T Regulatory Cell Activation Exists in Pathogenesis of Polycythaemia Vera.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4642-4642
Author(s):  
Xin Wang ◽  
Wenbo Zhao ◽  
Yanxia Liu ◽  
Ying Li
Keyword(s):  
T Cells ◽  
T Cell ◽  
Peripheral Blood ◽  
Protein Level ◽  
Treg Cells ◽  
T Cell Immunity ◽  
Polycythaemia Vera ◽  
Cell Immunity ◽  
And Function ◽  
Hematopoietic Activity

Abstract Polycythaemia vera (PV) is a clonal disorder arising from a pluripotent hematopoietic progenitor cell. The etiology of PV remains unknown and there is no consensus as to the optimal therapy for this disorder. T regulatory (Treg) cells play a vital role in the maintenance of self-tolerance, control of auto-immunity and regulation of T-cell homeostasis, and they modulate overall immune responses against a variety of pathogens. Recent studies revealed that Treg cells play a crucial role in the process of hematopoietic activity. However, the effect of Treg cells in PV has not been reported. The Treg cells might participate in the dysfunction of T-cell immunity in PV. The profile and function of Treg cells in PV patients were explored in this study. Peripheral blood was withdrawn from 21 PV patients (Female 8 ; Male 13), as well as 25 age-matched healthy donors (F 9 ; M 16) as controls. All samples were taken after informed consent and collected from PV patients prior to treatment. Diagnoses of PV were made according to clinical and laboratory criteria. The peripheral blood mononuclear cells (PBMCs) were subjected to flow cytometry analyses after labeling with anti-CD4, anti-CD25, and anti-Foxp3 antibodies. Real-time PCR and Western blotting were also performed to identify quantitative FOXP3 mRNA expression and protein level in the PBMCs from PV in comparison to controls. The relationships between the percentage of Treg cells, the expressions for quantitative mRNA and protein, with the clinical data were assessed. The percentage of CD4+ T-cells was significant decreased in the group of PV than in normal control (28.7±7.07% vs 38.6±8.38%, p<0.05). But the percentage of CD4+CD25+FOXP3+ T-cells (Treg cells) in PV patients was significantly increased when compared to the control (10.93±4.02% vs 5.86±1.99%, p<0.05). Moreover, the quantitative mRNA expression of FOXP3 (64.23±18.52 vs 16.06±4.78, p<0.05) and protein expression of FOXP3 (0.74±0.16 vs 0.62±0.10, p<0.05)) were significantly enhanced in PV patients (shown in Figure 1). In conclusion, we showed that patients with PV have enhanced percentage of Treg cells in their peripheral blood. This was substantiated further with the finding that overexpressions of FOXP3 in PV both in mRNA and protein level. These results highlight important Treg-cell abnormalities in patients with PV because natural Treg cells are significantly increased in number and function. The underlying mechanism is still undefined, but the increased frequency and function of Treg cells might account for the abnormal T cell immunity in PV patients. It was suggested that there may be differently suppressive machanisms for Treg in these patients. The elevated Treg cells in PV might be activated and then affect the hematopoietic activity. We believe that Treg cells might involved in the dysfunction of T/NK cells in their disability to downregulate the hematopoietic proliferation in PV. And the expansion of Treg cells may be a feature of PV and associated with the pathogenesis of PV. Further investigation in this abnormality might provide novel therapy clue for this disease. Figure Figure

CD4+ T-cell immunity predicts long-lasting antitumor immunity after PD-1 blockade therapy.

