T-bet Expression Research Articles

Zizania latifolia and Its Major Compound Tricin Regulate Immune Responses in OVA-Treated Mice.

Tricin, a flavone belonging to the Gramineae family, has been confirmed to be the primary compound in a Zizania latifolia extract (ZLE) that prevents allergies. Various allergic reactions occur because of the unbalanced differentiation of T help cells (Th) and the consequent overproduction of IgE. Therefore, the regulation of Th1 and Th2 responses by T helper cell differentiation is essential for suppressing allergic responses. This study confirmed the immunomodulatory effects of ZLE and the major compound tricin in an OVA-sensitized mouse model. The IgE and OVA-specific production of tricin and ZLE in plasma were investigated in OVA-sensitized mice. The effects of tricin and ZLE on the amount of Th1 and Th2 cytokines and transcription factors released in splenocytes were investigated in OVA-sensitized mice. The skin roughness and the number of mast cells were confirmed by staining the skin surface with H&E and toluidine blue. Tricin and ZLE reduced the plasma IgE and OVA-specific-IgE levels significantly compared to the OVA group. On the other hand, tricin and ZLE promoted the release of the Th1 cytokines IL-12 and IFN-γ and inhibited the release of Th2 cytokines (IL-4, -10, -13, and -5) in OVA-sensitized mice. Tricin and ZLE induced T-bet and NFATc2 expression, and-down regulated GATA-3 levels. The skin roughness and the number of mast cells decreased in the OVA-immunized mice. Overall, the data indicate that tricin and ZLE may prevent allergy-related diseases through immunomodulation.

IL-33 acts as a costimulatory signal to generate alloreactive Th1 cells in graft-versus-host disease.

Antigen-presenting cells (APCs) integrate signals emanating from local pathology and program appropriate T cell responses. In allogeneic hematopoietic stem cell transplantation (alloHCT), recipient conditioning releases damage-associated molecular patterns (DAMPs) that generate proinflammatory APCs that secrete IL-12, which is a driver of donor Th1 responses, causing graft-versus-host disease (GVHD). Nevertheless, other mechanisms exist to initiate alloreactive T cell responses, as recipients with disrupted DAMP signaling or lacking IL-12 develop GVHD. We established that tissue damage signals are perceived directly by donor CD4+ T cells and promoted T cell expansion and differentiation. Specifically, the fibroblastic reticular cell–derived DAMP IL-33 is increased by recipient conditioning and is critical for the initial activation, proliferation, and differentiation of alloreactive Th1 cells. IL-33 stimulation of CD4+ T cells was not required for lymphopenia-induced expansion, however. IL-33 promoted IL-12–independent expression of Tbet and generation of Th1 cells that infiltrated GVHD target tissues. Mechanistically, IL-33 augmented CD4+ T cell TCR-associated signaling pathways in response to alloantigen. This enhanced T cell expansion and Th1 polarization, but inhibited the expression of regulatory molecules such as IL-10 and Foxp3. These data establish an unappreciated role for IL-33 as a costimulatory signal for donor Th1 generation after alloHCT.

Graft-versus-host disease: establishing IL-33 as an important costimulatory molecule.

Approximately half of patients with hematologic malignancy who are treated with allogeneic hematopoietic stem cell transplantation (alloHCT) experience graft-versus-host disease (GVHD), which has high mortality rates despite immunosuppressive therapy. IL-12 is known to drive donor T cells toward an inflammatory Th1 lineage in GVHD, but other mechanisms also promote pathological Th1 alloimmune responses. In this issue of the JCI, Dwyer et al. report on their use of transgenic mice and alloHCT models of GVHD to demonstrate that IL-33 acts directly on donor T cells to increase Tbet expression independently of IL-12. Notably, IL-33 amplified T cell receptor–signaling pathways and inhibited production of regulatory molecules. These findings firmly establish IL-33 as an important costimulatory molecule for Th1 cells during GVHD and provide a target for reducing GVHD, especially in the gastrointestinal (GI) tract, where damage drives mortality.

T-bet+ B cells Dominate the Peritoneal Cavity B Cell Response during Murine Intracellular Bacterial Infection.

