Activated but impaired IFN-γ production of mucosal-associated invariant T cells in patients with hepatocellular carcinoma

ObjectiveMucosal-associated invariant T (MAIT) cells are innate T cells with immunoregulatory activity and were recently found to be associated with various tumor types. The role of intrasinusoidal MAIT cells in hepatocellular carcinoma (HCC) has not been fully characterized.DesignPeripheral blood samples were obtained from patients with HCC and healthy controls. Liver-associated mononuclear cells (LMCs) were collected from liver perfusions of donors and patients with HCC undergoing liver transplantation. Blood and liver perfusates from patients with HCC were analyzed by flow cytometry for CD3 +CD161+Vα7.2+MAIT cell frequency, phenotype, and function.ResultsThere were fewer MAIT cells in the peripheral blood and liver of patients with HCC than in the healthy controls. Interferon-γ (IFN-γ) production by these cells was also reduced. Peripheral MAIT cells showed upregulation of HLA-DR (Human Leukocyte Antigen DR） and the inhibitory molecule PD-1 (Programmed Cell Death Protein 1), but no significant differences in upregulation were found in intrasinusoidal MAIT cells. MAIT cells were significantly enriched in the liver relative to that in the peripheral blood of patients with HCC. High levels of activation markers and exhaustion markers including HLA-DR, CD69, and PD-1 were observed in LMCs of patients with HCC but not in the peripheral blood. Single-cell RNA sequencing revealed that intrasinusoidal MAIT cells exhibited distinct features in patients with HCC and the controls.ConclusionOur study showed that alterations in MAIT cells are associated with HCC. The distinct activity and function of MAIT cells in the peripheral blood and liver of patients with HCC might suggest a potential role of these cells in disease pathogenesis.

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Phenotypic and Functional Alterations of Immune Effectors in Periodontitis; A Multifactorial and Complex Oral Disease

Journal of Clinical Medicine ◽

10.3390/jcm10040875 ◽

2021 ◽

Vol 10 (4) ◽

pp. 875

Author(s):

Kawaljit Kaur ◽

Shahram Vaziri ◽

Marcela Romero-Reyes ◽

Avina Paranjpe ◽

Anahid Jewett

Keyword(s):

Periodontal Disease ◽

Peripheral Blood ◽

Mononuclear Cells ◽

Oral Disease ◽

Healthy Controls ◽

Healthy Individuals ◽

Tnf Α ◽

Blood Mononuclear Cells ◽

Ifn Γ ◽

And Function

Survival and function of immune subsets in the oral blood, peripheral blood and gingival tissues of patients with periodontal disease and healthy controls were assessed. NK and CD8 + T cells within the oral blood mononuclear cells (OBMCs) expressed significantly higher levels of CD69 in patients with periodontal disease compared to those from healthy controls. Similarly, TNF-α release was higher from oral blood of patients with periodontal disease when compared to healthy controls. Increased activation induced cell death of peripheral blood mononuclear cells (PBMCs) but not OBMCs from patients with periodontal disease was observed when compared to those from healthy individuals. Unlike those from healthy individuals, OBMC-derived supernatants from periodontitis patients exhibited decreased ability to induce secretion of IFN-γ by allogeneic healthy PBMCs treated with IL-2, while they triggered significant levels of TNF-α, IL-1β and IL-6 by untreated PBMCs. Interaction of PBMCs, or NK cells with intact or NFκB knock down oral epithelial cells in the presence of a periodontal pathogen, F. nucleatum, significantly induced a number of pro-inflammatory cytokines including IFN-γ. These studies indicated that the relative numbers of immune subsets obtained from peripheral blood may not represent the composition of the immune cells in the oral environment, and that orally-derived immune effectors may differ in survival and function from those of peripheral blood.

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Abstract W P87: Characteristics of T-cells Infiltrating Ruptured Intracranial Aneurysm

Stroke ◽

10.1161/str.46.suppl_1.wp87 ◽

2015 ◽

Vol 46 (suppl_1) ◽

Author(s):

Roger M Krzyzewski ◽

Magdalena K Stachura ◽

Mariusz Krupa ◽

Rafal Morga ◽

Agnieszka Sagan ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Intracranial Aneurysm ◽

