis modality.

CONCLUSIONS

Pretransplant recipient circulating CD4+CD127lo/-TNFR2+ Treg cell is potentially a simpler alternative to Treg cell function as a pretransplant recipient immune marker for AKI (DGF + SGF), independent from donor and organ procurement characteristics.

Cord blood T cells mediate enhanced antitumor effects compared with adult peripheral blood T cells

Unrelated cord blood transplantation (CBT) without in vivo T-cell depletion is increasingly used to treat high-risk hematologic malignancies. Following T-replete CBT, naïve CB T cells undergo rapid peripheral expansion with memory-effector differentiation. Emerging data suggest that unrelated CBT, particularly in the context of HLA mismatch and a T-replete graft, may reduce leukemic relapse. To study the role of CB T cells in mediating graft-versus-tumor responses and dissect the underlying immune mechanisms for this, we compared the ability of HLA-mismatched CB and adult peripheral blood (PB) T cells to eliminate Epstein-Barr virus (EBV)-driven human B-cell lymphoma in a xenogeneic NOD/SCID/IL2rg(null) mouse model. CB T cells mediated enhanced tumor rejection compared with equal numbers of PB T cells, leading to improved survival in the CB group (P < .0003). Comparison of CB T cells that were autologous vs allogeneic to the lymphoma demonstrated that this antitumor effect was mediated by alloreactive rather than EBV-specific T cells. Analysis of tumor-infiltrating lymphocytes demonstrated that CB T cells mediated this enhanced antitumor effect by rapid infiltration of the tumor with CCR7(+)CD8(+) T cells and prompt induction of cytotoxic CD8(+) and CD4(+) T-helper (Th1) T cells in the tumor microenvironment. In contrast, in the PB group, this antilymphoma effect is impaired because of delayed tumoral infiltration of PB T cells and a relative bias toward suppressive Th2 and T-regulatory cells. Our data suggest that, despite being naturally programmed toward tolerance, reconstituting T cells after unrelated T-replete CBT may provide superior Tc1-Th1 antitumor effects against high-risk hematologic malignancies.

Monitoring regulatory T cells in clinical samples: consensus on an essential marker set and gating strategy for regulatory T cell analysis by flow cytometry

Regulatory T cell (Treg)-mediated immunosuppression is considered a major obstacle for successful cancer immunotherapy. The association between clinical outcome and Tregs is being studied extensively in clinical trials, but unfortunately, no consensus has been reached about (a) the markers and (b) the gating strategy required to define human Tregs in this context, making it difficult to draw final conclusions. Therefore, we have organized an international workshop on the detection and functional testing of Tregs with leading experts in the field, and 40 participants discussing different analyses and the importance of different markers and context in which Tregs were analyzed. This resulted in a rationally composed ranking list of "Treg markers". Subsequently, the proposed Treg markers were tested to get insight into the overlap/differences between the most frequently used Treg definitions and their utility for Treg detection in various human tissues. Here, we conclude that the CD3, CD4, CD25, CD127, and FoxP3 markers are the minimally required markers to define human Treg cells. Staining for Ki67 and CD45RA showed to provide additional information on the activation status of Tregs. The use of markers was validated in a series of PBMC from healthy donors and cancer patients, as well as in tumor-draining lymph nodes and freshly isolated tumors. In conclusion, we propose an essential marker set comprising antibodies to CD3, CD4, CD25, CD127, Foxp3, Ki67, and CD45RA and a corresponding robust gating strategy for the context-dependent analysis of Tregs by flow cytometry.

Immunological profiling of haemodialysis patients and young healthy individuals with implications for clinical regulatory T cell sorting

With the increasing interest in clinical trials with regulatory T cells (Tregs), immunological profiling of prospective target groups and standardized procedures for Treg isolation are needed. In this study, flow cytometry was used to assess peripheral blood lymphocyte profiles of young healthy individuals and patients undergoing haemodialysis treatment. Tregs obtained from the former may be used in haematopoietic stem cell transplantation and Tregs from the latter in the prevention of kidney transplant rejection. FOXP3 mRNA expression with accompanying isoform distribution was also assessed by the quantitative reverse transcriptase polymerase chain reaction. Flow-cytometric gating strategies were systematically analysed to optimize the isolation of Tregs. Our findings showed an overall similar immunological profile of both cohorts in spite of great differences in both age and health. Analysis of flow-cytometric gating techniques highlighted the importance of gating for both CD25high and CD127low expression in the isolation of FOXP3-positive cells. This study provides additional insight into the immunological profile of young healthy individuals and uraemic patients as well as in-depth analysis of flow-cytometric gating strategies for Treg isolation, supporting the development of Treg therapy using cells from healthy donors and uraemic patients.