T-bet+ B cells have emerged as a major B cell subset associated with both protective immunity and immunopathogenesis. T-bet is a transcription factor associated with the type I adaptive immune response to intracellular pathogens, driving an effector program characterized by the production of IFN-γ. Murine infection with the intracellular bacterium, Ehrlichia muris, generates protective extrafollicular T cell-independent T-bet+ IgM-secreting plasmablasts, as well as T-bet+ IgM memory cells. Although T-bet is a signature transcription factor for this subset, it is dispensable for splenic CD11c+ memory B cell development, but not for class switching to IgG2c. In addition to the T-bet+ plasmablasts found in the spleen, we show that Ab-secreting cells can also be found within the mouse peritoneal cavity; these cells, as well as their CD138- counterparts, also expressed T-bet. A large fraction of the T-bet+ peritoneal B cells detected during early infection were highly proliferative and expressed CXCR3 and CD11b, but, unlike in the spleen, they did not express CD11c. T-bet+ CD11b+ memory B cells were the dominant B cell population in the peritoneal cavity at 30 d postinfection, and although they expressed high levels of T-bet, they did not require B cell-intrinsic T-bet expression for their generation. Our data uncover a niche for T-bet+ B cells within the peritoneal cavity during intracellular bacterial infection, and they identify this site as a reservoir for T-bet+ B cell memory.

IL-27 overexpression alleviates inflammatory response in allergic asthma by inhibiting Th9 differentiation and regulating Th1/Th2 balance

Objective To investigate the effect of IL-27 on Th9 differentiation and Th1/Th2 balance. Methods C57BL/6 (B6) mice were treated with ovalbumin to establish an allergic asthma (AA) model and subjected to IL-27 overexpression (OV) and empty vector (EV). Hematoxylin-eosin (HE) staining was performed to observe lung tissue inflammation. Flow cytometry was carried out to evaluate the percentage of Th9, Th1, and Th2 cells. The expression of IL-27, IL-27R, IL-9, T-bet, IFN-γ, and IgE was evaluated by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA). Western blot was conducted to observe the expression of pSTAT-1 and pSTAT-3. Results Compared with the Model group, the number of Th1 cells in the Model + OV group increased significantly (p < .05), while those of Th9 and Th2 cells decreased significantly (p < .05). The expression of IL-27, IL-27R, and IFN-γ in blood serum was increased (p < .05), and that of IL-9 and IgE was significantly decreased in the Model + OV group compared to the Model (p < .05). Western blot revealed that Model + OV exhibited lower expression of pSTAT-3 than that in the Model and Model + EV groups (p < .05), while pSTAT-1 expression was significantly increased (p < .05). Inflammatory infiltration in the Model + OV group was significantly reduced, and there was no significant difference between the Model and Model + EV groups. Conclusions IL-27 OV inhibits Th9 differentiation and regulates the imbalance of Th1/Th2, thereby alleviating inflammatory response in AA. The findings suggest that IL-27 OV may be a potential strategy for clinical treatment of AA.

PPAR-α Agonist Fenofibrate Ameliorates Sjögren Syndrome-Like Dacryoadenitis by Modulating Th1/Th17 and Treg Cell Responses in NOD Mice.

PurposeTo investigate the effects and mechanisms of fenofibrate, a synthetic ligand of peroxisome proliferator-activated receptor α (PPAR-α), on autoimmune dacryoadenitis in a mouse model of Sjögren syndrome (SS) dry eye.MethodsMale nonobese diabetic (NOD) mice were fed chow with or without 0.03% fenofibrate for 8 weeks, and clinical scores were determined by assessing tear secretion, fluorescein, and hematoxylin and eosin staining. Intracellular IFN-γ, IL-17, and Foxp3 in CD4+ T cells were measured by flow cytometry. The expressions of Th1, Th17, and Treg cell-related transcription factors and cytokines were detected by real-time PCR. The levels of PPAR-α and liver X receptor β (LXR-β) were detected with real-time PCR and Western blotting.ResultsFenofibrate efficiently diminished the lymphocytic inflammation in lacrimal glands (LGs), increased tear secretion, and decreased corneal fluorescein staining in NOD mice. Meanwhile, treatment of fenofibrate evidently reduced the proportion of Th1 and Th17 cells and increased the proportion of Treg cells in vivo and vitro, together with decreased expression of T-bet, IFN-γ, RORγt, and IL-17, as well as increased expression of Foxp3 and TGF-β1 in LGs. Furthermore, fenofibrate significantly upregulated the expressions of PPAR-α and LXR-β at the protein and mRNA levels.ConclusionsFenofibrate potently attenuated LG inflammation in a model of autoimmune dry eye, and this effect might partially result from regulating Th1/Th17/Treg cell responses by activating PPAR-α/LXR-β signaling. These data suggest that fenofibrate may be a novel class of therapeutic agent for SS-associated dacryoadenitis.

