bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fluvastatin elicits apoptosis in primary and transformed mast cells (INC6P.305)
Authors: Paez Patrick , Ryan John , Taruselli Marcela , Ndaw Victor 
Published: January 2023

Abstract
Mast cell leukemia is a rare subtype of acute myelogenous leukemia. A majority of mast cell leukemias express the c-Kit mutation, D816V, which yields factor-independent growth. Understanding and treating mast cell hyperplasias and leukemias could be beneficial to both allergic and malignant diseases. Recently the family of statin drugs, widely employed as HMG CoA Reductase inhibitors to lower serum cholesterol, have also been found to be immunosuppressive. We report that Fluvastatin induces apoptosis in mouse bone marrow-derived mast cells (BMMC) in a dose-and time-dependent manner. Apoptosis was evidenced by DNA fragmentation and Caspase-3/7 activation. Interestingly, BMMC from the C57BL/6 background were responsive to Fluvastatin-mediated death, while those from 129/SvJ mice were completely resistant. Resistance was matched by a 2-fold induction of HMG CoA Reductase after Fluvastain treatment. Importantly, the mastocytoma line P815, which expresses mutant c-Kit, was readily killed by Fluvastatin, with an IC50 between 5-10µM, and maximum effects after 72 hours. Mitochondrial staining detected membrane disintegration after 48-72 hours, while cells tested positive for active Caspase-9 as early as 24-48 hours. These preliminary data support the theory that statin family drugs may be a new therapeutic approach for suppressing growth of both normal and transformed mast cells, and emphasize the contribution of genetic background to drug responsiveness.
Macrophages are a central hub of innate immunity and inflammatory signaling programs induced by HCV/HIV coinfection. (INM6P.344)
Authors: Aarreberg Lauren , Gale Michael 
Published: January 2023

Abstract
Hepatic inflammation is a hallmark feature of pathogenesis due to HCV/HIV-1 coinfection but the processes that propagate this inflammatory response are not understood. Coinfection of HIV-1 within the HCV-infected liver results more commonly in inflammatory liver disease than monoinfection of either virus, with a quicker progression to end-stage disease. HCV causes significant liver inflammation by triggering inflammasome activation after uptake by hepatic macrophages. Also known as “Kupffer cells”, these CD4+ cells are targets of HIV-1 infection. Phagocytosed HCV particles are potent activators of the NLRP3 inflammasome driving IL1β secretion from macrophages to impart liver inflammation. Here, we evaluated coinfection in human THP1 macrophages as a model of Kupffer cells. We demonstrate that like HCV, HIV-1 activates the inflammasome in these cells upon infection. Coinfection synergizes the inflammatory response, resulting in the production of pro-inflammatory mediators known to drive immune infiltration, tissue damage, and liver fibrogenesis. Furthermore, we have defined the macrophage-secreted cytokine milieu that accompanies monoinfection vs coinfection, revealing how each virus directs an innate immune response on its own and during coinfection. Our studies identify the hepatic macrophage as a hub of inflammatory signaling and reveal crosstalk between virus-responsive inflammatory signaling pathways that underlie hepatic disease and destruction in HCV/HIV-1 coinfection.
Novel role for scavenger receptor B-I in neutrophilic asthma (IRC10P.419)
Authors: Gowdy Kymberly , Madenspacher Jennifer , Thomas Seddon , Nakano Hideki , Cook Donald , Fessler Michael 
Published: January 2023

Abstract
Asthma is a heterogeneous airway disease that has risen significantly in recent decades. While there has been a major research focus on eosinophilic asthma, the neutrophilic, Th17-predominant disease that characterizes severe asthmatics is less understood. Scavenger Receptor B-I (SR-BI) is a receptor mostly studied in the context of cellular uptake of cholesterol. Recently, we reported that SR-BI regulates the pulmonary innate immune response, but the role of SR-BI in asthma is unknown. Therefore, SR-BI+/+ and SR-BI-/- mice were sensitized on days 0 and 7 by oropharyngeal aspiration of ovalbumin (OVA) together with LPS and then challenged on day 14 with an aerosol OVA. Airway inflammation and cytokines were quantified 48hrs after challenge. Bone marrow-derived dendritic cells (BMDCs) from SR-BI+/+ and SR-BI-/- mice were co-cultured in the presence of OVA/LPS with CD4+ T cells from OT-II mice that carry a transgenic TCR specific for the MHC class II-restricted OVA peptide (OT-II Tg). Compared to SR-BI+/+ counterparts, SR-BI-/- mice had increased pulmonary neutrophils, Th17 cells, G-CSF and CXCL5 after OVA challenge, but had equivalent amounts of IL-4, IL-5, and eosinophils. BMDCs from SR-BI-/- mice have elevated levels of CD80 and CD86, and CD4+ OT-II Tg T cells produced more IL-17 after culture with OVA/LPS. SR-BI modulates the lung’s response to environmental adjuvants such as LPS by regulating Th17 polarization, suggesting a novel role for SR-BI in neutrophilic asthma.
IL-2 produced by memory CD4 T cells synergizes with influenza A virus to amplify detrimental lung inflammation (IRC10P.404)
Authors: Strutt Tara , McKinstry Karl , Swain Susan 
Published: January 2023

