bluuebunny/crossref_metadata_2025_split huggingface dataset:
Toll-like receptor-2 and interleukin-1 signaling in keratinocytes during Staphylococcus aureus infections (46.9)
Authors: Jensen Liselotte 
Published: January 2023

Abstract
Staphylococcus aureus is a significant human pathogen. Subcutaneous infections in mice trigger neutrophil recruitment in an IL-1β, but not IL-1α, dependent manner. Since S. aureus can colonize the skin we explored the role keratinocytes play as first responders to bacterial challenges. In mice, topical application of IL-1, S. aureus or the bacterial cell wall components lipoteichoic acid (LTA) and peptidoglycan (PGN) triggered neutrophil recruitment to the skin surface. In human tissue culture models IL-1α and IL-1β increased mRNA and protein production of the neutrophil chemotactic CXCL1, CXCL2 and IL-8. S. aureus, LTA and PGN induced similar expression profiles in a TLR2 dependent manner. The S. aureus activated chemokine production was preceded by significant IL-1α and IL-1β secretion. Expression of IL-1α was significantly higher than that of IL-1β. IL-1RI neutralization experiments revealed that S. aureus derived LTA and PGN induced chemokine expression requires IL-1RI signaling. Surprisingly, we further found that LTA and PGN initiated chemokine secretion is dependent upon endocrine IL-1α, but not IL-1β, signaling. Our data demonstrate that the innate immune response of keratinocytes is regulated differently than those of subcutaneous tissues. A multifaceted IL-1 scheme involving IL-1α in the skin and IL-1β in underlying tissues may represent a fail-safe system, which protects the host against genetic variation and immune evasion mechanisms developed by pathogens.
Multivariate analysis identifies biomarkers of intestinal inflammation (47.10)
Authors: McBee Megan , Zeng Yu , Parry Nicola , Nagler Cathryn , Tannenbaum Steven , Schauer David 
Published: January 2023

Abstract
Few predictive indicators are available for diagnosis of the chronic intestinal inflammation that characterizes inflammatory bowel disease (IBD). Identification of predictive serum biomarkers may allow for therapeutic intervention prior to disease onset in individuals bearing IBD susceptibility genes. Discriminatory multivariate modeling of 23 cytokines (plus chlorotyrosine [CT] and nitrotyrosine [NT], protein adducts from reactive oxygen and nitrogen species) in serum and tissue from two murine models of colitis was performed to identify disease- associated biomarkers. Citrobacter rodentium infection of C57BL/6J mice and Helicobacter-dependent spontaneous colitis in TLR4 x IL10 deficient mice were used as the acute and chronic colitis models. A subset of serum factors identified in the acute colitis model (NT, G-CSF, KC, IL-12/23p40 and IL-17) was also influential in the serum from mice with chronic disease. Surprisingly, the most influential acute tissue factors (11 total) were also influential in chronic tissue (15 total), and were dominated by Th17- and neutrophil-associated factors. Additionally, multivariate models generated from the influential serum or tissue factors predicted the severity of histological colonic lesions. This study has therefore identified neutrophil and Th17 associated factors in serum as predictive biomarkers of intestinal inflammation, in agreement with the presence of neutrophils and Th17 cells in the inflamed colonic tissue of patients with IBD.
Inducible ablation of Langerhans cells enhances skin immune responses (48.15)
Authors: Kaplan Daniel , Bobr Aleh , Olvera-Gomez Irlanda , Hogquist Kristin , Igyarto Botond 
Published: January 2023

Abstract
Although initially thought to be required for the development of contact hypersensitivity (CHS) responses, recent data obtained from two Langerhans cell (LC)-deficient mouse models has cast this role in doubt. We have previously described huLangerin-DTA mice in which LC are constitutively ablated but other Langerin+ DC are unaffected. In these mice, the absence of LC leads to the development of increased CHS responses. In the second model, muLangerin-DTR mice, LC and Langerin+ dermal dendritic cells (dDC) are inducibly ablated by administration of DT. LC, unlike Langerin+ dDC, repopulate slowly after diphtheria toxin (DT) administration. By comparing early and late time-points after DT administration, it appears that Langerin+ dDC are required for optimal CHS responses and efficient epicutaneous immunization but that LC are redundant. One major difference between these two models that could account for the disparate results is the timing of LC ablation: inducible (muLangerin-DTR) vs. constitutive (huLangerin-DTA). We now report the development of a new line of mice (huLangerin-DTR) in which administration of DT leads to inducible ablation of LC without affecting Langerin+ dDC. The acute and selective ablation of LC in these mice results in increased CHS responses. Thus, LC-mediated suppression does not require their absence during ontogeny or during the steady state. Rather, LC actively limit cutaneous immune responses and may function to terminate ongoing cutaneous immune responses and/or prevent responses against epidermal antigens.
The PD-Ligand Pathway regulates the development, maintenance and function of induced regulatory T cells in vitro and in vivo (49.16)
Authors: Francisco Loise , Salinas Victor , Brown Keturah , Vanguri Vijay , Freeman Gordon , Kuchroo Vijay , Sharpe Arlene 
Published: January 2023