Cimetidine and Ibuprofen Modulate T Cell Responses in a Mouse Model of Breast Cancer.

Cimetidine and ibuprofen exhibit immunomodulatory effects as an antagonist of histamine H2 receptor, and a cyclooxygenase inhibitor, respectively. Here, the effects of cimetidine and ibuprofen on some effector T cell-related parameters were investigated using a breast cancer (BC) model. BC was established in Balb/c mice using the 4T1 cell line. On day 10 after tumor induction, the BC-bearing mice were classified into four groups and treated with PBS, cimetidine (20 mg/kg), ibuprofen (20 mg/kg) or a combination of “cimetidine + ibuprofen” via intraperitoneal injection (daily from days 11 to 30). The mice were sacrificed on day 31 and the frequency of splenic Th1 and Treg cells, plasma IFN-γ and TGF-β levels, and intra-tumoral T-bet, GATA3, FOXP3 and RORγt expressions were detected using flowcytometry, ELISA and real-time-PCR, respectively. In untreated cancerous mice, the percentage of splenic Th1 cells and plasma IFN-γ levels were lower (P<0.003 and P<0.01, respectively), whereas the percentage of splenic Treg cells and plasma TGF-β levels were higher than in healthy mice (P<0.04 and P<0.005, respectively). Treatment of BC-bearing mice with cimetidine, ibuprofen or both drugs promoted the frequency of Th1 cells (P<0.05, P<0.007 and P<0.005, respectively) as well as IFN-γ levels (P<0.004, P<0.0001 and P<0.03, respectively), while reduced the frequencies of Treg cells (P<0.02, P<0.03 and P<0.01, respectively), TGF-β levels (P<0.006, P<0.02 and P<0.002, respectively), intra-tumoral expression of FOXP3 (P<0.006, P<0.005 and P<0.005, respectively), and intra-tumoral expression of RORγt (P<0.04, P<0.03 and P<0.05, respectively) compared with untreated BC mice. The “cimetidine + ibuprofen”-treated mice displayed greater T-bet expression than the un-treated mice (P<0.006). Cimetidine and/or ibuprofen-treated BC-bearing mice exhibited reduced intra-tumoral expression of GATA3 compared with the untreated BC mice, but the differences were not significant. Cimetidine and ibuprofen correct some effector T cell-related parameters in cancerous mice. Immunotherapeutic potentials cimetidine and ibuprofen in cancers need investigations.

188-OR: Metabolic Blockade of Glycolysis Can Delay the Adoptive Transfer of Type 1 Diabetes

Type 1 diabetes (T1D) is a result of insulin-secreting pancreatic β-cell destruction by autoreactive CD4 and CD8 T cells. There is no cure for T1D, but determining the role of immunometabolism in promoting autoreactive CD4+ T cell effector responses may provide a novel target in delaying T1D. Systemically inhibiting glycolysis with 2-deoxyglucose (2-DG) can decrease autoreactive CD8 T cell islet infiltration. However, the effects of 2-DG on CD4 T cell diabetogenicity is unknown. Proinflammatory Th1 cells mediate β-cell destruction prefer glycolysis for maintaining effector responses, while immunosuppressive Treg cells prefer oxidative phosphorylation. We hypothesize that metabolic inhibition of glycolysis will diminish proinflammatory Th1 cell responses and delay β-cell destruction in T1D. Utilizing 2-DG, we performed an adoptive transfer of diabetogenic CD4+ T cells from NOD.BDC-2.5 or NOD.BDC-6.9 mice into NOD.scid mice. Recipient mice were systemically treated with 30 mM 2-DG in the drinking water beginning 4 days prior to adoptive transfer and monitored for hyperglycemia for 80 days post-transfer. NOD.scid mice treated with 2-DG had a significant delay in diabetes onset when transferred with either BDC-2.5 (n=14, p=0.0284) or BDC-6.9 (n=17, p=0.0249) CD4+ T cells compared to vehicle-treated groups. To define the effects of 2-DG on autoreactive CD4 T cell effector responses, NOD.BDC-6.9 splenocytes were in vitro stimulated with their cognate hybrid insulin peptide (HIP; insulin C-peptide and islet amyloid polypeptide) with or without 2-DG. Flow cytometry analysis revealed a decrease in T cell proliferation, T cell activation, and Th1 lineage commitment as shown by Ki67, CD25, and T-bet expression, respectively. Effector responses were also dampened as IFN-γ synthesis was decreased in our 2-DG treatment group compared to HIP only controls. Future studies will investigate the effects of 2-DG on CD4 T cell chemokine secretion, trafficking into the islet, and cellular metabolic profiles. Disclosure M.D.Chavez: None. R.Mcdowell: None. H.M.Tse: None.

