CD161+CD127+CD8+ T cell subsets can predict the efficacy of anti-PD-1 immunotherapy in non-small cell lung cancer with diabetes mellitus.

The role of CD161+CD127+CD8+ T cells in non-small cell lung cancer (NSCLC) patients with diabetes remains unexplored. This study determined the prevalence, phenotype, and function of CD8+ T cell subsets in NSCLC with diabetes. We recruited NSCLC patients (n = 436) treated with anti-PD-1 immunotherapy as first-line treatment. The progression-free survival (PFS), overall survival (OS), T cells infiltration, and peripheral blood immunological characteristics were analyzed in NSCLC patients with or without diabetes. NSCLC patients with diabetes exhibited shorter PFS and OS (p = 0.0069 and p = 0.012, respectively) and significantly lower CD8+ T cells infiltration. Mass cytometry by time-of-flight (CyTOF) showed a higher percentage of CD161+CD127+CD8+ T cells among CD8+T cells in NSCLC with diabetes before anti-PD-1 treatment (p = 0.0071) than that in NSCLC without diabetes and this trend continued after anti-PD-1 treatment (p = 0.0393). Flow cytometry and multiple-immunofluorescence confirmed that NSCLC with diabetes had significantly higher CD161+CD127+CD8+ T cells to CD8+T cells ratios than NSCLC patients without diabetes. The RNA-sequencing analysis revealed immune-cytotoxic genes were reduced in the CD161+CD127+CD8+ T cell subset compared to CD161+CD127-CD8+ T cells in NSCLC with diabetes. CD161+CD127+CD8+ T cells exhibited more T cell-exhausted phenotypes in NSCLC with diabetes. NSCLC patients with diabetes with ≥ 6.3% CD161+CD127+CD8+ T cells to CD8+T cells ratios showed worse PFS. These findings indicate that diabetes is a risk factor for NSCLC patients who undergo anti-PD-1 immunotherapy.CD161+CD127+CD8+ T cells could be a key indicator of a poor prognosis in NSCLC with diabetes. Our findings would help in advancing anti-PD-1 therapy in NSCLC patients with diabetes.

ScRNA-Seq Analyses Define the Role of GATA3 in iNKT Cell Effector Lineage Differentiation.

While the transcription factor GATA-3 is well-established for its crucial role in T cell development, its specific influence on invariant natural killer T (iNKT) cells remains relatively unexplored. Using flow cytometry and single-cell transcriptomic analysis, we demonstrated that GATA-3 deficiency in mice leads to the absence of iNKT2 and iNKT17 cell subsets, as well as an altered distribution of iNKT1 cells. Thymic iNKT cells lacking GATA-3 exhibited diminished expression of PLZF and T-bet, key transcription factors involved in iNKT cell differentiation, and reduced production of Th2, Th17, and cytotoxic effector molecules. Single-cell transcriptomics revealed a comprehensive absence of iNKT17 cells, a substantial reduction in iNKT2 cells, and an increase in iNKT1 cells in GATA-3-deficient thymi. Differential expression analysis highlighted the regulatory role of GATA-3 in T cell activation signaling and altered expression of genes critical for iNKT cell differentiation, such as Icos, Cd127, Eomes, and Zbtb16. Notably, restoration of Icos, but not Cd127, expression could rescue iNKT cell development in GATA-3-deficient mice. In conclusion, our study demonstrates the pivotal role of GATA-3 in orchestrating iNKT cell effector lineage differentiation through the regulation of T cell activation pathways and Icos expression, providing insights into the molecular mechanisms governing iNKT cell development and function.

High common-γ cytokine receptor levels promote expression of Interleukin-2/Interleukin-7 receptor α-chains with implications on T-cell differentiation and function.

