bluuebunny/crossref_metadata_2025_split huggingface dataset:
GITRL-mediated costimulation in CD25−conventional and CD25+ regulatory CD4 T cells (88.16)
Authors: Igarashi Hanna , Piao Jinhua , Cao Yujia , Hashiguchi Masaaki , Iwai Hideyuki , Amagasa Teruo , Sakaguchi Shimon , Azuma Miyuki 
Published: January 2023

Abstract
We previously reported that GITR acts as a costimulatory molecule in both CD25− CD4+ conventional and CD25+ CD4+ Treg cells using agonistic anti-GITR mAb (DTA-1) (J. Immunol. 2004, 172:7306). However, CD4 T cell responses by the binding of natural ligand, GITRL and the physiological importance of GITR-GITRL pathway have not been well understood. In this study, we examined the involvement of GITR-GITRL pathway in T cell-mediated responses. We established P815 transfectants expressing high levels of mouse GITRL (GITRL/P815) and two anti-mouse GITRL mAbs. Proliferative responses and IL-4 and IL-10 production by CD25− CD4+ T cells in the presence of anti-CD3 mAb were markedly enhanced by GITRL-P815. Anti-GITRL mAb completely inhibited the proliferative responses over the levels of untransfected P815. Surprisingly, the addition of anti-GITRL mAb further enhanced IL-10 production by CD25− CD4+ T cells. Unlike stimulation by DTA-1, CD25+ Treg cells failed to show substantial proliferative responses by GITRL-P815. The addition of CD25+ Treg cells inhibited the proliferative responses enhanced by mGITRL-P815 and the remaining responses were completely inhibited by anti-GITRL mAb. Our results suggest that GITRL-P815 induce potent costimulatory signals to CD25− CD4+ T cells, however, the unknown GITRL pathway may be involved in the T-T interaction.
4-1BB engagement costimulates NKT cell activation and enhances airway hyperreactivity and airway inflammation mediated by NKT cells (88.19)
Authors: kang Chang-Yuil , Kim Dong-Hyeon , Chang Woo-Sung , Lee Yun-Suk 
Published: January 2023

Abstract
Multiple studies have demonstrated that 4-1BB (CD137), a member of the TNF receptor superfamily, is expressed in several immune cells, including activated T cells. However, the expression and the potential roles of 4-1BB on CD1d-restricted invariant NKT (iNKT) cell have not fully characterized. In this study, it was demonstrated that 4-1BB on iNKT cells was consititutively expressed, and the expressions was increased by TCR engagement. Also, 4-1BB signaling provided by 3H3, an anti-4-1BB agonistic mAb, promoted iNKT cells activation, resulting in enhanced proliferation and cytokine production of iNKT cells driven by alpha-galactosylcerimide (alpha-GalCer) or anti-CD3 mAb in vitro. Administration of 3H3 further increased IL-4 and IFN-gamma levels in serum induced by alpha-GalCer administration in vivo. When 3H3 and alpha-GalCer were intranasally co-administrated, airway hyperreacitivity and inflammatory cell accumulation were severely aggravated. In conclusion, 4-1BB on iNKT cell functions as a costimulatory molecule, and facilitates the induction of more severe airway hyperreacitivity and inflammatory cell accumulation in NKT cell-mediated airway inflammation.
Different anti-B7-DC monoclonal antibodies show differential functions in immune responses (88.20)
Authors: Ritprajak Patcharee , Hashiguchi Masaaki , Yagita Hideo , Okumura Ko , Azuma Miyuki 
Published: January 2023

Abstract
Both B7-H1 and B7-DC bind to co-inhibitory receptor PD-1. Various murine disease models using anti-B7-H1mAb (MIH5/MIH6) and/or anti-B7-DC mAb (TY25) demonstrated the preferential involvement of B7-H1 in the PD-1-mediated immune regulation. To verify the actual involvement of B7-DC pathway, we here established another new mAb against mouse B7-DC (MIH37) and compared differential properties between MIH37 and TY25.
Binding analyses using flow cytometry demonstrated that MIH37 showed higher binding affinity to B7-DC. In hapten-induced contact hypersensitivity, the treatment with MIH37 at either sensitization or challenge efficiently inhibited the ear swelling, whereas the treatment with TY25 enhanced at the late time point. Consistently, MIH37 treatment inhibited enhanced induction of activation Ags and IFN-γ production, while TY25 treatment enhanced. When blocking anti-PD-1 mAb was co-administrated at sensitization, the inhibitory effect by MIH37 was reversed at the late time point, whereas the enhancing effect by TY25 appeared at the earlier time point. Our results suggest that MIH37 interferes both B7-DC/PD-1 inhibitory and B7-DC/non-PD-1co-stimulatory pathways, whereas TY25 only blocks B7-DC/PD-1 pathway. PD-1-mediated inhibitory pathway and non-PD-1-mediated co-stimulatory pathway may contribute to the different phases of T cell responses.
B7-H3 co-stimulates T-cell immune responses via the B7-H3 receptor ligation (88.21)
Authors: Hashiguchi Masaaki , Kobori Hiroko , Ritprajak Patcharee , Piao Jinhua , Azuma Miyuki 
Published: January 2023