Tregitope: Immunomodulation powerhouse

IVIG is frequently used in the 'pre-conditioning' regimens for higher risk transplants; its effects are attributed in part to induction of Tregs. We have identified regulatory T cell (Treg) epitopes, now known as Tregitopes, in IgG, the main component of intravenous immunoglobulin therapy (IVIg). Tregitopes provide one explanation for the expansion and activation of Treg cells following IVIg treatment. Tregitopes are peptides that exhibit high affinity binding to multiple human HLA Class II DR; they are conserved across IgG isotypes and mammalian species. In vitro and in vivo, for human PBMC and in animal models, Tregitopes activate Tregs. Studies to delineate the mechanism of action have shown that Tregitopes' effects are very similar to IVIg in vitro. Here we demonstrate that Tregitopes induce Tregs to produce IL-10, leading to modulation of dendritic cell phenotype (down-regulation of Class II, CD80 and CD86 and up-regulation of ILT3), and describe the effects of Tregitopes in the ABM-TCR-transgenic skin transplantation model. The discovery of Tregitopes in IgG and other autologous proteins may contribute to improved understanding of the mechanism of action of IVIg and lead to the application of these powerful immunomodulators to improve transplantation success and suppress autoimmune disease, in the future.

Linking T-cell receptor sequence to functional phenotype at the single-cell level

Although each T lymphocyte expresses a T-cell receptor (TCR) that recognizes cognate antigen and controls T-cell activation, different T cells bearing the same TCR can be functionally distinct. Each TCR is a heterodimer, and both α- and β-chains contribute to determining TCR antigen specificity. Here we present a methodology enabling integration of information about TCR specificity with information about T cell function. This method involves sequencing of TCRα and TCRβ genes, and amplifying functional genes characteristic of different T cell subsets, in single T cells. Because this approach retains information about individual TCRα-TCRβ pairs, TCRs of interest can be expressed and used in functional studies, for antigen discovery, or in therapeutic applications. We apply this approach to study the clonal ancestry and differentiation of T lymphocytes infiltrating a human colorectal carcinoma.

Normal human pregnancy results in maternal immune activation in the periphery and at the uteroplacental interface

Pregnancy poses a unique challenge to the human immune system: the semi-allogeneic fetus must be protected from maternal immune attack while immunity towards pathogens is maintained. Breakdown in maternal-fetal tolerance can lead to pregnancy-specific diseases with potentially high degrees of morbidity and mortality for both the mother and her fetus. Various immune cell-types could mediate these functions, but a comprehensive evaluation of the peripheral and local maternal T cell and regulatory T cell compartments in normal human pregnancy is lacking. In this case-control study, we apply the Human Immunology Project Consortium proposed gating strategies to samples from healthy 3^rd trimester human subjects compared with healthy non-pregnant controls. The proportions of HLA-DR+ and CD38+ effector- and effector memory CD8 T cells are significantly increased in the peripheral blood of pregnant women. Utilizing a novel technique that takes advantage of the standard protocol for intrauterine cleanup after cesarean section, we isolate lymphocytes resident at the uteroplacental interface (UPI). At the UPI, the CD4 and CD8 T cell compartments largely mirror the peripheral blood, except that the proportion of HLA-DR+ activated T regulatory cells is significantly increased in direct proportion to an observed increase in the number of activated CD8 T cells. We find that cryopreservation and delayed sample processing (>12 hours) decreases our ability to identify regulatory T cell subsets. Further, the Consortium proposed method for Treg identification underrepresents Resting and Cytokine Tregs compared with Activated Tregs, thus skewing the entire population. Better understanding of the changes in the immune system during pregnancy in the peripheral blood and at the uteroplacental interface are essential for progress in treatment of pregnancy diseases such as pre-eclampsia and recurrent miscarriage.

