bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regulation of B cell differentiation by the adaptor protein HSH2 (87.53)
Authors: Justement Louis B. , Herrin Brantley R. , King R. Glenn 
Published: January 2023

Abstract
The adaptor protein HSH2 is selectively expressed at low basal levels in cells of the B lineage. However, stimulation of B cells via CD40, BAFF-R, TLR4 and TLR9 upregulates HSH2 expression within 6–12 h in a NF-kB-dependent manner. Thus, it was hypothesized that HSH2 may regulate B cell survival and/or differentiation. HSH2 transgenic (Tg) mice were generated that constitutively express HSH2 in cells of the B lineage to determine if HSH2 causes gross changes in B cell subpopulations or functional responses. No changes were observed in developing B cell subpopulations in the bone marrow and the peripheral B cell compartment appeared normal with the exception of a 50% decrease in marginal zone B cells. Analysis of serum Ig levels in HSH2 Tg mice revealed a 40–50% decrease in IgM, a 20% decrease in IgA and a 70–85% decrease in other class switched isotypes compared to control animals. HSH2 Tg mice exhibited a significant impairment in their response to immunization with T-independent type 1 and 2 antigens and exhibited a similar defect in their 1° and 2° response to T-dependent antigen. Constitutive HSH2 expression was not observed to alter BCR-mediated signaling. In contrast, HSH2 Tg B cells exhibited defective responses to CD40 and BAFF-R signaling in vitro, but responded normally to TLR agonists. Thus, HSH2 appears to be important for selectively regulating the B cell functional response to CD40 and BAFF-R signaling.
Ubiquitination of RIP1 regulates an NF-κB-independent cell death switch in TNF signaling. (87.8)
Authors: O’Donnell Marie Anne , Addison Diana Legarda , Ting Adrian 
Published: January 2023

Abstract
TNF receptor 1 (TNFR1) can trigger opposing responses within the same cell: one leads to a pro-survival response whereas the other leads to cell death. The pro-survival response is mediated primarily by activation of the NF-κB signaling pathway, which leads to the expression of pro-survival genes such as c-FLIP, c-IAPs, TRAFs and BCL-2 family members. On the other hand, TNF can also trigger activation of CASPASE 8 and 3 leading eventually to apoptosis. In most cell types, stimulation with TNF does not lead to apoptosis unless NF-κB signaling is blocked. Hence, NF-κB-mediated transcription of pro-survival genes acts as a cell death switch during TNF signaling. This current study demonstrates the existence of another cell death switch elsewhere in the pathway that is independent of NF-κB. Our results show that lysine 63-linked ubiquitination of RIP1 on lysine 377 inhibits TNF-induced apoptosis first through an NF-κB-independent mechanism, and subsequently, through an NF-κB-dependent mechanism. In contrast, in the absence of ubiquitination, RIP1 serves as a pro-apoptotic signaling molecule. Therefore, RIP1 is a dual-function molecule that can be either pro-survival or pro-death depending on its ubiquitination state and this serves as an NF-κB-independent cell death switch early in TNF signaling. These results provide an explanation for the conflicting reports on the role of RIP1 in cell death, which was previously implicated to be both pro-survival and pro-death. Since TRAF2 is the E3 ligase for RIP1, these observations also provide an explanation for the NF-κB-independent anti-apoptotic function of TRAF2 previously described.
New differentiation pathway for double-negative regulatory T-cells that regulates the magnitude of immune responses (87.9)
Authors: Zhang Dong , Yang Wei , Degauque Nicolas , Tian Yan , Mikita Allison , Zheng Xin Xaio 
Published: January 2023

Abstract
CD4−CD8− (double-negative, DN) T-cells are capable of down-regulating the immune response. However, the origin and developmental pathway of DN T-cells are still unclear.
In this study, we showed that proliferated CD4+ T-cells could convert to DN T-cells after 4–5 rounds of either allogeneic or syngeneic DC triggered proliferation, IL-2 and IL-15 enhanced the conversion. The disappearance of CD4 molecular on converted DN T-cells was a result of CD4 gene silence. Converted DN T-cells were resistant to AICD and expressed unique cell markers and gene profile. Moreover, DN T-cells retained a stable phenotype after re-stimulation. DN T-cells converted from CD4+ T-cells exerted powerful inhibition on same, but not third party, alloantigen triggered proliferation of naïve T cells. Perforin, a cytotoxic lymphocyte related cytokine, was highly expressed by DN T-cells, played a role in DN T-cell mediated suppression. Transferring of DN T-cells alone could prevent allograft rejection and the onset of autoimmune disease in vivo.
This previously unknown pathway of differentiating DN regulatory T-cells represents a negative feedback mechanism of immune response. The results of using ex vivo CD4+ T-cells converted DN T-cells in transplantation and autoimmune disease models support the concept and the feasibility of potentially utilizing this novel cell-based therapy.
T Regulatory Cells Control the Numbers of NK Cells and Thereby Protect CD8alpha+ Immature Dendritic Cells Presence in the Lymph Node Paracortex (88.13)
Authors: Giroux Martin , Yurchenko Ekaterina , St-Pierre Jessica , Piccirillo Ciriaco A , Perreault Claude 
Published: January 2023