Peripheral Blood ◽

Histological Finding ◽

Cell Phenotype ◽

Double Negative ◽

Activation Markers ◽

Hla Dr ◽

Ruptured Intracranial Aneurysm

Introduction: Recently the role of adaptive immunity has been implied by microarray studies. But the results are contradictory. T-cell infiltration is a frequent histological finding in ruptured IA, T-cell phenotype, characteristic and true quantitation remains unknown. We preformed a prospective study to determine the subpopulation and expression of activation markers of T-cells infiltrating ruptured IA in relation to peripheral blood. Hypothesis: IA have different subsets and activation levels of T-cells than peripheral blood. Methods: We collected the tissue of ruptured IA of 8 patients operated on within 24 hours after subarachnoid hemorrhage symptoms onset. IA tissue was digested, stained with fluorescently labeled monoclonal antibodies and submitted to flow cytometry. In addition we collected and analyzed venous blood from 6 age, sex and risk factor-matched controls. Results: CD4+ cells are less prevalent in IA tissue than in peripheral blood (42.14±17.28 vs. 65.88±5.32%; p=0.011), while there was no difference in CD8+ T-cells infiltrating IA (30.28±9.07 vs. 27.78±5.45%; p=0.585), and double negative (CD4-CD8-CD3+) T-cells were more prevalent in wall of IA than in circulation, (15.68±11.94 vs. 2.81±1.32%; p=0.026). Importantly, CD4+ infiltrating IA wall showed higher expression of HLA-DR (25.9±6.42 vs. 9.19± 3.58%; p<0.001) higher expression of CD 69 (26.8±19.66 vs. 2.73±0.93%; p=0.014). Similarly, there significantly more CD8+ cells showed HLA-DR+ in the IA than in blood. (45.96±15.57 vs. 22.47±11.46%; p=0.018) and CD69 (30.32±22.73 vs. 5.03±1.55%; p=0.022). Double negative cells in IA also had higher expression of HLA-DR (46.56±21.40 vs. 22.58±5.1%; p=0.025), CD69 (31.05±16.79 vs. 7.83±2.05%; p=0.016). Conclusion: The tissue of ruptured IA is highly infiltrated by T-cells which show high expression of activation markers such as CD69 or HLA-DR. The importance of these cells to immunopathogenesis of intracranial aneurysm rupture should be further characterized.

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Aberrant Contraction of Antigen-Specific CD4 T Cells after Infection in the Absence of Gamma Interferon or Its Receptor

Infection and Immunity ◽

10.1128/iai.00847-06 ◽

2006 ◽

Vol 74 (11) ◽

pp. 6252-6263 ◽

Cited By ~ 31

Author(s):

Jodie S. Haring ◽

John T. Harty

Keyword(s):

T Cells ◽

Cd4 T Cells ◽

Interleukin 2 ◽

Gamma Interferon ◽

Model Systems ◽

Important Regulator ◽

Ifn Γ ◽

And Function ◽

Deficient Mice

ABSTRACT Several lines of evidence from different model systems suggest that gamma interferon (IFN-γ) is an important regulator of T-cell contraction after antigen (Ag)-driven expansion. To specifically investigate the role of IFN-γ in regulating the contraction of Ag-specific CD4 T cells, we infected IFN-γ−/− and IFN-γR1−/− mice with attenuated Listeria monocytogenes and monitored the numbers of Ag-specific CD4 T cells during the expansion, contraction, and memory phases of the immune response to infection. In the absence of IFN-γ or the ligand-binding portion of its receptor, Ag-specific CD4 T cells exhibited normal expansion in numbers, but in both strains of deficient mice there was very little decrease in the number of Ag-specific CD4 T cells even at time points later than day 90 after infection. This significant delay in contraction was not due to prolonged infection, since mice treated with antibiotics to conclusively eliminate infection exhibited the same defect in contraction. In addition to altering the number of Ag-specific CD4 T cells, the absence of IFN-γ signaling also changed the phenotype of cells generated after infection. IFN-γR1−/− Ag-specific CD4 T cells reacquired expression of CD127 more quickly than wild-type cells, and more IFN-γR1−/− CD4 T cells were capable of producing both IFN-γ and interleukin 2 following Ag stimulation. From these data we conclude that IFN-γ regulates the contraction, phenotype, and function of Ag-specific CD4 T cells generated after infection.

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LncRNA-ENST00000421645 promotes T cells to secrete IFN-γ by sponging PCM-1 in neurosyphilis

Epigenomics ◽

10.2217/epi-2021-0163 ◽

2021 ◽

Author(s):

Wen-Na Liu ◽

Kai-Xuan Wu ◽

Xiao-Tong Wang ◽

Li-Rong Lin ◽

Man-Li Tong ◽

...

