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The gut microbiota plays a role in energy homeostasis: its composition differs in lean and obese mice and may impact insulin sensitivity. The immune system has co-evolved with the gut microbiota, but direct regulation of microbial communities by the immune system and its metabolic impact is unclear. Mice lacking the immune cell specific transcription factor T-bet (Tbx21) are insulin sensitive. Compared with wild-type mice, T-bet deficient mice were found to have a higher proportion of colonic regulatory T cells despite significantly fewer colonic T cells, B cells and NK cells. Microbiota deletion by administration of antibiotics, increased colonic immune cell numbers. Furthermore, we report that T-bet −/− mice have an altered gut microbial composition and fecal short-chain fatty acid content, with an increase in butyrate production, compared with wild-type mice. Finally, in a proof-of concept study, we show that the enhanced insulin sensitivity observed in T-bet −/− mice is temporarily transmissible to antibiotic-treated wild-type mice through fecal transfer. Immune regulation of the gut microbiota by T-bet may be a novel pathway modulating insulin sensitivity. [ABSTRACT FROM AUTHOR]

The cytotoxicity feature to eliminate malignant cells makes natural killer (NK) cells a candidate for tumor immunotherapy. However, this scenario is currently hampered by inadequate understanding of the regulatory mechanisms of NK cell development. Ten-Eleven-Translocation 2 (Tet2) is a demethylase whose mutation was recently shown to cause phenotypic defects in NK cells. However, the role of Tet2 in the development and maturation of NK cells is not entirely clear. Here we studied the modulatory role of Tet2 in NK cell development and maturation by generating hematopoietic Tet2 knockout mice and mice with Tet2 conditional deletion in NKp46+ NK cells. The results showed that both hematopoietic and NK cell conditional deletion of Tet2 had no effect on the early steps of NK cell development, but impaired the terminal maturation of NK cells defined by CD11b, CD43, and KLRG1 expression. In the liver, Tet2 deletion not only prevented the terminal maturation of NK cells, but also increased the proportion of type 1 innate lymphoid cells (ILC1s) and reduced the proportion of conventional NK cells (cNK). Moreover, hematopoietic deletion of Tet2 lowered the protein levels of perforin in NK cells. Furthermore, hematopoietic deletion of Tet2 downregulated the protein levels of Eomesodermin (Eomes), but not T-bet, in NK cells. In conclusion, our results demonstrate that Tet2 plays an important role in the terminal maturation of NK cells, and the Eomes transcription factor may be involved. [ABSTRACT FROM AUTHOR]

Abstract Natural killer (NK) cells are crucial innate immune cells that provide defense against viruses and tumors. However, aging is associated with alterations in NK cell composition and compromised cell functions. Melatonin, known for its anti-tumor effects, has been reported to improve NK cell function. However, the molecular mechanism underlying melatonin’s effect on senescent NK cells remains unclear. In this study, we aimed to elucidate the mechanism by which melatonin enhances the function of senescent NK cells. Our findings revealed that melatonin significantly increased the number and function of NK cells in aging mice. The results suggest that melatonin enhances NK cell proliferation, degranulation, and IFN-γ secretion. Further investigations demonstrated that melatonin promotes NK cell maturation and activation, mainly via the JAK3/STAT5 signaling pathway, leading to increased expression of T-bet. These discoveries provide a theoretical basis for potential immunotherapy strategies based on melatonin-mediated modulation of NK cell function in aging individuals.

Natural killer (NK) cells are crucial innate immune cells that provide defense against viruses and tumors. However, aging is associated with alterations in NK cell composition and compromised cell functions. Melatonin, known for its anti-tumor effects, has been reported to improve NK cell function. However, the molecular mechanism underlying melatonin's effect on senescent NK cells remains unclear. In this study, we aimed to elucidate the mechanism by which melatonin enhances the function of senescent NK cells. Our findings revealed that melatonin significantly increased the number and function of NK cells in aging mice. The results suggest that melatonin enhances NK cell proliferation, degranulation, and IFN-γ secretion. Further investigations demonstrated that melatonin promotes NK cell maturation and activation, mainly via the JAK3/STAT5 signaling pathway, leading to increased expression of T-bet. These discoveries provide a theoretical basis for potential immunotherapy strategies based on melatonin-mediated modulation of NK cell function in aging individuals. [ABSTRACT FROM AUTHOR]

Summary: Apart from serving as a Th1 lineage commitment regulator, transcription factor T-bet is also expressed in other immune cell types and thus orchestrates their functions. In case of B cells, more specifically, T-bet is responsible for their isotype switching to specific IgG sub-classes (IgG2a/c in mice and IgG1/3 in humans). In various autoimmune disorders, such as systemic lupus erythematosus and/or rheumatoid arthritis, subsets of T-bet expressing B cells, known as age-associated B cells (CD19+CD11c+CD21−T-bet+) and/or double-negative B cells (CD19+IgD−CD27−T-bet+), display an expansion and seem to drive disease pathogenesis. According to data, mostly derived from mice models of autoimmunity, the targeting of these specific B-cell populations is capable of ameliorating the general health status of the autoimmune subjects. Here, in this review article, we present a variety of therapeutic approaches for both mice and humans, suffering from an autoimmune disease, and we discuss the effects of each approach on T-bet+ B cells. In general, we highlight the importance of specifically targeting T-bet+ B cells for therapeutic interventions in autoimmunity. Targeting of ABCs/DN, in mice models of autoimmunity and/or humans suffering from autoimmune disorders, leads to diminished levels of T-bet expression in B cells and thus improves the general health status of the subjects. Graphical Abstract [ABSTRACT FROM AUTHOR]

CD11c, FcRL5, or T‐bet are commonly expressed by B cells expanding during inflammation, where they can make up >30% of mature B cells. However, the association between the proteins and differentiation and function in the host response remains largely unclear. We have assessed the co‐expression of CD11c, T‐bet, and FcRL5 in an in vitro B‐cell culture system to determine how stimulation via the BCR, toll‐like receptor 9 (TLR9), and different cytokines influence CD11c, T‐bet, and FcRL5 expression. We observed different expression dynamics for all markers, but a largely overlapping regulation of CD11c and FcRL5 in response to BCR and TLR9 activation, while T‐bet was strongly dependent on IFN‐γ signaling. Investigating plasma cell differentiation and APC functions, there was no association between marker expression and antibody secretion or T‐cell help. Rather the functions were associated with TLR9‐signalling and B‐cell‐derived IL‐6 production, respectively. These results suggest that the expression of CD11c, FcRL5, and T‐bet and plasma cell differentiation and improved APC functions occur in parallel and are regulated by similar activation signals, but they are not interdependent. [ABSTRACT FROM AUTHOR]

T‐bet, encoded by TBX21, is extensively expressed across various immune cell types, and orchestrates critical functions in their development, survival, and physiological activities. However, the role of T‐bet in non‐immune compartments, notably the epithelial cells, remains obscure. Herein, a Tet‐O‐T‐bet transgenic mouse strain is generated for doxycycline‐inducible T‐bet expression in adult animals. Unexpectedly, ubiquitous T‐bet overexpression causes acute diarrhea, intestinal damage, and rapid mortality. Cell‐type‐specific analyses reveal that T‐bet‐driven pathology is not attributable to its overexpression in CD4+ T cells or myeloid lineages. Instead, inducible T‐bet overexpression in the intestinal epithelial cells is the critical determinant of the observed lethal phenotype. Mechanistically, T‐bet overexpression modulates ion channel and transporter profiles in gut epithelial cells, triggering profound fluid secretion and subsequent lethal dehydration. Furthermore, ectopic T‐bet expression enhances gut epithelial cell apoptosis and markedly suppresses colon cancer development in xenograft models. Collectively, the findings unveil a previously unrecognized role of T‐bet in intestinal epithelial cells for inducing apoptosis, diarrhea, and local inflammation, thus implicating its potential as a therapeutic target for the treatment of cancer and inflammatory diseases. [ABSTRACT FROM AUTHOR]

The gut microbiota plays a role in energy homeostasis: its composition differs in lean and obese mice and may impact insulin sensitivity. The immune system has co-evolved with the gut microbiota, but direct regulation of microbial communities by the immune system and its metabolic impact is unclear. Mice lacking the immune cell specific transcription factor T-bet (Tbx21) are insulin sensitive. Compared with wild-type mice, T-bet deficient mice were found to have a higher proportion of colonic regulatory T cells despite significantly fewer colonic T cells, B cells and NK cells. Microbiota deletion by administration of antibiotics, increased colonic immune cell numbers. Furthermore, we report that T-bet−/− mice have an altered gut microbial composition and fecal short-chain fatty acid content, with an increase in butyrate production, compared with wild-type mice. Finally, in a proof-of concept study, we show that the enhanced insulin sensitivity observed in T-bet−/− mice is temporarily transmissible to antibiotic-treated wild-type mice through fecal transfer. Immune regulation of the gut microbiota by T-bet may be a novel pathway modulating insulin sensitivity.