Efficacy and safety of mesenchymal stromal cell treatment from related donors for patients with refractory aplastic anemia

BACKGROUND AIMS

This study evaluated the feasibility, safety and immunological effects of the intravenous administration of mesenchymal stromal cells (MSCs) from a related donor in patients with refractory aplastic anemia (AA).

METHODS

A mean of 6 × 10(5)/kg (range, 5.0-7.1 × 10(5)) MSCs were injected intravenously to 18 patients, including 14 patients with nonsevere AA and four patients with severe AA who were refractory to prior immunosuppressive treatment. The outcomes of patients treated with MSCs were evaluated and compared with a historic control cohort, including 18 patients with refractory AA.

RESULTS

Two patients had injection-related adverse events, including transient fever and headache. No major adverse events were reported during the follow-up period. An immunological analysis revealed an increased proportion of CD4(+)CD25(+) FOXP3(+)regulatory T cells in peripheral mononuclear cells. Following up for 1 year, six of 18 patients (33.3%) achieved a complete response or a partial response to MSC treatment. In six patients, two achieved a complete response including a recovery of three hematopoietic cell lines after MSCs therapy at days 88 and 92, two patients achieved only a red cell recovery with hemoglobin levels >100 g/L at days 30 and 48 and two patients had only a platelet recovery with a platelet count of >60 × 10(9)/L at days 54 and 81. In the control cohort, only one patient (5.56%) achieved a partial response during the follow-up period.

CONCLUSIONS

The data from the present study suggest that treatment with MSCs from a related donor may be a promising therapeutic strategy for patients with refractory AA. The trial has been registered at ClinicalTrials.gov: identifier NCT01305694.

T regulatory cells in childhood arthritis--novel insights

In recent years, there have been many new developments in the field of regulatory T cells (Treg), challenging the consensus on their behaviour, classification and role(s) in disease. The role Treg might play in autoimmune disease appears to be more complex than previously thought. Here, we discuss the current knowledge of regulatory T cells through animal and human research and illustrate the recent developments in childhood autoimmune arthritis (juvenile idiopathic arthritis (JIA)). Furthermore, this review summarises our understanding of the fields and assesses current and future implications for Treg in the treatment of JIA.

Increased frequency of CD4 and CD8 regulatory T cells in individuals under 15 years with multibacillary leprosy

Background

Leprosy is a chronic disease, caused by Mycobacterium leprae, which poses a serious public health problem worldwide. Its high incidence in people under 15 years old in Ceará state, Brazil, reflects the difficulty of its control. The spectrum of clinical manifestations is associated with the immune response developed, with the Th1 and Th2 responses being related to the paucibacillary and multibacillary forms, respectively. Regulatory T cells (Treg), which can suppress Th1 and Th2 response, have received special attention in the literature and have been associated with development of chronic infections. However, their role in leprosy in individuals under 15 years old has not yet been elucidated. We evaluated the frequency of CD4⁺/CD8⁺CD25^highFOXP3⁺ and CD4⁺/CD8⁺CD25^highFOXP3^high cells in leprosy patients and household contacts, in both cases under 15 years old.

Methodology/Principal Findings

PBMC from 12 patients and 17 contacts were cultured for 72 hours with anti-CD3 and anti-CD28 (activators) or with activators associated with total sonicated fraction of M. leprae. After culture, the frequency of CD4⁺/CD8⁺ Treg was identified by flow cytometry. Cells stimulated by activators and antigen from multibacillary patients showed Treg frequencies almost two times that of the contacts: CD4⁺FOXP3⁺ (21.93±8.43 vs. 13.79±8.19%, p = 0.0500), CD4⁺FOXP3^high (10.33±5.69 vs. 5.57±4.03%, p = 0.0362), CD8⁺FOXP3⁺ (13.88±9.19 vs. 6.18±5.56%, p = 0.0230) and CD8⁺FOXP3^high (5.36±4.17 vs. 2.23±2.68%, p = 0.0461). Furthermore, the mean fluorescence intensity of FOXP3 in Treg was higher in multibacillary patients than in the contacts. Interestingly, there was a positive correlation of the bacillary index and number of lesions with the frequency of all Treg evaluated in patients.