Keyword(s):

Flow Cytometry ◽

T Cells ◽

Peripheral Blood ◽

Long Noncoding Rna ◽

Noncoding Rna ◽

Chip Assay ◽

Rna Immunoprecipitation ◽

Ifn Γ ◽

Significant Expression

Aim: Neurosyphilis patients exhibited significant expression of long noncoding RNA (lncRNA) in peripheral blood T lymphocytes. In this study, we further clarified the role of lncRNA- ENST00000421645 in the pathogenic mechanism of neurosyphilis. Methods: lncRNA- ENST00000421645 was transfected into Jurkat-E6-1 cells, namely lentivirus (Lv)-1645 cells. RNA pull-down assay, flow cytometry, RT-qPCR, ELISA (Neobioscience Technology Co Ltd, Shenzhen, China) and RNA immunoprecipitation chip assay were used to analyze the function of lncRNA- ENST00000421645. Results: The expression of IFN-γ in Lv-1645 cells was significantly increased compared to that in Jurkat-E6-1 cells stimulated by phorbol-12-myristate-13-acetate (PMA). Then, it was suggested that lncRNA- ENST00000421645 interacts with PCM1 protein. Silencing PCM1 significantly increased the level of IFN-γ in Lv-1645 cells stimulated by PMA. Conclusion: This study revealed that lncRNA- ENST00000421645 mediates the production of IFN-γ by sponging PCM1 protein after PMA stimulation.

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Reduction of Tregs with Expansion of Th1 Cells and Lack of IFN-γ Secretion by GPI Negative T-Cells In PNH

Blood ◽

10.1182/blood.v116.21.2240.2240 ◽

2010 ◽

Vol 116 (21) ◽

pp. 2240-2240

Author(s):

Shahram Kordasti ◽

Modupe Elebute ◽

Pilar Perez Abellan ◽

Austin G Kulasekararaj ◽

Janet Hayden ◽

...

Keyword(s):

Bone Marrow ◽

T Cells ◽

High Resolution ◽

Peripheral Blood ◽

Clonal Expansion ◽

T Cell Subsets ◽

Th1 Cells ◽

Healthy Controls ◽

Significant Difference ◽

Ifn Γ

Abstract Abstract 2240 Introduction and Aim: Paroxysmal nocturnal haemoglobinuria (PNH) is an acquired haematopoietic stem cell disorder characterized by intravascular haemolysis and thrombosis. The pathogenetic link with bone marrow failure syndromes is well recognized, however the process of clonal expansion of the glycosylphosphatidylinositol (GPI)-deficient cells over normal haemotopoiesis remains unclear. To further elucidate mechanisms leading to clonal expansion in PNH, we investigated the immunological profile and performed high-resolution genome-wide karyotyping using Affymetrix SNP6 microarrays. Patients and Methods: The percentage and absolute numbers of CD4+ and CD8+ T-cell subsets, NK cells and B cells in peripheral blood were assessed in 8 patients with PNH prior to any therapy and 8 healthy age matched controls. High resolution SNP6 karyotyping was performed on bone marrow (n=15) and peripheral blood (n=12) of these patients. Bone marrow from an additional 8 patients was enriched for CD34+59- and CD34+59+ cell fractions for SNP array karyotyping. Abberations that overlapped by >50% with variations found in the Database of Genomic Variants, as well as an internal series of 91 normal subjects were excluded from further analysis. T-cells were stimulated and then stained intracellularly for TNF-α and IFN-γ (Th1), IL-4 (Th2) and IL-17 (Th17). NK cells were defined as CD3– CD56+. B cells were defined as CD3-CD19+. CD3+ CD4+ T-cell subsets were defined as CD45RO–CD27+ naïve, CD45RO+ CD27+ CD62L+ central memory, CD45RO+ CD27+ CD62L– effector memory, CD45RO+CD27– effectors and CD45RO–CD27– terminal effectors. CD4+ Tregs were defined as CD3+CD4+ CD25high CD27+Foxp3+. Results: There were no significant differences in the number or percentage of different CD8+ and CD4+ T-cells compared to healthy controls except for the number of Tregs and Th1 cells. In our cohort of patients, the number of Th1 cells was significantly higher than healthy controls (4.1×107/L v 0.93 × 107/L, p=0.039), whereas the number of Tregs cells was lower (0.75 × 107/L v 1.36 × 107/L, p=0.028). There was no significant difference in the number of Th2 and Th17 cells between patient and healthy subjects. Within CD4+ T-cells two distinct CD59+ and CD59- populations were identified, of which the CD59- cells were unable to secrete IFN-γ in response to stimulation compared to CD59+ population. On average 48% of CD4+ CD59+ T-cells secrete IFN-γ compared to 2% in the CD59- population. There was no significant difference in IL17 and IL4 secretion between CD59+ and CD59- T-cells. SNP karyotyping revealed three regions of uniparental disomy (UPD); UPD1p26.11-p34.3, UPD1p13.3-p13.1in one peripheral blood sample and UPD7q32.1-q34 in one bone marrow sample. There were no additional somatic genomic aberrations detected in any of the samples. Of note, purified CD34+59- cells did not reveal any clonal copy number changes or regions of UPD. Conclusion: Specific analysis of Xp22.1 did not reveal any aberrations of the PIGA gene, suggesting aberrations of the PIGA gene may be restricted to mutations or epigenetic abnormalities. Our immunological profiling revealed an expansion of Th1 cells and diminished Tregs in the peripheral blood, which is in contrast to our published data from both MDS and AA patients. The lack of IFN-γ secretion by GPI deficient T-cells also suggests an additional immunological defect in these patients, which may contribute in disease pathogenesis. Disclosures: No relevant conflicts of interest to declare.