Cytokines of the common-γ receptor chain (γc) family are crucial for T-cell differentiation and dysregulation of γc cytokine pathways is involved in the pathogenesis of autoimmune diseases. There is increasing evidence that the availability of the γc receptor (CD132) for the associated receptor chains has implications for T-cell functions. Here we studied the influence of differential γc expression on the expression of the IL-2Rα (CD25), the IL-7Rα (CD127) and the differentiation of activated naïve T cells. We fine-tuned the regulation of γc expression in human primary naïve T cells by lentiviral transduction using small hairpin (sh)RNAs and γc cDNA. Differential γc levels were then analysed for effects on T-cell phenotype and function after activation. Differential γc expression markedly affected IL-2Rα and IL-7Rα expression on activated naïve T cells. High γc expression (γc-high) induced significantly higher expression of IL-2Rα and re-expression of IL-7Rα after activation. Inhibition of γc caused lower IL-2Rα/IL-7Rα expression and impaired proliferation of activated naïve T cells. In contrast, γc-high T cells secreted significantly higher concentrations of effector cytokines (i.e., IFN-γ, IL-6) and showed higher cytokine-receptor induced STAT5 phosphorylation during initial stages as well as persistently higher pSTAT1 and pSTAT3 levels after activation. Finally, accelerated transition towards a CD45RO expressing effector/memory phenotype was seen especially for CD4+ γc-high naïve T cells. These results suggested that high expression of γc promotes expression of IL-2Rα and IL-7Rα on activated naïve T cells with significant effects on differentiation and effector cytokine expression.

Unraveling the immunological landscape in acute pancreatitis progression to sepsis: insights from a Mendelian randomization study on immune cell traits.

Background: Acute pancreatitis (AP) is a severe digestive system disorder with a significant risk of progressing to sepsis, a major cause of mortality. Unraveling the immunological pathways in AP is essential for developing effective treatments, particularly understanding the role of specific immune cell traits in this progression. Methods: Employing a bidirectional two-sample Mendelian Randomization (MR) approach, this study first examined the causal relationship between AP and 731 immune cell traits to identify those significantly associated with AP. Subsequently, we explored the causal associations between 731 immune cell traits and sepsis. The analysis utilized extensive genome-wide association studies (GWAS) summary datasets, with a focus on identifying common immune cell traits with statistically significant causal associations between AP and sepsis. Results: Our investigation identified 44 immune cell traits unidirectionally associated with AP and 36 traits unidirectionally associated with sepsis. Among these, CD127 on CD28+ CD45RA- CD8+ T cells emerged as a common mediator, accounting for 5.296% of the increased risk of sepsis in AP patients. This finding highlights the significant role of specific memory CD8+ T cells in the pathophysiology of AP and its progression to sepsis. Conclusion: This study elucidates the critical role of specific immune cell traits, particularly CD127hi memory CD8+ T cells, in the progression of AP to sepsis. Our findings provide a foundation for future research into targeted immune-modulatory therapies, potentially improving patient outcomes in AP-related sepsis and offering new insights into the complex immunological dynamics of this condition.

Bone Marrow-Derived C-Kit+ Cells Improved Inflammatory IL-33/ST-2/ILC2 Axis in the Lung Tissue of Type 2 Diabetic Rats.

Inflammation is an essential factor in pulmonary complications of diabetes. Bone marrow (BM)-derived C-kit+ cells have immunomodulatory properties and their transplantation is suggested as a promising strategy for ameliorating diabetes complications. This study evaluated the effect of BM-derived C-kit+ cells on the inflammation signaling pathway in lung tissue of type 2 diabetic male rats. Ten rats were used to extract C-kit cells, and 48 male Wistar rats weighing 180 ± 20 g were randomly divided into four equal groups: (1) Control (Cont), (2) Diabetic (D), (3) Diabetic + C-kit+ cells (D + C-kit pos) intravenously injected 50-µl phosphate buffer saline (PBS) containing 300,000 C-kit+ cells, and (4) Diabetic + C-kit- cells (D + C-kit neg), intravenously injected C-kit- cells. Diabetes induction increased IL-33, ST-2, CD127, and IL-2 levels and decreased IL-10. C-kit+ cell therapy significantly decreased IL-33 and CD127 and increased IL-10. In addition, lung histopathological changes significantly improved in the C-kit+ group compared to the diabetic group. These findings suggest that C-kit+ cells may have a potential therapeutic role in mitigating diabetes-induced respiratory complications via ameliorating the inflammation and histopathological changes in lung tissue.

In patients with primary Sjögren's syndrome innate-like MAIT cells display upregulated IL-7R, IFN-γ, and IL-21 expression and have increased proportions of CCR9 and CXCR5-expressing cells.

