bluuebunny/crossref_metadata_2025_split huggingface dataset:
Butyric acid inhibits a Toll-like receptor 2 agonist-mediated increase of Toll-like receptor 3-induced chemokine production by HT-29 intestinal epithelial cells (IRC10P.413)
Authors: Shastri Padmaja , Green-Johnson Julia 
Published: January 2023

Abstract
The intestinal epithelium interacts with varied microbial components and metabolites, integrating multiple signals that influence immunity. We examined the time and dose-dependent effects of a Toll-Like Receptor (TLR) 2 agonist lipoprotein Pam3Cys (P3C) and the bacterial fermentation metabolite butyric acid (BA) (10mM and 25mM) on TLR3 agonist (poly(I:C)) (pIC)-induced chemokine production by HT-29 intestinal epithelial cells (IEC). Pre-treatment of HT-29 IEC with P3C enhanced (p(IC))-induced IL-8 production. However, pre-treatment of HT-29 IEC with P3C and 25mM BA together inhibited p(I:C)-induced IL-8 production, suggesting BA blocked the enhancing effect of this TLR2 agonist on TLR3-induced chemokine production. This inhibitory effect was not observed when IEC were pre-treated with a lower concentration of BA (10mM). Co-incubation of IEC with P3C and p(I:C) did not enhance TLR3 agonist-induced IL-8 production, while co-incubation with 10mM or 25mM BA acid significantly reduced p(I:C)-induced IL-8 and CXCL-10 production by HT-29 IEC. In addition, a p38 blocker (SB203580) significantly inhibited p(I:C)-induced IL-8 production by HT-29 IEC, while co-incubation with SB203580 and 10mM BA showed no additive inhibition. These findings suggest that while TLR2 agonists can upregulate TLR3-induced chemokine production, butyric acid inhibits this process, and the effects of TLR2 agonists and BA are dependent on timing of contact with IEC relative to TLR3 agonist stimulation.
Apoptotic cell-treated dendritic cells induce immune tolerance through specifically facilitating development of CD4+ effector memory T cells (IRC10P.408)
Authors: Zhang Guang-Xian , Zhou Fang , Rostami A 
Published: January 2023

Abstract
CD4+ memory T cells play an important role in induction of autoimmunity and chronic inflammatory responses. However, regulatory mechanisms of CD4+ memory T cell-mediated inflammatory responses are poorly understood. Here we showed that apoptotic cell-treated dendritic cells inhibit development and differentiation of CD4+ effector and central memory T cells in vitro and in vivo. Simultaneously, i.v. transfer of apoptotic T cell-induced tolerogenic dendritic cells can block development of experimental autoimmune encephalomyelitis (EAE), an inflammatory disease in central nervous system of C57BL/6J mouse. However, our results imply that it is effector memory CD4+ T cells, not central memory CD4+ T cells which play a major role in chronic inflammatory responses in mice with EAE. I.v. transfer of tolerogenic dendritic cells induced by apoptotic T cells leads to immune tolerance through specifically blocking development of CD4+ effector memory T cells compared with results of EAE control mice. Our results reveal a new mechanism of apoptotic cell-treated dendritic cell-mediated immune tolerance in vivo.
Infectious tolerance of LAG-3+ regulatory T cells with attenuated T-bet induction (IRC11P.433)
Authors: Huang Ching-Tai , Dutta Avijit , Miaw Shi-Chuen , Drake Charles , Powell Jonathan , Pardoll Drew 
Published: January 2023

Abstract
Infectious tolerance describes the maintenance of tolerance by a small number of antigen-specific regulatory T (Treg) cells through converting naïve T cells into further cohorts of Treg cells in vivo. Thus a very small number of antigen-specific Treg cells can be so efficient in exerting long-term suppressive effect with self-perpetuating immune homeostasis in vivo. We have previously shown LAG-3+ CD4+ Treg cells are engaged in dominant immune regulation in vivo. Here we revealed that LAG-3+ CD4+ Treg cells pass on the suppressive activity to the naïve CD4+ T cells they suppress and enable them to become the next generation of Treg cells. The effector function of suppressed CD4+ T cells is modulated with diminished T-bet induction and interferon-γ production. However, they still expand, acquire LAG-3 expression and in turn suppress the activation of another batch of naïve CD4+ T cells in vivo. The suppressed cells express elevated level of active TGF-β but not IL-10. Suppressed cells with Foxp-3 expression acquire LAG-3, although the overall Foxp-3 expression is not increased. Our results imply activation with attenuated effector function as the major mechanism by which LAG+ CD4+ Treg cells propagates their suppressive abilities and the infectious tolerance.
Intravenous immunoglobulin drives regulatory B cell expansion in the absence of endogenous regulatory T cells (IRC11P.436)
Authors: Kaufman Gabriel , Xue Di , Beland Marianne , Massoud Amir , Mazer Bruce 
Published: January 2023