Abstract
In the absence of infection, the spleen contains numerous natural killer (NK) cells located mainly in the red pulp and whose differentiation profile is characterized by a preponderance of mature elements. In contrast, lymph nodes (LNs) contain few NK cells that are sited mostly in T-cell zones and that are phenotypically skewed toward immature developmental stages. We present evidence that CD4+CD25+ T regulatory (Treg) cells hamper generation of mature NK cells in the LNs through short-range interactions with NK precursors. Moreover, we show that Treg cells are both necessary and sufficient to repress accumulation of NK cells in resting LNs and an absence of Treg totally alleviates the differentiation blockade and leads to an accumulation of mature NK cells in the LN paracortex. In turn, mature NK cells specifically regulate the amount of CD8α+ phenotypically immature dendritic cells (iDCs) present in LN T-cell zones. We propose that the dominant influence of Treg cells on NK cell precursors and consequently on CD8α+ iDCs explains why “quiescent” LNs, in the absence of infection, function as privileged sites for induction and maintenance of tolerance to peripheral self antigens.
CD101 surface expression discriminates potency among murine FoxP3+ regulatory T cells (88.18)
Authors: Fernandez Irina , Zeiser Robert , Karsunky Holger , Kambham Neeraja , Beilhack Andreas , Sodestrom Kalle , Negrin Robert , Engleman Edgar 
Published: January 2023

Abstract
CD4+CD25+FoxP3+ regulatory T cells (Treg) have been shown to be protective in animal models of autoimmunity and acute graft-versus-host disease (GVHD). However, owing to the functional heterogeneity among CD4+CD25+ T cells, surface markers expressed selectively on functionally active Treg would be useful for purposes of identifying and isolating such cells. We generated a rabbit monoclonal antibody against murine CD101, a transmembrane glycoprotein involved in T cell activation. Among freshly isolated T cells, CD101 was detected on 25–30% of CD4+CD25+ Treg and a small population of conventional memory T cells. CD101+ Treg displayed greater in vitro suppression of alloantigen driven T cell proliferation as compared to CD101 negative (CD101-) Treg. In a model of GVHD induced by allogeneic bone marrow transplantation in vivo bioluminescence imaging demonstrated reduced expansion of donor-derived luciferase-labeled conventional T cells in mice treated with CD101+ Treg, compared to CD101− Treg. Moreover, treatment with CD101+ Treg resulted in improved survival, reduced proinflammatory cytokine levels and reduced end organ damage. We conclude that CD101 expression distinguishes murine Treg with potent suppressor activity.
Gamma irradiation alters the phenotype and function of CD4+CD25+ regulatory T cells (88.2)
Authors: Cao Mengde , Xu Yiling , Cabrera Roniel , Liu Chen , Nelson David 
Published: January 2023