Abstract
Both the PD-1:PD-Ligand pathway and regulatory T cells (Tregs) are instrumental to the maintenance of peripheral tolerance. PD-1 has two ligands, PD-L1 and PD-L2. We demonstrate that PD-L1 plays a pivotal role in the de novo differentiation of regulatory T cells and the maintenance of Treg function. PD-L1-/- APCs minimally convert naïve CD4 T cells to become induced-regulatory T cells (iTregs). Moreover, PD-L1-coated beads profoundly increase the CD4+Foxp3+ Treg population, mediated by attenuation of the Akt-mTOR axis and concomitant with upregulation of PTEN. These PD-L1-iTregs suppress T effector cell proliferation more efficiently than control-iTregs and express high levels of CD25, PD-1, B7-1 and GITR. Furthermore, when control or PD-L1-induced Tregs are sorted and re-cultured with PD-L1-coated beads, PD-L1 enhances Foxp3 expression and suppressive function of iTregs. The obligatory role for PD-L1 in controlling iTreg development and function in vivo is illustrated by a marked reduction in iTreg conversion and rapid onset of a fatal inflammatory phenotype in PD-Ligand-/- Rag-/- recipients of naïve CD4 T cells. Parallel studies with PD-L2 reveal similar effects on the de novo differentiation of iTregs. Thus, the PD-1:PD-Ligand pathway can inhibit T cell responses by promoting both the induction and maintenance of induced Tregs. These studies define a novel mechanism for iTreg development and function, as well as a new strategy for controlling Treg plasticity.
Altered intestinal homing molecule expression prevents effective Treg trafficking in the FVB.mdr1a-/- model of colitis. (49.22)
Authors: Tanner Scott , Lorenz Robin 
Published: January 2023

Abstract
The FVB.mdr1a-/- mouse, lacking the small molecule pump P-glycoprotein, is a commonly used model for the study of spontaneous T cell mediated colitis. Our lab has shown that a defect in regulatory T cells (Treg) in this model could be a cause of disease. One possible mechanism for the defect in immune regulation is the inability of Tregs to traffic to the gut where they are needed to effectively maintain homeostasis. To investigate this, we examined the numbers of Tregs within various lymphoid organs in the FVB.mdr1a-/- mice. While splenic Treg percentages remained similar between knockout and wild type controls, a decrease in Treg percentages was observed within the MLN, Peyer’s patches and lamina propria. We then adoptively transferred FVB effector T cells (Teff) + FVB or FVB.mdr1a-/- Treg cells into FVB.Rag-/- recipients. After 4 weeks, tissue was harvested to monitor Treg trafficking. Significantly fewer Tregs were observed in the lamina propria of FVB.mdr1a-/- recipients (9.47±5.26% vs. 2.83±0.70%). In addition, FVB.mdr1a-/- Treg recipients showed significantly less expression of the gut homing receptors CCR9 (63.36±3.85% vs. 29.69±2.19%) on splenic Tregs and α4β7 (49.85±2.49% vs. 12.26±5.61%) within lamina propria Tregs. Interestingly, an increase in total splenic cell numbers was observed in the recipients of FVB.mdr1a-/- Tregs. This suggests mdr1a deficient Tregs remain in the spleen and are unable to utilize CCR9 and α4β7 to traffic to the intestine.
Defects of Regulatory T Cell function In The Wiskott-Aldrich Syndrome. (49.25)
Authors: Adriani Marsilio , Jones Krystin , Kirby Martha , Anderson Stacie , Silvin Christopher , Wincowitch Stephen , Candotti Fabio 
Published: January 2023

