bluuebunny/crossref_metadata_2025_split huggingface dataset:
A role for interleukin-15Rα signaling in the homeostasis of early T cell progenitors (LYM7P.716)
Authors: Colpitts Sara , Lefrancois Leo , Puddington Lynn 
Published: January 2023

Abstract
A deficiency in interleukin-15 receptor α (IL-15Rα) expression is associated with an overall decrease in thymic cellularity. To further investigate this defect, we examined T cell progenitors in the thymus of wild-type (WT) and IL-15Rα KO mice. We identified a significant reduction specifically within the subset of CD27high cells in the CD44highCD25- double negative (DN1) population of T cell progenitors in the absence of IL-15Rα. Since T cell development begins early in ontogeny, we also examined the thymus of WT and IL-15Rα KO neonates (&lt;24hrs post-birth). Surprisingly, we found no differences in the total numbers of neothymocytes or CD27high DN1 cells suggesting that the aforementioned deficiencies are acquired over time. Finally, while IL-15Rα functions largely through the transpresentation of IL-15, it also has the capacity to signal directly. To determine which of these two roles might be involved in the long-term homeostasis of thymic progenitors, we used a transgenic mouse strain that expresses a chimeric receptor composed of the extracellular domain of IL-15Rα and the intracellular domain of the IL-2Rα, thus efficiently disrupting IL-15Rα signaling while maintaining transpresentation. We found that, similar to IL-15Rα KO mice, IL-15Rα signaling transgenics also exhibited a significant decrease in the subset of CD27high DN1 cells suggesting that direct signaling through IL-15Rα is required for optimal homeostasis of early T cell progenitors in the thymus.
Limited frequency of cytokine-producing T cells in tuberculosis lung granulomas (MPF6P.736)
Authors: Gideon Hannah , Myers Amy , Phuah JiaYao , Rutledge Tara , Coleman Teresa , Maiello Pauline , Lin Philana , Flynn JoAnne 
Published: January 2023

Abstract
Lung granulomas are the pathologic hallmark of Tuberculosis (TB). T cells are a major cellular component of tuberculosis lung granulomas and are known to play an important role in containment and progression of Mtb infection. We used cynomolgus macaques, a non-human primate model that recapitulates human TB, with clinically active disease and latent infection, to understand the functional characteristics and dynamics of T cells in individual granulomas and to correlate T cell cytokine response of granulomas to its bacterial burden and its systemic response. Our results suggest that each granuloma within an individual host is independent with respect to total cell numbers, proportion of T cells, pattern of cytokine response, and bacterial burden. The spectrum of these components overlaps greatly amongst various clinical status of these animals, indicating that a diversity of granulomas exist in individual hosts. Multi-parametric flow cytometry analysis of functional T cells in granulomas suggests that on average only ~6% of T cells respond to Mtb antigens with production of Th1/Th17 or IL-10 cytokines. An inverse correlation was observed between bacterial burden and Th1/Th17 response in individual granulomas. The systemic responses do not accurately reflect responses in granulomas, and suggests that, especially in active TB, the blood is a negative reflection of granuloma responses. Overall, these data provide insight into the local and systemic responses in tuberculosis.
Vanilloid receptor-1 as a regulator of gut homeostasis (MUC8P.800)
Authors: Acharya Nandini , Penukonda Sasi , Basu Sreyashi 
Published: January 2023

Abstract
The intestinal mucosa is exposed to myriads of foreign antigens. Hence the immune responses elicited to innocuous antigens in the gut are highly regulated to avoid overt inflammation. CX3CR1hi macrophages , also known as regulatory macrophages, play a critical role in maintenance of immune homeostasis in the gut. Thus therapeutic strategies leading to increase in CX3CR1hi macrophages would be beneficial for treatment of inflammatory diseases. Our present study demonstrates that Vanilloid receptor 1 (VR1), an ion channel previously identified on sensory neurons, is specifically expressed in the CD64+CX3CR1hi macrophages in intestinal lamina propria (LP). VR1-/- mice under normal steady state conditions have significantly reduced number of CX3CR1hi macrophages as compared to wild type counterpart. This data indicates a homeostatic role of VR1 and its endogenous ligands in regulating inflammation and maintaining immune tolerance in the gut. Interestingly, engagement of VR1 by orally administering its exogenous ligand Capsaicin (CP), the pungent component of chili peppers, increases the frequency of CD64+CX3CR1hi macrophages in LP. Furthermore we have shown that CP administration plays a key role in promotion of tolerance via the induction of immune-suppressive CD4+IL10+ IFN- γ+FoxP3- Tr1 cells in IL27 dependent manner. The therapeutic relevance of this phenomenon is highlighted by our study that oral administration of CP to NOD mice provides protection from Type 1 diabetes.
Enteric antigens are delivered to the infant colonic immune system to promote enhance and long-lasting tolerance (MUC8P.801)
Authors: Knoop Kathryn , McDonald Keely , Newberry Rodney 
Published: January 2023