Abstract
We have shown that induced regulatory T cells (iTreg) are necessary and sufficient to rescue antigen-challenged mice in a murine model of allergic airways disease (AAD). Intravenous immunoglobulin (IVIg) treatment of wild-type mice sensitized and challenged to antigen induces Treg in a dendritic-cell (DC) dependent mechanism. In the present study, DEREG mice (which co-express diphtheria toxin (DT) receptor with Foxp3, allowing for selective transient depletion of Treg) were treated with IVIg after depletion of all endogenous Treg with DT. This induces a phenotypically distinct population of functional iTreg. This increase in iTreg is associated with significant augmentation of systemic regulatory B cells (Breg), which express IL-10 and are CD138-high Blimp-low plasmablasts. Under these conditions, all aspects of AAD are ameliorated. However, in animals with an intact endogenous Treg compartment, Breg are not significantly increased by IVIg treatment. We postulate a balance between regulatory cells which favors Treg, and may shift to Breg in the absence of endogenous Treg. Further work will delineate the Breg:Treg balance and how these regulatory subsets contribute to suppression of allergic inflammation.
Characterization of cannabidiol-induced increases in CD25 and FOXP3 expression on CD4+ T cells (IRC11P.421)
Authors: Dhital Saphala , Stokes John , L. Kaplan Barbara 
Published: January 2023

Abstract
Cannabis sativa-derived cannabinoid compounds are being investigated as potential immunosuppressive agents and important drug candidates for immune related diseases. Our previous data demonstrated that under conditions of suboptimal T cell activation, cannabidiol (CBD) could increase interleukin-2 (IL-2) production. Initially this result was surprising given that cannabinoids are immunosuppressive, but IL-2 can also contribute to regulatory T cell (Treg) induction. We tested the hypothesis that part of the mechanism for immunosuppression by CBD is induction of a Treg population in response to suboptimal activation. Splenocytes were treated with CBD or vehicle (VH; 0.1% ethanol) for 30 minutes, then stimulated with low concentrations of PMA and ionomycin (Io). CBD induced IL-2, TGF-β, CD25 and FOXP3 on CD4+ T cells in response to 4 nM PMA/0.05 µM Io after an overnight stimulation. Further characterization of this effect demonstrated that CBD also induced CD25 and FOXP3 on CD4+ T cells after a 5-day incubation with 1 nM PMA/0.01 µM Io. Interestingly, while CBD robustly induced IL-2 after an overnight incubation with 4 nM PMA/0.05 µM Io, the IL-2 in the culture supernatant dropped by day 5. Overall, these data suggest that the mechanism by which CBD is immunosuppressive might involve induction of Tregs in response to suboptimal activation of T cells.
ITK controls the functional stability of regulatory T cells by limiting pathogenic reprograming in inflamed mucosa (IRC11P.422)
Authors: Huang Weishan , Deol Simrita , Koylass Nicholas , August Avery 
Published: January 2023

Abstract
CD25hiFoxp3+CD4+ regulatory T cells (Tregs) are important immune regulators that promote immune tolerance, but can also form barriers to effective immunity against tumor and chronic infection. IL-2-inducible T cell kinase (ITK) is highly expressed in T cells and regulates T cell development and function. We find that ITK is required for full suppressive function of natural Tregs in preventing the expansion of pro-inflammatory CD4+ effector T cells and chronic pulmonary and colonic inflammation upon transfer into Rag-/- mice. In the absence of ITK, Treg homing to these inflamed mucosal systems is intact, however, a significant proportion is converted into pathogenic effector T cells with ability to produce IL-17A and/or IFN-γ in the inflamed lung and colon, but not in the spleen. Such loss of functional stability and gain of pathogenic reprograming are T cell intrinsic and can be rescued by re-expression of ITK in Itk-/- Tregs. Homeostatic expansion contributed to the initiation of Itk-/- Treg destabilization and pathogenic conversion but did not trigger pathogenesis. Stimulation through the T cell receptor in the presence or absence of various cytokines revealed that ITK is required for sustaining Foxp3 expression. We conclude that ITK signals suppress pathogenic conversion of Tregs by maintaining Foxp3 expression, and contributes to the functional stability of Tregs in the face of inflammation by limiting their reprograming towards the pathogenic effectors.
Highly focused TCR Vβ repertoire is associated with a large number of naive precursors and robust CD8 T cell responses specific for a Plasmodium antigen (IRM14P.450)
Authors: Van Braeckel-Budimir Natalija , Harty John 
Published: January 2023