Abstract
B7-H3 is a new member of B7 family molecules and is widely expressed on various types of tissue and tumor cells as well as immune cells, such as macrophages and dendritic cells. It was suggested that B7-H3 binds a putative counter-receptor on activated T cells that is distinct from the already identified CD28 family molecules. Here we report the functional roles of B7-H3 and its newly identified B7-H3 receptor (B7-H3R) in immune responses.
Co-stimulation of mouse B7-H3 in the presence of CD3 ligation resulted in enhanced proliferation and IFN-γ production by CD8+ T cells in vitro. The in vivo expriments also showed costimulatory roles of B7-H3; Blockade of B7-H3 using anti-B7-H3 mAb inhibited hapten-induced contact hypersensitivity reactions and anti-tumor host responses. Inoculation of B7-H3-introduced tumors efficiently suppressed tumor growth via CD8+ T cell-mediated manners.
We picked up several candidates for B7-H3R from database homology search and identified a B7-H3R that binds to the B7-H3-Fc chimera protein. The transduction of B7-H3R into activated CD4+ T cells and DO11.10 hybridoma enhanced production of IFN-γ and IL-2, respectively. Furthermore, the expression of B7-H3R was recognized in freshly isolated CD8+ T cells and myeloid cells as well as activated CD4+ T cells.
Our results suggested that B7-H3 positively co-stimulates T (preferentially CD8+ T) cell responses via the B7-H3R ligation.
Involvement of GITRL-GITR costimulatory pathway in T cell-mediated immune responses in vivo (88.23)
Authors: Piao Jinhua , Yosuke Kamimura , Hanna Igarashi , Iwai Hideyuki , Massaaki Hashiguchi , Shimon Sakaguchi , Azuma Miyuki 
Published: January 2023

Abstract
GITR is expressed on CD25+ regulatory T cells at high levels. GITR is also expressed on conventional CD4 and CD8 T cells and acts as a potent costimulatory molecule based on the studies using agonistic anti-GITR mAb. The physiological impact of GITR-mediated signal that is delivered by GITRL is still unknown. Here, we report the effects of neutralizing anti-GITRL mAb (MIH44) treatment in tumor and hapten-induced contact hypersensitivity (CH) models.
Inoculation of GITRL-transduced tumor cells (GITRL-P815 and GITRL-SCCVII) into the syngeneic mice efficiently inhibited their tumor growth, suggesting the enhanced antitumor immune responses by tumor-associated GITRL. Administration of anti-GITRL mAb reversed the GITRL-induced antitumor responses, but these effects were decreased in the anti-CD25 mAb treated mice. Treatment with anti-GITRL mAb did not affect the tumor growth of parental tumors.
In a CH model, the anti-GITRL mAb treatment at the sensitization, but not at the challenge, efficiently suppressed ear swelling. This inhibitory effect was long-lasting. The anti-GITRL mAb treatment significantly decreased the percentages of IFN-γ+CD8+ and CD25+ T cells. These inhibitory effects by anti-GITRL treatment were reduced in the anti-CD25 pre-treated mice.
Our data suggest that GITR-GITRL costimulatory pathway is involved certainly in activation of conventional T cells and regulatory T cells may affect the GITRL-costimulatory pathway.
Foxp3+ Treg Cell Activity increases in Secondary Lymphoid Organs of Aged Mice (88.25)
Authors: Chiu Bochin , Stolberg Valerie , Chensue Stephen 
Published: January 2023