Abstract
Epidemiological studies indicate early exposure to microbial and dietary antigens via the gastrointestinal (GI) tract is associated with a decreased susceptibility for food allergy and inflammatory bowel disease later in life. However, the properties of the infant GI tract conferring this benefit are largely unknown. We found introduction of a dietary antigen during infancy, as opposed to early adulthood, promoted enhanced and lasting tolerance. Using in vivo imaging and ex vivo analysis of lamina propria antigen presenting cells following intraluminal antigen administration, we observed, in contrast to adults, enteric antigens were delivered to the colonic immune system in infants, which had an increased tolerogenic capacity. Antigen delivery to the infant colon immune system was mediated by goblet cell-associated antigen passages (GAPs) and the formation of colonic GAPs was regulated by goblet cell intrinsic sensing of the luminal microbiota, which inhibited antigen delivery and GAP formation in the colon as the microbiota expanded after weaning. Additionally, inhibition of colonic GAPs during enteric antigen exposure during infancy abrogated the tolerance induction. We propose antigen delivery to the infant colon allows the immune system to become ‘educated’ to dietary and microbial antigens, preventing responses to innocuous antigens encountered in the adult colon where the environment contains abundant and complex microbial stimuli.
A role for hormones, gut microbiota and tolerogenic CD103DC in protection of male (NZBxNZW)F1 (BWF1) mice from lupus (MUC8P.805)
Authors: Chhabra Anita , Alard Pascale , Jala Venkatakrishna , Haribabu Bodduluri , Kosiewicz Michele 
Published: January 2023

Abstract
Mechanisms leading to gut homeostasis affect both mucosal and systemic immune function, and involve gut microbiota. Tolerogenic dendritic cells (CD103DC) play a role in gut homeostasis, including generation of induced regulatory T cells (iTregs). Previously, we found that treatment of male BWF1 mice with anti-CD103 antibody significantly increases disease incidence/mortality. Male CD103DC exhibit significantly greater tolerogenic function than either female or castrated male CD103DC in vitro. This study examines the mechanism of sex differences in CD103DC function, and the role of microbiota in lupus. Sex differences in CD103DC function correlated with increased expression of genes associated with tolerogenic/anti-inflammatory function in males, and pro-inflammatory function in females, and changes in iTreg frequency and function in vivo. Male BWF1 CD103DC expressed more Raldh2, an enzyme required for retinoic acid (RA) synthesis and CD103DC function, and supplementation with RA restored tolerogenic function in female CD103DC. Further, we found that male gut microbiota differed significantly from adult, but not immature, female microbiota, suggesting hormones influence the gut microbiota. Importantly, transfer of male gut microbiota to female BWF1 mice significantly reduced anti-dsDNA antibody production. These data suggest that an interplay between hormones, gut microbiota and tolerogenic CD103DC may play a critical role in providing protection to male BWF1 mice.
A novel intestinal intraepithelial CD8α+ population involved in innate immunity (MUC8P.807)
Authors: Olivares-Villagómez Danyvid , Algood Holly , Singh Kshipra , Parekh Vrajesh , Piazuelo Maria , Chaturvedi Rupesh , Weitkamp Jörn-Hendrik , Wilson Keith , Van Kaer Luc 
Published: January 2023

Abstract
Innate immune responses play a critical role during the early stages of defense against infection and other immunological processes. Here, we describe a novel lymphoid population, referred to as innate CD8α+ (iCD8α+) cells. iCD8α+ cells display a lymphoid-like morphology and are present in the intestinal mucosa, primarily residing between intestinal epithelial cells (IEC). iCD8α+ cells are a population characterized by the expression of CD45, CD103, and CD69, and by lacking expression of TCR and markers associated with intraepithelial ILC1, such as NKp46 and NK1.1. Our results indicate that iCD8α+ cells are lymphoid-derived, but contrary to ILC, they do not depend on Id2 for their development, suggesting that iCD8α+ cells belong to a new class of innate lymphoid cells. Interestingly, iCD8α+ cell numbers are considerably reduced in thymus leukemia (TL) antigen-deficient mice, indicating that expression of TL by IEC is important for the development and/or maintenance of iCD8α+ cells. iCD8α+ cells produce cytokines and chemokines associated with innate immune responses such as MCP-1, MIP-1α, MIP1-β, IFN-γ and RANTES. Moreover, iCD8α+ cells can phagocytose and kill bacteria, and are important during Citrobacter rodentium infection. In summary, here we present the description of a novel innate immune cell involved in mucosal immune responses of the intestine.
Effects of exercise and anxiety on salivary IgA production in female college athletes (MUC9P.820)
Authors: King Debra , Lamb Ashley , Carrillo Andres , Appasamy Pierette 
Published: January 2023