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Elevated Expression of IL-17 and IL-23 in Patients with Immune Thrombocytopenic Purpura

Blood ◽

10.1182/blood.v112.11.4537.4537 ◽

2008 ◽

Vol 112 (11) ◽

pp. 4537-4537

Author(s):

Feng Li ◽

Shanhua Zou ◽

Yunfeng Cheng

Keyword(s):

T Cells ◽

Immune Thrombocytopenic Purpura ◽

Peripheral Blood ◽

Th17 Cells ◽

Statistical Difference ◽

Plasma Concentrations ◽

Healthy Controls ◽

Cd4 Cells ◽

Thrombocytopenic Purpura ◽

Ifn Γ

Abstract Introduction: In conjunction with IL-6 and TGF-β, IL-23 stimulates naïve CD4+ T cells to differentiate into Th17 cells. Th17 cells produce IL-17, a pro-inflammatory cytokine that play an important role in the pathogenesis of several autoimmune disorders. However, to date, the role of Th17 cells in immune thrombocytopenic purpura (ITP), a type of autoimmune diseases, has not been clearly established yet. Methods: Peripheral bloods were obtained from 10 patients with ITP at onset, in remission and from 15 healthy control subjects. The frequencies of IL-17 producing T cells in peripheral blood were analyzed by flow cytometry. Peripheral blood Mononuclear cells (PBMCs) were isolated using Ficoll density-gradient centrifugation and the CD4+ cells were separated by immuno-magnetic microbeads selection. Plasma concentrations of Th17 cell-associated cytokines such as IL-12, IL-17, IL-23, IFN-γ, IL-6 and TGF-β were measured using ELISA. The mRNA expression levels of IL-17, IL-12p40, IFN-γ, IL-23p19 in CD4+ cells were determined by Real-Time PCR. Results: The frequencies of IL-17-producing T cells were significantly increased in ITP patients at onset, compared to ITP patients in remission (10.7±5.5 % vs 4.1±3.5 %, p < 0.05) and healthy controls (10.7±5.5 % vs 2.1±1.6 %, p < 0.05), however there was no statistical difference between ITP patients in remission and healthy controls. Comparing to healthy subjects, the plasma concentrations of IL-12 (33.3±15.25 pg/ ml vs 12.8±7.24 pg/ml, p<0.05), IL-17 (37.3±12.1 pg/ml vs 5.1±3.6 pg/ml, p < 0.05), IL-23 (30.01±9.33 pg/ml vs 10.42±13.19 pg/ml, p < 0.05) in patients with ITP at onset were found significantly elevated whereas no statistical difference was observed for the levels of IL-12, IL-17 and IL-23 between ITP patients in remission and healthy controls. Furthermore, the expression levels of IL-23p19 mRNA were significantly increased in ITP patients at onset, compared to healthy controls. Changes in IL-23p19 mRNA expression and IL-17 were strongly correlated (R = 0.66, p < 0.05). Conclusion: Our results support the hypothesis that Th17 cells are involved in the development of ITP and Th17 cells could potentially constitute a novel therapeutic target.