Abstract
Natural Tregs from both WAS patients and WASp-deficient (WKO) mice were previously reported as unable to suppress the proliferation of conventional T-cells in vitro. Because WAS T-cells have a known defect of IL-2 production and this cytokine is important for the generation of Treg cells induced from naïve T-cells, we assessed the efficiency with which WKO naïve T-cells can differentiate in Tregs and observed a significant defect compared to WT. Such defect was not corrected by increasing concentration of anti-CD3 and TGF-β. Preliminary experiments indicated a role for endogenous IL-2 production in the generation of iTregs and pointed again to the IL-2 pathway as a major determinant of the Treg cells defects in WAS. Furthermore, we previously observed that the impaired suppression of T-cell proliferation could be partially rescued by pre-activation of nTregs. Because activated nTregs are known to be able to induce B-cell apoptosis, we set out to evaluate the function of WKO nTregs on B-cells. We found that pre-activated WKO Treg cells fail to effectively suppress B-cell proliferation. The reduced granzyme-B secretion by WKO nTregs compared to WT, suggest that the defective suppressive activity on B-cells may be due to a degranulation defect of WKO cells. In summary, our data suggest that both natural and induced arms of T regulatory cells are defective in WAS and that defective peripheral Treg induction may be involved in the pathogenesis of autoimmunity in this disease.
Interleukin-35-mediated induction of a novel regulatory T cell population (49.7)
Authors: Collison Lauren , Henderson Abigail , Chaturvedi Vandana , Turk Mary , Vignali Dario 
Published: January 2023

Abstract
Regulatory T cells (Tregs) play a critical role in the maintenance of immunological self tolerance and immune homeostasis. Due to their potent immunosuppressive properties, the ex vivo generation of regulatory T cells is an important goal of immunotherapy. We show that treatment of conventional T cells (Tconv) with the inhibitory cytokine IL-35 induces IL-35 expression and confers suppressive capacity, in the absence of Foxp3, IL-10 and TGFβ expression, upon Tconv cells. IL-35-dependent induced Tregs, termed iTR35, are strongly suppressive in vitro and in in vivo models including IBD, EAE, and a B16 tumor model. Treg-mediated suppression induces the generation of iTR35 in an IL-35- and IL-10-dependent manner in vitro and within the tumor microenvironment. Human IL-35 can mediate the generation of human iTR35 that express IL-35 and are suppressive. iTR35 may constitute a key mediator of infectious tolerance and ex vivo generated iTR35 may possess therapeutic utility in various human diseases.
The Zinc binding site in the BH domain of Itk is required for interaction with Gα13 (50.10)
Authors: Huang Weishan , Morale Luis , Qi Qian , August Avery 
Published: January 2023

Abstract
The Tec family kinase, Itk has been shown to be critical in T cell activation and development downstream of the T cell receptor (TCR). Migratory responses to chemokines such as CCL11/Eotaxin and CXCL12/SDF-1α require Itk. However, the mechanism by which chemokine receptor signals connect to Itk is not clear. We speculate Gα13 may serve to couple GPCRs, Itk and downstream signals. Using a Bimolecular Fluorescence Complementation system, we show that Itk and Gα13 are in close physical proximity, less than 80Å. This interaction requires the membrane localization of Itk, as the membrane targeting deficient mutants (S15P, R29C), lost their association with Gα13. Moreover, we found that mutations in the Zn2+ binding Bruton’s tyrosine kinase homology (BH) motif (C132GC133G), disrupted the interaction, even though this Itk mutant was still able to get recruited to membrane associated clusters. However, this interaction is Itk kinase activity independent. We also show that both GTP bound and GDP bound forms of Gα13 can interact with Itk. Surprisingly, co-expression of Itk and Gα13 resulted in tyrosine phosphorylation of Gα13. Taken together, we propose that interactions between Gα13 and Itk may connect chemokine/chemokine receptor stimulation and downstream responses regulated by Itk. Itk may also modulate the function of Gα13 by tyrosine phosphorylation. These data provide evidence for better understanding of the mechanism by which chemokines regulate immune cell responses.
STAT5 is Critical to Maintain Effector CD8+, but not CD4+, T cell Responses (50.17)
Authors: Tripathi Pulak , Kurtulus Sema , Wojciechowski Sara , Sholl Allyson , Hoebe Kasper , Morris Suzanne , Finkelman Fred , Grimes H. , Hildeman David 
Published: January 2023