Abstract
Here we describe, to our knowledge, the most TCRβ focused CD8 T cell response to date. This TCR is specific for a conserved Plasmodium-derived epitope in mice (GAP5041-48), presented by H-2Db. After various immunization regimens, &gt;99% of epitope-specific CD8 T cells detected by tetramer staining expressed TCR Vβ8.1 (TRB). Interestingly, priming with dendritic cells coated with GAP5041-48 peptide resulted in the same TCR Vβ distribution, suggesting that the observed bias does not evolve with multiple antigen exposures. Additionally, DC-priming induced exceptionally strong responses only 4 days post-immunization (~20% of total CD8 T cells were tetramer positive), suggesting an unusually large antigen-specific naïve CD8 T cell repertoire. Currently, the upper limit for the size of antigen-specific naive CD8 T cell repertoire ranges from 600-1500 cells (VacV B8R, MCMV M45). We show that GAP5041-48-specific naïve CD8 T cell repertoire, with its size of ~2,200 cells, extends this upper limit by more than 40%. Finally, classical Ala-substitution screening of the peptide (SQLLNAKYL), showed that amino acids (aa) at positions 6 and 7 are critical for TCR recognition. This epitope could be used as a valuable tool for better understanding the relation between a TCR structure and thymic selection. Moreover, the unique property of GAP5041-48-specific response make it a powerful tool to study fundamental processes underlying CD8 T cell activation upon Plasmodium infection.
Distinct stage-specific function of T-box transcription factors in the antiviral NK cell response (IRM14P.446)
Authors: Madera Sharline , Sun Joseph 
Published: January 2023

Abstract
The T-box transcription factors T-bet and Eomesodermin (Eomes) instruct discrete stages of natural killer (NK) cell development. Their role in the response of mature NK cells against pathogen infection has not been investigated. Here, we use an inducible gene deletion system to elucidate the role of T-bet and Eomes in mature NK cells during the course of murine cytomegalovirus (MCMV) infection. We show that although both transcription factors are dispensable for maintaining NK cell numbers during homeostatic proliferation, T-bet and Eomes are necessary for the proliferation of virus-specific NK cells during MCMV infection. T-bet, but not Eomes, is upregulated in NK cells early after viral infection, through pro-inflammatory cytokine and STAT4 signaling. However, deletion of either T-bet or Eomes in mature NK cells during viral infection led to a diminished NK cell response in lymphoid and nonlymphoid organs. Interestingly, maintenance of memory NK cell numbers was dependent on T-bet, but not Eomes. These data uncover a non-redundant and stage-specific influence of T-bet and Eomes on the NK cell response against infection.
Beyond innate immunity: the role of interferon regulatory factor 3 in CD4+ T cell function (IRM15P.462)
Authors: Fares-Frederickson Nancy , Otero Dennis , Macal Monica , Zuniga Elina , David Michael 
Published: January 2023

Abstract
Interferon regulatory factor 3 (IRF3) is a transcription factor found in the cytoplasm of most nucleated cells. Upon pathogen recognition, IRF3 becomes activated and translocates to the nucleus where it mediates the production of type I interferon (IFN). Whereas IRF3 has been studied extensively in the context of type I IFN production and innate immunity, its role in adaptive immunity has remained largely unexplored. The objective of our research is to elucidate the role of IRF3 in CD4+ T cell function. Our findings demonstrate that IRF3-deficient CD4+ T cells show robust proliferation in response to TCR engagement, but are compromised in their ability to differentiate into specialized T helper cell subsets—most notably IL-17-producing Th17 cells. As such, CD4+ T cells lacking IRF3 expression fail to induce disease in the T cell transfer model of colitis. These studies reveal a novel, T cell-intrinsic function of IRF3 and extend its role beyond the innate immune response to pathogens.
Tspan33 is differentially expressed during B cell differentiation (LYM7P.620)
Authors: Perez-Martinez Cesar , Zlotnik Albert , Santos-Argumedo Leopoldo 
Published: January 2023