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. 2545-2545
Author(s):  
Kyoichi Kaira ◽  
Ou Yamaguchi ◽  
Kenichi Yoshimura ◽  
Atsuto Mouri ◽  
Ayako Shiono ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Peripheral Blood ◽  
Mononuclear Cells ◽  
Therapy Response ◽  
T Cell Immunity ◽  
Prediction Formula ◽  
Short Term ◽  
Peripheral Blood Mononuclear ◽  
Cell Immunity

2545 Background: Patients treated with programmed cell death 1 (PD-1)-blockade therapy fall into 3 distinct subgroups: non-responders presenting early disease progression, long survivors who achieve durable disease control, and the remaining short-term responders. We reported that the prediction formula comprised of the percentages of CD62L-downregulated (CD62Llow) and CD25+FOXP3+CD4+T cells in the peripheral blood predicted non-responders of non-small cell lung cancer patients (n = 50) scheduled to receive anti-PD-1-antibody (nivolumab) therapy in the 2017 ASCO meeting. In this study, we included 171 patients with NSCLC who were scheduled for nivolumab treatment after obtaining written informed consent. Peripheral blood mononuclear cells (PBMC) were examined before and after Nivolumab therapy up to 2 years to investigate the differences between long survivors and short-term responders. Methods: The patients received Nivolumab at a dose of 3 mg per kilogram of body weight every 2 weeks. Tumor response was assessed with the use of the Response Evaluation Criteria in Solid Tumors (RECIST), version 1.1, at week 8 and every 8 weeks thereafter. PBMCs were analyzed with a 18-color microfluorometer, LSR Fortessa and a masscytometer, CyTOF. Results: The responder-type patient group whose prediction formula values were greater than 192 showed significantly longer PFS ( P< 0.0001) and OS ( P< 0.0001). The long survivors who consisted of tail plateau of PFS exhibited significantly more CD62LlowCD4+T cells than the short-term responders as pre-existing immunity. The remaining responders kept significantly higher percentages of CD62LlowCD4+T cells ( P= 0.0088) and prediction formula values ( P= 0.017) than the patients with acquired resistance. Conclusions: The pre-existing CD4+T cell balance between primed effector and regulatory T cells correlated with anti-PD-1 therapy response. Further, CD62Llowcell-dominant CD4+T cell immunity was required to maintain durable antitumor reactivity induced by anti-PD-1 antibody therapy. These results have important clinical implication, as they support anti-PD-1 therapy provision to all potentially responding patients and pave the way for new treatment strategies for patients with distinct CD4+T cell immune statuses. Clinical trial information: UMIN000020719.

scholarly journals Targeting of Cdc42 GTPase in regulatory T cells unleashes anti-tumor T cell immunity

2021 ◽  
Author(s):  
Khalid W Kalim ◽  
Jun-Qi Yang ◽  
Mark Wunderlich ◽  
Vishnu Modur ◽  
Phuong Nguyen ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Treg Cell ◽  
Cell Function ◽  
Treg Cells ◽  
T Cell Response ◽  
T Cell Immunity ◽  
Cell Plasticity ◽  
Effector T Cell ◽  
Cell Immunity

Regulatory T (Treg) cells play an important role in maintaining immune tolerance through inhibiting effector T cell function. In the tumor microenvironment, Treg cells are utilized by tumor cells to counteract effector T cell-mediated tumor killing. Targeting Treg cells may thus unleash the anti-tumor activity of effector T cells. While systemic depletion of Treg cells can cause excessive effector T cell responses and subsequent autoimmune diseases, controlled targeting of Treg cells may benefit cancer patients. Here we show that Treg cell-specific heterozygous deletion or pharmacological targeting of Cdc42 GTPase does not affect Treg cell numbers but induces Treg cell plasticity, leading to anti-tumor T cell immunity without detectable autoimmune reactions. Cdc42 targeting potentiates an immune checkpoint blocker anti-PD-1 antibody-mediated T cell response against mouse and human tumors. Mechanistically, Cdc42 targeting induces Treg cell plasticity and unleashes anti-tumor T cell immunity through carbonic anhydrase I-mediated pH changes. Thus, rational targeting of Cdc42 in Treg cells holds therapeutic promises in cancer immunotherapy.