Abstract
During an immune response, most effector T cells die, while some are maintained and become memory T cells. Factors controlling the survival of effector CD4+ and CD8+ T cells remain unclear. Here, we assessed the role of IL-7, IL-15, and their common signal transducer, STAT5, in maintaining effector CD4+ and CD8+ T cell responses. Following viral infection, IL-15 was required to maintain the KLRG1hiCD127lo subpopulation of effector CD8+ T cells, while IL-7 and IL-15 acted together to maintain KLRG1loCD127hi CD8+ effector T cells. In contrast, effector CD4+ T cell numbers were not affected by the individual or combined loss of IL-15 and IL-7. Both IL-7 and IL-15 drove phosphorylation of STAT5 (pSTAT5) within effector CD4+ and CD8+ T cells. When STAT5 was deleted during the course of infection, both KLRG1hiCD127lo and KLRG1loCD127hi CD8+ T cells were lost, while effector CD4+ T cell populations were maintained. Further, STAT5 was required to maintain expression of Bcl-2 in effector CD8+, but not CD4+, T cells. Finally, IL-7 and IL-15 required STAT5 to induce Bcl-2 expression and to maintain effector CD8+ T cells. Together, these data demonstrate that IL-7 and IL-15 signaling converge on STAT5 to maintain effector CD8+ T cell responses.
TNFR1 functions as a survival receptor in TNFR2-/- CD8 T cells (50.19)
Authors: Twu Yuh-Ching , Teh Hung-Sia 
Published: January 2023

Abstract
TNF/TNFR superfamily members play central roles in host defense, inflammation, apoptosis, autoimmunity and organogenesis. Previous reports showed that TNFR2 regulates T cell activation by lowering the activation threshold and providing costimulatory signaling. Furthermore, activated TNFR2-/- CD8 cells are highly resistant to AICD. Here, we show that blocking of activated wild-type (wt) CD8 cells with anti-TNFR2 antibodies also renders these cells resistant to AICD. The resistance of activated TNFR2-/- CD8 cells to AICD correlates with the accumulation of TRAF2. Retroviral transfection studies showed that TRAF2 overexpression was partially effective in preventing AICD in activated wt CD8+ cells. Furthermore, neutralization of TNF-α inhibits the proliferation of anti-CD3-stimulated wt CD8 T cells and increases apoptotic death cells in activated TNFR2-/- cells. TNF-α blocking also reduced TRAF2 accumulation in activated TNFR2-/- CD8 cells, which correlates with their increase susceptibility to AICD. AICD-resistant TNFR2-/- CD8 cells expressed elevated levels of phosphorylated IκBα and neutralization of TNF-α blocked this increase. These results indicate that in activated TNFR2-/- CD8 cells, TNFR1 functions as a survival receptor by promoting TNF-α-mediated regulation of TRAF2 levels and the extent of phosphorylation of pro-survival signaling molecules such as IκBα. This work is supported by the Canadian Cancer Society.
CD8 T cells require intrinsic GITR signaling for their clonal expansion during influenza infection in vivo (50.21)
Authors: Snell Laura , McPherson Ann , Lin Gloria , Sakaguchi Shimon , Pandolfi Pier , Riccardi Carlo , Watts Tania 
Published: January 2023

Abstract
Several members of the tumor necrosis factor receptor family regulate T cell expansion by influencing T cell activation and survival. Among these, glucocorticoid-induced TNF receptor family-related gene (GITR) is of interest, as it is expressed on both effector and regulatory T cells. While much work has focused on the role of GITR on regulatory T cells, little is known about its role on effector T cells in an infectious disease context. We sought, therefore, to examine the intrinsic role of GITR on CD8 T cells during a viral infection. To do this, we employed an adoptive transfer model where WT and GITR-/- TCR transgenic OT-I CD8 T cells were forced to compete with each other in response to infection with a recombinant influenza virus carrying the ovalbumin epitope recognized by OT-I, Influenza A/X31-OVA. In both the primary and secondary response to virus profound defects in GITR-/- OT-I T cell numbers were detected in all organs examined. Further investigation revealed that the decreased number of GITR-/- OT-I T cells was not due to a homing or proliferative defect, but rather that GITR was important for TRAF2 and TRAF5 mediated T cell survival signaling. Moreover, we also used a similar adoptive transfer model to show that GITR is required on CD8 T cells for enhancement of influenza-specific CD8 T cell expansion upon administration of agonistic anti-GITR antibody. These results highlight the importance of GITR as a CD8 T cell costimulator during acute viral infection.
The Effector phase of the CD8+ T cell response is not programmed during initiation (50.25)
Authors: Duttagupta Priyanka , Dolfi Douglas , Boesteanu Alina , Mueller Yvonne , Katsikis Peter 
Published: January 2023