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TNF-Alpha Priming Enhances CD4+ FoxP3+ Regulatory T Cell Suppressive Function in GvHD Prevention and Treatment

Blood ◽

10.1182/blood.v126.23.1885.1885 ◽

2015 ◽

Vol 126 (23) ◽

pp. 1885-1885

Author(s):

Antonio Pierini ◽

Caitlin Moffett ◽

Dominik Schneidawind ◽

Jeanette Baker ◽

Hidekazu Nishikii ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Mouse Model ◽

Peripheral Blood ◽

Activation Markers ◽

Suppressive Function ◽

Prevention And Treatment ◽

And Function

Abstract CD4+ CD25+ FoxP3+ regulatory T cells (Treg) have been shown to effectively prevent graft versus host disease (GvHD) when adoptively transferred in murine models of hematopoietic cell transplantation (HCT) and phase I/II clinical trials. Critical limitations to the clinical application of Treg are the paucity of cells and limited knowledge of the mechanism(s) of in vivo function. In physiologic conditions Treg regulate immune responses during inflammation. We hypothesized that inflammatory conditions in GvHD modify Treg characteristics and function. To test this hypothesis, we primed Treg with irradiated (3000 cGy) peripheral blood from acute GvHD (aGvHD) affected mice for 20-24 hours and then transferred these cells in a mouse model of GvHD where allogeneic T cell depleted bone marrow (TCD BM) from C57BL/6 mice was transplanted into lethally irradiated (8 Gy) BALB/c recipients together with 7.5x105 to 1x106 /animal donor derived conventional CD4+ and CD8+ T cells (Tcon). C57BL/6 Treg primed with irradiated aGvHD peripheral blood were injected at day 0 after HCT for preventing GvHD or at day +7 or +8 as GvHD treatment. Their adoptive transfer resulted in improved survival in comparison to unprimed natural occurring Treg when used for both GvHD prevention (p=0.01) and treatment (p=0.04). Moreover treatment with irradiated aGvHD peripheral blood-primed Treg did not impact graft versus tumor effects in a mouse model of T cell mediated tumor killing. BLI demonstrated that injected allogeneic Tcon completely cleared previously infused luc+ A20 tumor cells even in the presence of primed Treg (primed Treg + Tcon + A20 vs A20 alone p<0.001). Irradiated aGvHD peripheral blood-primed Treg express increased levels of activation markers with suppressive function such as CTLA4 (p<0.001) and LAG3 (p<0.05) in comparison to unprimed Treg in vitro. We also found that Treg primed with irradiated cells of aGvHD affected animals after removing the serum did not enhance the expression of the same markers (p>0.05) demonstrating that serum from aGvHD animals is required for Treg priming and function. We further tested the ability of several inflammatory cytokines that are normally secreted during GvHD such as IFN-γ, IL-6, IL-12 and TNFα to induce similar in vitro Treg activation. We found that TNFɑ selectively activated Treg without impacting CD4+ FoxP3- T cells. TNFɑ-primed Treg have increased expression of activation markers such as CD69 (p<0.0001), CD25 (p<0.0001), and LAG3 (p=0.0002), produce a greater amount of suppressive cytokines such as IL-10 (p=0.03) and TGF-β (p=0.02), and enhance the expression of homing markers such as CD62L (p=0.005) that are required for in vivo function. TNFɑ-primed Treg had increased ability to proliferate (p=0.02) and, at the same time, to suppress Tcon proliferation (p=0.04) in a mixed lymphocyte reaction against irradiated allogeneic splenocytes, while, on the contrary, TNFɑ-primed Tcon had reduced ability to proliferate in similar conditions in comparison to unprimed Tcon (p=0.0004). To test the effect of TNFɑ priming on in vivo Tcon proliferation we injected TNFɑ-primed and unprimed luc+ Tcon in allogeneic BALB/c Rag2-/- γ-chain-/- immune deficient animals that were sublethally irradiated (400 cGy). BLI at day +7 after Tcon injection revealed reduced TNFɑ-primed Tcon in vivo proliferation (p=0.01) that resulted in milder GvHD symptoms (p=0.02). Finally, in a GvHD prevention mouse model TNFɑ-primed Treg infused at 1:10 Treg/Tcon ratio resulted in improved animal survival as compared to unprimed Treg (p=0.02), demonstrating enhanced efficacy of TNFɑ priming in the in vivo function of Treg. In summary, our study demonstrates that Treg respond to TNFɑ acquiring an activated status resulting in increased function. As TNFɑ is produced by several immune cells during inflammation, our work elucidates aspects of the physiologic mechanisms of Treg function. Furthermore TNFɑ priming of Treg in vitro provides a new tool to optimize Treg cellular therapies also allowing for the use of a reduced cell number for GvHD prevention and treatment. Disclosures No relevant conflicts of interest to declare.