Conclusions/Significance

We have demonstrated for the first time that multibacillary leprosy patients under 15 years old have greater CD4⁺ and CD8⁺ Treg frequencies and these correlate with clinical and laboratorial aspects of disease. These findings suggest the involvement of these cells in the perpetuation of M. leprae infection.

Phenotype and regulation of immunosuppressive Vδ2-expressing γδ T cells

The proliferation and interleukin-2 production of CD4(+)CD25(-) αβ T cells were inhibited in a cell-contact manner by Vδ2 γδ T cells. The transcription factor Helios was constitutively expressed in about one-third of circulating γδ T cells and was upregulated by CD28-signaling. Our data suggest that Helios could serve as a marker for differential activation status rather than for regulatory T cells (Treg). Our findings also indicate that the interaction of CD86 on activated Vδ2 T cells and cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) on activated αβ T cells mediated the suppression because the suppressive effect was abolished by blocking the CD86:CTLA-4 interaction. Pre-treatment of Vδ2 T cells with Toll-like receptor 2 ligands enhanced phosphorylation of MAPKs, Akt, and NF-κB and partially abrogated the suppressive capacity, whereas on co-cultured responder T cells inhibitory molecules were downregulated and Akt and NF-κB phosphorylation was restored. Our results suggest that the regulation of αβ T cell proliferation by activated Vδ2 T cells might contribute to fine-tuning of αβ T cell responses.

Effects of adjuvant chemoradiotherapy on the frequency and function of regulatory T cells in patients with head and neck cancer

PURPOSE

Regulatory T cells (Treg) accumulate in tumor tissues and the peripheral blood of cancer patients and may persist after therapies. This cross-sectional study examines effects of adjuvant chemoradiotherapy (CRT) on Treg numbers and function in head and neck squamous cell carcinoma (HNSCC) patients.

EXPERIMENTAL DESIGN

The frequency and absolute numbers of CD4(+), ATP-hydrolyzing CD4(+)CD39(+) and CD8(+) T cells, and expression levels of CD39, CD25, TGF-β-associated LAP and GARP on Treg were measured by flow cytometry in 40 healthy donors (NC) and 71 HNSCC patients [29 untreated with active disease (AD); 22 treated with surgery; 20 treated with CRT]. All treated subjects had no evident disease (NED) at the time of phlebotomy. In an additional cohort of 40 subjects with AD (n = 15), NED (n = 10), and NC (n = 15), in vitro sensitivity of CD4(+) T-cell subsets to cisplatin and activation-induced cell death (AICD) was tested in Annexin V-binding assays.

RESULTS

CRT decreased the frequency of circulating CD4(+) T cells (P < 0.002) but increased that of CD4(+)CD39(+) Treg (P ≤ 0.001) compared with untreated or surgery-only patients. Treg frequency remained elevated for >3 years. CRT increased surface expression of LAP, GARP, and CD39 on Treg. In vitro Treg were resistant to AICD or cisplatin but conventional CD4(+) T cells (Tconv) were not. CRT-induced Treg from AD or NC subjects upregulated prosurvival proteins whereas Tconv upregulated proapoptotic Bax.

CONCLUSIONS

Highly suppressive, cisplatin-resistant Treg increase in frequency and persist after CRT and could be responsible for suppression of antitumor immune responses and recurrence in HNSCC.