First-in-human dose escalation and expansion study of MT-6402, a novel engineered toxin body (ETB) targeting PD-L1, in patients with PD-L1 expressing relapsed/refractory advanced solid tumors: Interim data.

2521 Background: MT-6402 is a unique and potent PD-L1-targeted engineered toxin body (ETB) capable of directly killing PD-L1 expressing tumor and immune cells by internalization of a fused Shiga-like toxin A subunit (SLTA) resulting in permanent SLTA-mediated ribosomal inactivation. The targeting of PD-L1 expressing tumor cells may directly drive tumor regression whereas targeting of PD-L1 expressing immune cells may release immunosuppression and drive immune recognition of the tumor. MT-6402 also delivers an HLA-A*02 restricted cytomegalovirus (CMV) class I antigen into PD-L1 expressing cells (antigen seeding) that can be recognized by existing CMV-specific cytotoxic T cells. Methods: A first-in-human dose escalation and expansion study in patients with PD-L1-expressing advanced solid tumors was initiated in 2021. As of 1 Jan 2022, 6 patients received at least one dose of MT-6402, 4 of whom were eligible for Dose Limiting Toxicity (DLT) assessment in Cohort 1. Results: A significant reduction in CD14+ monocytes starting in cycle 2 was observed in patients on therapy after each MT-6402 administration, indicating an HLA-independent PD effect consistent with preclinical observations. 5 of 6 patients had a marked decrease in Monocytic Myeloid Derived Suppressor Cells (MDSC). The reduction in MDSC and monocytes in the periphery overlapped with increased CCL2 levels, a chemokine that directs movement of myeloid cells. One patient with osseous metastases from non-small cell lung cancer (NSCLC) who is HLA-A*02 and CMV+ showed complete CMV-specific T-cell extravasation at day 8 and serum cytokine signatures consistent with antigen dependent responses and T cell mobilization. This patient had reduced tracer uptake of metastatic bone lesions with 3/4 lesions resolving completely. A second HLA A*02 CMV+ patient followed a similar trend towards loss of peripheral CMV-specific T cells with a concurrent increase in total CD8 T cells. The CD8 T cells from these 2 patients had elevated T-bet expression from baseline, indicating antigen specific TCR stimulation and expansion. The activated immune response was also accompanied by increased IP-10 and IL-2 cytokine signatures in the serum. Consistent with these findings, one of these two patients had transient (1-12 h) grade 2 infusion related reaction and the other had transient (1-12 h) grade 2 cytokine release syndrome, both on Day 15. These results describe a novel approach to checkpoint modulation by MT-6402, that adds antigen seeding to PD-L1 directing mechanisms. MT-6402 was well tolerated and no DLT was observed in Cohort 1 (16 µg /kg, QW in 4-week cycles). Conclusions: Dose escalation is ongoing. The results hold promise for development of MT-6402 for solid tumors, including in the R/R setting. Data for additional patients will be presented at the meeting. Clinical trial information: NCT04795713.

CXCR2 antagonist SB332235 mitigates deficits in social behavior and dysregulation of Th1/Th22 and T regulatory cell-related transcription factor signaling in male BTBR T+ Itpr3tf/J mouse model of autism

Autism spectrum disorders is a complex neurodevelopmental disorder characterized by abnormal social interaction, defective communication, repetitive and stereotyped patterns of behaviors or interests. The BTBR T+ Itpr3tf/J (BTBR) inbred mice are generally used as a model for ASD, display a range of autistic phenotypes. Recent studies suggest that the CXCR2 antagonist is crucial for targets in the treatment of inflammatory and neurodegenerative diseases. In this study, we investigated the potential effects of the CXCR2 antagonist SB332235 on sociability behaviors, marble burying, and self-grooming, we also explored the treatment of SB332235 on Th1 (IFN-γ, Stat1, and T-bet), Th22 (IL-22, TNF-α, and AhR), and T regulatory (Treg, IL-10, Helios and Foxp3) production in CD4+ T cells in male BTBR and C57BL/6 (C57) mice in spleen. We also investigated the effects of SB332235 on IFN-γ, IL-10, IL-22, T-bet, AhR, and Foxp3 mRNA expression levels in the brain tissues. The SB332235-treated mice significantly improve behavioral abnormalities in BTBR mice. In addition, SB332235 administration causes a significantly decreases in IFN-γ, Stat1, T-bet, IL-22, TNF-α, and AhR, and increases in IL-10, Foxp3 and Helios production CD4+ T cells in BTBR mice. We further observed that SB332235 downregulated IFN-γ, IL-10, IL-22, T-bet, and AhR, and upregulated IL-10 and Foxp3 mRNA expression in the brain tissues. Our findings demonstrated that SB332235 treatment attenuated behavior deficits, through inhibiting Th1/Th22 and upregulating Treg cell-related transcription factors signaling pathway. Therefore, CXCR2 antagonist administration may be a promising therapeutic agent to attenuate behavior deficits via its anti-inflammatory effect.