Abstract
Memory CD4 T cells capable of producing IL-2 in addition to IFNγ are often more effective at combating pathogens than those producing IFNγ alone. The impact of IL-2 on protective memory responses, however, is not well defined. To test if IL-2 contributes to memory CD4 T cell protection, we transferred wild type or IL-2-deficient memory CD4 T cells to unprimed mice and challenged with lethal doses of influenza A virus (IAV). We find comparable expansion of both donor populations and kinetics of viral clearance in both recipients. Strikingly, recipients of IL-2-deficient cells exhibit reduced weight loss, improved lung function, and earlier recovery. The improved outcome in recipients of IL-2-deficient memory cells correlates with significantly tempered inflammatory responses. To more directly assess the pro-inflammatory capacity of IL-2, we administered IL-2: anti-IL-2 antibody complexes targeting delivery to cells expressing distinct IL-2 receptors. IL-2 administration dramatically up-regulates a remarkably broad array of inflammatory mediators systemically and particularly in the lung. Multiple adaptive and innate cell populations contribute. IL-2 administration rapidly impaired lung function in unprimed animals and synergized with IAV infection to cause lethal lung damage. Our findings highlight that IL-2 produced by memory CD4 T cells can contribute to pulmonary inflammation during protective responses and have implications for improving IL-2 based therapies.
TGF-β1-induced regulatory T cells directly suppress B cells through non-cytotoxic manner (IRC11P.423)
Authors: Zheng Song , Liu Ya , Chen Weiqian , Xu Anping , Wang Julie , Olsen Nancy 
Published: January 2023

Abstract
Methods: Naïve CD4+ T cells and B cells were isolated from C57BL/6 mice. Peripherally induced CD4+Foxp3+ regulatory T cells (itregs) was induced with IL-2 and TGF-β. The thymus-derived naturally CD4+Foxp3+ regulatory T cells (ntregs) was obtained from C57BL/6 mice. iTregs and nTregs cells were cultured with B cells for 3-5 days in vitro. The activation marker, proliferation, Annexin-V and 7-AAD expression by B cells was determined by FACS. For in vivo experiment, iTregs and nTregs cells were transferred to endogenous T cell-deleted lupus prone mice. The IgG antibody production was measured by ELISA at the indicated time points. Results: We found that iTregs share similar functional characteristics with nTregs, both iTregs and nTegs can directly suppress the proliferation and production of autoantibodies of B cells. Unlike nTregs, iTregs suppressed B cells through non-cytotoxic manner. Moreover, the TGF-β signal is important for the effects of iTregs on B cells. We further showed that iTregs directly suppress B cells in vitro and in vivo in lupus prone mice. Conclusions: Our data implicate the role and advantage of iTregs in treating B cell-mediated autoimmune diseases.
IRF3 deficiency contributes to impaired memory T cell function in response to influenza infection (IRM14P.453)
Authors: Vogel Alexander , Moore Tyler , Petro Thomas , Brown Deborah 
Published: January 2023

Abstract
The role of IRF3 in initiating the type I interferon response in innate immune cells has been well studied in the context of viral infection. However, it remains unclear what impact IRF3 has in shaping and maintaining adaptive immune responses. To address this, IRF3 deficient (IRF3 KO) mice were infected with influenza A virus (IAV) and T cell responses measured. At day 9 post infection, the frequency of IFN-γ and Granzyme B (GrB) positive T cells were similar between IRF3 KO and wildtype mice. Despite similar primary responses, IRF3 KO mice exhibited significant deficits in recall memory T cell responses to IAV with reduced expression of IFN-γ and GrB. Since IRF3 has been implicated in the expression of cytokines that influence effector and memory T cells responses, cytokine supplementation studies were performed. Addition of IL-12 was the only cytokine tested that was able to rescue the IFN-γ deficiencies in IRF3 KO T cells. Interestingly, peptide specific GrB re-expression could not be restored by any cytokines tested. These results suggest that IRF3 plays a role in the maintenance of antigen specific memory T cell responses and that IRF3 deficiency has a substantial impact on the cytotoxic potential of memory T cells and recall responses. Together, this work provides further insight into the molecular regulation of adaptive immune responses to viral infections and may serve to inform future vaccine strategies that require the development of memory T cells.
Insights into MHC class II regulation of T cell responses (IRM15P.463)
Authors: LeGuern Christian , Germana Sharon 
Published: January 2023