Long-term survival in multiple myeloma is associated with a distinct immunological profile, which includes proliferative cytotoxic T-cell clones and a favourable Treg/Th17 balance

Despite improved outcomes in multiple myeloma (MM), a cure remains elusive. However, even before the current therapeutic era, 5% of patients survived >10 years and we propose that immune factors contribute to this longer survival. We identified patients attending our clinic, who had survived >10 years (n=20) and analysed their blood for the presence of T-cell clones, T-regulatory cells (Tregs) and T helper 17 (Th17) cells. These results were compared with MM patients with shorter follow-up and age-matched healthy control donors. The frequency of cytotoxic T-cell clonal expansions in patients with <10 years follow-up (MM patients) was 54% (n=144), whereas it was 100% (n=19/19) in the long-survivors (LTS-MM). T-cell clones from MM patients proliferated poorly in vitro, whereas those from LTS-MM patients proliferated readily (median proliferations 6.1% and 61.5%, respectively (P<0.0001)). In addition, we found significantly higher Th17 cells and lower Tregs in the LTS-MM group when compared with the MM group. These results indicate that long-term survival in MM is associated with a distinct immunological profile, which is consistent with decreased immune suppression.

Myeloma skews regulatory T and pro-inflammatory T helper 17 cell balance in favor of a suppressive state

Abstract Discrepancies in the literature between regulatory T cell (Treg) and pro-inflammatory T helper 17 (Th17) numbers in multiple myeloma (MM) can be largely explained by technical differences in methodology and patient selection. In this study, Treg cells were defined as CD3(+)CD4(+)CD25(++)CD127(lo) cells. Patients with MM (n = 20) had a significant imbalance in Treg/Th17 ratio when compared with either aged-matched controls (n = 28) or other monoclonal gammopathies, and this was associated with a significantly worse survival. The percent Treg in bone marrow of patients with MM was higher than that in matched peripheral blood samples (p = 0.02), although FOXP3 expression within bone marrow T cells was lower (p = 0.02). We observed increased Treg function, both in vivo and in vitro, due at least partially to an increase in CTLA-4 expression by concurrent treatment with dexamethasone and immune modulatory compounds (iMiDs). We suggest that immunoregulatory balance is important during active chemotherapy and that conclusions related to the immunostimulatory effect of iMiDs based on in vitro testing must be considered with caution.

FOXP3 subcellular localization predicts recurrence in oral squamous cell carcinoma

Forkhead box protein P3 (FOXP3) expression in tumor infiltrating CD4(+)T cells is generally associated with an intrinsic capacity to suppress tumor immunity. Based on this notion, different studies have evaluated the prognostic value of this maker in cancer but contradictory results have been found. Indeed, even within the same cancer population, the presence of CD4(+)FOXP3(+)T cells has been associated,with either a poor or a good prognosis, or no correlation has beenfound. Here, we demonstrate,in patients with oral squamous cell carcinoma (OSCC), that what really represents a prognostic parameter is not the overall expression of FOXP3 but its intracellular localization.While overallFOXP3 expression in tumor infiltrating CD4(+)T cells does not correlate with tumor recurrence, its intracellular localization within the CD4 cells does: nuclear FOXP3 (nFOXP3) is associated with tumor recurrence within 3 years, while cytoplasmicFOXP3 (cFOXP3) is associated with a lower likelihood of recurrence. Thus, we propose elevated levels of the cFOXP3/nFOXP3 ratio within tumor infiltrating CD4(+) T cells as a predictor of OSCC recurrence.

CD4⁺CD73⁺ T cells are associated with lower T-cell activation and C reactive protein levels and are depleted in HIV-1 infection regardless of viral suppression

BACKGROUND

The role of the adenosine (ADO) suppression pathway, specifically CD39-expressing and CD73-expressing CD4⁺ T cells in HIV-1 infection is unclear.

METHODS

We evaluated the frequency and numbers of CD4⁺CD39⁺ and CD4⁺CD73⁺ T cells, activated T cells, and plasma C reactive protein (CRP) levels in 36 HIV-1-positive individuals and 10 normal controls (NC). Low-level plasma viremia was evaluated using single copy assay. Mass spectrometry was used to measure hydrolysis of ATP by ectoenzyme-expressing CD4⁺ T cells, whereas cyclic adenosine monophosphate (cAMP) levels were measured using enzyme immunoassay. Suppression of T-cell function by exogenous ADO and CD4⁺CD73⁺ T cells was tested by flow cytometry.