Genome‐wide association studies analysis has revealed associations between ankylosing spondylitis (AS) and loci on the TBX21 gene across various populations. This study aimed to investigate if there is a connection between a higher risk of AS in a Chinese population and two polymorphism loci on the TBX21 gene. To achieve this, we performed a case–control investigation involving 363 patients with AS and 907 healthy individuals. Genotyping was carried out using the iPLEX Gold genotyping assay. The analysis of genotypes and haplotypes was performed using SPSS 23.0 and SHEsis software. The results revealed no statistically significant correlation between the two specified single‐nucleotide polymorphisms of TBX21 (rs11657479 C/T and rs4794067 C/T) and susceptibility to AS. However, upon conducting stratification analysis, our findings demonstrated a significant association between rs11657479 and susceptibility to human leucocyte antigen (HLA)‐B27+ AS in allelic (C vs. T: odds ratio [OR] = 1.52, 95%CI = 1.09–2.11, corrected p [pc] =.028), heterozygous (CT vs. TT: OR = 1.63, 95%CI = 1.13–2.34, pc =.016) and dominant (CT + CC vs. TT: OR = 1.60, 95%CI = 1.12–2.28, pc =.018) models. Furthermore, the haplotype rs4794067/C‐rs11657479/C of TBX21 was found to increase the risk of HLA‐B27+ AS cases. In conclusion, our findings indicate a correlation between TBX21 gene polymorphism and HLA‐B27+ AS patients within the Chinese population. [ABSTRACT FROM AUTHOR]

Abstract T‐bet, encoded by TBX21, is extensively expressed across various immune cell types, and orchestrates critical functions in their development, survival, and physiological activities. However, the role of T‐bet in non‐immune compartments, notably the epithelial cells, remains obscure. Herein, a Tet‐O‐T‐bet transgenic mouse strain is generated for doxycycline‐inducible T‐bet expression in adult animals. Unexpectedly, ubiquitous T‐bet overexpression causes acute diarrhea, intestinal damage, and rapid mortality. Cell‐type‐specific analyses reveal that T‐bet‐driven pathology is not attributable to its overexpression in CD4+ T cells or myeloid lineages. Instead, inducible T‐bet overexpression in the intestinal epithelial cells is the critical determinant of the observed lethal phenotype. Mechanistically, T‐bet overexpression modulates ion channel and transporter profiles in gut epithelial cells, triggering profound fluid secretion and subsequent lethal dehydration. Furthermore, ectopic T‐bet expression enhances gut epithelial cell apoptosis and markedly suppresses colon cancer development in xenograft models. Collectively, the findings unveil a previously unrecognized role of T‐bet in intestinal epithelial cells for inducing apoptosis, diarrhea, and local inflammation, thus implicating its potential as a therapeutic target for the treatment of cancer and inflammatory diseases.

Primary Sjögren's disease (pSD) (also referred to as Sjögren's syndrome) is an autoimmune disease that primarily occurs in women. In addition to exocrine gland dysfunction, pSD patients exhibit B cell hyperactivity. B cell–intrinsic TLR7 activation is integral to the pathogenesis of systemic lupus erythematosus, a disease that shares similarities with pSD. The role of TLR7-mediated B cell activation in pSD, however, remains poorly understood. We hypothesized that age-associated B cells (ABCs) were expanded in pSD and that TLR7-stimulated ABCs exhibited pathogenic features characteristic of disease. Our data revealed that ABC expansion and TLR7 expression were enhanced in a pSD mouse model in a Myd88-dependent manner. Splenocytes from pSD mice showed enhanced sensitivity to TLR7 agonism as compared with those derived from control animals. Sort-purified marginal zone B cells and ABCs from pSD mice showed enhanced inflammatory cytokine secretion and were enriched for antinuclear autoantibodies following TLR7 agonism. Finally, IgG from pSD patient sera showed elevated antinuclear autoantibodies, many of which were secreted preferentially by TLR7-stimulated murine marginal zone B cells and ABCs. These data indicate that pSD B cells are hyperresponsive to TLR7 agonism and that TLR7-activated B cells contribute to pSD through cytokine and autoantibody production. Thus, therapeutics that target TLR7 signaling cascades in B cells may have utility in pSD patients. [ABSTRACT FROM AUTHOR]

The NK cell exhaustion state evolving during extensive and prolonged cultivation is still one of the limitations of NK cell approaches. In this research, we transduced NK cells with the hTERT and iCasp9 genes. hTERT overexpression can prevent the functional exhaustion of NK cells during long-term cultivation, but, still, the therapeutic use of such cells is unsafe without irradiation. To overcome this obstacle, we additionally transduced NK cells with the iCasp9 transgene that enables the rapid elimination of modified cells. We compared the proliferative and functional activities of the hTERT- and/or iCasp9-modified NK cells, determined their exhaustion state and monitored the levels of EOMES and T-BET, the main NK cell transcription factors. The hTERT and iCasp9 genes were shown to affect the EOMES and T-BET levels differently in the NK cells. The EOMES+T-BET+ phenotype characterized the functionally active NK cells during two months of culture upon stimulation with IL2 and K562-mbIL21 feeder cells, which induced the greatest expansion rates of the NK cells, independently of the transgene type. On the other hand, under cytokine stimulation, the hTERT-iCasp9-NK cells displayed improved proliferation over NK cells modified with iCasp9 alone and showed an increased proliferation rate compared to the untransduced NK cells under stimulation with IL2 and IL15, which was accompanied by reduced immune checkpoint molecule expression. The individual changes in the EOMES and T-BET levels strictly corresponded to the NK cell functional activity, the surface levels of activating and inhibitory receptors along with the expansion rate and expression levels of pro-survival and pro-apoptotic genes. [ABSTRACT FROM AUTHOR]

Multiple sclerosis (MS) is a common and devastating chronic inflammatory disease of the CNS. CD4+ T cells are assumed to be the first to cross the blood–central nervous system (CNS) barrier and trigger local inflammation. Here, we explored how pathogenicity‐associated effector programs define CD4+ T cell subsets with brain‐homing ability in MS. Runx3‐ and Eomes‐, but not T‐bet‐expressing CD4+ memory cells were diminished in the blood of MS patients. This decline reversed following natalizumab treatment and was supported by a Runx3+Eomes+T‐bet− enrichment in cerebrospinal fluid samples of treatment‐naïve MS patients. This transcription factor profile was associated with high granzyme K (GZMK) and CCR5 levels and was most prominent in Th17.1 cells (CCR6+CXCR3+CCR4−/dim). Previously published CD28− CD4 T cells were characterized by a Runx3+Eomes−T‐bet+ phenotype that coincided with intermediate CCR5 and a higher granzyme B (GZMB) and perforin expression, indicating the presence of two separate subsets. Under steady‐state conditions, granzyme Khigh Th17.1 cells spontaneously passed the blood–brain barrier in vitro. This was only found for other subsets including CD28− cells when using inflamed barriers. Altogether, CD4+ T cells contain small fractions with separate pathogenic features, of which Th17.1 seems to breach the blood–brain barrier as a possible early event in MS. [ABSTRACT FROM AUTHOR]