Abstract
It is believed that CD8+ T cell responses are programmed at initiation in the lymph nodes by activated antigen presenting cells to undergo further proliferation in the absence of antigen and costimulation signals. We examined the effector CD8+ T cell response in the lungs of influenza virus infected mice during the late phase of infection, in the absence of costimulation, antigen and dendritic cells (DC). Blocking CD28-CD80/CD86 signaling with antibodies or depleting DCs after day six of the infection results in a 6-fold reduction in the absolute number of lung NP366-374- specific CD8+ T cells at the peak of the infection on day 10. Adoptive transfer of effector OVA257-264- specific CD8+ T cells into WSN-OVA infected wild type mice, CD80/CD86 knockout mice and DC depleted CD11c-DTR mice showed a 7-fold reduction in the number of effector CD8+ T cells in the lungs. Importantly effector CD8+ T cells need antigen to expand. Transferred effector OVA257-264 specific CD8+ T cells from lungs of WSN-OVA infected mice fail to expand in mice infected with influenza virus that does not carry cognate antigen. Moreover the absence of costimulation and dendritic cells leads to increased apoptosis of effector CD8+ T cells. In conclusion our results show that antigen-specific CD8+ T cells at the effector site need the continuous presence of dendritic cells, antigen and costimulation for expansion and survival during the late effector phase of the immune response
Genome-wide transcription profiling identifies the mechanisms of LFA-1 contributing to CD8+ T Cell Activation and immune signal network (50.26)
Authors: Li Dan , Li Hua , Liang Shoudan , Molldrem Jeffery , Ma Qing 
Published: January 2023

Abstract
Our previous data demonstrated that the function of LFA-1 is to enhance TCR signaling through the immunological synapse and deliver distinct signal in CD8+ T cell activation. However, the detailed molecular pathways that regulate these processes and global impact on immune functions are poorly defined. The purpose of this genomic study is to explore and understand the LFA-1 and TCR signaling network with CD8+ T cell transcription profiling. CD8+ T cells from C57BL/6 mice and LFA-1-KO mice before and after stimulation were applied to the Mouse Whole Genome Oligo Microarray. Statistic analysis identified a list of LFA-1-associated genes differentially expressed in activated LFA-1-KO CD8+ T cells. Pathway analysis indicated that most of these genes are enriched in IL-10 signaling/ p38 MAPK signaling/ cell cycle regulation/ notch signaling/ NK signaling/ chemokine signaling. Furthermore, biological function analysis implicated these genes enriched in the functions of antigen presentation/ cell-mediated immune response/ inflammatory response/ cellular development/ cell-to-cell signaling and interaction/ immune cell trafficking/ cellular growth and proliferation/ inflammatory disease/ lymphoid tissue structure and development. Our results indicated that LFA-1 plays an important role in the immune signal network and has a global impact on immune system, and provided a complete genome-wide database to further characterize the molecular mechanisms of LFA-1 during T cell activation.
Signaling via PD-1 controls the expression of cyclins and the activation of cdk2 in human primary CD4+ T cells (50.30)
Authors: Brown Julia , Boussiotis Vassiliki 
Published: January 2023

Abstract
The Programmed Death 1 (PD-1) pathway plays a critical role in the inhibition of T cell activation and the maintenance of T cell tolerance. Expressed by activated T cells, PD-1 downregulates T cell effector function upon engagement with its ligands PD-L1 and PD-L2. Although vital for the inhibition of self-directed immune responses in several models of autoimmunity, expression of PD-L1 and PD-L2 by malignant tissues can prevent effective tumor-specific immunity. Furthermore, the ligation of PD-1 results in T cell exhaustion in several chronic viral infections. PD-1 mediated signaling via SHP-2 decreases Akt activation via inhibition of PI3K, but little is known about mechanisms of cell cycle regulation. Using anti-CD3 with or without anti-PD-1 conjugated to magnetic beads plus soluble anti-CD28, we have examined the expression of cell cycle mediators upon stimulation of human primary CD4+ T cells. Analysis of cell lysates by western blot revealed that signaling via PD-1 inhibited the upregulation of Skp2 and prevented the degradation of p27kip1 and the expression of cyclin E and cyclin A. Furthermore, despite abundant levels of cdk2, ligation of PD-1 prevented cdk2 phosphorylation on Thr 160 thereby inhibiting the G1/S phase transition and progression through S phase. We conclude that inhibition of T cell activation via PD-1 signaling has direct consequences for the expression and regulation of integral proteins involved in the cell cycle.