scholarly journals Assessment of T-cell immunity to SARS-CoV-2 in COVID-19 convalescents and vaccinated subjects, using TigraTest® SARS-CoV-2 ELISPOT kit

2021 ◽  
Vol 21 (3) ◽  
pp. 178-192
Author(s):  
D. A. Poteryaev ◽  
S. G. Abbasova ◽  
P. E. Ignatyeva ◽  
O. M. Strizhakova ◽  
S. V. Kolesnik ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Peripheral Blood ◽  
Cell Response ◽  
Human Peripheral Blood ◽  
T Cell Response ◽  
T Cell Immunity ◽  
Cell Immunity

With the onset of the COVID-19 pandemic, a number of molecular-based tests have been developed to diagnose SARS-CoV-2 infection. However, numerous available serological tests lack sufficient sensitivity or specificity. They do not detect specific antibodies in a significant proportion of patients with PCR-confirmed COVID-19. There is evidence that some convalescents have a relatively short-lived humoral immunity. In contrast, a number of publications have shown that T-cell response to human coronaviruses, including SARS-CoV-1, MERS, and SARS-CoV-2, can be strong and long-term. Assessment of T-cell immunity to SARS-CoV-2 is important not only for stratification of risks and identification of potentially protected populations with immunity acquired as a result of previous infection, but also for determining immunogenicity and potential efficacy of vaccines under development. The existing methods of quantitative or semi-quantitative assessment of specific T-cell response are mainly used in scientific research and are not standardised. The aim of the study was to develop and verify experimentally a test kit to be used in a standardised procedure for in vitro determination of T-cells specific to SARS-CoV-2 antigens, in human peripheral blood. Materials and methods: the TigraTest® SARS-CoV-2 kit developed by GENERIUM, which determines the number of T-cells secreting interferon gamma in vitro, was tested in the study. Samples of venous blood of volunteers from three different groups were analysed in the study: presumably healthy volunteers; COVID-19 convalescents; individuals vaccinated against SARS-CoV-2. Results: the authors developed the TigraTest® SARS-CoV-2 kit for in vitro determination of T-cells specific to SARS-CoV-2 antigens in human peripheral blood, demonstrated its specificity and performed preliminary assessment of its sensitivity. The study analysed the range and magnitude of the T-cell response in convalescent and vaccinated individuals. A pronounced T-cell response was also shown in some individuals with no symptoms or with unconfirmed diagnosis. It was discovered that the mean T-cell response to peptides of the spike protein (S-protein) was higher in the vaccinated individuals than in the convalescent patients. A correlation was determined between the severity of the disease and the level of T-cell response. Specific contributions of various groups of antigens to the T-cell response after COVID-19 infection were also determined. Conclusions: the TigraTest® SARS-CoV-2 kit is a specific and sensitive tool for the assessment of T-cell immunity to the SARS-CoV-2 virus, which can also be used for vaccinated individuals. The kit may be used in clinical practice for comprehensive assessment of immunity to SARS-CoV-2.

scholarly journals Tissue reservoirs of antiviral T cell immunity in persistent human CMV infection

2017 ◽  
Vol 214 (3) ◽  
pp. 651-667 ◽  
Author(s):  
Claire L. Gordon ◽  
Michelle Miron ◽  
Joseph J.C. Thome ◽  
Nobuhide Matsuoka ◽  
Joshua Weiner ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Virus Detection ◽  
Distribution Patterns ◽  
T Cell Immunity ◽  
T Cell Homeostasis ◽  
Intrinsic Factors ◽  
Cell Immunity ◽  
Human Cmv ◽  
And Function