Therapeutic effects of myricetin on atopic dermatitis in vivo and in vitro

BackgroundMyricetin (Myr) is a flavonoid compound that exist widely in many natural plants. Myr has been proven to have multiple biological functions, including immunomodulatory and anti-inflammatory effects. PurposeIn this study, we investigated the therapeutic effect of Myr on calcipotriol (MC903) induced atopic dermatitis (AD) mouse model and tumor necrosis factor (TNF)-α/interferon (IFN)-γ stimulated human immortal keratinocyte line (HaCaT) in vivo and in vitro. MethodsMC903 was applied topically to the left ears of mice to establish AD mouse model. After the AD model established successfully, the cream base, dexamethasone (DEX) cream or Myr cream were applied on the lesions of mice for 8 days. Through measuring ear thickness and scoring dermatitis severity, we evaluated the therapeutic effect of Myr, the draining lymph nodes (DLNs) and ears of the mice were collected for mechanistic study. In addition, TNF-α and IFN-γ-activated HaCaT cells were used to investigate the underlying mechanism. ResultsOur data demonstrated that Myr alleviated the symptoms of AD by exerting anti-inflammatory and anti-allergic functions in vivo. We found that Myr treatment suppressed ear swelling and IgE level in the serum, reduced the infiltration of mast cells in skin lesions, decreased expressions of thymus and activation regulated chemokine (TARC), IL-4, IFN-γ and thymic stromal lymphopoietin (TSLP) in ear lesions, increased the expressions of filaggrin (FLG). Furthermore, our experimental results demonstrated that Myr down-regulated the mRNA expressions of T-bet and GATA-3 in DLNs. In vitro, Myr treatment decreased MDC and TARC expressions in IFN-γ and TNF-α-induced HaCaT cells by blocking the NF-κB and STAT1 signal pathway. ConclusionThe present study is the first to investigate the anti-atopic effects of Myr. Our findings suggested the therapeutic effects of Myr against MC903-induced AD-like skin lesions in mice. Therefore, Myr may be a potential therapeutic agent for AD.

Astilbin improves pregnancy outcome in rats with recurrent spontaneous abortion by regulating Th1/Th2 balance

Objective The purpose of this study was to investigate the effect of astilbin on pregnancy outcome in rats with recurrent spontaneous abortion (RSA). Methods 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. Results 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. Conclusions Astilbin has a therapeutic effect on RSA in rats by regulating the balance of Th1/Th2 in maternal circulation and likely in decidual tissue.

Distinct Effector Programs of Brain-Homing CD8+ T Cells in Multiple Sclerosis.

The effector programs of CD8+ memory T cells are influenced by the transcription factors RUNX3, EOMES and T-bet. How these factors define brain-homing CD8+ memory T cells in multiple sclerosis (MS) remains unknown. To address this, we analyzed blood, CSF and brain tissues from MS patients for the impact of differential RUNX3, EOMES and T-bet expression on CD8+ T cell effector phenotypes. The frequencies of RUNX3- and EOMES-, but not T-bet-expressing CD8+ memory T cells were reduced in the blood of treatment-naïve MS patients as compared to healthy controls. Such reductions were not seen in MS patients treated with natalizumab (anti-VLA-4 Ab). We found an additional loss of T-bet in RUNX3-expressing cells, which was associated with the presence of MS risk SNP rs6672420 (RUNX3). RUNX3+EOMES+T-bet− CD8+ memory T cells were enriched for the brain residency-associated markers CCR5, granzyme K, CD20 and CD69 and selectively dominated the MS CSF. In MS brain tissues, T-bet coexpression was recovered in CD20dim and CD69+ CD8+ T cells, and was accompanied by increased coproduction of granzyme K and B. These results indicate that coexpression of RUNX3 and EOMES, but not T-bet, defines CD8+ memory T cells with a pre-existing brain residency-associated phenotype such that they are prone to enter the CNS in MS.