Myeloid‐derived suppressor cells (MDSC) are a group of immature inhibitory cells of bone marrow origin. Human γδ T cells (mainly Vγ9Vδ2 T cells) have emerged as dominant candidates for cancer immunotherapy because of their unique recognition pattern and broad killing activity against tumor cells. Intestinal mucosal intraepithelial lymphocytes are almost exclusively γδ T cells, so it plays an important role in inhibiting the development of colorectal cancer. In this study, we investigated the effects and molecular mechanism of human MDSC on anticolorectal cancer cells activity of Vγ9Vδ2 T cells. Our results suggested that MDSC can reduce the NKG2D expression of Vγ9Vδ2 T cells through direct cell–cell contact, which is associated with membrane‐type transforming growth factor‐β. In contrast, MDSC can increase Vγ9Vδ2 T cells activation and production of IFN‐γ, perforin, Granzyme B through direct cell–cell contact. This may be related to the upregulation of T‐bet in Vγ9Vδ2 T cells by MDSC. However, MDSC had a dominant negative regulatory effect on the anticolorectal cancer cells activity of Vγ9Vδ2 T cells. Our study provides a theoretical basis for the immune regulatory function of human MDSC on γδ T cells. This will be conducive to the clinical development of a new antitumor therapy strategy. Significance statement: In this study, we found e‐myeloid‐derived suppressor cells (e‐MDSC) is the majority of MDSC differentiated in vitro. These MDSC can reduce the NKG2D expression of Vγ9Vδ2 T cells through direct cell–cell contact, which is associated with membrane‐type transforming growth factor‐β. In contrast, MDSC can increase Vγ9Vδ2 T cells activation and production of IFN‐γ, perforin, Granzyme B through direct cell–cell contact. This may be related to the upregulation of T‐bet in Vγ9Vδ2 T cells by MDSC. However, MDSC had a dominant negative regulatory effect on the anticolorectal cancer cells activity of Vγ9Vδ2 T cells. Our study provides a theoretical basis for the immune regulatory function of human MDSC on γδ T cells. This will be conducive to the clinical development of a new antitumor therapy strategy. [ABSTRACT FROM AUTHOR]

Chronic obstructive pulmonary disease (COPD) is a chronic and progressive respiratory disease. Transcription factor T-bet is involved in the inflammatory response and lung function changes of COPD, which is expected to become a new target for the prevention and treatment of COPD. It might provide a new idea for the targeted research of COPD.

Systemic lupus erythematosus (SLE) is an inflammatory disorder related to immunity dysfunction. The Th1 cell family including Th1 cells, transcription factor T-bet, and related cytokines IFNγ, TNFα, IL-2, IL-18, TGF-β, and IL-12 have been widely discussed in autoimmunity, such as SLE. In this review, we will comprehensively discuss the expression profile of the Th1 cell family in both SLE patients and animal models and clarify how the family members are involved in lupus development. Interestingly, T-bet-related age-associated B cells (ABCs) and low-dose IL-2 treatment in lupus were emergently discussed as well. Collection of the evidence will better understand the roles of the Th1 cell family in lupus pathogenesis, especially targeting IL-2 in lupus. [ABSTRACT FROM AUTHOR]

To investigate the effect of the transcription factor T-bet on the pathogenesis of nonalcoholic fatty liver disease (NAFLD) and the regulation of the intrahepatic immune microenvironment. Wild-type and T-bet knockout NASH mouse models were constructed. The effect of T-bet knockout on the pathogenesis of NAFLD was observed by histochemical staining. The expression of T-bet in immune cells in the liver and the effect of T-bet knockout on the proportion and function of immune cell subsets in the liver were determined by flow analysis. Flow cytometry results indicated that T-bet expression was increased in immune cells, especially NKT cells, in the livers of NAFLD mice. Knocking out the transcription factor T-bet reduced intrahepatic inflammation, reduced lipid accumulation, and ameliorated the pathogenesis of NAFLD. Based on the analysis of immune cell subsets, knocking out the transcription factor T-bet decreased the proportion, survival, and degree of activation of NK, NKT, and CD8 T cells in NAFLD liver; additionally, it decreased the secretion of IFN-γ by T cells and NKT cells but had no effect on the proportion of Th17 cells and Treg cells. Knocking out the transcription factor T-bet also reduced the proportion of proinflammatory myeloid-derived macrophages (MoMFs) in NAFLD liver, mainly the proportion of proinflammatory Ly6Chigh MoMFs. Furthermore, knocking out the transcription factor T-bet had no significant effect on the secretion of TNF-α from MoMFs but significantly reduced the expression of MHC class II molecules. Further analysis showed that the transcription factor T-bet may directly affect the expression of MHC class II molecules H2-AB1 and H2-Dmb1 through transcriptional regulation. Knocking out the transcription factor T-bet reduced the proinflammatory effect of innate immune cells (MoMFs, NK cells, and NKT cells) and T lymphocytes in NAFLD liver, thereby reducing intrahepatic inflammation and delaying the pathogenesis of NAFLD. • T-bet expression was increased in immune cells, especially NKT, in NAFLD liver. • Knockout T-bet reduced intrahepatic inflammation and the pathogenesis of NAFLD. • T-bet deletion decreased NK, NKT, and CD8 T cells survival and pro-inflammation. • T-bet knockout also reduced MoMFs proportion and MHC II expression in NAFLD liver. [ABSTRACT FROM AUTHOR]

STUDY QUESTION Is the ratio of endometrial T-box expressed in T cell (T-bet) and GATA-binding protein 3 (GATA3) changed in patients with recurrent miscarriage (RM) compared to fertile controls? SUMMARY ANSWER Our study showed a significantly higher T-bet/GATA3 ratio in patients with RM compared with fertile controls. WHAT IS KNOWN ALREADY The endometrial T-bet (Th1 lineage-committed transcription factor)/GATA3 (Th2 lineage-committed transcription factor) ratio could represent the Th1/Th2 balance, which is particularly important for healthy pregnancy. However, a reliable reference range for the T-bet/GATA3 ratio during the peri-implantation period has not yet been established for use in clinical practice. STUDY DESIGN, SIZE, DURATION This was a retrospective study carried out in a private fertility center. The control group included 120 women in couples undergoing IVF treatment for male infertility, who had experienced a live-birth baby following the first IVF cycle. The study group included 93 women diagnosed with RM that experienced at least two consecutive clinically spontaneous miscarriages before gestational week 12. The ratio of T-bet/GATA3 was calculated in the control group and RM group. PARTICIPANTS/MATERIALS, SETTING, METHODS Endometrium samples were collected at mid-luteal phase of the menstrual cycle prior to IVF treatment or pregnancy. The percentage of T-bet+ and GATA3+ cells in total endometrial cells was analyzed using immunohistochemical staining and quantitative analysis. MAIN RESULTS AND THE ROLE OF CHANCE Using the 95th percentile to define the upper limits of the endometrial T-bet/GATA3 ratio during the mid-luteal phase, the reference range of control fertile women was ≤0.22. Compared with the control group, the RM group exhibited a significantly higher T-bet/GATA3 ratio (P  =   0.02), and 19.4% (18/93) women with RM exhibited a T-bet/GATA3 ratio above the reference range in the mid-luteal phase. LIMITATIONS, REASONS FOR CAUTION All patients were recruited from a single center. The stability and clinical value of the endometrial T-bet/GATA3 ratio require further investigation. WIDER IMPLICATIONS OF THE FINDINGS The present study suggests that an abnormal endometrial T-bet/GATA3 ratio may be one of the risk factors of RM. Further studies are needed to follow up the pregnancy outcomes in patients with RM with normal and abnormal endometrial T-bet/GATA3 ratio according to the reference range. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by Shenzhen Fundamental Research Program (JCYJ20180228164631121, JCYJ20190813161203606, JCYJ20220530172817039). There are no conflicts of interest to declare. TRIAL REGISTRATION NUMBER N/A. [ABSTRACT FROM AUTHOR]