Introduction: Mucosal-associated invariant T (MAIT) cells might play a role in B cell hyperactivity and local inflammation in primary Sjögren's syndrome (pSS), just like previously studied mucosa-associated CCR9+ and CXCR5+ T helper cells. Here, we investigated expression of CCR9, CXCR5, IL-18R and IL-7R on MAIT cells in pSS, and assessed the capacity of DMARDs to inhibit the activity of MAIT cells. Methods: Circulating CD161+ and IL-18Rα+ TCRVα7.2+ MAIT cells from pSS patients and healthy controls (HC) were assessed using flow cytometry, and expression of CCR9, CXCR5, and IL-7R on MAIT cells was studied. Production of IFN-γ and IL-21 by MAIT cells was measured upon IL-7 stimulation in the presence of leflunomide (LEF) and hydroxychloroquine (HCQ). Results: The numbers of CD161+ and IL-18Rα+ MAIT cells were decreased in pSS patients compared to HC. Relative increased percentages of CD4 MAIT cells in pSS patients caused significantly higher CD4/CD8 ratios in MAIT cells. The numbers of CCR9 and CXCR5-expressing MAIT cells were significantly higher in pSS patients. IL-7R expression was higher in CD8 MAIT cells as compared to all CD8 T cells, and changes in IL-7R expression correlated to several clinical parameters. The elevated production of IL-21 by MAIT cells was significantly inhibited by LEF/HCQ treatment. Conclusion: Circulating CD161+ and IL-18Rα+ MAIT cell numbers are decreased in pSS patients. Given their enriched CCR9/CXCR5 expression this may facilitate migration to inflamed salivary glands known to overexpress CCL25/CXCL13. Given the pivotal role of IL-7 and IL-21 in inflammation in pSS this indicates a potential role for MAIT cells in driving pSS immunopathology.

IL7RA single nucleotide polymorphisms are associated with the size and function of the MAIT cell population in treated HIV-1 infection.

MAIT cells are persistently depleted and functionally exhausted in HIV-1-infected patients despite long-term combination antiretroviral therapy (cART). IL-7 treatment supports MAIT cell reconstitution in vivo HIV-1-infected individuals and rescues their functionality in vitro. Single-nucleotide polymorphisms (SNPs) of the IL-7RA gene modulate the levels of soluble(s)IL-7Rα (sCD127) levels and influence bioavailability of circulating IL-7. Here we evaluate the potential influence of IL-7RA polymorphisms on MAIT cell numbers and function in healthy control (HC) subjects and HIV-1-infected individuals on long-term cART. Our findings indicate that IL-7RA haplotype 2 (H2*T), defined as T-allele carriers at the tagging SNP rs6897932, affects the size of the peripheral blood MAIT cell pool, as well as their production of cytokines and cytolytic effector proteins in response to bacterial stimulation. H2*T carriers had lower sIL-7Rα levels and higher MAIT cell frequency with enhanced functionality linked to higher expression of MAIT cell-associated transcription factors. Despite an average of 7 years on suppressive cART, MAIT cell levels and function in HIV-1-infected individuals were still significantly lower than those of HC. Notably, we observed a significant correlation between MAIT cell levels and cART duration only in HIV-1-infected individuals carrying IL-7RA haplotype 2. Interestingly, treatment with sIL-7Rα in vitro suppressed IL-7-dependent MAIT cell proliferation and function following cognate stimulations. These observations suggest that sIL-7Rα levels may influence MAIT cell numbers and function in vivo by limiting IL-7 bioavailability to MAIT cells. Collectively, these observations suggest that IL-7RA polymorphisms may play a significant role in MAIT cell biology and influence MAIT cells recovery in HIV-1 infection. The potential links between IL7RA polymorphisms, MAIT cell immunobiology, and HIV-1 infection warrant further studies going forward.

Research Note: Development and characterization of monoclonal antibodies specific for chicken interleukin-7 receptor α (CD127).