Abstract
This study determined whether the fitness status of college athletes, and/or their measurable anxiety levels, had an effect on production of salivary sIgA. High-intensity physical training in elite sports has a negative effect on immune responses, while moderate-intensity training has a positive effect. In addition, psychological stress has a negative impact on immune function. Few studies have looked at the interplay between physical training and stress on the immune response. In this study, we evaluated 2 populations of female college athletes (Division III): one population participating in intense training (ice hockey), and the other group was in the “off season” (soccer). Maximal oxygen consumption (aerobic fitness) was estimated using the modified Balke sub-maximal treadmill test. Saliva samples were collected for sIgA and cortisol measurement. The anxiety levels were measured using a GAD-7 survey. We found that the team participating in their sport (hockey) had higher salivary IgA levels than the team that was “off season” (soccer). There was a wide range of anxiety levels and no correlation between anxiety and salivary IgA or sport. Higher levels of salivary IgA may confer added immune protection to the in-season athletes and these data suggest that the female college athletes were not training to the point of negatively impacting their immune responses. Strategies to maintain immune health are important to consider in designing training programs for athletes.
1-D-Methyl tryptophan treatment of lupus-prone B6.Nba2 mice reduces antinuclear autoantibody levels and B cell differentiation (THER5P.837)
Authors: Davison Laura , Carroll Thomas , Gurion Reut , Mellor Andrew , Jorgensen Trine 
Published: January 2023

Abstract
The enzyme indoleamine 2,3-dioxygenase (IDO) drives tryptophan degradation via the kynurenine pathway. IDO enzymatic activity is significantly elevated in lupus patients compared with controls; however the ramifications of this are unclear. The role of IDO in autoimmunity is debated, as pathogenic or protective effects have been shown in different mouse models of autoimmunity. For example, basal levels of IDO are elevated in MRL/lpr lupus-prone mice and systemic inhibition of IDO accelerates disease in this model. In contrast, systemic inhibition of IDO blocks autoreactive B cells in the K/BxN model of rheumatoid arthritis. Congenic B6.Nba2 mice spontaneously develop a lupus-like disease characterized by elevated levels of serum antinuclear autoantibodies (ANA) and glomerulonephritis. We here show that B6.Nba2 mice express significantly elevated basal levels of IDO. We therefore treated female B6.Nba2 mice with the IDO-specific inhibitor 1 methyl-D-tryptophan (1-MT) administered through the drinking water starting at 8 weeks of age. After 4 weeks of treatment, serum ANA levels were significantly and specifically reduced. This reduction was not due to differences in splenic cell subsets and treatment did not affect total IgG levels. Interestingly, cytokine-induced plasma cell differentiation was reduced in the presence of 1-MT in vitro, suggesting that inhibition of IDO may represent a novel treatment specifically targeting autoantibody production in lupus.
Targeting RhoB as a novel approach for the treatment of Rheumatoid Arthritis (THER6P.856)
Authors: Laury-Kleintop Lisa , Mulgrew Jennifer , Pigott Elizabeth , DuHadaway James , Prendergast George , Mandik-Nayak Laura 
Published: January 2023