Abstract
Besides their ability to present antigenic peptides and stimulate antigen-specific T lymphocytes, MHC class II (MHCII) molecules have also been implicated in the regulation of ensuing T cell responses. However, the substance of MHCII regulation remains elusive to this day. Defining the variables of this phenomenon appears to be critical for developing rational therapeutic approaches. Using models in which MHCII regulation has been demonstrated, we have revisited the concept by evaluating the impact of MHCII-restricted CD4 regulatory T cells (Tregs) on T cell reactivity to either allogeneic or self-antigens. Studies performed in vitro and in vivo showed that graft host Tregs specific to donor MHCII peptides / host MHCII complexes promoted T cell tolerance of fully allogeneic grafts. These pMHCII complexes - hereafter called TLo - were also involved in Treg-mediated suppression and in initial host Treg activation by graft MHCII. Extending these observations to Treg biology of normal animals, we have also shown that substantial amounts of TLo complexes selectively decorate antigen-presenting cells (APC) from the thymic medulla and participate in the differentiation of suppressive, TLo-specific Treg cells. Together these results suggest that, under steady-state conditions, MHCII genes regulate T cell responses by 1) generating self-TLo complexes on thymic APC to direct thymic Treg development and 2) modulating peripheral T cell activation via TLo-specific Tregs.
Hepatic stellate cells inhibit T cells through active TGFβ1 from a cell-surface-bound latent TGFβ1/GARP complex (IRM15P.609)
Authors: Li Yan , Kim B , Qian Shiguang , Letterio John , Fung John , Lu Lina , Lin Feng 
Published: January 2023

Abstract
Hepatic stellate cells (HSCs) potently inhibit T cells, a process that could help the liver to maintain its immunoprivileged status. HSCs secrete latent TGFβ1, but the detailed mechanisms by which latent TGFβ1 is activated and whether it plays any role in HSC-mediated T-cell suppression remain unclear. Glycoprotein A repetitions predominant (GARP) is a surface marker of activated regulatory T cells (Tregs). GARP binds latent TGFβ1 for its activation, which is critical for Tregs to suppress effector T cells; however, it remains unclear whether GARP is present on HSCs and whether it has any impact on HSC function. We found that TGFβ1+/‑ HSCs, which produce reduced levels of TGFβ1, showed decreased potency in inhibiting T cells. Pharmaceutical inhibition of the TGFβ1 signaling pathway reduced the T-cell-inhibiting activity of HSCs. SMAD3‑/‑ T cells with genetically impaired TGFβ1 signaling were resistant to HSC-mediated suppression. We demonstrated that GARP was constitutively expressed on primary HSCs. Blocking GARP function with antibodies or knocking down GARP expression using shRNAs significantly impaired the potency of HSCs to suppress T cells. These results demonstrate the presence of GARP on HSCs and its critical role in regard to the ability of HSCs to activate latent TGFβ1 and thereby inhibit T cells. Our study reveals a novel mechanism for HSC-mediated immune regulation and potentially for other liver conditions that involve HSC-secreted TGFβ1.
Molecular chaperone gp96/grp94 is critical for immunosuppressive functions of regulatory T cells (IRM15P.458)
Authors: Zhang Yongliang , Wu Bill , Alessandra Metelli , Hong Feng , Ansa-Addo Ephraim , Sun Shaoli , Liu Bei , Li Zihai 
Published: January 2023