Abstract
As potent suppressors of immune responses to self and foreign antigens, Foxp3+ Treg cells are suspected to be involved in immunosuppression leading to cancer, neurodegeneration and infection. Since aging is associated with increased incidence of these diseases, we compared Treg activity in blood, lymphoid organs and lungs of young (5–6 months) and old (21–22 months) C57BL/6 mice, using flow cytometric detection and characterization of Foxp3+ cells. Both the proportion and absolute number of Treg cells increased with age in secondary lymphoid organs but not in blood and lungs. Whereas numbers of thymic and peripheral naive Treg cells decreased with age, the number and proportion of Treg cells with CD103+ memory/effector phenotype increased in peripheral lymphoid tissues. Moreover, the increased Treg activity had in vivo influence since CD40 and CD86 co-stimulatory molecule expression by lymph node dendritic cells (DCs) was impaired in old mice, but could be restored to levels of young mice by inactivating Treg cells with anti-CD25 mAb. Our findings suggest that immunosenecence involves a cumulative imbalance of Treg cell activity and have profound implication for the understanding of age-associated immune dysfunction.
This work was supported by the American Foundation for Aging Research (AFAR) and the Department of Veterans Affairs.
The inverse agonist activity of soluble CTLA-4 ligands requires oligomerization of this receptor and CD28 expression (88.26)
Authors: Teft Wendy A , Madrenas Joaquin 
Published: January 2023

Abstract
CTLA-4 can inhibit or activate T cells depending on the ligand it engages. We have shown that CTLA-4 ligation with a bi-specific in-tandem single chain Fv, known as 24:26, can activate CTLA-4-expressing primary human T cells in the absence of TCR and CD28 engagement. To understand the basis of such an inverse agonist activity, we examined the requirements for CTLA-4-mediated T cell activation. We observed that 24:26 and soluble B7.1 Ig, but not B7 molecules on APCs, induced the formation of a unique CTLA-4 oligomer that disappeared from the soluble cell lysate fraction and subsequently appeared in the insoluble cellular fraction. Oligomerization occurred upon ligation of CTLA-4 homodimers and was necessary but not sufficient for T cell activation. The inverse agonist activity of these soluble ligands required the cytoplasmic domain of CTLA-4 since CTLA-4 molecules lacking this domain did not induce T cell activation. CD28 expression was necessary for the inhibitory and activating functions of CTLA-4 suggesting a functional interaction between these two receptors.
Understanding the functional responses to soluble ligands of costimulatory receptors is important in the wake of the side effects observed with CD28 superagonists. Our data indicates that the biological effect of soluble ligands of CTLA-4 will be determined by the oligomerization of this receptor.
Supported by the Canadian Institutes of Health Research.
T Cells are Capable of Effector and Regulatory Function Simultaneously during Activation (88.3)
Authors: pillai vinodh 
Published: January 2023

Abstract
CD4+CD25+ regulatory T (Treg) cells are an important arm of the immune system that downregulate potentially harmful effector immune responses. FOXP3 expression and in vitro suppressor function have been considered to be the hallmarks of a unique and stable lineage of T-cells with immune regulatory function. Here we show that human CD4+CD25−FOXP3− T-cells attain a transient FOXP3+CD25+ state following activation. In this state of activation, these cells possess the classic marker profile and suppressive phenotype of regulatory/suppressor T-cells. However, the vast majority of these cells eventually down regulate FOXP3 and suppressor activity. Cytokine studies indicate that they are also capable of secreting effector cytokines when they are regulatory in function. Interestingly, CD8+CD25−FOXP3− T-cells also exhibit similar dynamics following activation. Our results show that, in humans, FOXP3 expression and Treg functionality are not distinct features of a separate lineage of T-cells, but rather a state attained by almost all T-cells during their activation. This suggests that attempts to increase “Tregs” in humans may paradoxically result in increased effector T-cells, with potentially deleterious effects. These results warrant caution in interpreting human studies using FOXP3 and suppressive activity as readouts.
This work was supported by grants (to N.J.K) from the NIH and the National MS society NMSS.
CD4 T cell expression of costimulatory receptors is directly enhanced by Toll-like receptor ligands (88.37)
Authors: Taylor Devon K , LaRosa David F , Rahman Adeeb H , zhang Jidong , Turka Laurence A 
Published: January 2023