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Activation of mucosal-associated invariant T cells in the lungs of sarcoidosis patients

Scientific Reports ◽

10.1038/s41598-019-49903-6 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 1

Author(s):

Hisayo Matsuyama ◽

Takuma Isshiki ◽

Asako Chiba ◽

Tetsuo Yamaguchi ◽

Goh Murayama ◽

...

Keyword(s):

T Cells ◽

Peripheral Blood ◽

Lavage Fluid ◽

Interferon Γ ◽

Healthy Controls ◽

Expression Levels ◽

Mait Cells ◽

Clinical Biomarkers ◽

Cd69 Expression ◽

Factor Α

Abstract Although the pathogenesis of sarcoidosis is not fully understood, immunological characterization has elucidated highly polarized expression of the type 1 T helper cell response. Mucosal-associated invariant T (MAIT) cells are innate T cells that recognize bacterial riboflavin and rapidly produce cytokines such as interferon γ and tumor necrosis factor α. We prospectively evaluated the proportion of MAIT cells and the expression levels of cell surface markers in peripheral blood from 40 sarcoidosis patients and 28 healthy controls. MAIT cells in bronchoalveolar lavage fluid (BALF) were also examined in 12 sarcoidosis patients. In peripheral blood, the proportion of MAIT cells was lower (P = 0.0002), but the expression levels of CD69 and programmed death 1 on MAIT cells were higher in sarcoidosis patients than in healthy controls. Moreover, CD69 expression levels were significantly correlated with clinical biomarkers. Sarcoidosis patients with parenchymal infiltration in the lungs showed a significantly higher proportion and number of MAIT cells in BALF compared to patients without parenchymal infiltration. CD69 expression levels on MAIT cells in BALF were higher than levels in peripheral blood. The activation status of MAIT cells might reflect the disease activity of sarcoidosis. Therefore, it is a potential target for sarcoidosis treatment.

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Insufficient Phosphorylation of STAT5 in Tregs Inhibits the Expression of BLIMP-1, Leading to a Lack of Tregs in Pediatric Aplastic Anemia

Blood ◽

10.1182/blood-2021-152339 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 2183-2183

Author(s):

Lifen Huang ◽

Junbin Huang ◽

Chengming Zhu ◽

Hongman Xue ◽

Chi Kong Li ◽

...

Keyword(s):