Abstract
Rheumatoid arthritis (RA) is an autoimmune disease characterized by high titers of autoantibodies and increased levels of proinflammatory cytokines leading to chronic inflammation of the distal joints. Current biologic therapies, such as the B cell depleting antibody rituximab, have uncovered the important role that autoreactive B cells play in the disease process. Unfortunately, neither immunosuppressive nor biologic therapies specifically target autoreactive B cells. Here, we present data identifying a novel molecular target and newly developed therapeutic that may specifically target these cells. The small GTPase RhoB is a stress response protein that mediates tyrosine kinase receptor stimulated proliferation and migration. While much of the work on RhoB has focused on its function in cancer, we suggest a new role for this GTPase in autoimmune disease. Using the K/BxN model of RA, we show that treatment with an anti-RhoB antibody lowers autoantibody production and attenuates joint swelling. Mice genetically deficient in RhoB exhibit reduced arthritis, providing genetic confirmation of RhoB’s role in mediating autoimmunity. Interestingly, both RhoB deficient mice and mice treated with anti-RhoB Ig mounted productive antibody responses to immunization with model antigens, suggesting that RhoB may have a specific role in the autoreactive B cell. Our data suggest that RhoB antibody therapy could be a new effective therapeutic to treat antibody-mediated autoimmune diseases.
Ex vivo pre-conditioning of hematopoietic stem/progenitor cells impairs long-term hematopoietic repopulation after transplantation (TRAN3P.881)
Authors: Lee Hakmo , Park Ho Seon , Oh Ju Eun , Park Jongwoo , Chung Sung Soo , Park Kyong Soo , Jung Hye Seung 
Published: January 2023

Abstract
A number of investigators have tried to facilitate engraftment with limited numbers of available HSPCs by enhancing responsiveness of HSPCs to CXCL12. Recently, granulocyte derived cationic peptide, LL-37, has been suggested as a useful pre-conditioning component to overcome the shortage of available HSPCs. In this study, we first evaluated the character of LL-37 pre-conditioned HSPCs and found that LL-37 pre-conditioning effects are specific only to the clonogenic stem cells which are considered relatively dormant. This raised our concern regarding the fate of LL-37 pre-conditioned cells after transplantation and led us to evaluate their repopulation capacity as HSPCs. Not betraying our expectations, hematopoietic recovery of LL-37 pre-conditioned cells gradually decreased from 4 weeks after transplantation in competitive repopulation experiments. Further, in vitro studies revealed that LL-37 lead HSPCs to be more vulnerable to extracellular stimuli such as extracellular glucose followed by increased calcium influx from extracellular sources, which dampen self-renewal capacity by activating mammalian target of rapamycin and its downstream signaling. These results suggest that a future strategy must focus on maintaining HSPCs in dormant and protecting them from various stimuli during their long journey to the bone marrow niches rather than activating them before transplantation for successful transplantation outcome.
Low levels of SDF-1α constrain DC recovery and diminish homeostatic proliferation of naïve CD4+ T cells during graft-versus-host disease. (TRAN3P.892)
Authors: Gauthier Simon David , Leboeuf Dominique , Guimond Martin 
Published: January 2023

Abstract
Graft-versus-host disease (GVHD) is the major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (SCT) and its effect on T cell regeneration greatly increases the immunodeficiency normally associated with SCT. As a result, GVHD patients experience profound lymphopenia and lymphocyte reconstitution takes generally several months or years. The goal of this work was to assess the impact of GVHD on homeostatic proliferation (HP) of non-alloreactive naïve CD4+ T lymphocytes with the hypothesis that regeneration of the peripheral niche permissive to CD4 HP is constrained by GVHD. To study the impact of GVHD on the peripheral niche regulating CD4 HP, we used a Parent→F1 mouse model and observed a complete abrogation of CD4 HP in GVHD hosts. Loss of HP was related to depletion of all DC subsets as well as low levels of IL-7. While Flt3-ligand (FL) levels were normal, Stromal Derived Factor-1α (SDF-1α) was significantly diminished in GVHD mice. Administration of FL or SDF-1α significantly increased DC counts but CD4 HP was restored only when FL or SDF-1α was combined to IL-7. Importantly, while FL treatment aggravated GVHD, GVHD was improved by SDF-1α therapy. Our study shows that lack of immune reconstitution of CD4+ T cells is primarily due to failure of DC recovery owing to diminished SDF-1α production and diminished IL-7 and that the combination of SDF-1α and IL-7 could be used to enhance CD4 HP in GVHD hosts.
Engineering an ectopic thymus in the lymph node to induce central tolerance and long-term allograft acceptance (TRAN3P.896)
Authors: Rao Aparna , Gupta Avni , Lagasse Eric 
Published: January 2023