T cell responses to viruses are initiated and maintained in tissue sites; however, knowledge of human antiviral T cells is largely derived from blood. Cytomegalovirus (CMV) persists in most humans, requires T cell immunity to control, yet tissue immune responses remain undefined. Here, we investigated human CMV-specific T cells, virus persistence and CMV-associated T cell homeostasis in blood, lymphoid, mucosal and secretory tissues of 44 CMV seropositive and 28 seronegative donors. CMV-specific T cells were maintained in distinct distribution patterns, highest in blood, bone marrow (BM), or lymph nodes (LN), with the frequency and function in blood distinct from tissues. CMV genomes were detected predominantly in lung and also in spleen, BM, blood and LN. High frequencies of activated CMV-specific T cells were found in blood and BM samples with low virus detection, whereas in lung, CMV-specific T cells were present along with detectable virus. In LNs, CMV-specific T cells exhibited quiescent phenotypes independent of virus. Overall, T cell differentiation was enhanced in sites of viral persistence with age. Together, our results suggest tissue T cell reservoirs for CMV control shaped by both viral and tissue-intrinsic factors, with global effects on homeostasis of tissue T cells over the lifespan.

scholarly journals B and T Cell Immunity in Tissues and Across the Ages

Vaccines ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 24
Author(s):  
Jayaum S. Booth ◽  
Franklin R. Toapanta
Keyword(s):  
T Cells ◽  
Immune System ◽  
T Cell ◽  
Peripheral Blood ◽  
T Cell Immunity ◽  
T Cell Subsets ◽  
Adaptive Immune ◽  
Adaptive Immune Cells ◽  
Cell Immunity ◽  
Blood Specimens

B and T cells are key components of the adaptive immune system and coordinate multiple facets of immunity including responses to infection, vaccines, allergens, and the environment. In humans, B- and T-cell immunity has been determined using primarily peripheral blood specimens. Conversely, human tissues have scarcely been studied but they host multiple adaptive immune cells capable of mounting immune responses to pathogens and participate in tissue homeostasis. Mucosal tissues, such as the intestines and respiratory track, are constantly bombarded by foreign antigens and contain tissue-resident memory T (TRM) cells that exhibit superior protective capacity to pathogens. Also, tissue-resident memory B (BRM) cells have been identified in mice but whether humans have a similar population remains to be confirmed. Moreover, the immune system evolves throughout the lifespan of humans and undergoes multiple changes in its immunobiology. Recent studies have shown that age-related changes in tissues are not necessarily reflected in peripheral blood specimens, highlighting the importance of tissue localization and subset delineation as essential determinants of functional B and T cells at different life stages. This review describes our current knowledge of the main B- and T-cell subsets in peripheral blood and tissues across age groups.

scholarly journals Reduced immune-regulatory molecule expression on human colonic memory CD4 T cells in older adults

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Stephanie M. Dillon ◽  
Tezha A. Thompson ◽  
Allison J. Christians ◽  
Martin D. McCarter ◽  
Cara C. Wilson
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Older Persons ◽  
Age Groups ◽  
T Cell Immunity ◽  
Cd4 T Cell ◽  
Cell Immunity ◽  
Memory Cd4 T Cells