CD127, also named interleukin-7 receptor (IL-7R), is expressed on various cell types including naive and memory T cells, and plays a critical role in the differentiation and activation of T lymphocytes. The availability of poultry-specific immune reagents to identify and measure chicken CD127 response will enhance fundamental and applied research in poultry immunology. Mouse monoclonal antibodies (MAbs) against chicken CD127 (chCD127) were developed and characterized. More specifically, a 678 bp ectodomain of chCD127 gene was cloned in the pET28a (+) vector and expressed in BL21-AI E. coli competent cells. The recombinant chCD127 protein with a size of 30 KDa which was also recognized by a mouse anti-human CD127 MAb (Clone G-11) was used to immunize mice, and 6 new mouse MAbs which specifically detected chicken CD127 were developed and characterized. Availability of these new sets of chCD127-specific MAbs will facilitate the immunological studies on CD127 in poultry, especially in understanding effector and memory T immune cell responses in normal and diseased states.

Interleukin-7 regulates CD127 expression and promotes CD8+ T cell activity in patients with primary cutaneous melanoma.

BACKGROUND: Interleukin (IL)-7 signaling through CD127 is impaired in lymphocytes in cancers and chronic infections, resulting in CD8+ T cell exhaustion. The mechanisms underlying CD8+ T cell responses to IL-7 in melanoma remain not completely elucidated. We previously showed reduced IL-7 level in melanoma patients. Thus, the aim of this study was to investigate the effect of IL-7 regulation on CD127 expression and CD8+ T cell responses in melanoma. METHODS: Healthy controls and primary cutaneous melanoma patients were enrolled. Membrane-bound CD127 (mCD127) expression on CD8+ T cells was determined by flow cytometry. Soluble CD127 (sCD127) protein level was measured by ELISA. Total CD127 and sCD127 mRNA level was measured by real-time PCR. CD8+ T cells were stimulated with recombinant human IL-7, along with signaling pathway inhibitors. CD8+ T cells were co-cultured with melanoma cell line, and the cytotoxicity of CD8+ T cells was assessed by measurement of lactate dehydrogenase expression. RESULTS: Plasma sCD127 was lower in melanoma patients compared with controls. The percentage of CD8+ T cells expressing mCD127 was higher, while sCD127 mRNA level was lower in peripheral and tumor-infiltrating CD8+ T cells from melanoma patients. There was no significant difference of total CD127 mRNA expression in CD8+ T cells between groups. IL-7 stimulation enhanced total CD127 and sCD127 mRNA expression and sCD127 release by CD8+ T cells. However, mCD127 mRNA expression on CD8+ T cells was not affected. This process was mainly mediated by phosphatidylinositol 3-kinase (PI3K) pathway. CD8+ T cells from melanoma patients exhibited decreased cytotoxicity. IL-7 stimulation promoted CD8+ T cell cytotoxicity, while inhibition of PI3K dampened IL-7-induced elevation of CD8+ T cell cytotoxicity. CONCLUSION: The current data suggested that insufficient IL-7 secretion might contribute to CD8+ T cell exhaustion and CD127 dysregulation in patients with primary cutaneous melanoma.

An efficient and cost-effective method for the purification of human basophils.

Human basophils are terminally differentiated granulocytes that are least abundant in the peripheral blood but play important roles in allergic diseases. Studies on human basophils are limited by the high cost on the isolation of human basophils by magnetic-activated cell sorting (MACS) for negative depletion of non-basophils, followed by CD123-based positive selection of basophils. Moreover, such CD123-based purification of basophils may be limited by blocking of the binding of IL-3/anti-CD123 to the surface CD123. Here we identified SSClow CD4- CD127- HLA-DR- CRTH2high as unique markers for the identification of human basophils through stringent flow cytometric analysis of leukocytes from buffy coat. We established an efficient and cost-effective method for isolating human basophils from buffy coat based on positive magnetic selection of CRTH2+ cells followed by flow cytometric sorting of SSClow CD4- CD127- HLA-DR- CRTH2high cells. Approximately 1 to 1.5 million basophils were isolated from one buffy coat with a purity of >97%. Basophils purified by this method were viable and efficiently responded to key regulators of basophils including IL-3 and anti-IgE. This method can be used for purifying human basophils for subsequent functional studies.