Chronic obstructive pulmonary disease (COPD) is a chronic and progressive respiratory disease. Transcription factor T-bet is involved in the inflammatory response and lung function changes of COPD, which is expected to become a new target for the prevention and treatment of COPD. It might provide a new idea for the targeted research of COPD. [ABSTRACT FROM AUTHOR]

Systemic Lupus Erythematosus (SLE) is characterized by pathogenic autoantibodies against nucleic acid‐containing antigens. Understanding which B‐cell subsets give rise to these autoantibodies may reveal therapeutic approaches for SLE that spare protective responses. Mice lacking the tyrosine kinase Lyn, which limits B and myeloid cell activation, develop lupus‐like autoimmune diseases characterized by increased autoreactive plasma cells (PCs). We used a fate‐mapping strategy to determine the contribution of T‐bet+ B cells, a subset thought to be pathogenic in lupus, to the accumulation of PCs and autoantibodies in Lyn‐/‐ mice. Approximately, 50% of splenic PCs in Lyn‐/‐ mice originated from T‐bet+ cells, a significant increase compared to WT mice. In vitro, splenic PCs derived from T‐bet+ B cells secreted both IgM and IgG anti‐dsDNA antibodies. To determine the role of these cells in autoantibody production in vivo, we prevented T‐bet+ B cells from differentiating into PCs or class switching in Lyn‐/‐ mice. This resulted in a partial reduction in splenic PCs and anti‐dsDNA IgM and complete abrogation of anti‐dsDNA IgG. Thus, T‐bet+ B cells make an important contribution to the autoreactive PC pool in Lyn‐/‐ mice. [ABSTRACT FROM AUTHOR]

Background: Interferon-gamma (IFN-γ) is a key mediator of sarcoidosis-related granulomatous inflammation. Previous findings of IFN-γ-producing Th17 cells in bronchoalveolar lavage fluid from sarcoidosis patients invokes the transition of Th17.0 cells to Th17.1 cells in the disease's pathogenesis. Since the T-bet transcription factor is crucial for this transition, the goal of this study was to determine if T-bet expression in Th17.0 cells reflects the extent of granulomatous inflammation in sarcoidosis patients as assessed by clinical outcomes. Methods: Using a case-control study design, we identified two groups of sarcoidosis subjects (total N = 43) with pulmonary function tests (PFTs) that either (1) changed (increased or decreased) longitudinally or (2) were stable. We used flow cytometry to measure the transcription factors T-bet and RORγt in Th1, Th17.0, and Th17.1 cell subsets defined by CCR6, CCR4 and CXCR3 in blood samples. We compared the percentages of T-bet+ cells in RORγt+Th17.0 cells (defined as CCR6+CCR4+CXCR3-) based on subjects' PFT group. We also assessed the relationship between the direction of change in PFTs with the changes in %T-bet+ frequencies using mixed effects modeling. Results: We found that T-bet expression in subjects' RORγt+Th17.0 cells varied based on clinical outcome. The T-bet+ percentage of RORγt+Th17.0 cells was higher in the cases (subject group with PFT changes) as compared to controls (stable group) (27 vs. 16%, p = 0.0040). In comparisons before and after subjects' PFT changes, the T-bet+ frequency of RORγt+Th17.0 cells increased or decreased in the opposite direction of the PFT change. The percentage of these T-bet+ cells was also higher in those with greater numbers of involved organs. Serum levels of interferon-γ-induced chemokines, CXCL9, CXCL10, and CXCL11, and whole blood gene expression of IFN-γ-related genes including GBP1, TAP1, and JAK2 were independently positively associated with the T-bet+ frequencies of RORγt+Th17.0 cells. Conclusions: These data suggest that expression of T-bet in Th17.0 cells could reflect the extent of granulomatous inflammation in sarcoidosis patients because they represent a transition state leading to the Th17.1 cell phenotype. These findings indicate that Th17 plasticity may be part of the disease paradigm.

Background. Breast milk (BM) is an optimal nutritional product for newborns and a source of exogenous microRNAs (miR). MiR-148a is one of the most highly expressed miR of BM. Currently, there is a lack of data on the miR-148a effect on the development of necrotizing enterocolitis (NEC) in premature newborns. The purpose of the study was to determine the influence of miR-148a of the mother’s BM on the risk of NEC development in preterm newborns. Materials and methods. We examined 74 newborns, who were treated in neonatal departments. We determined the level of miR-148a in the BM of 44 mothers of exclusively breastfed children. In parallel, we evaluated gene expression of the transcription factor T-bet in scrapings of the buccal mucosa of all the newborns. Three groups for comparison were selected: group 1 consisted of 32 newborns up to 37 weeks of gestation on breastfeeding (BF); group 2 — of 30 preterm newborns on artificial feeding; the control group — 12 full-term newborns on BF. Results. The gestational age median of group 1 children was 33 (31; 34) weeks; group 2 — 32.5 (32; 35) weeks; and it was comparatively higher in the control group (p 0.05). In group 2 compared to the first one, manifestations of NEC occurred significantly more often (p

Некротизуючий ентероколіт (НЕК) - тяжке гастроінтестинальне захворювання, що уражує переважно недоношених немовлят. Неспецифічність клінічної картини та високий відсоток ускладнень обумовлюють необхідність ранньої діагностики та профілактики захворювання. Мета - встановити зв’язок між рівнем експресії T-bet у клітинах букальної слизової оболонки, розвитком НЕК та способом вигодовування в недоношених новонароджених немовлят. Матеріали та методи. Обстежено 74 новонароджених, які проходили лікування в неонатальних відділеннях. Виділено три групи порівняння: 1-шу становили 32 дитини, народжені до 37 тижнів гестації, які перебували на грудному вигодовуванні (ГВ); 2-гу - 30 недоношених новонароджених на штучному вигодовуванні (ШВ); контрольну - 12 доношених новонароджених на ГВ. Визначено рівень експресії гена фактора транскрипції T-bet у клітинах зіскрібка букальної слизової оболонки новонароджених. Для статистичного аналізу розраховано нормалізовані рівні експресії T-bet у клітинах слизових оболонок немовлят 1 і 2-ї груп дослідження щодо групи контролю, де рівень експресії визначених факторів прийнято за 1 у.о. Результати. Медіана гестаційного віку дітей 1-ї групи становила 33 (31; 34) тижні; 2-ї групи - 32,5 (32; 35) тижня; порівняно вищою вона була в групі контролю (р

Current dogma holds that functional differentiation of helper T cells expressing lineage-specifying transcription factors and signature cytokines requires three signals provided by dendritic cells (DCs). T cell receptor (TCR) signaling (or signal 1) defines specificity, costimulation (or signal 2) ensures full T activation and expansion, and polarizing cytokines (or signal 3) upregulate specific master transcription factors thereby guiding T cell differentiation into distinct functional helper subsets. However, in vitro and in vivo studies provide evidence suggesting that Th2 cell differentiation may follow a particular DC–T cell two-signal activation model, in which signals 1 and 2 are required in the absence of signal 3. We propose a model that bypasses the need for signal 3, and instead, Th2 cell commitment requires the active suppression of polarizing cytokine secretion by DCs. A precise understanding of the signals driving and licensing T helper 2 (Th2) cell responses is key to manipulating Th2 cell immunity in health and disease. The current paradigm assumes that the polarizing signals provided by dendritic cells dictates the choice of T helper cell response. However, recent evidence suggests that the induction of Th2 cell responses might follow a different path requiring the suppression of polarizing signals. Conventional dendritic cells (cDCs) can integrate multiple stimuli from the environment and provide three separate outputs in terms of antigen presentation, costimulation, and cytokine production; this guides the activation, expansion, and differentiation of distinct functional T helper subsets. Accordingly, the current dogma posits that T helper cell specification requires these three signals in sequence. Data show that T helper 2 (Th2) cell differentiation requires antigen presentation and costimulation from cDCs but does not require polarizing cytokines. In this opinion article, we propose that the 'third signal' driving Th2 cell responses is, in fact, the absence of polarizing cytokines; indeed, the secretion of the latter is actively suppressed in cDCs, concomitant with acquired pro-Th2 functions. [ABSTRACT FROM AUTHOR]