Abstract Background The etiology of the low-level chronic inflammatory state associated with aging is likely multifactorial, but a number of animal and human studies have implicated a functional decline of the gastrointestinal immune system as a potential driver. Gut tissue-resident memory T cells play critical roles in mediating protective immunity and in maintaining gut homeostasis, yet few studies have investigated the effect of aging on human gut T cell immunity. To determine if aging impacted CD4 T cell immunity in the human large intestine, we utilized multi-color flow cytometry to measure colonic lamina propria (LP) CD4 T cell frequencies and immune-modulatory marker expression in younger (mean ± SEM: 38 ± 1.5 yrs) and older (77 ± 1.6 yrs) adults. To determine cellular specificity, we evaluated colon LP CD8 T cell frequency and phenotype in the same donors. To probe tissue specificity, we evaluated the same panel of markers in peripheral blood (PB) CD4 T cells in a separate cohort of similarly aged persons. Results Frequencies of colonic CD4 T cells as a fraction of total LP mononuclear cells were higher in older persons whereas absolute numbers of colonic LP CD4 T cells per gram of tissue were similar in both age groups. LP CD4 T cells from older versus younger persons exhibited reduced CTLA-4, PD-1 and Ki67 expression. Levels of Bcl-2, CD57, CD25 and percentages of activated CD38+HLA-DR+ CD4 T cells were similar in both age groups. In memory PB CD4 T cells, older age was only associated with increased CD57 expression. Significant age effects for LP CD8 T cells were only observed for CTLA-4 expression, with lower levels of expression observed on cells from older adults. Conclusions Greater age was associated with reduced expression of the co-inhibitory receptors CTLA-4 and PD-1 on LP CD4 T cells. Colonic LP CD8 T cells from older persons also displayed reduced CTLA-4 expression. These age-associated profiles were not observed in older PB memory CD4 T cells. The decline in co-inhibitory receptor expression on colonic LP T cells may contribute to local and systemic inflammation via a reduced ability to limit ongoing T cell responses to enteric microbial challenge.

538 Harnessing cross-dressing dendritic cells to strengthen anti-tumor immunity

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A574-A574
Author(s):  
Ellen Duong ◽  
Timothy Fessenden ◽  
Arjun Bhutkar ◽  
Stefani Spranger
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Cancer Cell ◽  
Tumor Immunity ◽  
T Cell Responses ◽  
T Cell Immunity ◽  
Cell Responses ◽  
Cell Immunity ◽  
Cross Dressing

BackgroundCytotoxic (CD8+) T-cells are required for tumor eradication and durable anti-tumor immunity.1 The induction of tumor-reactive CD8+ T-cells is predominately attributed to a subset of dendritic cells (DC) called Batf3-driven DC1, given their robust ability to cross-present antigens for T-cell priming and their role in effector T-cell recruitment.2–4 Presence of the DC1 signature in tumors correlates with improved survival and response to immunotherapies.5–7 Yet, most tumors with a DC1 infiltrate still progress, suggesting that while DC1 can initiate tumor-reactive CD8+ T-cell responses, they are unable to sustain them. Therefore, there is a critical need to identify and engage additional stimulatory DC subsets to strengthen anti-tumor immunity and boost immunotherapy responses.MethodsTo identify DC subsets that drive poly-functional CD8+ T-cell responses, we compared the DC infiltrate of a spontaneously regressing tumor with a progressing tumor. Multicolor flow immunophenotyping and single-cell RNA-sequencing were used to profile the DC compartment of both tumors. IFNγ-ELISpot was performed on splenocytes to assess for systemic tumor-reactive T-cell responses. Sorted DC subsets from tumors were co-cultured with TCR-transgenic T-cells ex vivo to evaluate their stimulatory capacity. Cross-dressing (in vivo/ex vivo) was assayed by staining for transfer of tumor-derived H-2b MHC complexes to Balb/c DC, which express the H-2d haplotype. Protective systemic immunity was assayed via contralateral flank tumor outgrowth experiments.ResultsRegressor tumors were infiltrated with more cross-presenting DC1 than progressor tumors. However, tumor-reactive CD8+ T-cell responses and tumor control were preserved in Batf3-/- mice lacking DC1, indicating that anti-tumor immune responses could be induced independent of DC1. Through functional assays, we established that anti-tumor immunity against regressor tumors required CD11c+ DC and cGAS/STING-independent type-I-interferon-sensing. Single-cell RNA-sequencing of the immune infiltrate of regressor tumors revealed a novel CD11b+ DC subset expressing an interferon-stimulated gene signature (ISG+ DC). Flow studies demonstrated that ISG+ DC were more enriched in regressor tumors than progressor tumors. We showed that ISG+ DC could activate CD8+ T-cells by cross-dressing with tumor-derived peptide-MHC complexes, thereby bypassing the requirement for cross-presentation to initiate CD8+ T-cell-driven immunity. ISG+ DC highly expressed cytosolic dsRNA sensors (RIG-I/MDA5) and could be therapeutically harnessed by exogenous addition of a dsRNA analog to drive protective CD8+ T-cell responses in DC1-deficient mice.ConclusionsThe DC infiltrate in tumors can dictate the strength of anti-tumor immunity. Harnessing multiple stimulatory DC subsets, such as cross-presenting DC1 and cross-dressing ISG+ DC, provides a therapeutic opportunity to enhance anti-tumor immunity and increase immunotherapy responses.ReferencesFridman WH, et al. The immune contexture in human tumours: impact on clinical outcome. Nature Reviews Cancer 2012;12(4): p. 298–306.Hildner K, et al. Batf3 deficiency reveals a critical role for CD8alpha+ dendritic cells in cytotoxic T cell immunity. Science 2008;322(5904):p. 1097–100.Spranger S, et al. Tumor-Residing Batf3 dendritic cells are required for effector T cell trafficking and adoptive T cell therapy. Cancer Cell 2017;31(5):p. 711–723.e4.Roberts, EW, et al., Critical role for CD103(+)/CD141(+) dendritic cells bearing CCR7 for tumor antigen trafficking and priming of T cell immunity in melanoma. Cancer Cell 2016;30(2): p. 324–336.Broz ML, et al. Dissecting the tumor myeloid compartment reveals rare activating antigen-presenting cells critical for T cell immunity. Cancer Cell 2014;26(5): p. 638–52.Salmon H., et al., Expansion and activation of CD103(+) dendritic cell progenitors at the tumor site enhances tumor responses to therapeutic PD-L1 and BRAF inhibition. Immunity, 2016. 44(4): p. 924–38.Sánchez-Paulete AR, et al., Cancer immunotherapy with immunomodulatory anti-CD137 and Anti-PD-1 monoclonal antibodies requires BATF3-dependent dendritic cells. Cancer Discov, 2016;6(1):p. 71–9.