Age-associated B cells indicate disease activity in rheumatoid arthritis

Age-associated B cells (ABCs) are characterized by CD11c and T-bet expression. ABCs are elevated in several autoimmune diseases and may be associated with RA. This study aimed to investigate ABCs’ role in RA and identify potential factors affecting ABCs in RA patients. Peripheral blood mononuclear cells (PBMCs) and plasma samples were collected from 75 RA patients and 27 sex- and age-matched healthy controls. Proportions of ABCs (CD19+CD11c+T-bet+), plasmablasts (CD19+CD27+CD38hi), Bregs (CD19+IL-10+), and T follicular helper (Tfh) cells (CD4+CXCR5+PD-1hi) in PBMCs were detected using flow cytometry. Plasma IL-21, IFN-γ, and IL-10 levels were detected by ELISA. Plasma miRNAs (miR-34a, -122, -133a, -142, -146a, -208a, and -155) were detected by RT-PCR. Naïve B cells transfected with different miRNA mimics were deteced after 3 days culture under stimulation of anti-IgM and anti-CD40 or IL-21, IFN-γ, anti-IgM and anti-CD40. ABC proportions in PBMCs were increased in RA patients with higher disease activity and decreased in those with good treatment responses. Additionally, ABC proportions in PBMCs in RA patients were positively correlated with DAS28 scores. Plasma levels of IL-21, miR-142, and miR-146a and proportions of Tfh cells were positively correlated with ABC percentages in PBMCs. Herein, ABCs were identified as potential biological indicators for disease activity and treatment responses. Moreover, miR-142 and miR-146a could induce the differentiation of ABCs in naïve B cells in conjunction with IL-21 and IFN-γ.

Clinical, Virological and Immunological Subphenotypes in a Cohort of Early Treated HIV-Infected Children.

BackgroundIdentifying subphenotypes within heterogeneous diseases may have an impact in terms of therapeutic options. In this study, we aim to assess different subphenotypes in children living with human immunodeficiency virus (HIV-1), according to the clinical, virological, and immunological characteristics.MethodsWe collected clinical and sociodemographic data, baseline viral load (VL), CD4 and CD8 count and percentage, age at initiation of ART, HIV DNA reservoir size in peripheral blood mononuclear cells (PBMCs), cell-associated RNA (CA-RNA), ultrasensitive VL, CD4 subsets (T effector CD25+, activated memory cells, Treg cells), humoral-specific HIV response (T-bet B cells), innate response (CD56dim natural killer (NK) cells, NKp46+, perforin), exhaustion markers (PD-1, PD-L1, DNAM), CD8 senescence, and biomarkers for T-lymphocyte thymic output (TREC) and endothelial activation (VCAM). The most informative variables were selected using an unsupervised lasso-type penalty selection for sparse clustering. Hierarchical clustering was performed using Pearson correlation as the distance metric and WARD.D2 as the clustering method. Internal validation was applied to select the best number of clusters. To compare the characteristics among clusters, boxplot and Kruskal Wallis test were assessed.ResultsThree subphenotypes were discovered (cluster1: n=18, 45%; cluster2: n=11, 27.5%; cluster3: n=11, 27.5%). Patients in cluster1 were treated earlier, had higher baseline %CD4, low HIV reservoir size, low western blot score, higher TREC values, and lower VCAM values than the patients in the other clusters. In contrast, cluster3 was the less favorable. Patients were treated later and presented poorer outcomes with lower %CD4, and higher reservoir size, along with a higher percentage of CD8 immunosenescent cells, lower TREC, higher VCAM cytokine, and a higher %CD4 PD-1. Cluster2 was intermediate. Patients were like those of cluster1, but had lower levels of t-bet expression and higher HIV DNA reservoir size.ConclusionsThree HIV pediatric subphenotypes with different virological and immunological features were identified. The most favorable cluster was characterized by a higher rate of immune reconstitution and a slower disease progression, and the less favorable with more senescence and high reservoir size. In the near future therapeutic interventions for a path of a cure might be guided or supported by the different subphenotypes.