Abstract
Background: Allogeneic transplant rejection is one of the major problems plaguing the field of organ transplants. Our previous studies have established the lymph node as a functional site for thymus transplant. In this study, we hypothesized that conditioning transplant recipients with thymic cells immune-matched to the donor will induce long-term acceptance of a subsequent allograft. Methods: We transplanted Balb/c-GFP thymuses into the lymph nodes of FAH-/- mice on a 129sv background. After 6 weeks, the animals were challenged with donor-matched skin grafts or hepatocyte transfer and monitored for long-term allograft acceptance. We also assessed tolerance induction by performing mixed lymphocyte reaction assays (MLR), immunostaining of native and ectopic thymus, as well as thymic dendritic cell (tDC)-T cell co-cultures. Results: Mice receiving thymus transplants successfully accepted subsequent allografts long-term. MLR reactions demonstrated Balb/c-specific tolerance in these mice. We also observed migration of cells (mostly tDCs) from the ectopic to the native thymus. tDC-T cell co-cultures revealed that migrating DCs from the ectopic as well as native thymus were instrumental in generating the increased numbers of Tregs observed in recipient mice. Conclusion: We were able to achieve long-term allograft acceptance in mice receiving thymic transplants, which was possibly mediated by the increased Treg induction associated with cross-talk between the two thymuses.
Intrinsic MyD88-activation in B cells is necessary for development of alloreactive memory T cells (TRAN3P.902)
Authors: Singh Tripti , Ng Yue-Harn , Ramaswami Balathiripurasundari , Ippolito Renee , Chalasani Geetha 
Published: January 2023

Abstract
B cells help alloreactive T cells to differentiate into memory T cells. Since B cells express TLRs, we asked whether MyD88-mediated activation of B cells is required for T cell activation and differentiation to memory T cells. Methods: Irradiated μMTCD45.1 mice were transplanted with bone marrow cells from μMTCD45.1 and wtCD45.2 (μMT+wt) or μMTCD45.1 and MyD88-/-CD45.2 (μMT+MyD88-/-). Differences in congenic background allowed us to confirm that following reconstitution, MyD88 deficiency was essentially restricted to B cells. μMT+MyD88-/- and μMT+wt received Balb/c skin transplants. Results: Rejection of allografts was comparable between μMT+MyD88-/- and μMT+wt chimeras (MST=18 days). μMT+MyD88-/- recipients showed 3-fold more alloreactive IFNγ+ CD4 and CD8 effector T cells when compared to μMT+wt mice at day 14 (p&lt;0.05). IL-10+ B cells were diminished (p&lt;0.005) in μMT+MyD88-/- than in μMT+wt chimeras. CD8 memory precursor T cells (CD44hi CD62Llo CD127hi) in μMT+MyD88-/- showed predominantly Bcl2lo expression in both KLRG1lo memory precursor effector cell (MPEC) and KLRG1hi short-lived effector cell (SLEC) populations. Consistent with these findings, fewer alloreactive CD4 and CD8 IFNγ+ memory T cells were seen in μMT+MyD88-/- (p&lt;0.005) resulting in impaired memory recall (MST = 27 vs. 15 days, p &lt; 0.005) than in μMT+wt chimeras. Conclusions: Intrinsic MyD88-dependent B cell functions are important for alloreactive T cell differentiation into long-lived memory T cells.
Neddylation regulates T cell responses. (TRAN3P.914)
Authors: Mathewson Nathan , Toubai Tomomi , Sun Yaping , Wu Julia , Oravecz-Wilson Katherine , Wang Ying , Hou Guoqing , Reddy Pavan 
Published: January 2023

Abstract
Post-translational modifications (PTM) of proteins regulate cellular processes by proteasomal degradation. PTM of Cullin-RING ligase (CRL) protein via neddylation and the presence of its critical adapter element, sensitive to apoptosis gene (SAG) protein, modulate the process of neddylation-dependent ubiquitination. The role of neddylated proteins in regulating T cells is not known. We explored the role of neddylation in T cells by utilizing two different, but complementary approaches. We generated a T-cell specific knockout (SLCK-KO) of SAG (critical for the neddylation process) and utilized a small molecule inhibitor specific for neddylation (MLN4924). Phenotypic analysis of thymic and splenic T cells from SLCK-KO showed no differences when compared to WT. In vitro analysis of SLCK-KO T cells, with either allo-splenocytes or non-specific CD3/CD28 antibodies demonstrated reduced activation (CD69, CD44), proliferation, and secretion of T helper signature cytokines (IFNγ, IL-4, IL-17) (P&lt;0.003). In vivo studies utilizing multiple MHC disparate models of BMT (B6→BALB/c, B6→B6D2F1), demonstrated that SLCK-KO T cells in the recipient animals caused reduced severity of GVHD and increased survival (P&lt;0.01). Similar results were obtained in vitro and in vivo with small molecule, MLN4924. Our results demonstrate a novel biological role for neddylation in regulating T cell functions in vitro and in vivo.