scholarly journals T Cell Immunity against Influenza: The Long Way from Animal Models Towards a Real-Life Universal Flu Vaccine

Viruses ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 199
Author(s):  
Anna Schmidt ◽  
Dennis Lapuente
Keyword(s):  
T Cells ◽  
T Cell ◽  
Animal Models ◽  
Respiratory Tract ◽  
Memory T Cells ◽  
Real Life ◽  
T Cell Immunity ◽  
Cell Immunity ◽  
Flu Vaccine ◽  
Resident Memory T Cells

Current flu vaccines rely on the induction of strain-specific neutralizing antibodies, which leaves the population vulnerable to drifted seasonal or newly emerged pandemic strains. Therefore, universal flu vaccine approaches that induce broad immunity against conserved parts of influenza have top priority in research. Cross-reactive T cell responses, especially tissue-resident memory T cells in the respiratory tract, provide efficient heterologous immunity, and must therefore be a key component of universal flu vaccines. Here, we review recent findings about T cell-based flu immunity, with an emphasis on tissue-resident memory T cells in the respiratory tract of humans and different animal models. Furthermore, we provide an update on preclinical and clinical studies evaluating T cell-evoking flu vaccines, and discuss the implementation of T cell immunity in real-life vaccine policies.

scholarly journals Regulatory T Cells Fail to Suppress Fast Homeostatic Proliferation In Vitro

Life ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 245
Author(s):  
Daniil Shevyrev ◽  
Valeriy Tereshchenko ◽  
Elena Blinova ◽  
Nadezda Knauer ◽  
Ekaterina Pashkina ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
Autoimmune Diseases ◽  
Peripheral Blood ◽  
Treg Cells ◽  
Homeostatic Proliferation ◽  
Suppressive Activity ◽  
Healthy Donors