Introduction: The prevalence of coronavirus disease 2019 (COVID-19) has rapidly increased worldwide. More investigation is needed to progress toward understanding the exact role of immune responses in the pathology of the disease, leading to improved anticipation and treatment options. Methods: In the present study, we examined the relative expression of T-bet, GATA3, RORγt, and FoxP3 transcription factors as well as laboratory indicators in 79 hospitalized patients along with 20 healthy subjects as a control group. In order to make an exact comparison between various degrees of severity of disease, patients were divided into critical (n = 12) and severe (n = 67) groups. To evaluate the expression of genes of interest by performing real-time PCR, blood samples were obtained from each participant. Results: We found a significant increase in the expression of T-bet, GATA3, and RORγt and a reduction in the expression of FoxP3 in the critically ill patients compared to the severe and control groups. Also, we noticed that the GATA3 and RORγt expressions were elevated in the severe group in comparison with healthy subjects. Additionally, the GATA3 and RORγt expressions showed a positive correlation with elevation in CRP and hepatic enzyme concentration. Moreover, we observed that the GATA3 and RORγt expressions were the independent risk factors for the severity and outcome of COVID-19. Discussion: The present study showed that the overexpression of T-bet, GATA3, and RORγt, as well as a decrease in the FoxP3 expression was associated with the severity and fatal outcome of COVID-19. [ABSTRACT FROM AUTHOR]

In severe respiratory virus infections, including influenza, an exaggerated host immune response has been linked to the severe disease and death. Control of the overwhelming immune response is thus essential. Efforts with broad‐spectrum immunosuppressive agents such as steroids are disappointing. A better understanding of host immune response using animal experimental system is required to avoid undesired outcome of experimental manipulation. Following severe influenza virus infection in influenza hemagglutinin antigen‐specific transgenic mouse experimental model, step‐wise evolving cells from a pool of naïve hemagglutinin‐specific CD4+ T cells were studied for phenotypic, genomic, and functional characterization in vivo. Naïve CD4+ T cells respond with Th1 commitment in the absolute majority. They first develop into LAG‐3MedIFN‐γ‐secreting Th1 effectors and then evolve into LAG‐3HighIFN‐γ‐not‐secreting regulators with increasing LAG‐3 expression upon continuous activation and cell division. The LAG‐3MedIFN‐γ‐secreting effectors contribute to inflammation, boost inflammatory response of cognate antigen‐specific CD8+ T cells, and aggravate the disease despite facilitated virus clearance. In contrast, LAG‐3High regulators do not contribute to inflammation, suppress CD8+ T cell inflammatory response, alleviate lung pathology, and ameliorate the disease with preserved virus clearance. Moderated CD8+ T cells retain proliferative capacity, and persist beyond virus clearance. Such moderation is distinct from Foxp‐3+ regulator‐mediated suppression, which suppresses proliferative and inflammatory responses of the CD8+ T cells and impairs virus clearance with inflammation alleviation. Origin of regulatory from the effector cells of LAG‐3‐marked Th1 immunity alleviates lung inflammation without impairment of virus eradication. [ABSTRACT FROM AUTHOR]

Th cells play an important role in pathogenesis of type 1 diabetes (T1D). Peripheral blood mononuclear cells were isolated from peripheral blood samples from newly diagnosed (ND), 1-year (1YD), and 5-year T1D (5YD) patients (n:8 of each group), 8 healthy controls (HC), and cultured for 24 h under unstimulated (US) and stimulated conditions. Cell ratios of Th1, Th2, Th17, Treg, and intracellular levels of IFN-γ, TNF-α, IL-10, TGF-β, IL-5, IL-13, IL-17, and IL-21 cytokines were evaluated using the flow cytometry. mRNA expressions of transcription factors T-bet, GATA3, ROR-γt, and FOXP3 of these cells were determined by real-time PCR. Reduced CD4+CD25high cell ratios were detected in ND. CD4+CD25high cells were found to be reduced in ND and 1YD compared to HC under IL-2-stimulated conditions. Intracellular IFN-γ and TNF-α levels were low in all patients under US and IL-12-stimulated conditions. IL-17A and IL-21 were found to be high in patients with IL-6-stimulated conditions. Expressions of IL-10 and TGF-β have been observed to be reduced in patients. Th1/Th2, Th17/Treg, and Th1/Treg ratios were higher in patient groups. FOXP3 and GATA3 mRNA expressions were found to be low in patients, while RORγt and T-bet mRNA levels were higher than HC. Th1, Th17, and Treg cells and their cytokines have been shown to be associated with type 1 diabetes. [ABSTRACT FROM AUTHOR]

Inhibitory CD4+ T cells have been linked with suboptimal immune responses against cancer and pathogen chronicity. However, the mechanisms that underpin the development of these regulatory cells, especially in the context of ongoing antigen exposure, have remained obscure. To address this knowledge gap, we undertook a comprehensive functional, phenotypic, and transcriptomic analysis of interleukin (IL)-10-producing CD4+ T cells induced by chronic infection with murine cytomegalovirus (MCMV). We identified these cells as clonally expanded and highly differentiated TH1-like cells that developed in a T-bet-dependent manner and coexpressed arginase-1 (Arg1), which promotes the catalytic breakdown of L-arginine. Mice lacking Arg1-expressing CD4+ T cells exhibited more robust antiviral immunity and were better able to control MCMV. Conditional deletion of T-bet in the CD4+ lineage suppressed the development of these inhibitory cells and also enhanced immune control of MCMV. Collectively, these data elucidated the ontogeny of IL-10-producing CD4+ T cells and revealed a previously unappreciated mechanism of immune regulation, whereby viral persistence was facilitated by the site-specific delivery of Arg1.

The NK cell exhaustion state evolving during extensive and prolonged cultivation is still one of the limitations of NK cell approaches. In this research, we transduced NK cells with the hTERT and iCasp9 genes. hTERT overexpression can prevent the functional exhaustion of NK cells during long-term cultivation, but, still, the therapeutic use of such cells is unsafe without irradiation. To overcome this obstacle, we additionally transduced NK cells with the iCasp9 transgene that enables the rapid elimination of modified cells. We compared the proliferative and functional activities of the hTERT- and/or iCasp9-modified NK cells, determined their exhaustion state and monitored the levels of EOMES and T-BET, the main NK cell transcription factors. The hTERT and iCasp9 genes were shown to affect the EOMES and T-BET levels differently in the NK cells. The EOMES+T-BET+ phenotype characterized the functionally active NK cells during two months of culture upon stimulation with IL2 and K562-mbIL21 feeder cells, which induced the greatest expansion rates of the NK cells, independently of the transgene type. On the other hand, under cytokine stimulation, the hTERT-iCasp9-NK cells displayed improved proliferation over NK cells modified with iCasp9 alone and showed an increased proliferation rate compared to the untransduced NK cells under stimulation with IL2 and IL15, which was accompanied by reduced immune checkpoint molecule expression. The individual changes in the EOMES and T-BET levels strictly corresponded to the NK cell functional activity, the surface levels of activating and inhibitory receptors along with the expansion rate and expression levels of pro-survival and pro-apoptotic genes.