Abstract
Tetraspanin 33 (Tspan33) is a transmembrane protein highly expressed in activated B cells. Tspan33 is a member of the tetraspanin family, which is characterized by conserved domains and functions. Tetraspanins provide a scaffold for the formation of membrane microdomains, called Tetraspanin Enriched Microdomains. Other members of this family have been implicated in cellular adhesion, motility, invasion and signaling. Tspan33 is important for the Notch signaling pathway, because it is essential for the correct membrane localization of ADAM10, an important sheddase in the Notch pathway. The aim of this study is to describe the expression pattern of Tspan33 in different subsets of human B cells. Peripheral and Umbilical cord blood mononuclear cells were separated using density gradients and cell sorting to separate different B cells subsets based on the markers CD19, CD27, IgD, CD38 and CD24. We then used RT-PCR to measure Tspan33 expression. These results were confirmed by flow cytometry. Our results indicate that Tspan33 is differentially expressed during B cell differentiation, with the lowest expression in Naïve B cells and the highest in the Memory B cell compartment.
Notch signaling regulates antigen sensitivity of naive CD4+ T cells by tuning co-stimulation (LYM7P.613)
Authors: Laky Karen , Evans Sharron , Fowlkes B 
Published: January 2023

Abstract
Adaptive immune responses begin when naïve CD4+ T cells engage peptide+major histocompatibility complex class II and costimulatory molecules on antigen-presenting cells (APC). Notch signaling can influence effector functions in differentiated CD4+ T helper and T regulatory cells. Whether and how ligand-induced Notch signaling influences the initial priming of CD4+ T cells has not been addressed. We have found that Delta Like Ligand 4 (DLL4)-induced Notch signaling potentiates phosphatidyl inositol 3-OH kinase (PI3K)-dependent signaling downstream of the T cell receptor+CD28, allowing naïve CD4+ T cells to respond to lower doses of antigen. In vitro, DLL4-deficient APC were less efficient stimulators of CD4+ T cell activation, metabolism, proliferation, and cytokine secretion. With deletion of DLL4 from CD11c+ APC in vivo, these deficits translated to an impaired ability to mount effective CD4+ T cell-dependent immune responses. These data implicate Notch signaling as an important regulator of adaptive immune responses.
IFNγ restrains Th1 expansion in experimental autoimmune encephalomyelitis (LYM8P.634)
Authors: Sestero Christine , Naves Rodrigo , De Sarno Patrizia , Raman Chander 
Published: January 2023

Abstract
We found that the enhanced experimental autoimmune encephalomyelitis (EAE) severity in Ifngr1-/- mice was associated with elevated numbers of Th1 cells and level of IFNγ in brain and spinal cord. Furthermore, encephalitogenic Th1 polarized T cell cultures generated from Ifngr1-/- mice immunized with MOG35-55 peptide to induce EAE contained several fold greater numbers of IFNγ-expressing Th cells than in similar T cell cultures from WT mice. These observations oppose the dogma that IFNγ signaling has a feed forward activity for Th1 expansion and led us to investigate the possibility that IFNγ functions as a negative feedback for Th1 differentiation and/or expansion. The addition of neutralizing anti-IFNγ mAb during in vitro Th1 polarization of in vivo primed CD4 T cells resulted in the generation of at least a two-fold greater number of IFNγ+ T cells. This effect of anti-IFNγ mAb was not observed with CD4 T cells primed in vitro or with CD4 T cells lacking IFNGR or STAT1. We further determined that IFNγ constrained Th1 expansion by T cell intrinsic expression of iNOS and production of nitric oxide. IFNγ treatment effectively attenuated EAE induced by encephalitogenic Th1 cells but not Th17 cells. Our results reveal that IFNγ has a primary role in restraining Th1 program in vivo. Thus targeting the IFNγ signaling pathway might be effective in a Th1 predominant autoimmune disease. Supported by grants from the IRACDA/NIGMS (CS), NIH (PD, CR), NMSS (CR); and FONDECYT 1140049 (RN).
Tpl2 differentially regulates IFNγ and IL-17 production by CD4+ T cells in a T cell transfer model of colitis. (LYM8P.636)
Authors: Acuff Nicole , Li Xin , Kirkland Rebecca , Nagy Tamas , Watford Wendy 
Published: January 2023