Abstract
Naturally occurring regulatory T cells (Tregs) are importantmodulators of immune responses to pathogens, tumors, and transplantationantigens. Gamma irradiation of stimulator cells is commonly used to achieve unidirectionality of response in the mixed lymphocyte reaction (MLR), but little is known about effects of gamma irradiation on phenotype and suppression function of Tregs. To elucidate the effects of gamma irradiation on Tregs, we analyzed changes in phenotype and suppression function in Tregs treated with or without gamma ray. We investigated and found that proliferation of Tregs in response to gamma irradiation was reduced in a dose-dependent way ( 0Gy: 44007 ±6785cpm; 1.875Gy: 15038 ±5542cpm; 7.5Gy: 6618 ±1069cpm; 30Gy: 439 ±100cpm; p&lt;0.05), and the apoptosis induction of Tregs was increased compared with untreated cells (0Gy: 6.88%; 1.875Gy: 17.71%; 7.5Gy: 21.70%; 30Gy: 54.49%). Gamma irradiation down-regulated the expression of CD62L, FOXP3, membrane TGF-β, CD127, but up-regulated PD-1, CD25, caspase3, Bax and GITR expression in Tregs. High dose gamma irradiation (30 Gy) significantly abolished the suppression of Tregs on CD4+CD25− T cells proliferation. The neutralization of anti-TGF-β has the same function as high dose gamma irradiation to block the suppressive ability of Tregs. It was concluded that gamma irradiation of Tregs not only influences the phenotype of Tregs but also alters their capacity to suppress the proliferation of autologous T cells. Our findingssuggest that Tregs could be potential targetsfor improving the efficacy of radiotherapy for cancer.
PD-L1 interacts specifically with B7-1 to regulate T cell function (88.24)
Authors: Butte Manish J , Keir Mary E , Phamduy Theresa B , Sharpe Arlene H , Freeman Gordon J 
Published: January 2023

Abstract
Pathways in the B7:CD28 family regulate T cell activation and tolerance. The demonstration of B7 dependent responses in CD28/CTLA-4−/− T cells together with studies pointing to stimulatory and inhibitory functions for PD-L1 and PD-L2, have suggested additional receptors for these B7 family members. We show that B7-1 and PD-L1 can bind to one another with an affinity greater than the affinity of B7-1 for CD28 but less than CTLA-4. The B7-1:PD-L1 interaction can be shown in both biophysical and cell-based assays, and is functionally significant. We demonstrate that this interaction is restricted to B7-1 and PD-L1. B7-2 does not interact with PD-L1, nor does PD-L2 interact with B7-1. We have identified anti-PD-L1 antibodies with either dual-specificity, which can block two interactions (PD-L1:B7-1 and PD-L1:PD-1), or mono-specificity, which can block only one (PD-L1:B7-1). The effects of this pathway on T cell proliferation and cytokine production will be discussed. Our findings give increased significance to B7-1 and PD-L1 on T cells, and add an additional dimension to immunoregulatory functions of the B7:CD28 family.
Regulation of CD28 costimulation versus anergy in T cells by RasGRP and DGK-α (88.27)
Authors: Gajewski Thomas F , Zha Yuan-yuan , Praveen Kesavannair , Janardhan Sujit 
Published: January 2023

Abstract
Although the functional attributes of CD28 costimulation and T cell anergy are well-defined, the biochemical basis of these processes have been incompletely understood. Details of Ras regulation in T cells have provided new insights into CD28 costimulation and anergy. Using confocal microscopy, we have observed that CD28 costimulation facilitates recruitment of the DAG-activatable guanine nucleotide exchange factor RasGRP to the plasma membrane. In addition, T cells from RasGRP-deficient mice show defective IL-2 production and ERK activation in response to TCR/CD28 ligation but not through the IL-2R. Moreover, introduction of CA Ras can bypass the need for CD28 costimulation for multiple functional outputs. In contrast, anergic T cells show upregulated expression of the DAG-metabolizing enzyme diacylglycerol kinase-α (DGK-α). Introduction of DGK-α can mimic the anergic state, and inhibition of endogenous DGK-α can recover function of anergic cells. Together, these results support a yin-yang model in which T cell activation is centrally influenced by DAG-dependent signaling, with CD28 costimulation promoting RasGRP-dependent Ras activation and DGK-α negating this process in the anergic state.
IL-10 secretion from BALB-neuT mice cells after stimulation with murine breast tumor cell lines (88.28)
Authors: Cabrera Rosalyn , Nava-Parada Pilar , Pease Larry R 
Published: January 2023