Interferon Gamma Induction of TH1-like Tregs Controls Anti-viral Responses

Abstract Regulatory T cells (Tregs) are an immunosuppressive cell population that inhibits immune cell function to maintain peripheral tolerance and homeostasis. We have previously shown that Treg-- response to interferon gamma (IFNγ) is required for response to cancer immunotherapy. We aimed to broaden these findings and determine the impact of Treg response to IFNγ and the IFNγ-inducing cytokine IL12, during viral infection. Mice with Treg-restricted deletion of the IFNγ receptor (IFNGR1, Ifngr1L/LFoxp3Cre-YFP) or the IL12 receptor β2 subunit (IL12Rβ2, Il12b2L/LFoxp3Cre-YFP), were infected with the acute (Armstrong), or chronic (Clone 13), strain of lymphocytic choriomeningitis virus (LCMV). Surprisingly, Treg response to IFNγ but not IL12 induced helper T cell 1 (TH1)-like polarization (expression of T-bet, CXCR3 and IFNγ) of Tregs in mice with chronic LCMV infection. Importantly, this effector-like TH1 Treg state was required for adequate suppression of effector T cells during LCMV infection. Additionally, during LCMV infection, Treg-restricted deletion of IFNGR1 not only prevented TH1-like polarization but also reverted these Tregs to a TH2-like state (expression of GATA-3, CCR4 and IL-4). scRNAseq of viral antigen-specific CD8+ T cells from Clone 13 infected mice showed that Ifngr1-deficient Tregs favored CD8+ T cell memory. These findings were confirmed in an Armstrong/Listeria monocytogenes-GP33 memory model. Further, Ifngr1 deletion from Tregs enhanced response to CD8+ T cell-mediated vaccination when challenged with Clone 13. These findings provide fundamental insight on how Tregs sense inflammatory cues from the environment (IFNγ) during viral infection to prevent overt tissue damage and shape the memory response. Supported by grants from NIH (F32 CA247004-01, T32 CA082084, P01 AI108545, R35 CA263850, R01 CA203689, R01 DK130897, P30 DK120531, P30 CA047904, R01 HL107380, R01 CA206517, R01 AI138504)

Transcriptional profiling of human Vδ1 Tcells reveals a pathogen-driven adaptive differentiation program.

SUMMARYγδ T cells are generally considered innate-like lymphocytes, however, an ‘‘adaptive-like’’ γδ compartment has now emerged. To understand transcriptional regulation of adaptive γδ T cell immunobiology, we combined single-cell transcriptomics, T cell receptor (TCR)-clonotype assignment, ATAC-seq, and immunophenotyping. We show that adult Vδ1+ T cells segregate into TCF7+LEF1+Granzyme Bneg (Tnaive) or T-bet+Eomes+ BLIMP-1+Granzyme B+ (Teffector) transcriptional subtypes, with clonotypically expanded TCRs detected exclusively in Teffector cells. Transcriptional reprogramming mirrors changes within CD8+ αβ T cells following antigen-specific maturation and involves chromatin remodeling, enhancing cytokine production and cytotoxicity. Consistent with this, in vitro TCR engagement induces comparable BLIMP-1, Eomes, and T-bet expression in naive Vδ1+ and CD8+ T cells. Finally, both human cytomegalovirus and Plasmodium falciparum infection in vivo drive adaptive Vδ1 T cell differentiation from Tnaive to Teffector transcriptional status, alongside clonotypic expansion. Contrastingly, semi-invariant Vγ9+Vδ2+ T cells exhibit a distinct ‘‘innate-effector’’ transcriptional program established by early childhood. In summary, adaptive-like γδ subsets undergo a pathogen-driven differentiation process analogous to conventional CD8+ T cells.

Neonatal Immunity to Malaria using a mouse model

Abstract High mortality rates caused by malaria are seen in children under five years, but there is limited knowledge on neonatal immunity to the Plasmodium infection due to the lack of a reliable neonatal animal model to study the disease in children. By utilizing a newly developed young rodent model in our lab, we have observed that purified CD4+ T cells from day 14 old young mice (pups) proliferate slower than those purified from 8-week adult mice when stimulated in vitro. To investigate neonatal CD4+ T cell response to malaria, we infected 14-day old pups or adult mice with Plasmodium chabaudi and determined the activation status (CD127−CD44+CD11a+) and differentiation of effector (Teff) subsets, using the expression of CD62L or CD27. Pup CD4+ T cells were activated by downregulating CD127, even though in lower proportions and numbers when compared to adult CD4+ T cells. Surprisingly, there were more proportions of TeffEarly (CD27+CD62L+) and TeffInt (CD27+CD62L−) subsets in the pups than adult mice, which had mostly TeffLate (CD27−CD62L−), suggesting that the transition of Teff subsets is slower in the young mice. We next determined cytokine secretion and Tbet expression by the Teff. Apart from IL-2 which was high in the pups, there was no difference in the proportions of protective cytokines including IFNγ, IL-10 and TNFα in both groups. Effector CD4+ T cells from the pups expressed high proportions of the Tbet transcription factor when compared to adult cells. Taken together, these data suggest that pup CD4 T cells may require more Tbet to differentiate into functional effector cells during Plasmodium infection. Supported by Depart of Biology Appalachian State University