RESULTS

CD39 and CD73 are expressed in different CD4⁺ T-cell subsets. CD4⁺CD73⁺ T cells do not express CD25 and FOXP3, and their frequency and numbers were lower in HIV-1-positive individuals regardless of virologic suppression (P=0.005 and P<0.001, respectively). CD4⁺CD73⁺ numbers inversely correlated with CD4⁺CD38⁺DR⁺ (P=0.002), CD8⁺CD38⁺DR⁺ T-cell frequency (P=0.05), and plasma CRP levels (P=0.01). Both subsets are required for hydrolysis of exogenous ATP to ADO and can increase CD4⁺ T-cell cAMP levels when incubated with exogenous ATP. Low-level viremia did not correlate with activated T-cell frequency. In vitro, ADO suppressed T-cell activation and cytokine expression. CD4⁺CD7⁺ T cells suppressed T-cell proliferation only in the presence of exogenous 5'-AMP.

CONCLUSION

The ADO-producing CD4⁺CD73⁺ subset of T cells is depleted in HIV-1-positive individuals regardless of viral suppression and may play a key role in controlling HIV-1-associated immune activation.

Circulating regulatory T cells are reduced in obesity and may identify subjects at increased metabolic and cardiovascular risk

OBJECTIVE

Reduced numbers of regulatory T (Treg ) cells have been observed in visceral adipose tissue of obese mice and humans. However, it is unknown whether human obesity affects circulating Treg cells and whether their number is associated with markers of systemic inflammation or glucose intolerance.

DESIGN AND METHODS

Peripheral blood mononuclear cells were isolated from venous blood of obese (BMI ≥ 27 kg/m(2) ; n = 30) and nonobese (BMI ≥ 27 kg/m(2) ; n = 13) individuals and analyzed using flow cytometry for the expression of CD4, CD25, and Foxp3.

RESULTS

Reduced circulating Treg -cell numbers were detected in obese compared with nonobese study participants (P = 0.038). Circulating CD4(+) CD25(+) CD127(-) Foxp3 Treg cells inversely correlated with body weight (P = 0.009), BMI (P = 0.004) and plasma leptin levels (P = 0.004) and were reduced in subjects with hsCRP ≥ 3.0 mg/L (P = 0.034) or HbA1c ≥ 5.5% (P < 0.005). Receiver operating characteristic curve analysis revealed a cutoff of circulating Treg cells < 1.06% to be predictive for hsCRP levels ≥ 3.0 mg/L, and logistic regression showed that the risk of having hsCRP levels ≥ 3.0 mg/L was increased 9.6-fold (P = 0.008), if Treg cells were below this threshold. The Treg cutoff for HbA1c levels ≥ 5.5% was 0.73%, and this cutoff also predicted an increased risk of having elevated levels of both hsCRP and HbA1c, if only obese subjects were examined.

CONCLUSION

Our findings thus reveal an association between circulating Treg cells and measures of adiposity, inflammation, and glucose intolerance. Although further prospective studies are needed, we present data suggesting that the determination of Treg cells might be useful to identify obese subjects at increased risk of developing cardiovascular and/or metabolic complications.

Impaired function of regulatory T cells in cord blood of children of allergic mothers

Allergy is one of the most common diseases with constantly increasing incidence. The identification of prognostic markers pointing to increased risk of allergy development is of importance. Cord blood represents a suitable source of cells for searching for such prognostic markers. In our previous work, we described the increased reactivity of cord blood cells of newborns of allergic mothers in comparison to newborns of healthy mothers, which raised the question of whether or not this was due to the impaired function of regulatory T cells (T(regs)) in high-risk children. Therefore, the proportion and functional properties of T(regs) in cord blood of children of healthy and allergic mothers were estimated by flow cytometry. The proportion of T(regs) [CD4(+)CD25(high)CD127(low) forkhead box protein 3 (FoxP3(+))] in cord blood of children of allergic mothers tends to be higher while, in contrast, the median of fluorescence intensity of FoxP3 was increased significantly in the healthy group. Intracellular presence of regulatory cytokines interleukin (IL)-10 and transforming growth factor (TGF)-beta was also higher in T(regs) of children of healthy mothers. Although we detected an increased proportion of T(regs) in cord blood of children of allergic mothers, the functional indicators (intracellular presence of regulatory cytokines IL-10 and TGF-beta, median of fluorescence intensity of FoxP3) of those T(regs) were lower in comparison to the healthy group. We can conclude that impaired function of T(regs) in cord blood of children of allergic mothers could be compensated partially by their increased number. Insufficient function of T(regs) could facilitate allergen sensitization in high-risk individuals after subsequent allergen encounter.