Abstract
Failures in tolerance mechanisms cause autoimmunity. Self reactive cells in the periphery are kept in check by peripheral tolerance. Mice expressing a neoself antigen, called BALB-neuT, were used as a model for delineating mechanisms of peripheral tolerance. Two questions were addressed: Are BALB-neuT tolerant to neoself antigen? Can BALB-neuT tolerance be broken? We first established that BALB-neuT are tolerant to Her2/neu peptide while parental BALB/c mounted a significant response after immunization with Her2/neu peptide in CFA and repeated CpG stimulations. Next we depleted CD25+ cells and used the immunomodulating antibody B7-DC XAb to study the mechanism involved. CD8+ T cells from treated BALB-neuT generated a potent response when compared to untreated BALB-neuT or BALB/c, as measured by IFNγ secretion. Interestingly, IL-10 secretion from BALB-neuT T cells was high after incubation with murine breast cell lines, irrespective of expression of BALB-neuT antigen. After depletion of CD4+CD25+ T cells, secretion of IL-10 was diminished, suggesting that the IL-10 is being secreted by T regulatory cells. In conclusion, BALB-neuT are tolerant to neoself antigen. Tolerance can be broken by depleting Tregs or using B7-DC Xab to modulate immunity. Future studies are aimed at identifying mechanisms regulating IL-10 secretion to unravel pathways important in regulation of autoimmunity.
Definition of a Qa-1-Qdm-dependent interaction between NK cells and activated T cells that inhibits expansion and memory development of pathogenic T cells (88.31)
Authors: Lu Linrong , Ikizawa Koichi , Werneck Miriam B.F. , Cantor Harvey 
Published: January 2023

Abstract
The ability of natural killer (NK) cells to recognize and lyse activated T cells in vitro may allow these cells to participate in regulating adaptive immune response through inhibition of clonal expansion of antigen-activated T cells. This interaction may be tightly constrained by an interaction between inhibitory NKG2A receptors on NK cells and Qa-1-Qdm ligands on activated T cells (Qa-1-NKG2A interaction).
We tested the hypothesis that Qa-1-NKG2A interaction protects activated T cells from NK lysis and is essential for clonal expansion and development of immunologic memory. We found that Qa-1-deficient CD4 cells fail to undergo antigen-induced or homeostatic expansion and develop autoimmune EAE disease due to increased susceptibility to NK cells lysis. Re-expression of Qa-1-Qdm on autoreactive CD4 cells rescues expansion of self-reactive T cell clones. These findings were confirmed using Qa-1 knock-in mice which express an amino acid exchange mutation (R72A) that eliminates Qa-1 binding to NKG2A but spares binding to the TCR. Dissection of the NK cell population revealed that the NKG2A+ but not NKG2A– subset of NK cells mediate lysis of Qa-1-deficient CD4 cells. Blockage of the Qa-1-NKG2A interaction that constrains NK lysis of activated T cells resulted in potent NK-dependent elimination of activated autoreactive T cells and amelioration of autoimmune EAE. These findings extend the functional reach of the NK system to include regulation of adaptive T cell responses and demonstrate that antibody-mediated blockade of NKG2A-Qdm interactions as a new clinical approach to eliminate antigen-activated T cells in the context of autoimmune disease or transplantation.
Role of Epitope Valency in inducing Tolerance or Immunity (88.34)
Authors: Shah Shivanee , Qiao Liang 
Published: January 2023

Abstract
Different antigens result in different immune responses. Soluble antigens, such as food, are tolerogenic; whereas microbes, which generally have repeating eptitopes, are immunogenic. Thus, we hypothesize that epitope valency of the antigen plays a role in deciding the immune outcome. B cells are antigen presenting cells that specifically recognize antigenic epitopes and become activated in the presence of multi-valent epitopes. Thus, we studied the effect of different epitope valencies on B cell activation and consequently T cell activation. Using monovalent and divalent fragments of the same antigen, we determined B cell activation markers by flow cytometry; and T cell activation by proliferation assays and cytokine analysis (ELISA).
We found that like unstimulated B cells, univalent epitopes cannot activate B cells but can expand a population of CD4+CD25+Foxp3+T cells (Tregs); whereas divalent epitopes activate B cells and consequently help T cell activation, but do not induce T regs. Interestingly, the mechanism of expansion of this Treg population is via TGFβ3 and not via known cytokines TGFβ1 or IL-10. This implies not only that structure of the antigen plays a critical role in setting off a competitive immune response, but also that resting B cells can maintain a population of regulatory T cells that can prevent the activation of self-reactive T cells and thus prevent autoimmunity.
Complement-bearing immune complexes induce IL-10 and granzyme B production by human CD4+ T cells (88.35)
Authors: Price Jeffrey D. , Kemper Claudia , Atkinson John P. 
Published: January 2023