Abstract
Autoimmune diseases are approaching epidemic levels, estimated to affect 5-8% of the population. A number of autoimmune diseases are driven by autoreactive T cells, specifically T helper 1 (Th1) and T helper 17 (Th17) cells. One molecule gaining interest as a therapeutic target is the serine-threonine kinase, Tpl2, which promotes expression of proinflammatory mediators. We previously demonstrated that Tpl2 regulates Th1 differentiation, secretion of the inflammatory cytokine IFNγ, and host defense against the intracellular parasite Toxoplasma gondii. The goal of this study was to determine whether Tpl2 also regulates Th1 or Th17 differentiation in vivo in a T cell transfer model of colitis associated with mixed Th1/Th17 pathology. In vitro, Tpl2-/- naïve CD4+ T cells were impaired in IL-17A secretion under traditional Th17 inducing conditions of IL-6+TGF-β. Reduced IL-17A secretion correlated with increased expression of FoxP3, a transcription factor known to antagonize RORγt function. In vivo, transfer of Tpl2-/- T cells resulted in reduced proportions of CD4+ T cells expressing IFNγ, but not IL-17A, compared to that induced by wild type T cells. Further studies revealed that Th17 cells alternatively induced by IL-6+IL-23 was unaffected by Tpl2 deficiency. Collectively, these results implicate Tpl2 in TGF-β-induced FoxP3 expression. Additionally, they underscore the contribution of Tpl2 to Th1-dependent responses, including Th1-mediated immunopathology during autoimmunity.
Deep sequencing of the TCRB repertoire of human Foxp3+ and Foxp3- T cells demonstrates that they are completely distinct and non-overlapping (LYM8P.638)
Authors: Golding Amit , Darko Samuel , Wylie William , Douek Daniel , Shevach Ethan 
Published: January 2023

Abstract
Maintenance of peripheral tolerance requires a balance between auto-reactive conventional T cells (Tconv) and thymically-derived Foxp3+ regulatory T cells (tTregs). Considerable controversy exists regarding the similarities/differences in TCR repertoires expressed by Tconv and tTregs. We generated highly purified populations of human Tconv and tTregs based on the differential expression of CD25 and CD127. The purity of the sorted populations was validated by intracellular staining for Foxp3 and Helios. We used deep sequencing of entire TCRB sequences to analyze the TCR repertoire of Tconv and tTregs. Our studies demonstrate that Tconv and tTreg cells are, in fact, entirely distinct CD4+ T cell lineages.
Differential regulation of PTEN and Akt by TCR signal strength controls CD4+ T cell fate decisions (LYM8P.627)
Authors: Hawse William , Morel Penelope 
Published: January 2023

Abstract
Akt/mTOR signaling influences CD4+ T cell differentiation; low levels favor Treg induction and high levels favor Th induction. Here, we identify several key elements in this pathway that are differentially regulated by TCR signal strength, including Akt, mTORC2 and the lipid phosphatase PTEN. The control of PTEN is poorly studied in T cells. Here, we identify multiple mechanisms that regulate PTEN. During Th induction, PTEN function is suppressed via lower mRNA levels, lower protein levels and an increase in phosphorylation. During Treg induction, PTEN function is maintained through the stabilization of PTEN mRNA transcription and sustained protein levels. Differential Akt/mTOR signaling regulates PTEN transcription via FoxO1. Additionally, Akt is controlled by the TCR signal. Phosphorylation of FoxO1 by Akt requires that Akt is phosphorylated on Thr308 and Ser473 by PDK1 and mTORC2 respectively. Different TCR signal strengths resulted in alternate phosphorylation on Akt where low TCR signal strength only induces phosphorylation of Thr308 on Akt. Low TCR signals result in the phosphorylation of an inhibitory site on Rictor, a subunit of mTORC2, thus providing a mechanism by which Akt activity is controlled by TCR signal strength. Proteomic data suggests that low and high TCR signal strength induce non-overlapping sets of phosphorylated Akt substrates. This work reveals how differential regulation of the Akt/mTOR pathway drives alternate CD4+ T cell fate outcomes.
ICOS-ICOSL interaction-independent Tfh cell differentiation of Foxp1-deficient CD4+ T cells (LYM8P.629)
Authors: Geng Jianlin , Wei Hairong , Shi Bi , Wang Haikun , Stevens Anna , Sprout Stephanie , Hu Hui 
Published: January 2023

Abstract
CD4+ T follicular helper (Tfh) cells are essential for germinal center (GC) and long-lived antibody responses. Studies have shown that the deletion of the inducible T cell co-stimulator (ICOS) results in severe defects of Tfh cell differentiation and germinal center responses. It has been shown that ICOS-ICOS ligand (ICOSL) interaction is not only critical for Bcl6 induction, but also essential for the follicular recruitment of activated CD4+ T cells by follicular bystander B cells that collectively form an ICOS-engaging field. Previously we have identified transcription factor Foxp1 as a critical negative regulator of Tfh cell differentiation. We now provide evidence showing that naïve CD4+ T cells deficient in both Foxp1 and ICOS still differentiate into Tfh cells at high frequencies with Bcl6 induced. Such results are confirmed in ICOSL-deficient recipient mice, in which Foxp1-deficient CD4+ T cell differentiate into Tfh cells. Taken together, our studies suggest that Foxp1 plays a profoundly dominant role in regulating Tfh cell differentiation.