Abstract
Regulatory T (Treg) cells are essential for self tolerance and immune homeostasis, which is subjected to regulation by multiple molecular switches. gp96/grp94 is an endoplasmic reticulum (ER) resident chaperone, and it plays an important immune regulatory function by folding Toll-like receptors and integrins. In this study, we demonstrated that gp96 is critically required for immune suppressive function of Treg cells. Disruption of gp96 in mice through Treg-specific gp96 knockout (KO) leads to impairment of suppressive function of Treg cells in vivo and development of fatal inflammatory diseases. Mechanistically, we found that Treg cells showed lineage instability in the absence of gp96, and underwent conversion to IFN-γ producing pathogenic T cells. Moreover, we unveiled that GARP, a cell surface docking receptor for latent membrane-associated TGF-b (mLTGF-b), is the client protein of gp96. The dual loss of GARP and integrins renders gp96 KO Treg cells incapable of expressing mLTGF-b and inefficient in producing active TGF-b. In the B16 tumor bearing mice, transient and inducible depletion of gp96 in Treg cells robustly improved therapeutic efficacy of adoptively transferred gp100-specific CD8 T cells without causing auto-inflammatory diseases. In summary, our study demonstrates that gp96 regulates multiple facets of Treg cell biology, and it suggests a manipulation of gp96 expression in Treg cells as a promising strategy to enhance cancer immunotherapy.
The transcription factor Bcl-3 regulates the development of marginal zone, germinal center and B1 B cells (LYM7P.624)
Authors: Hoevelmeyer Nadine , Wörns Marcus , Reissig Sonja , Adams-Quack Petra , Waisman Ari 
Published: January 2023

Abstract
Bcl-3 is an atypical member of the IkB family and functions as a transcriptional suppressor or promoter by associating with the NF-kB members p50/NF-kB1 and p52/NF-kB2 homodimers. The bcl3 gene was first identified at the breaking point of recurring chromosomal translocations in B cell chronic lymphocytic leukemias, and therefore supposed to function as a proto-oncogene via regulation of cell proliferation and apoptosis. To investigate the role of Bcl-3 on B cells we generated mice that overexpress Bcl-3 specifically in B cells and Bcl-3 deficient mice. Interestingly, mice overexpressing Bcl-3 lack marginal zone B and germinal center B cells and exhibit a significant reduction of B-1 B cells. Further, B cells of these mice are impaired in their proliferative capacity, especially upon anti-IgM stimulation. In line with these findings Bcl-3 deficient mice showed increased numbers of marginal zone and germinal center B cells. Our data demonstrate that the transcription cofactor Bcl-3 is important for B cell maturation, especially in the maintenance of marginal zone, germinal center and the B1 B cell compartment probably by inhibiting NF-kB activation.
Insulin-like growth factors are essential for the differentiation of Th17s in EAE (LYM8P.635)
Authors: DiToro Daniel , Frank Stuart , Weaver Casey 
Published: January 2023

Abstract
Insulin-like growth factors (Igfs) are highly conserved proteins similar to pro-insulin in both sequence and structure. They function primarily by binding the Igf1 receptor (Igf1R) and exert pleiotropic effects on many tissues throughout life. These factors were shown to be essential for the normal development and proliferation of B and T lymphocytes, and to positively influence their proliferation and survival following activation. But early attempts to identify potential roles in T cell differentiation and function lead to conflicting results, and the field was largely abandoned. More recent advances in our understanding of T cell biology, however, including the discovery of Th17 and Treg C4s, have permitted a more sophisticated analysis of the role of this system in T cells. Our data indicate that Th17 and Treg CD4s express Igf1R and insulin-like growth factor binding protein 4 (Igfbp4), a critical regulator of Igf activity, at much higher levels than other CD4 T cells, and appear uniquely capable of responding to Igfs. Exogenous Igfs promote Th17 and suppress Treg differentiation in-vitro, yet fail to influence Th1 or Th2 differentiation. Deletion of Igf1R leads to a defect in Stat3 phosphorylation and IL17a production, and enhanced Treg differentiation in-vitro. Mice lacking Igf1R on T cells are substantially protected from Experimental Autoimmune Encephalomyelitis, an effect that can be recapitulated through the in-vivo administration of Igf1R blocking antibodies.
GITR costimulation redirects regulatory T cells into Th9 cells to promote antitumor immunity (LYM8P.643)
Authors: Shi Xiaomin , Xiao Xiang , wu minhao , Fan Yihui , zhang xiaolong , wu chenglin , Ghobrial Rafik , Li Xian 
Published: January 2023