Abstract
Toll-like receptors (TLR) play an integral role in bridging the innate and adaptive response. The stimulation of TLRs on antigen presenting cells promotes their maturation through the upregulation of MHC class II molecules, costimulatory ligands, the release of pro-inflammatory cytokines.
Emerging data support the presence of TLR2, 3, 5, 8 and 9 on non-regulatory CD4+ T cells. Our group has shown the direct ligation of TLR 9 on activated CD4+ T cells promotes survival and proliferation through the production of IL-2 and the activation of PI3K and NF-κB-dependent pathways.
Using mice deficient in MyD88, TLR9 and TLR3, we investigated the effects of TLR ligation on T-cell costimulatory receptor expression. We found that stimulation of activated CD4+ T cells with TLR ligands leads to the selective upregulation of costimulatory receptors in both a MyD88 and TLR9 dependent manner. Both CpG DNA and dsRNA synthetic analog poly(I:C) enhanced the expression of OX40, GITR, CTLA-4 and CD28 in activated CD4+ T cells. Furthermore, responses to CpG DNA were TLR 9 and MyD88 dependent, although responses to poly(I:C) were not dependent on TLR3. Ongoing studies examine the functional consequences of TLR-enhanced costimulatory receptor expression in T cells and focus on its contribution to effector function and memory cell formation.
This work is funded by NIH grant (R01-AI-062789) to L.A.T.
Mechanism of Action of Abatacept: Insights from Predictive Biosimulation Studies (88.38)
Authors: Whiting Chan Chung , Ramanujan Saroja , Young Daniel L. , Kellermann Sirid-Aimee , Defranoux Nadine A. 
Published: January 2023

Abstract
While clinical reports demonstrate that CTLA-4 Ig (abatacept) is efficacious in rheumatoid arthritis (RA) patients refractory to standard therapies, its mode of action is poorly characterized. Using the Entelos® RA PhysioLab® platform, a mechanistic mathematical model of a prototypical human RA joint, we evaluated abatacept’s potential mechanisms of action to gain insight into the basis of its clinical efficacy. The hypothesized effects of abatacept on (a) T cell functions (e.g., inhibition of proliferation, costimulation, and Th1 activity and induction of T regulatory cells (Tregs)), (b) antigen presenting cell functions (e.g., inhibition of cytokine production and antigen presentation), and (c) cross talk between T cells and macrophages, fibroblast-like synoviocytes, and dendritic cells were investigated by altering the model values that define each process. Biosimulation of abatacept therapy demonstrated that a 50% modulation of these targeted functions is sufficient to reproduce clinical responses in a ‘virtual’ RA patient, whereas a 20% effect is insufficient. Analysis of these results shows that inhibition of macrophage activation and cytokine production, and skewing of T cells to a Treg phenotype drive abatacept efficacy in silico. By reducing the uncertainty regarding the mechanisms critical for abatacept efficacy, biosimulation can lead to better and more targeted RA treatments.
CD25+CD4+ T regulatory cells utilize β-galactoside-binding protein to suppress proliferation of CD8+T cells. (88.40)
Authors: Baatar Dolgor , Olkhanud Purevdorj , Almanzar Giovanni , Wells Valerie , Mallucci Livio , Biragyn Arya 
Published: January 2023

Abstract
CD25+CD4+ T regulatory cells (Tregs) are important cells that control induction of autoimmunity. They induce peripheral T cell tolerance via contact-dependent process, though the precise mechanism remains poorly understood. Here we report that βGBP (β-galactoside binding protein), a cytokine with a physiological role in cell cycle control and a putative role in the silencing phase of T cell immune response and the switching off of T cell effector functions, participates in Tregs-mediated regulation of T cells. We found that freshly isolated human PBL-derived natural Tregs constitutively express βGBP and utilize it to mediate suppression of proliferation of naïve CD8+ T cells. Although large amounts of βGBP can be secreted from stimulated Tregs, suppression of proliferation by βGBP is mediated by nM concentrations of βGBP bound to the cell surface, which is in accord with its cytokine-like function. Interestingly, Tregs utilize βGBP to specifically and transiently inhibit proliferation of CD8+ T cells without inducing apoptosis. Inhibition of proliferation is associated with the ability of βGBP to inhibit downstream signaling events of TCR. Our data indicate that Tregs use βGBP as a key mediator of contact-dependent regulation of T cell proliferation.
This work was supported by the Intramural Research Program of the National Institute on Aging, NIH.
Injury- and antigen-specific control of CD4 T cell reactivity by CD4+CD25+ regulatory T cells (88.42)
Authors: MacConmara Malcolm , Delisle Adam , Stallwood Christopher , McKenna Ann , Mannick John , Lederer James 
Published: January 2023