Introduction: The favorable effects of probiotics have been demonstrated in allergic disorders. However, the underlying immunological mechanisms are poorly understood. In the present study, we investigated the improvement of clinical symptoms and immunological balance after receiving probiotics in patients with asthma. Methods: The present study was a randomized, double-blind, placebo-controlled trial in which 40 patients with asthma were enrolled. They were treated with probiotics or placebo: 1 capsule/day for 8 weeks. Pulmonary function test, percentage of CD4+ CD25+ FoxP3+ Tregs, and gene expression of T-bet, GATA-3, RORγt, and Foxp3 in PBMCs were assessed at baseline and after treatment. Results: Our results showed a significant increase in the expression of FoxP3 and CD4+ CD25+ FoxP3+ Tregs population, while RORγt and GATA3 expression were reduced. In addition, pulmonary function tests showed a significant improvement in forced expiratory volume and forced vital capacity after receiving probiotics. Discussion/Conclusion: Our findings demonstrate that 8-week treatment with probiotic supplementation can control T-helper 2-predominant and Th17 pro-inflammatory responses and improve forced vital and forced expiratory volume in asthmatic patients. It seems probiotics can be used besides common treatments for patients with asthma. [ABSTRACT FROM AUTHOR]

After exposure to an antigen, CD8 T cells reach a decision point about their fate: to become either short-lived effector cells (SLECs) or memory progenitor effector cells (MPECs). SLECs are specialized in providing an immediate effector function but have a shorter lifespan and lower proliferative capacity compared to MPECs. Upon encountering the cognate antigen during an infection, CD8 T cells rapidly expand and then contract to a level that is maintained for the memory phase after the peak of the response. Studies have shown that the contraction phase is mediated by TGFβ and selectively targets SLECs, while sparing MPECs. The aim of this study is to investigate how the CD8 T cell precursor stage determines TGFβ sensitivity. Our results demonstrate that MPECs and SLECs have differential responses to TGFβ, with SLECs being more sensitive to TGFβ than MPECs. This difference in sensitivity is associated with the levels of TGFβRI and RGS3, and the SLEC-related transcriptional activator T-bet binding to the TGFβRI promoter may provide a molecular basis for increased TGFβ sensitivity in SLECs. [ABSTRACT FROM AUTHOR]

• The mechanism of T-bet and Eomes affecting the development of NK cells. • T-bet and Eomes synergistically regulate NK cell function through the mTOR pathway. • T-bet and Eomes play a key role in enhancing responses and defense against infections and tumors. T-bet and Eomes, both T-box transcription factors, have been extensively studied for their critical roles in the differentiation and functional maintenance of various immune cells. In this review, we provide a focused overview of their contributions to the transcriptional activation and differentiation, development, and terminal maturation of natural killer cells and innate lymphoid cell 1 cells. Furthermore, the interplay between T-bet and Eomes in regulating NK cell function, and its subsequent implications for immune responses against infections and tumors, is thoroughly examined. The review explores the ramifications of dysregulated transcription factor expression, examining its impact on homeostatic balance and its role in a spectrum of disease models. Expression variances among distinct NK cell subsets resident in different tissues are highlighted to underscore the complexity of their biological roles. Collectively, this work aims to expand the current understanding of NK cell biology, thereby paving the way for innovative approaches in the realm of NK cell-based immunotherapies. [ABSTRACT FROM AUTHOR]

Allergic diseases, including atopic dermatitis, allergic rhinitis, asthma, and food allergy, are caused by abnormal responses to relatively harmless foreign proteins called allergens found in pollen, fungal spores, house dust mites (HDM), animal dander, or certain foods. In particular, the activation of allergen-specific helper T cells towards a type 2 (Th2) phenotype during the first encounters with the allergen, also known as the sensitization phase, is the leading cause of the subsequent development of allergic disease. Infants and children are especially prone to developing Th2 cell responses after initial contact with allergens. But in addition, the rates of allergic sensitization and the development of allergic diseases among children are increasing in the industrialized world and have been associated with living in urban settings. Particularly for respiratory allergies, greater susceptibility to developing allergic Th2 cell responses has been shown in children living in urban environments containing low levels of microbial contaminants, principally bacterial endotoxins [lipopolysaccharide (LPS)], in the causative aeroallergens. This review highlights the current understanding of the factors that balance Th2 cell immunity to environmental allergens, with a particular focus on the determinants that program conventional dendritic cells (cDCs) toward or away from a Th2 stimulatory function. In this context, it discusses transcription factor-guided functional specialization of type-2 cDCs (cDC2s) and how the integration of signals derived from the environment drives this process. In addition, it analyzes observational and mechanistic studies supporting an essential role for innate sensing of microbial-derived products contained in aeroallergens in modulating allergic Th2 cell immune responses. Finally, this review examines whether hyporesponsiveness to microbial stimulation, particularly to LPS, is a risk factor for the induction of Th2 cell responses and allergic sensitization during infancy and early childhood and the potential factors that may affect early-age response to LPS and other environmental microbial components.

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Natural Killer (NK) cells are key innate effectors of antiviral immune response, and their activity changes in ageing and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Here, we investigated the age-related changes of NK cell phenotype and function during SARS-CoV-2 infection, by comparing adult and elderly patients both requiringmechanical ventilation. Adult patients had a reduced number of total NK cells, while elderly showed a peculiar skewing of NK cell subsets towards the CD56lowCD16high and CD56neg phenotypes, expressing activation markers and check-point inhibitory receptors. Although NK cell degranulation ability is significantly compromised in both cohorts, IFN-g production is impaired only in adult patients in a TGFb- dependent manner. This inhibitory effect was associated with a shorter hospitalization time of adult patients suggesting a role for TGF-β in preventing an excessive NK cell activation and systemic inflammation. Our data highlight an age-dependent role of NK cells in shaping SARS-CoV-2 infection toward a pathophysiological evolution. [ABSTRACT FROM AUTHOR]

Mendelian susceptibility to mycobacterial disease (MSMD) is characterized by a selective predisposition to infections caused by intracellular pathogens, such as mycobacteria, due to impaired IFN-γ immunity. To date, 18 different genes associated with MSMD have been reported. This review describes recent discoveries, a 2020–2021 update, in MSMD through the introduction of three novel genetic disorders, namely, AR IFN-γ, T-bet, and ZNFX1 complete deficiency, as well as molecular mechanisms underlying multifocal osteomyelitis in patients with this condition. PubMed databases were searched for reports of MSMD since January 2020. Relevant articles and their references were screened. The review covers a general overview, known genes, classifications, symptoms, and treatments for MSMD. MSMD is classified into two groups: isolated MSMD and syndromic MSMD. Among the 18 genes responsible, 13 cause isolated MSMD, which is characterized by selective predisposition to one or more mycobacterial and related infections, and 8 cause syndromic MSMD, which involves the combination of the mycobacterial disease infectious phenotype with additional clinical phenotypes. Among the three genetic etiologies described herein, AR IFN-γ deficiency is classified as isolated MSMD, whereas AR T-bet and ZNFX1 deficiency are classified as syndromic MSMD. Multifocal osteomyelitis is a representative symptom of MSMD, and a high frequency of multifocal osteomyelitis is reported in MSMD patients due to impaired IFN-γ responses, such as with AD IFN-γR1, AD IFN-γR2, or AD STAT1 deficiency. Impaired inhibition of osteoclast differentiation and bone resorption owing to a poor response to IFN-γ has been shown to be in association with multifocal osteomyelitis in MSMD. Over the past decade, genetic dissection by next-generation sequencing techniques has contributed to the understanding of the molecular bases of human immunity to mycobacteria. However, genetic etiologies are lacking for half of MSMD cases. Further studies will be needed to elucidate the pathogenesis of MSMD. [ABSTRACT FROM AUTHOR]