Abstract
GITR is a potent T cell costimulatory molecule with diverse effects on effector and regulatory T cells, and because of this, GITR is of high potential for clinical development including anti-tumor immunity. However, the underlying mechanisms remain unclear. Here, we found that GITR ligation converted iTregs into Th9 cells in vitro. Mechanistically, GITR induced the sustained expression of p50 in activated CD4+ T cells, and p50 then recruited histone deacetylases HDAC1 and Sirt1 to the Foxp3 locus upon binding to the locus; this subsequently led to hypoacetylation, thus resulting in a closed epigenetic configuration of Foxp3 locus. Consistent with this, both p50-/- cells and treatment of HDAC inhibitor rescued iTregs from GITR-mediated suppression. We also found that Foxp3 is a potent repressor of IL-9, mainly through recruiting histone deacetylases to the IL-9 locus, and absence of Foxp3 rendered IL-9 locus accessible. In addition, p50 also promoted the expression of Th9 permissive transcription factors, including PU.1, Batf and Irf4, and all these factors together led to the induction of Th9 cells. Importantly, in a melanoma model in vivo, ligation of GITR using agonistic anti-GITR Ab blocked iTreg differentiation and inhibited tumor progression. In conclusion, our study identifies a new mechanism in which GITR ligation redirects iTregs into Th9 cells to mediate potent anti-tumor immunity. This new finding may have important clinical implications in cancer therapy.
BCL6 orchestrates Tfh cell differentiation via multiple distinct mechanisms (LYM8P.628)
Authors: Crotty Shane , Hatzi Katerina , Nance John Philip , Kroenke Mark , Bothwell Marcella , Haddad Elias , Takemori Toshitada , Melnick Ari 
Published: January 2023

Abstract
Generation of long term humoral immunity is a complex process predominantly dependent on germinal centers and CD4 T cell help to B cells. Follicular helper T cells (Tfh) are the specialized CD4 T cells for B cell help. We and others have now resolved many of the stages of Tfh differentiation, and molecules involved. BCL6 is the defining transcription factor of Tfh cells. However, the functions of BCL6 in Tfh have largely remained unclear. We have defined the BCL6 cistrome in primary human germinal center Tfh cells to assess mechanisms of BCL6 regulation of CD4 T cells, comparing and contrasting BCL6 function in T and B cells. BCL6 primarily acts as a repressor in Tfh cells, and BCL6 binding was associated with control of Tfh cell migration, Tfh differentiation, and repression of alternative cell fates. Interestingly, although some BCL6 bound genes possessed BCL6 DNA binding motifs, more BCL6-bound loci were instead characterized by the presence of DNA motifs for AP1 or STAT. AP1 complexes are key positive downstream mediators of TCR signaling and external stimuli. We show that BCL6 can directly bind AP1, and AP1 and BCL6 co-occupied BCL6 binding sites with AP1 motifs, suggesting that BCL6 subverts AP1 activity. These findings reveal that BCL6 has broad and multifaceted effects on Tfh biology, and provide insight into how this master regulator mediates distinct cell-context dependent phenotypes.
Pattern of cytokine response to Mycobacterium leprae following interruption of persistent exposure to leprosy and BCG vaccination (MPF6P.653)
Authors: de Carvalho Fernanda , Rodrigues Luciana , Alvim Iris Maria , Alves Marcelo , Pinheiro Roberta , Duppre Nádia , Sarno Euzenir , Pereira Geraldo , Pessolani Maria Cristina 
Published: January 2023

Abstract
In 1973 Godal and collaborators investigated the in vitro response to M. leprae in leprosy patients and their household contacts. The authors observed a defective proliferative response to ML in lepromatous leprosy patients (LP), and also a reduced responsiveness specific for M. leprae, in household contacts of lepromatous leprosy patients. The responsiveness of these contacts to M. leprae improved upon treatment of the lepromatous patients (index cases). In the present study we assessed the impact of BCG vaccination and the leprosy index case treatment on the in vitro pattern of response to ML of household contacts of multibacillary leprosy patients (HCMB). Blood leukocytes of HCMB (n=16) were isolated at the beginning (T0) and during the course of the leprosy index case treatment (at least six month of treatment) (T1). At T0 thirteen HCMB were vaccinated with BCG. Most of the HCMB showed increased frequency of central memory and effector memory CD69+CD4+ T cells in response to M. leprae and peptides at T1. The evaluation of ratios of T1/T0 cytokine responses, using principal component analysis, indicates that in response to M. leprae the cytokines IL-6, IL1β, TNF-α, IL-17 and IFN-γ increased following interruption of exposure to ML, and BCG vaccination. Thus , the persistent exposure to ML may facilitate evolution of infection to active disease by inhibiting the effector response against ML.