Phenotypic and functional characteristics of CD4+ CD39+ FOXP3+ and CD4+ CD39+ FOXP3neg T-cell subsets in cancer patients

Human CD4(+) CD39(+) regulatory T (Treg) cells hydrolyze exogenous adenosine triphosphate (ATP) and participate in immunosuppressive adenosine production. They contain two T-cell subsets whose role in mediating suppression is not understood. Frequencies of both CD4(+) CD39(+) subsets were evaluated in peripheral blood lymphocytes of 57 cancer patients and in tumor infiltrating lymphocytes (TILs) of 6 patients. CD4(+) CD39(+) and CD4(+) CD39(neg) T cells isolated using immunobeads and cell sorting were cultured under various conditions. Their conversion into CD39(+) FOXP3(+) CD25(+) or CD39(+) FOX(neg) CD25(neg) cells was monitored by multiparameter flow cytometry. Hydrolysis of exogenous ATP was measured in luminescence assays. Two CD4(+) CD39(+) cell subsets differing in expression of CD25, FOXP3, CTLA-4, CD121a, PD-1, latency associated peptide (LAP), glycoprotein A repetitions predominant (GARP), and the cytokine profile accumulated with equal frequencies in the blood and tumor tissues of cancer patients. The frequency of both subsets was significantly increased in cancer. CD39 expression levels correlated with the subsets' ability to hydrolyze ATP. Conventional CD4(+) CD39(neg) T cells incubated with IL-2 + TGF-β expanded to generate CD4(+) CD39(+) FOXP3(+) Treg cells, while CD4(+) CD39(+) FOXP3(neg) CD25(neg) subset cells stimulated via the TCR and IL-2 converted to FOXP3(+) CTLA4(+) CD25(+) TGF-β-expressing Treg cells. Among CD4(+) CD39(+) Treg cells, the CD4(+) CD39(+) FOXP3(neg) CD25(neg) subset serves as a reservoir of cells able to convert to Treg cells upon activation by environmental signals.

Determination of Absolute Counts of Circulating Regulatory T Cells in Cynomolgus Macaques Using an Optimized Flow Cytometric Method

Regulatory T cells (Tregs) are a rare subset of lymphocytes that inhibit the activation and effector functions of T cells and are important regulators of immune responses. Although Tregs are well characterized in humans and rodents, little is known about their immunophenotyping (IP) profile in cynomolgus macaques ( Macaca fascicularis), which is an important species for pharmacological and toxicological evaluation of potential immune modulators because of their similar physiologic, genetic, and metabolic response patterns to humans. The authors have developed an immunophenotyping panel using a high-throughput 96-well microtiter plate–based assay to detect circulating Tregs (CD3+CD4+CD25hiFoxP3+) and have determined the normal range for the number of Tregs in naive healthy cynomolgus macaques to be 56.4 to 179.7 cells/µL (mean ± SEM = 113.6 ± 5.1 cells/µL; n = 25). Furthermore, the authors compared the resulting FoxP3+ Treg profiles with a CD127lo cell-surface panel (CD3+CD4+CD25hi CD127lo) and found a close correlation between the absolute numbers of CD3+CD4+CD25hiFoxP3+ and CD3+CD4+CD25hiCD127lo cells (mean ± SD = 120 ± 8.0 cells/µL). Quantification of circulating Tregs in cynomolgus macaques in this high-throughput assay may help to identify drug candidates that affect this rare, but critical, immunoregulatory cell population.