Flow Cytometry ◽

T Cells ◽

Aplastic Anemia ◽

Inflammatory Cytokines ◽

Peripheral Blood ◽

Cd4 T Cells ◽

Healthy Controls ◽

Healthy Donors ◽

Ifn Γ ◽

Low Expression

Abstract Aplastic anemia (AA) is a group of bone marrow failure diseases characterized by three-line blood cell reduction and decreased myeloproliferation. It is believed that T cell immune disorder is the leading cause of the disease, especially the number and functional damage of regulatory T cells (Tregs). BLIMP-1 is a transcription factor encoded by PRDM1 gene, which is indispensable for Tregs. The expression of BLIMP-1 is mainly induced by the IL-2/STAT5 signaling pathway. However, the level of phosphorylation of STAT5 and the expression of BLIMP-1 in Tregs from patients with AA has not been revealed, and the mechanism of Tregs damage in AA has not yet been clarified. In the present study, we collected peripheral blood from 10 newly diagnosed AA children and 10 age-matched healthy donors. We observed that the ratio of Tregs/lymphocytes and Tregs/CD4 + T cells decreased significantly in AA patients, compared with healthy controls by flow cytometry. In addition, we found significantly elevated levels of inflammatory cytokines IL-2, IL-6, and IFN-γ, but decreased levels of anti-inflammatory cytokines IL-10 and TGF-β in plasma of children with AA, compared with healthy controls. Quantitative real-time PCR showed decreased transcriptional level of BLIMP-1 in peripheral blood mononuclear cells (PBMC) from children with AA, compared with healthy donors. We used flow cytometry to detect the protein level of BLIMP-1 in Tregs and found that the level of BLIMP-1 in Tregs in the peripheral blood of children with AA was significantly lower than that of healthy donors. The correlation analysis showed that the percentage of BLIMP-1 + Tregs was positively correlated with the ratio of Tregs/CD4 + T cells (r=0.829, p＜0.001), the plasma level of IL-10 (r=0.492, p=0.027), and TGF-β (r=0.482, p=0.030), suggesting that low expression level of BLIMP-1 in Tregs may lead to decreased number of Tregs in peripheral blood and declined levels of IL-10 and TGF-β in children with AA. When stimulated IL-2, the level of pSTAT5 in CD4 + T cells of children with AA was significantly reduced compared with that of healthy donors. The level of pSTAT5 in CD4 + T cells was also positively correlated with the ratio of Tregs/CD4 + T cells (r= 0.575, p= 0.008) and the expression of BLIMP-1 in Tregs (r=0.693, p＜0.0001)，suggesting that STAT5 signal is poorly activated in pediatric AA, and it may be an important cause for the low expression of BLIMP-1 in Tregs and the decrease in the number of Tregs in children with AA. Furthermore, we constructed an AA mouse model by co-administering IFN-γ and busulfan for 10 consecutive days. These mice exhibited decreased ratio of Tregs/CD4 +T cells in the spleen and lower BLIMP-1 in Tregs, compared with controls. Also, we isolated Tregs with immunomagnetic beads from spleens of mice and observed that the level of IL-2-stimulated pSTAT5 was lower in isolated Tregs from AA mice than controls. These phenotypes were partially rescued by intervention of IL-2-JES6-1, an antibody complex tends to promote the proliferation of Tregs in mice, while inhibiting the proliferation of effector T cells. IL-2-JES6-1 increased the level of pSTAT5 and the expression of BLIMP-1 in Tregs from spleen of the AA mice, and elevated the ratio of Tregs/CD4 + T cells in the spleen. In conclusion, we found that Tregs from AA patients have impaired phosphorylation of STAT5 and insufficient expression of BLIMP-1, which may contribute to the pathogenesis of AA. Disclosures No relevant conflicts of interest to declare.

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Activation and Functional Alteration of Mucosal-Associated Invariant T Cells in Adult Patients With Community-Acquired Pneumonia

Frontiers in Immunology ◽

10.3389/fimmu.2021.788406 ◽

2021 ◽

Vol 12 ◽

Author(s):

Lichen Ouyang ◽

Mi Wu ◽

Zhijun Shen ◽

Xue Cheng ◽

Wei Wang ◽

...

Keyword(s):

T Cells ◽

Peripheral Blood ◽

Lavage Fluid ◽

Community Acquired Pneumonia ◽

Healthy Individuals ◽

Cell Frequency ◽

Mait Cells ◽

Ifn Γ ◽

Invariant T Cells ◽

Mait Cell

Community-acquired pneumonia (CAP) remains the significant infectious cause of morbidity and mortality worldwide. Although mucosal-associated invariant T cells (MAIT) play roles in the pathogenesis of children CAP and ICU-associated pneumonia, their roles in adult CAP are largely unexplored. In this study, we investigated the frequency, phenotype, and function of MAIT cells in peripheral blood and bronchoalveolar lavage fluid (BALF) of adult CAP patients. Our data indicate that MAIT-cell frequency is profoundly lower in the peripheral blood of CAP patients compared to that in healthy individuals. Furthermore, the circulatory MAIT cells express higher levels of CD69 and PD-1 compared to those in healthy individuals. In BALF of CAP patients, MAIT-cell frequency is higher and MAIT cells express higher levels of CD69 and PD-1 compared to their matched blood counterparts. Levels of IL-17A and IFN-γ are increased in BALF of CAP patients compared to those in BALF of patients with pulmonary small nodules. The IL-17A/IFN-γ ratio is significantly positively correlated with MAIT frequency in BALF of CAP patients, suggesting a pathogenic role of MAIT-17 cells in CAP. Of note, blood MAIT-cell frequency in CAP patients is strongly negatively correlated with high-sensitivity C-reactive protein (hsCRP) and neutrophil count percentage in blood. The ability of circulating MAIT cells in CAP patients to produce IFN-γ is significantly impaired compared to those in healthy individuals. In summary, our findings suggest the possible involvement of MAIT cells in the immunopathogenesis of adult CAP.

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