Type 3 innate lymphoid cells (ILC3s) are characterized by RORγt expression and they produce IL-22 upon activation. ILC3s play a role in maintenance of barrier integrity in the intestine. Under inflammatory conditions, the ILC composition of the mucosal tissues is altered due to a high degree of plasticity. It has been extensively demonstrated that both murine and human ILC3s convert into ILC1s to mediate appropriate immune responses. However, plasticity between human ILC3s and NK cells is less well documented. As T-BET and EOMES are key transcription factors in NK cell differentiation, we investigated whether ectopic T-BET or EOMES expression converts human ILC3s into NK cells. ILC3s with ectopic T-BET and EOMES expression downregulate RORγt expression, while T-BET-overexpressing ILC3s additionally upregulate EOMES expression. High E ctopic T-BET expression in ILC3s results in transdifferentiation towards CD94+ NK cells, whereas ectopic EOMES overexpression results in dedifferentiation of ILC3s into CD94-CD117-/low cells but is ineffective in NK cell generation. Dedifferentiating ILC3s from both T-BET and EOMES overexpression cultures upregulate NK cell receptors, perforin and granzyme B. Finally, IL-22 secretion is completely blocked in transdifferentiating ILC3s with both T-BET and EOMES ectopic expression, whereas only T-BET overexpression increases IFN-γ secretion and cytotoxicity. Altogether, these findings demonstrate that human ILC3s can convert into functional NK cells, wherein T-BET, and not EOMES, is the main driver. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the effect of astilbin on pregnancy outcome in rats with recurrent spontaneous abortion (RSA). A total of 40 pregnant female Sprague–Dawley rats were randomly divided into four groups: the control, model, astilbin, and prednisone groups. An RSA rat model was established by gavage with hydroxyurea and mifepristone. The number of surviving and reabsorbed embryos was counted on day 9 of gestation in each group. The rat serum was collected to detect the levels of IFN-γ, IL-2, IL-4, and IL-10 by enzyme-linked immunosorbent assay. The expressions of T-bet and GATA-3 in the decidual and placental tissues of the rats were determined by immunohistochemistry. The absorptivity of embryos was significantly higher in the model group than in the control group. The levels of serum IFN-γ and IL-2 were significantly lower in the astilbin group than in the model group, while the levels of serum IL-4 and IL-10 were significantly higher. Astilbin treatment significantly increased GATA-3 expression, while it significantly reduced T-bet expression and the T-bet/GATA-3 ratio. Astilbin has a therapeutic effect on RSA in rats by regulating the balance of Th1/Th2 in maternal circulation and likely in decidual tissue. [ABSTRACT FROM AUTHOR]

Time to AIDS in HIV-2 infection is approximately twice as long compared to in HIV-1 infection. Despite reduced viremia, HIV-2-infected individuals display signs of chronic immune activation. In HIV-1-infected individuals, B-cell hyperactivation is driven by continuous antigen exposure. However, the contribution of viremia to B-cell perturbations in HIV-2-infected individuals remains largely unexplored. Here, we used polychromatic flow cytometry, consensus hierarchical clustering and pseudotime trajectory inference to characterize B-cells in HIV-1- or HIV-2-infected and in HIV seronegative individuals. We observed increased frequencies of clusters containing hyperactivated T-bethighCD95highCD27int and proliferating T-bet+CD95highCD27+CD71+ memory B-cells in viremic HIV-1 (p < 0.001 and p < 0.001, respectively), viremic HIV-2 (p < 0.001 and p = 0.014, respectively) and in treatment-naïve aviremic HIV-2 (p = 0.004 and p = 0.020, respectively)-infected individuals, compared to seronegative individuals. In contrast, these expansions were not observed in successfully treated HIV-1-infected individuals. Finally, pseudotime trajectory inference showed that T-bet-expressing hyperactivated and proliferating memory B-cell populations were located at the terminal end of two trajectories, in both HIV-1 and HIV-2 infections. As the treatment-naïve aviremic HIV-2-infected individuals, but not the successfully ART-treated HIV-1-infected individuals, showed B-cell perturbations, our data suggest that aviremic HIV-2-infected individuals would also benefit from antiretroviral treatment. [ABSTRACT FROM AUTHOR]

The transcription factor T-bet is essential for the anti-tumor effector function of NK cells, but the mechanism regulating its expression in NK cells remains unclear. In this study, we aimed to identify an NK cell intrinsic regulator that controls T-bet expression. Using T-bet-luciferase reporter assay screening, we identified a protein phosphatase inhibitor as a potential activator of T-bet expression. A series of PP2A-specific inhibitors (PP2Ai) or PP2A siRNA induced the expression of T-bet. In PP2Ai-treated mice, the expressions of T-bet and its downstream effector molecules, granzyme B and IFN-γ, were also upregulated in NK cells. Mechanistically, PP2Ai increased the phosphorylation of mTOR and ribosomal protein S6 in NK cells, and mTOR inhibitor canceled the effects of PP2Ai in NK cells. Importantly, NK cells isolated from PP2Ai-treated mice showed higher cytotoxicity and IFN-γ production; therefore, they increased the anti-tumor effector function of NK cells. Accordingly, PP2Ai treatment inhibited lung metastasis of B16 melanoma by NK cell- and mTOR-dependent mechanisms. These results suggest that PP2A negatively regulates NK cell T-bet expression and effector function by an mTOR-dependent mechanism., (© The Author(s) 2024. Published by Oxford University Press on behalf of The Japanese Society for Immunology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Abstract We evaluated the peripheral blood immune responses of lymphocytes in severe Coronavirus disease 2019 (COVID-19) patients in different stages of recovery using single-cell mass cytometry. The patients with prolonged hospitalization did not show recovery of B lymphocyte counts and CD4-positive T lymphocyte counts but did show abundant CD8-positive T lymphocytes. CD4 and CD8 T cells expressing high levels of T-bet and Granzyme B were more abundant in post-recovery patients. This study showed that cytotoxic Th1 and CD8 T cells are recruited to the peripheral blood long after recovery from COVID-19.

Natural Killer (NK) cells are key innate effectors of antiviral immune response, and their activity changes in ageing and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Here, we investigated the age-related changes of NK cell phenotype and function during SARS-CoV-2 infection, by comparing adult and elderly patients both requiring mechanical ventilation. Adult patients had a reduced number of total NK cells, while elderly showed a peculiar skewing of NK cell subsets towards the CD56lowCD16high and CD56neg phenotypes, expressing activation markers and check-point inhibitory receptors. Although NK cell degranulation ability is significantly compromised in both cohorts, IFN-γ production is impaired only in adult patients in a TGF-β−dependent manner. This inhibitory effect was associated with a shorter hospitalization time of adult patients suggesting a role for TGF-β in preventing an excessive NK cell activation and systemic inflammation. Our data highlight an age-dependent role of NK cells in shaping SARS-CoV-2 infection toward a pathophysiological evolution.