Abstract
Induction of complement-induced regulatory T cells (cTregs) occurs through concurrent cross-linking of the TCR and the complement regulatory protein CD46 on naive human CD4+ T cells. The phenotype of cTregs includes the secretion of large amounts of IL-10 as well as production of granzyme B, providing cell-contact independent and cell-contact dependent mechanisms for immunosuppression. Previous work in our lab has demonstrated cTreg induction by both natural and pathogenic ligands for CD46: C3b dimers and the M protein of group A streptococci, respectively. The current studies examine whether a physiological presentation of complement components on immune complexes can stimulate CD46 in a similar fashion. BSA:α-BSA complexes and antibodies to CD3 were used to stimulate human CD4+ T cells. Immune complexes that were opsonized with complement C3b and C4b fragments through treatment with normal human serum induce IL-10 secretion by T cells and production of intracellular granzyme B. Immune complexes that lack opsonizing complement components due to heat-inactivation or EDTA treatment of serum do not induce IL-10 or granzyme B production. As immune responses mature towards many pathogens, immune complexes are formed. We propose that these complexes, when presented to T cells by antigen-presenting cells bearing Fc or complement receptors, generate a regulatory phenotype and thereby quench the immune response.
Funding provided by NIH grant AI070489 AADCRC, and the Sandler Program for Asthma Research.
Inhibition of glycogen synthase kinase-3 promotes human CD4+ T regulatory type 1 activity (88.48)
Authors: Garcia Carlos Armando , Rehani Kunal , Martin Michael 
Published: January 2023

Abstract
T regulatory type 1 cells (Tr1) are a distinct subset of a heterogeneous population of regulatory CD4+ T cells present in humans whose main function is to prevent chronic immune activation and maintain normal immune homeostasis via the production of interleukin-10 (IL-10). Although several studies have identified particular in vitro conditions that promote Tr1 differentiation, none to date have identified a putative molecule when pharmacologically targeted promotes Tr1 differentiation. Identifying such a target has proven difficult due to the inherent complexity and lack of information regarding IL-10 gene regulation in T cells. In the present study, we examined the influence of the serine/threonine kinase, glycogen synthase kinase-3 (GSK3) to regulate IL-10 production by CD4+ T cells. CD3 stimulated peripheral blood mononuclear cells (PBMCs) or CD4+ T cells treated with GSK3 inhibitors promotes IL-2 and IL-10 production while suppressing interferon-gamma (IFN-?) levels as compared to cells treated with anti-CD3 alone. The ability of GSK3 inhibition to promote IL-10 and suppress IFN-? production in CD4+ T cells was restricted to the memory (CD45RA− CD45RO+) population of CD4+ T cells, whereas naïve (CD45RA+ CD45RO-) CD4+ T cells solely increased IL-2 production. Memory CD4+ T cells activated in the presence of GSK3 inhibition acquired the capacity to suppress the bystander activation of CD4+ T cells; an effect dependent on the presence of IL-10. Our findings illustrate a dichotomy present in the role of GSK3 in naïve and memory CD4+ T cells and identify GSK3 as a key kinase in Tr1 differentiation.
CD28 Regulates de novo Generation of Tregs through IL-2 in the Periphery (88.49)
Authors: Yu Xue-Zhong , Liang Yaming , Anasetti Claudio , Guo Fei 
Published: January 2023

Abstract
CD28 plays a critical role in Treg development in the thymus and also contributes to Treg survival and homeostasis in the periphery. However, the role of CD28 in the differentiation of Tregs (CD4+Foxp3+) from naïve T cells (CD4+Foxp3-) in the periphery is unclear. To address this question, we stimulated naïve T cells (CD4+CD25-) with APCs plus anti-CD3 mAb in the presence of TGF-beta. We found that differentiation of Tregs was essentially blocked when CD28 costimulation was absent either by using CD28−/− T cells or B7−/− APCs in the culture. The requirement of CD28 for Treg differentiation was further confirmed in vivo, where WT or CD28−/− naïve T cells were adoptively transferred into irradiated syngeneic or allogeneic recipient. Using CFSE labeling, we found that differentiation of Tregs from WT naïve T cells was irrelevant to the number of cell division, and even T cells without division could also be “converted” into Tregs. Naïve T cells without CD28 divided much more slowly and did not differentiate into Tregs regardless of cell division. The requirement of CD28 for Treg differentiation was mediated through IL-2, in that neutralization of IL-2 with its specific antibody blocked Treg differentiation from WT naïve T cells and additional IL-2 restored Treg differentiation from CD28−/− naïve T cells. We further asked whether other common gamma-chain cytokines have a similar role as IL-2, and found that IL-7, but not IL-4 or IL-15, could partially restored Treg differentiation in the replacement of IL-2. In conclusion, our current study indicates that CD28 is required for Treg differentiation from naïve T cells through IL-2 production in the periphery.