Short- and long-term effects of antiretroviral therapy on peripheral regulatory CD4+/CD25hi/CD127low T lymphocytes in people living with HIV/AIDS

ABSTRACT The effect of antiretroviral therapy (ART) on CD4+/CD25hi/CD127low T lymphocyte changes in people living with HIV/AIDS (PLWHA) is still a matter of debate. From October 2015 to December 2019, peripheral blood from 70 cases of PLWHA were collected for the detection of CD4+/CD25hi/CD127low T lymphocytes by flow cytometry. Statistical analysis was performed to detect changes of CD4+/CD25hi/CD127low T lymphocytes in patients with different duration of ART and different treatment effects. We found that the number of CD4+/CD25hi/CD127low T lymphocytes in ART-naive PLWHA were lower than those in healthy volunteers (10.3±٦.٠ cells/uL vs 31.7±8.0 cells/uL, P < 0.05). CD4+/CD25hi/CD127low T lymphocyte counts increased to 17.8±٤.٠ cells/uL 6 months post-ART and 25.0±١١.٩ cells/uL 9 months post-ART, respectively (P < 0.05). There was no significant difference in CD4+/CD25hi/CD127low T lymphocyte counts between PLWHA who reached a complete immune reconstruction after ART and healthy volunteers. The growth of CD4+/CD25hi/CD127low T lymphocyte counts in patients who had baseline CD4 > 200 cells/uL was greater than those who had baseline CD4 ≤ 200 cells/uL (12.6±٤.٦ cells/uL vs 5.6±٥.٠ cells/uL, P = 0.027). CD4+/CD25hi/CD127low T lymphocyte counts were positively correlated with CD4+ T lymphocyte counts (r = 0.923, P < 0.001) and CD4+/CD8+ ratio (r = 0.741, P < 0.001), but were negatively correlated with HIV-VL (r = −0.648, P = 0.000). In conclusion, the results of the present study showed that changes in CD4+/CD25hi/CD127low T lymphocyte counts can be used to assess the effect of ART in PLWHA.

IL-7 regulates in vitro activity of CD8 + T cells in patients with sepsis through modulation of CD127 expression / 中华微生物学和免疫学杂志

Objective:To investigate the expression of membrane-bound CD127 (mCD127) and soluble CD127 (sCD127) in patients with sepsis, and to assess the mechanism of IL-7 in regulating CD8 + T cell activity in these patients. Methods:A prospective cohort study was conducted on 47 patients with sepsis (sepsis group) and 18 healthy controls (control group). Serum samples and peripheral blood mononuclear cells (PBMCs) were isolated. CD8 + T cells were purified. IL-7 and sCD127 levels in serum were measured by enzyme-linked immunosorbent assay. Expression of mCD127 on CD8 + T cells was measured by flow cytometry. Total CD127 and sCD127 expression at mRNA level in CD8 + T cells was semi-quantified by real-time PCR. CD8 + T cells were stimulated with recombinant human IL-7, along with signal transducer and activator of transcription 5 (STAT5) inhibitor or phosphatidylinositol 3-kinase (PI3K) inhibitor. Changes in mCD127 expression on CD8 + T cells and the expression of total CD127 and sCD127 at mRNA level were then measured. The cytotoxicity of CD8 + T cells in response to IL-7 stimulation was assessed using a co-culture system with CD8 + T cells and MCF-7 cells. Student′s t test and LSD- t test were used for statistical analysis. Results:Serum IL-7 and sCD127 were lower in sepsis group than in control group [(101.82±12.58) pg/ml vs (111.07±11.10) pg/ml, P<0.01; (278.58±62.31) pg/ml vs (334.62±70.55) pg/ml, P<0.01]. Serum IL-7 was positively correlated with serum sCD127 in patients with sepsis ( r=0.46, P<0.01). The percentage of mCD127 + CD8 + T cells in CD8 + T cells and the mean fluorescence intensity of mCD127 in sepsis group were higher than those in control group ( P<0.05). The expression of sCD127 at mRNA level in CD8 + T cells was lower in sepsis group than in control group (1.34±0.33 vs 1.80±0.60, P<0.001). Stimulation with recombinant human IL-7 promoted sCD127 secretion and total CD127 and sCD127 expression at mRNA level in CD8 + T cells ( P<0.05). Inhibition of STAT5 suppressed the IL-7-induced sCD127 secretion and total CD127 and sCD127 expression at mRNA level ( P<0.05). However, inhibition of PI3K could not achieve those effects ( P>0.05). CD8 + T cells-induced target cell death was inhibited in sepsis group as compared with that in control group [(12.49±2.12)% vs (23.83±3.76)%, P<0.001]. Recombinant human IL-7 promoted the CD8 + T cell-induced target cell death ( P<0.05) and increased the secretion of cytokines and cytotoxic granule proteins ( P<0.05). Inhibition of STAT5 suppressed IL-7-mediated CD8 + T cell cytotoxicity ( P<0.05). However, inhibition of PI3K did not affect IL-7-mediated CD8 + T cell cytotoxicity ( P>0.05). Conclusions:IL-7 promoted sCD127 secretion and enhanced the in vitro cytotoxicity of CD8 + T cells in patients with sepsis through STAT5 signal pathway.