Radiation therapy (RT) to the chest increases the patients’ risk of cardiovascular disease (CVD). A complete understanding of the mechanisms by which RT induces CVD could lead to specific preventive, therapeutic approaches. It is becoming evident that both genotoxic chemotherapy agents and radiation induce mitochondrial dysfunction and cellular senescence. Notably, one of the common phenotypes observed in cancer survivors is accelerated senescence, and immunosenescence is closely related to both cancer risk and CVD development. Therefore, suppression of immunosenescence can be an ideal target to prevent cancer treatment-induced CVD. However, the mechanism(s) by which cancer treatments induce immunosenescence are incompletely characterized. We isolated peripheral blood mononuclear cells (PBMCs) before and 3 months after RT from 16 thoracic cancer patients. We characterized human immune cell lineages and markers of senescence, DNA damage response (DDR), efferocytosis, and determinants of clonal hematopoiesis of indeterminant potential (CHIP), using mass cytometry (CyTOF). We found that the frequency of the B cell subtype was decreased after RT. Unsupervised clustering of the CyTOF data identified 138 functional subsets of PBMCs. Compared with baseline, RT increased TBX21 (T-bet) expression in the largest B cell subset of Ki67–/DNMT3a+naïve B cells, and T-bet expression was correlated with phosphorylation of p90RSK expression. CD38 expression was also increased in naïve B cells (CD27–) and CD8+ effector memory CD45RA T cells (TEMRA). In vitro, we found the critical role of p90RSK activation in upregulating (1) CD38+/T-bet+ memory and naïve B, and myeloid cells, (2) senescence-associated β-gal staining, and (3) mitochondrial reactive oxygen species (ROS) after ionizing radiation (IR). These data suggest the crucial role of p90RSK activation in immunosenescence. The critical role of p90RSK activation in immune cells and T-bet induction in upregulating atherosclerosis formation has been reported. Furthermore, T-bet directly binds to the CD38 promoter region and upregulates CD38 expression. Since both T-bet and CD38 play a significant role in the process of immunosenescence, our data provide a cellular and molecular mechanism that links RT-induced p90RSK activation and the immunosenescence with T-bet and CD38 induction observed in thoracic cancer patients treated by RT and suggests that targeting the p90RSK/T-bet/CD38 pathway could play a role in preventing the radiation-associated CVD and improving cancer prognosis by inhibiting immunosenescence.

Type 3 innate lymphoid cells (ILC3s) are characterized by RORγt expression and they produce IL-22 upon activation. ILC3s play a role in maintenance of barrier integrity in the intestine. Under inflammatory conditions, the ILC composition of the mucosal tissues is altered due to a high degree of plasticity. It has been extensively demonstrated that both murine and human ILC3s convert into ILC1s to mediate appropriate immune responses. However, plasticity between human ILC3s and NK cells is less well documented. As T-BET and EOMES are key transcription factors in NK cell differentiation, we investigated whether ectopic T-BET or EOMES expression converts human ILC3s into NK cells. ILC3s with ectopic T-BET and EOMES expression downregulate RORγt expression, while T-BET-overexpressing ILC3s additionally upregulate EOMES expression. High E ctopic T-BET expression in ILC3s results in transdifferentiation towards CD94+ NK cells, whereas ectopic EOMES overexpression results in dedifferentiation of ILC3s into CD94-CD117-/low cells but is ineffective in NK cell generation. Dedifferentiating ILC3s from both T-BET and EOMES overexpression cultures upregulate NK cell receptors, perforin and granzyme B. Finally, IL-22 secretion is completely blocked in transdifferentiating ILC3s with both T-BET and EOMES ectopic expression, whereas only T-BET overexpression increases IFN-γ secretion and cytotoxicity. Altogether, these findings demonstrate that human ILC3s can convert into functional NK cells, wherein T-BET, and not EOMES, is the main driver.

Simple Summary: The Epstein–Barr virus (EBV) is a γ-herpes virus that primarily infects human B cells, and more than 90% of adults have experienced infection. EBV+ B cells express several viral proteins, transmitting signals important for the transformation and tumorigenesis of the infected B cells. Immune surveillance by the host immune system is important to suppress such abnormal expansion of EBV-infected B cells. Here we found that both CD4+ T cells and CD8+ T cells show similar gene expression patterns relating to cytotoxicity towards EBV-infected B cells. EBV-specific cytotoxic CD4+ T cells markedly expressed T-bet, Granzyme B, and Perforin alongside killing activity, which could reflect mechanisms shared with cytotoxic CD8+ T cells. Our findings support the concept that, upon EBV and perhaps other viral infections, T cells of different subsets can be drawn into common pathways mediating immune surveillance through cytotoxicity. Most people infected by EBV acquire specific immunity, which then controls latent infection throughout their life. Immune surveillance of EBV-infected cells by cytotoxic CD4+ T cells has been recognized; however, the molecular mechanism of generating cytotoxic effector T cells of the CD4+ subset remains poorly understood. Here we compared phenotypic features and the transcriptome of EBV-specific effector-memory CD4+ T cells and CD8+ T cells in mice and found that both T cell types show cytotoxicity and, to our surprise, widely similar gene expression patterns relating to cytotoxicity. Similar to cytotoxic CD8+ T cells, EBV-specific cytotoxic CD4+ T cells from human peripheral blood expressed T-bet, Granzyme B, and Perforin and upregulated the degranulation marker, CD107a, immediately after restimulation. Furthermore, T-bet expression in cytotoxic CD4+ T cells was highly correlated with Granzyme B and Perforin expression at the protein level. Thus, differentiation of EBV-specific cytotoxic CD4+ T cells is possibly controlled by mechanisms shared by cytotoxic CD8+ T cells. T-bet-mediated transcriptional regulation may explain the similarity of cytotoxic effector differentiation between CD4+ T cells and CD8+ T cells, implicating that this differentiation pathway may be directed by environmental input rather than T cell subset. [ABSTRACT FROM AUTHOR]

Objective To investigate regulatory effect of the Lentivirus-mediated-GATA-3 RNAi （si-GATA-3）on the Th1/Th2 imbalance in a murine model of allergic rhinitis in vitro. Methods The lentiviral vector SI-GATA-3 with GATA-3 gene mediated by RNAi was developed and packaged, purified and titrated. BALB/C mice were randomly divided into AR group and normal control group. The allergic rhinitis model of BALB/C mice was developed by using ovalbumin （OVA）. The peripheral blood of BALB/C mice was collected and their mononuclear cells （PBMCs） were isolated. The PBMCs were randomly divided into three groups, namely, si-GATA-3 group, si-NC group and AR group. si-GATA-3, si-NC and normal saline were used to intervene PBMCs in allergic rhinitis mice for 72 h, and normal saline was used to replace si-GATA-3 to intervene PBMCs in normal control mice. PBMCs and cell culture supernatant were separated after the intervention. The relative expression levels of GATA-3 mRNA, T-bet mRNA and GATA-3, T-bet protein in PBMCs were detected by fluorescence quantitative qPCR and Western bloting, respectively. The contents of IL-4 and IFN-γ in supernatant of cell culture were determined by ELISA. Results The RNAi mediated lentiviral vector si-GATA-3 with a titer of 5×108 TU/mL was successfully deeloped. The allergic rhinitis mice models were established successfully. The relative expression levels of GATA-3 mRNA and GATA-3 protein and the content of IL-4 in supernatant of PBMCs in si-GATA-3 group were significantly lower than those in AR group and si-NC group （P < 0.01）, and the expression levels of GATA-3 in AR group and si-NC group were significantly higher than those in normal control group （P < 0.01）. There was no difference between AR group and si-NC group （P > 0.05）. The relative expression of T-bet mRNA and T-bet protein in si-GATA-3 group was significantly higher than that in AR group and si-NC group （P < 0.01）, and the expression of T-bet mRNA and T-bet protein in AR group and si-NC group was significantly lower than that in control group （P < 0.01）. There was no difference between AR group and si-NC group （P > 0.05）. However, the content of IFN-γ in cell culture supernatant of si-GATA-3 group was higher than that of normal control group （P < 0.05）, and the content of IFN-γ in AR and si-NC groups was significantly higher than that of normal control group and si-GATA-3 group （P < 0.01）. There was no significant difference in IFN-γ expression between AR group and si-NC group （P > 0.05）. Conclusions si-GATA-3 could down-regulate the relative expression of GATA-3 mRNA, GATA-3 protein and IL-4 level in Th2 cells, and up-regulate the relative expression of T-bet mRNA and T-bet protein in Th1 cells. Therefor, it can effectively correct the immune imbalance of Th2/Th1 in PBMCs in mouse AR model. [ABSTRACT FROM AUTHOR]