Abstract
Severe injury augments the potency of CD4+CD25+ regulatory T cells (Tregs) suggesting that Tregs might play a role in controlling unwanted CD4 T cell responses in the injured host. To test whether enhanced Treg activity might occur by an antigen driven process, we compared T cell responses in Treg-depleted sham and burn mice that received unsorted or CD25-depleted CD4+ T-cells from DO-11.10 T cell receptor (TCR) transgenic mouse. Unsorted DO-11.10 CD4+ T cells contain 10% CD25+FoxP3+ T-cells. Treg-depleted or control mice received 5 x 106 CD4 T cells or CD25-depleted CD4 T cells by i.v. injection, were immunized OVA323-339 peptide and then underwent sham or burn injury under anesthesia. At day 7, lymph node and spleen cells were prepared and stained with DO-11.10 TCR specific antibody. We observed a significant increase in DO-11.10 T cell expansion in sham and burn Treg-depleted mice that received CD4+CD25− T cells. This increased expansion occurred in sham, but not burn mice, receiving unsorted CD4 T cells suggesting that the co-transfer of CD25+ DO-11.10 T cells was sufficient to suppress T cell expansion in injured mice. The results of CFSE-studies confirmed that antigen-stimulated CD4+CD25− T-cells proliferate more vigorously in burn as compared to sham mice, but that transferring unsorted T cells prevents the injury-induced CD4 T cell expansion. These results indicate that injury influences Treg activity in an antigen-specific fashion and suggest that Tregs may play an active role in modulating CD4 T cell reactivity following injury
PD-1 plays a stimulatory role in CD8 T cell priming and an inhibitory role after activation (88.43)
Authors: Chen Jian , Zajac Allan , Wu Qi , Yang Pingar , Xu Xin , Hsu Hui-Chen , Mountz John D 
Published: January 2023

Abstract
The expression of the program death-1 (PD-1) receptor, a member of the CD28 costimulatory receptor family, is induced by T cell activation. It is still controversial whether PD-1 plays an inhibitory role or act as a stimulatory factor in T cell activation. It is yet to be determined if PD-1 contributes to age-related defect in CTL response to virus. We hypothesized that in the initiation stage, PD-1 plays a stimulatory role in T cell activation, and that upregulated PD-1 on activated T cells delivers an inhibitory signal to T cells. In the present study, we measured PD-1 expression in aged mice after adenovirus (Ad) infection and correlated it with Ad specific CTL activation using an MHC I tetramer, Db-E1Bp. First, to determine the need for PD-1 in the primary CTL response, we administered Ad into PD-1 deficient mice (PD-1 KO) in parallel with CD28 deficient (CD28 KO) mice. There is a significant decrease in the generation of Db-E1Bp+CD8+ cells in both CD28 KO and PD-1 KO mice 8 days after Ad infection, compared to WT mice (1% and 4% of total CD8+ cells, respectively, compared to 9%. p &lt; 0.05). We next demonstrated that PD-1 upregulation was associated with a decrease in Ad specific CTL response and a defect in activation induced cell death in aged mice. Eight days after Ad infection, 83% of Db-E1Bp+CD8+ cells expressed high level of PD-1 in 24-mo old mice, compared to 16% in young mice (p &lt; 0.05). The expression of PD-1 on non-activated, Db-E1Bp−CD8+ cells was similar in young and old mice. These results indicated that PD-1 on naïve CD8 T cells plays a costimulatory role in T cell activation and high level of PD-1 expression induced upon activation turn it into an inhibitory receptor. Its inhibitory function might also account for the defective activation induced cell death in virus specific CD8 T cells in old mice.
Contrasting effects of Cyclosporine and Rapamycin in de novo generation of alloantigen-specific regulatory T cells (88.45)
Authors: Gao Wenda , Lu Yan , ElEssawy Basset , Oukka Mohamed , Kuchroo Vijay , Strom Terry B 
Published: January 2023

Abstract
The outcome of T cell-mediated responses critically depends on the balance of cytopathic versus regulatory T (Treg) cells. Induction of stable tolerance to allografts requires limiting donor-reactive T effector (Teff) cells via apoptosis. Cyclosporine (CsA) blocks AICD of Teff cells, and is detrimental to co-stimulation blockade-induced tolerance, whereas Rapamycin (RPM) preserves AICD, potentiating such tolerance. While differences between CsA and RPM in influencing apoptosis of Teff are apparent, their effects on graft-protective Treg cells remain enigmatic. Moreover, it is unclear whether tolerizing regimens foster conversion of naïve peripheral T cells into alloantigen-specific Treg cells. Here we show, using reporter mice for Treg marker Foxp3, that RPM promotes de novo conversion of alloantigen-specific Treg cells, whereas CsA completely inhibits this process. Upon transfer, in vivo converted Treg cells potently suppress the rejection of donor but not third party skin grafts. Thus, the use of RPM over CsA is favorable in shifting the balance of aggressive to protective type alloimmunity.
(Supported in part by grants from NIH and JDRF (NIH NS 30843; NIH A141521-08; JDRF 5-2005-108)).