The variation of CD4+CD25+ regulatory T cells in the periphery blood and tumor microenvironment of non-small cell lung cancer patients and the downregulation effects induced by CpG ODN

The aim of the study was to observe the variation of CD4(+)CD25(+) regulatory T cells in periphery blood and tumor microenvironment of non-small cell lung cancer (NSCLC) patients and the effects of CpG ODN. The proportion of CD4(+)CD25(+) regulatory T cells, Foxp3 gene expression, levels of tumor growth factor-β (TGF-β) and immunoreactive fibronectin-γ (IFN-γ) in the periphery blood of 30 NSCLC patients and 30 healthy volunteers were compared. These indicators were compared before and after CpG ODN treatment. Foxp3 gene expression in the tumor microenvironment of NSCLC patients was also observed. The results showed CD4(+)CD25(+) regulatory T cell proportion, Foxp3 expression and TGF-β levels in the periphery blood of NSCLC patients were higher than those of healthy volunteers (p < 0.05), and these indicators of patients were significantly decreased after CpG ODN 2006 treatment (p < 0.05). Foxp3 expression in the metastatic lymph nodes was higher than that in the non-metastatic ones of NSCLC patients (p = 0.000). In conclusion, a rise in the proportion of CD4(+)CD25(+)Foxp3(+) regulatory T cells was demonstrated in the periphery blood and tumor microenvironments of NSCLC patients. CpG ODN 2006 downregulated the CD4(+)CD25(+)Foxp3(+) regulatory T cells proportion and TGF-β levels in the periphery blood of these patients.

Immunologic monitoring of cellular responses by dendritic/tumor cell fusion vaccines

Although dendritic cell (DC)- based cancer vaccines induce effective antitumor activities in murine models, only limited therapeutic results have been obtained in clinical trials. As cancer vaccines induce antitumor activities by eliciting or modifying immune responses in patients with cancer, the Response Evaluation Criteria in Solid Tumors (RECIST) and WHO criteria, designed to detect early effects of cytotoxic chemotherapy in solid tumors, may not provide a complete assessment of cancer vaccines. The problem may, in part, be resolved by carrying out immunologic cellular monitoring, which is one prerequisite for rational development of cancer vaccines. In this review, we will discuss immunologic monitoring of cellular responses for the evaluation of cancer vaccines including fusions of DC and whole tumor cell.

Separation of human CD4+CD39+ T cells by magnetic beads reveals two phenotypically and functionally different subsets

OBJECTIVE

The ectonucleotidase CD39 is an enzyme involved in adenosine production. Its surface expression on human regulatory T cells (Treg) allows for their flow-cytometry-based isolation from peripheral blood. To further develop and improve this method on a scale supporting translational studies, we introduced capture of CD39(+) Treg on magnetic immunobeads.

METHODS

Peripheral blood mononuclear cells (PBMC) obtained from healthy donors were used for negative selection of CD4(+) T cells on AutoMACS using antibodies (Abs) specific for all lineage(+) cells. CD4(+)CD39(+) Treg were captured by biotin-conjugated anti-CD39 Abs and anti-biotin Ab-coated magnetic beads. Isolated CD4(+)CD39(+) T cells were phenotyped by flow cytometry for Treg-associated markers: CD39, CD73, FOXP3, CD25, CTLA-4, CCR4, CD45RO and CD121a or for the absence of CD127 and CD49d. CFSE-based proliferation assays and ATP hydrolysis were used to measure Treg functions.

RESULTS

The purity, recovery and viability of the separated CD4(+)CD39(+) T cells were satisfactory. The isolated CD4(+)CD39(+) T cell population consisted of FOXP3(+)CD25(+) T cells which hydrolyzed exogenous ATP and suppressed autologous CD4(+) T cell proliferation and of FOXP3(neg)CD25(neg) T cells without suppressor function. The same two subsets were detectable by flow cytometry in normal PBMC, gating on CD4(+)CD39(+), CD4(+)CD127(neg), CD4(+)CD49d(neg) or CD4(+)CD25(high) Treg.

CONCLUSION

CD4(+)CD39(+) Treg capture on immunobeads led to a discovery of two CD39(+) subsets. Similar to CD39(+) Treg in the peripheral blood, half of these cells are CD25(+)FOXP3(+) active suppressor cells, while the other half are CD25(neg)FOXP3(neg) and do not mediate suppression.