Increased frequency of TIGIT+CD73-CD8+ T cells with a TOX+ TCF-1low profile in patients with newly diagnosed and relapsed AML.

The inhibitory receptor TIGIT, as well as theectonucleotidases CD39 and CD73 constitute potential exhaustion markers for T cells. Detailed analysis of these markers can shed light into dysregulation of the T-cell response in acute myeloid leukemia (AML) and will help to identify potential therapeutic targets.  The phenotype and expression of transcription factors was assessed on different T-cell populations derived from peripheral blood (PB, n = 38) and bone marrow (BM, n = 43). PB and BM from patients with AML diagnosis, in remission and at relapse were compared with PB from healthy volunteers (HD) (n = 12) using multiparameter flow cytometry. An increased frequency of terminally differentiated (CD45R-CCR7-)CD8+ T cells was detected in PB and BM regardless of the disease state. Moreover, we detected an increased frequency of two distinct T-cell populations characterized by the co-expression of PD-1 or CD39 on TIGIT+CD73-CD8+ T cells in newly diagnosed and relapsed AML in comparison to HDs. In contrast to the PD-1+TIGIT+CD73-CD8+ T-cell population, the frequency of CD39+TIGIT+CD73-CD8+ T cells was normalized in remission. PD-1+- and CD39+TIGIT+CD73-CD8+ T cells exhibited additional features of exhaustion by decreased expression of CD127 and TCF-1 and increased intracellular expression of the transcription factor TOX. CD8+ T cells in AML exhibit a key signature of two subpopulations, PD-1+TOX+TIGIT+CD73-CD8+- and CD39+TOX+TIGIT+CD73-CD8+ T cells that were increased at different stages of the disease. These results provide a rationale to analyze TIGIT blockade in combination with inhibition of the purinergic signaling and depletion of TOX to improve T-cell mediated cytotoxicity in AML. Abbreviations: AML: Acute myeloid leukemia; pAML: newly diagnosed AML; rAML: relapse AML; lrAML: AML in remission; HD: healthy donor; PB: peripheral blood; BM: bone marrow; TIGIT: T-cell immunoreceptor with Ig and ITIM domains; PD-1: Programmed cell death protein 1; CD73: ecto-5'-nucleotidase; CD39: ectonucleoside triphosphate diphosphohydrolase 1; ATP: adenosine triphosphate; ADO: adenosine; CD127: interleukin-7 receptor; CAR-T cell: chimeric antigen receptor T cell; TCF-1: transcription factor T-cell factor 1; TOX: Thymocyte selection-associated high mobility group box protein; NFAT: nuclear factor of activated T cells; NA: Naïve; CM: Central Memory; EM Effector Memory; EMRA: Terminal Effector Memory cells; FMO: Fluorescence minus one; PVR: poliovirus receptor; PVRL2: poliovirus receptor-related 2; IFN-γ: Interferon-γ; IL-2: interleukin-2; MCF: multiparametric flow cytometry; TNFα: Tumornekrosefaktor α; RT: room temperature.

Distinctive features of SARS-CoV-2-specific T cells predict recovery from severe COVID-19.