Abstract 503: Multiparameter Mass Cytometry Reveals The Unique Response Of NaïVe B Cell Cd27 - Subset With The Increase Of T-bet And Cd38 Expression After Radiation Therapy In Thoracic Cancer Patients

Cancer Radiation therapy (RT) induces cardiovascular disease (CVD) even when the heart is shealed or not irradiated, but there is a paucity of available preventive measures for RT-induced CVD. Ionizing radiation (IR) induces senescence, which was originally discovered to suppress tumorigenesis by inducing cell cycle blockade and necrosis, and positioned IR as pro-senescence cancer therapy. IR-induced senescence cells secrete cytokines, growth factors, and reactive oxygen species (ROS), becoming so called senescence associated secretory phenotype (SASP), and we hypothesize that SASP induction in immune cells cause CVD after RT. Although the involvement of DNA damage response (DDR), efferocytosis, and clonal hematopoiesis drivers (CHD) to SASP induction has been suggested, the exact mechanisms through which RT induces SASP in a specific cell type remains unclear. We characterize most of the major human immune cell lineages in a single assay using mass cytometery (CyTOF). We generated a CyTOF panel which includes antibodies against various senescence phenotype, DDR, efferocytosis, and CHD. We isolated peripheral blood mononuclear cells (PBMCs) before and 3 month after RT from 16 thoracic cancer patients. First, we found the frequency of only B cell subtype was decreased after RT. Second, we obtained 138 functional profiling subsets by unsupervised clustering with our antibody set, and found that T-bet expression was increased in the largest B cell subset of naïve B Cell (CD27 - ) Ki67 lo CD38 lo DNMT3a hi after RT, which showed the good correlation with p-p90RSK expression in the samples from pre-RT and post-RT. Lastly, the significant increase of CD38 expression in the subsets of naïve B cell (CD27 - ) and CD8 + T cell (EMRA) was detected. These data suggest the unique response of naïve B cell (CD27-) to RT with the increase of CD38 expression, and T-bet in the subset of B Cell (CD27 - ) Ki67 lo CD38 lo DNMT3a hi , and also the potential role of p90RSK activation in IR-induced T-bet expression. T-bet plays a role in developing the age-associated B cell (ABC), and the increase of CD38 expression promotes aging-related events. Therefore, the induction of T-bet and CD38 in naïve B (CD27 - ) cell after RT supports the novel role of naïve B cell in IR-induced SASP and subsequent CVD.

Psychological Stress of aged mice has long-term impact on Mycobacterium tuberculosis infection by altering composition of lung T cell populations

Abstract Aging is a major risk factor for chronic infections, including tuberculosis (TB). Elderly TB patients also suffer from elevated levels of psychological stress. It is not known how psychological stress impacts TB pathogenesis. To study the effects of stress on Mycobacterium tuberculosis (M.tb) we used a social disruption stress (SDR) model which involves repeated social defeat in subordinate mice. Young (3 month) and Old (18 month) C57BL/6 mice were subjected to SDR and infected with M.tb. Mice were sacrificed at 30 and 60 days post infection and M.tb burden analyzed by CFU assay and lung pathology by HE staining of lung sections. At day 30, M.tb burden was lower in control old mice compared to young mice and SDR did not significantly alter M.tb burden. However, at day 60, SDR in old mice significantly increased M.tb burden compared to SDR in young mice, indicating that SDR in old mice has a detrimental effect on the ability to control the infection. Our gene expression analysis revealed that T cell genes (JAK3 and LCP2) in the lungs of old SDR infected mice were increased but not in young SDR mice, suggesting that SDR in old mice increased T cell recruitment in the lung. Additionally, we found that Tbet (Th1) and GATA3 (Th2) gene expression were unchanged by SDR, in contrast the expression of RORγT (Th17) was increased by SDR in old mice at day 60. Also, mRNA levels of IL-10 at day 60 were increased by SDR in old mice, but not in young mice, while SDR decreased IFN-γ in both young and old mice. To further define T cell populations, we are analyzing lung sections by confocal microscopy. In conclusion, our studies suggest that psychological stress prior to M.tb prior to infection has long-term impact by altering composition of T cell populations in the lung. Supported by NIH grants (PO1-AG051428, AI146252 and AI146690)