Homeostatic proliferation (HP) is a physiological process that reconstitutes the T cell pool after lymphopenia involving Interleukin-7 and 15 (IL-7 and IL-15), which are the key cytokines regulating the process. However, there is no evidence that these cytokines influence the function of regulatory T cells (Tregs). Since lymphopenia often accompanies autoimmune diseases, we decided to study the functional activity of Tregs stimulated by HP cytokines from patients with rheumatoid arthritis as compared with that of those from healthy donors. Since T cell receptor (TCR) signal strength determines the intensity of HP, we imitated slow HP using IL-7 or IL-15 and fast HP using a combination of IL-7 or IL-15 with anti-CD3 antibodies, cultivating Treg cells with peripheral blood mononuclear cells (PBMCs) at a 1:1 ratio. We used peripheral blood from 14 patients with rheumatoid arthritis and 18 healthy volunteers. We also used anti-CD3 and anti-CD3 + IL-2 stimulation as controls. The suppressive activity of Treg cells was evaluated in each case by the inhibition of the proliferation of CD4+ and CD8+ cells. The phenotype and proliferation of purified CD3+CD4+CD25+CD127lo cells were assessed by flow cytometry. The suppressive activity of the total pool of Tregs did not differ between the rheumatoid arthritis and healthy donors; however, it significantly decreased in conditions close to fast HP when the influence of HP cytokines was accompanied by anti-CD3 stimulation. The Treg proliferation caused by HP cytokines was lower in the rheumatoid arthritis (RA) patients than in the healthy individuals. The revealed decrease in Treg suppressive activity could impact the TCR landscape during lymphopenia and lead to the proliferation of potentially self-reactive T cell clones that are able to receive relatively strong TCR signals. This may be another explanation as to why lymphopenia is associated with the development of autoimmune diseases. The revealed decrease in Treg proliferation under IL-7 and IL-15 exposure can lead to a delay in Treg pool reconstitution in patients with rheumatoid arthritis in the case of lymphopenia.

scholarly journals Indoleamine 2,3-dioxygenase specific, cytotoxic T cells as immune regulators

Blood ◽  
2011 ◽  
Vol 117 (7) ◽  
pp. 2200-2210 ◽  
Author(s):  
Rikke Bæk Sørensen ◽  
Sine Reker Hadrup ◽  
Inge Marie Svane ◽  
Mads Christian Hjortsø ◽  
Per thor Straten ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Effector T Cells ◽  
T Cell Immunity ◽  
Regulatory Function ◽  
Cytotoxic T Cell ◽  
Interleukin 17 ◽  
Patients With Cancer ◽  
Indoleamine 2,3 Dioxygenase ◽  
Cell Immunity

Abstract Indoleamine 2,3-dioxygenase (IDO) is an immunoregulatory enzyme that is implicated in suppressing T-cell immunity in normal and pathologic settings. Here, we describe that spontaneous cytotoxic T-cell reactivity against IDO exists not only in patients with cancer but also in healthy persons. We show that the presence of such IDO-specific CD8+ T cells boosted T-cell immunity against viral or tumor-associated antigens by eliminating IDO+ suppressive cells. This had profound effects on the balance between interleukin-17 (IL-17)–producing CD4+ T cells and regulatory T cells. Furthermore, this caused an increase in the production of the proinflammatory cytokines IL-6 and tumor necrosis factor-α while decreasing the IL-10 production. Finally, the addition of IDO-inducing agents (ie, the TLR9 ligand cytosine-phosphate-guanosine, soluble cytotoxic T lymphocyte–associated antigen 4, or interferon γ) induced IDO-specific T cells among peripheral blood mononuclear cells from patients with cancer as well as healthy donors. In the clinical setting, IDO may serve as an important and widely applicable target for immunotherapeutic strategies in which IDO plays a significant regulatory role. We describe for the first time effector T cells with a general regulatory function that may play a vital role for the mounting or maintaining of an effective adaptive immune response. We suggest terming such effector T cells “supporter T cells.”

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