Although T cells are likely players in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunity, little is known about the phenotypic features of SARS-CoV-2-specific T cells associated with recovery from severe coronavirus disease 2019 (COVID-19). We analyze T cells from 34 individuals with COVID-19 with severity ranging from mild (outpatient) to critical, culminating in death. Relative to individuals who succumbed, individuals who recovered from severe COVID-19 harbor elevated and increasing numbers of SARS-CoV-2-specific T cells capable of homeostatic proliferation. In contrast, fatal COVID-19 cases display elevated numbers of SARS-CoV-2-specific regulatory T cells and a time-dependent escalation in activated bystander CXCR4+ T cells, as assessed by longitudinal sampling. Together with the demonstration of increased proportions of inflammatory CXCR4+ T cells in the lungs of individuals with severe COVID-19, these results support a model where lung-homing T cells activated through bystander effects contribute to immunopathology, whereas a robust, non-suppressive SARS-CoV-2-specific T cell response limits pathogenesis and promotes recovery from severe COVID-19.

Ecto-5'-Nucleotidase (CD73) Regulates the Survival of CD8+ T Cells.

Ecto-5'-nucleotidase (CD73) is an enzyme present on the surface of tumor cells whose primary described function is the production of extracellular adenosine. Due to the immunosuppressive properties of adenosine, CD73 is being investigated as a target for new antitumor therapies. We and others have described that CD73 is present at the surface of different CD8+ T cell subsets. Nonetheless, there is limited information as to whether CD73 affects CD8+ T cell proliferation and survival. In this study, we assessed the impact of CD73 deficiency on CD8+ T cells by analyzing their proliferation and survival in antigenic and homeostatic conditions. Results obtained from adoptive transfer experiments demonstrate a paradoxical role of CD73. On one side, it favors the expression of interleukin-7 receptor α chain on CD8+ T cells and their homeostatic survival; on the other side, it reduces the survival of activated CD8+ T cells under antigenic stimulation. Also, upon in vitro antigenic stimulation, CD73 decreases the expression of interleukin-2 receptor α chain and the anti-apoptotic molecule Bcl-2, findings that may explain the reduced CD8+ T cell survival observed in this condition. These results indicate that CD73 has a dual effect on CD8+ T cells depending on whether they are subject to an antigenic or homeostatic stimulus, and thus, special attention should be given to these aspects when considering CD73 blockade in the design of novel antitumor therapies.

Peripheral Blood from Rheumatoid Arthritis Patients Shows Decreased Treg CD25 Expression and Reduced Frequency of Effector Treg Subpopulation.

Rheumatoid arthritis (RA) is a common autoimmune disease characterized by immune cell infiltration of the synovium, leading to the loss of cartilage, bone, and joint function. Although regulatory T (Treg) cells are thought to modulate the initiation and progression of RA, a consensus has yet to be reached regarding the function and composition of Treg cells in RA patients. To address these discrepancies, we analyzed not only the total Treg frequency but also that of Treg subpopulations in the peripheral blood of RA patients and healthy controls by flow cytometry. We found that the total Treg population was not significantly different between RA and control subjects. However, the effector Treg cell subgroup, defined as CD45RA-CD25hi, showed markedly decreased frequency in RA patients. In addition, the total Treg population from RA patients showed a significant decline in the expression of CD25. Both the naïve and effector Treg subgroups also showed marked reduction of CD25 expression in RA patients compared to controls. These data suggest that the decreased frequency of effector Treg cells and overall reduction of CD25 expression in Treg cells in the peripheral blood may be evidence of altered Treg homeostasis associated with RA pathogenesis.

Peculiarities of Immune Regulation in Men of Perm Region with Atherosclerosis Related to Polymorphism of Candidate Genes.

The study examined peculiarities of immune regulation and associated polymorphic variants of candidate genes in men with atherosclerosis in Perm region. The revealed deficiency of CD127 lymphocytes and Annexin V-FITC+7AAD- cells, as well as enhanced level of CD3+CD4+ lymphocytes against the background of variant alleles of candidate genes FAS (rs1159120), CPOX (rs1131857) and wild-type alleles SULT1A1 (rs9282861), MMP9 (rs17576) are responsible for peculiar features of hereditary determination and pathogenesis of atherosclerosis in examined sample (p<0.05). The genetically determined degradation of extracellular matrix in vascular wall and implication of regulated Fas/APO1 apoptosis in the development of progressive atherosclerotic lesions indicate important role of immune system in atherogenesis. The revealed immunological and genetic features are recommended as the markers for early diagnosis of atherosclerosis and its prevention in men of Perm region.

Human Adipose Tissue-Derived Mesenchymal Stromal Cells Inhibit CD4+ T Cell Proliferation and Induce Regulatory T Cells as Well as CD127 Expression on CD4+CD25+ T Cells.

Mesenchymal stromal cells (MSC) exert their immunomodulatory potential on several cell types of the immune system, affecting and influencing the immune response. MSC efficiently inhibit T cell proliferation, reduce the secretion of pro-inflammatory cytokines, limit the differentiation of pro-inflammatory Th subtypes and promote the induction of regulatory T cells (Treg). In this study, we analyzed the immunomodulatory potential of human adipose tissue-derived MSC (ASC), on CD4+ T cells, addressing potential cell-contact dependency in relation to T cell receptor stimulation of whole human peripheral blood mononuclear cells (PBMC). ASC were cultured with not stimulated or anti-CD3/CD28-stimulated PBMC in direct and transwell cocultures; PBMC alone were used as controls. After 7 days, cocultures were harvested and we analyzed: (1) the inhibitory potential of ASC on CD4+ cell proliferation and (2) phenotypic changes in CD4+ cells in respect of Treg marker (CD25, CD127 and FoxP3) expression. We confirmed the inhibitory potential of ASC on CD4+ cell proliferation, which occurs upon PBMC stimulation and is mediated by indoleamine 2,3-dioxygenase. Importantly, ASC reduce both pro- and anti-inflammatory cytokine secretion, without indications on specific Th differentiation. We found that stimulation induces CD25 expression on CD4+ cells and that, despite inhibiting overall CD4+ cell proliferation, ASC can specifically induce the proliferation of CD4+CD25+ cells. We observed that ASC induce Treg (CD4+CD25+CD127-FoxP3+) only in not stimulated cocultures and that ASC increase the ratio of CD4+CD25+CD127+FoxP3- cells at the expense of CD4+CD25+CD127-FoxP3- cells. Our study provides new insights on the interplay between ASC and CD4+ T cells, proposing that ASC-dependent induction of Treg depends on PBMC activation which affects the balance between the different subpopulations of CD4+CD25+ cells expressing CD127 and/or FoxP3.

Level of Foxp3, DNMTs, methylation of Foxp3 promoter region, and CD4 + CD25 + CD127low regulatory T cells in vulvar lichen sclerosus.

This study is to investigate the pathogenesis of vulvar lichen sclerosus (VLS) by analyzing the level of Foxp3, DNMTs, methylation of Foxp3 promoter region, and CD4 + CD25 + CD127low Regulatory T cells (Tregs). This study enrolled 15 VLS patients and 25 controls. Lesional and extralesional vulvar skin tissues, normal vulvar skin tissues and peripheral blood were collected. Compared with the control group, Foxp3 protein in the lesional and extralesional skin of VLS group was significantly reduced. The levels of DNMT1 and DNMT3b proteins in lesional skin of VLS group were significantly increased. There was no difference in the total methylation rates of the promoter region of the Foxp3 gene. The methylation rates of CpG1, CpG4, CpG9, and CpG10 were significantly higher in lesional skin of VLS group than in control group. There was no correlation between the total methylation rates of 10 CpG sites and the level of Foxp3 and DNMT1 proteins; there was a positive correlation between Foxp3 and DNMT1 protein in lesional skin of VLS group (r = 0.675, p < 0.05), and a negative correlation (r = -0.665, p < 0.05) in extralesional skin of VLS group. However, there was no correlation of Foxp3 with DNMT3b. The number of CD4 + CD25 + CD127low Tregs VLS decreased significantly. The expression of Foxp3 protein and the quantity of CD4 + CD25 + CD127low Tregs in patients with VLS decreased, which may cause local or systemic abnormal immunosuppression of Tregs, leading to the occurrence of VLS. This may be related with methylation or DNMT1, which needs further verification.