bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mild cold stress resulting from standard housing conditions for laboratory mice masks the severity of graft vs. host disease in mouse models of bone marrow transplantation (TRAN3P.887)
Authors: Leigh Nicholas , Kokolus Kathleen , Qiu Jingxin , McCarthy Philip. , Cao Xuefang , Repasky Elizabeth 
Published: January 2023

Abstract
Clinical bone marrow transplants (BMT) yield lethal graft vs. host disease (GVHD) after transplant of un-manipulated bone marrow (BM). This differs from murine GVHD models that typically require addition of spleen or lymph node derived T cells. Recent work has shown that mice housed at mandated sub-thermoneutral ambient temperatures (22°C) are cold stressed, resulting in heat generation activated by the sympathetic nervous system. Since cold stressed mice exhibit weakened immune responses, we hypothesize that baseline GVHD is reduced compared to that seen in mice at thermoneutral temperatures (30°C). We compared GVHD in mice receiving MHC-mismatched un-manipulated BM while housed at 22 vs. 30°C at which cold stress is alleviated. In this BMT model, mice housed at 22°C show no signs of GVHD, however, we found weight loss and lethal GVHD in mice housed at 30°C. The same trend was observed with MHC-matched allogeneic BMT. As housing at 22°C activates the sympathetic nervous system, we blocked its activation by administering propranolol, a commonly prescribed β-blocker. Following BMT, mice at 22°C treated with β-blocker displayed lethal GVHD similar to untreated mice at 30°C. This suggests that T cell responses are dampened by cold stress through a β-adrenergic pathway which is circumvented by thermoneutral housing. This study provides insight into translational discrepancies of clinical and murine BMT and demonstrates lethal GVHD in a mouse model generated by un-manipulated BM.
Origin and function of host-derived dendritic cells in vascularized organ transplants (TRAN3P.889)
Authors: Zhuang Quan , Shen Lin , Zeng Qiang , Williams Amanda , Oberbarnscheidt Martin , Lakkis Fadi 
Published: January 2023

Abstract
Donor DC exit organ grafts after transplantation and are replaced by host DC. The origin and function of these tissue-resident, host DC however is unknown. Using flow cytometry and 2-photon intravital microscopy, we observed rapid replacement of donor DC by host DC in both syngeneic and allogeneic heart and kidney grafts within 3 days after transplantation, and demonstrated that the vast majority of host DC were monocyte-derived (Mono-DC). By day 7, allografts harbored &gt;5-fold more DC than syn grafts and &gt;45-fold more than native tissue. Enhanced DC accumulation in allografts was inhibited by treating recipients with cyclosporine A, indicating a crucial role for the host alloimmune response in DC influx. DC accumulation was only partially dependent on fractalkine receptor (CX3CR1) expression on host monocytes. Host DC that infiltrated grafts localized to perivascular areas, extended dendrites into the vessel lumens, mediated the transmigration of cognate effector T cells (Teff) into the graft, and continued to make stable contacts with the Teff after they had transmigrated. Depletion of host Mono-DC by administering DT to CD11b-DTR mice significantly reduced T cell infiltration and IFN-γ production in the graft. Hence, host Mono-DC amass rapidly in transplanted organs, replacing donor DC, and accelerate rejection by enhancing Teff migration, retention, and activation. Our results provide novel insights into the pathogenesis and treatment of allograft rejection.
Anti-porcine abumin IgG antibodies are elicited in diabetic non-human primate recipients after intraportal porcine islet transplantation (TRAN3P.890)
Authors: Kang Hee Jung , Lee Haneulnari , Park Eun Mi , Park Chung-Gyu , Miyagawa Shuji 
Published: January 2023

Abstract
Xenoreactive antibody responses were investigated in non-human primate (NHP) recipients after porcine islet transplantation (pITx). The levels of anti-αGal and anti-nonGal IgG Abs in serial sera of the recipients were measured by ELISA and flow cytometry using GalT-KO porcine endothelial cells (PECs), respectively. We detected an elicited anti-nonGal IgG response in some sera of the recipients. Through a series of work including EP of protein extracts from GalT-KO PECs, Western blot and MALDI-TOF/TOF mass spectrometry, the putative antigen was identified as bovine albumin. The sera positive of anti-nonGal Ab revealed strong IgG binding to both bovine and porcine albumin, but no binding to human albumin by ELISA. When anti-human, bovine and porcine albumin Abs were measured in pre- and post-pITx sera of 29 NHP recipient, the frequencies of the development of anti-porcine albumin IgG Abs were significantly different according to the types of immunosuppression (IS) regimen: 5/5 (100%) receiving conventional IS regimen, 2/2 (100%) receiving anti-CD154 and sirolimus and 2/21 (9.5%) receiving CD40-CD40L blockade, sirolimus and either anti-ICAM-1 or ATG (P&lt;0.0001 vs. other groups, χ2 test). The anti-bovine albumin IgG was also detected in the sera of 6 (67%) from 9 recipients positive for elicited anti-porcine albumin IgG. These experiments indicate that anti-porcine/bovine albumin Abs are elicited in NHP recipients after porcine ITx, which can be prevented by an adequate IS.
The role of myeloid cells in graft rejection (TRAN3P.893)
Authors: Chain Robert , Chakhtoura Marita , Gallucci Stefania 
Published: January 2023

Abstract
Acceptance of a mismatched graft is achieved through immunosuppression that requires long-term treatment. A variety of methods have been explored to prevent rejection and achieve transplant tolerance in mouse models. The combination of LPS from gram-negative Bacteria, and tissue damage from the transplant procedure has been suggested to prevent rejection and deserves further investigation. We implemented a mouse skin transplant model to determine the effects of LPS and endogenous danger signals released during engraftment, on myeloid cell functions and study their ability to induce rejection or tolerance in transplantation. We used the spontaneous single minor histocompatibility mismatch model of skin graft rejection and performed skin grafts from male mice onto syngeneic female recipients then treated the mice with LPS or PBS. Control mice completely rejected the graft between 24-34 days, while mice treated with LPS did not show graft rejection until an average of 64 days, with 50% graft acceptance. When we studied the graft immune infiltrate, we found that within 48 hours post transplantation, there was an influx of GR-1+ CD11b+ double positive cells. LPS-treated recipients showed a significant decrease in the recruitment of these GR-1+ CD11b+ double positive cells at the graft site. These results indicate that GR-1+ CD11b+ myeloid cells migrate to the site of transplantation following trauma and suggest they play a key role in graft rejection, warranting further study.
Memory CD4 T cell helps alter isotype and specificity of donor-reactive alloantibody (TRAN3P.894)
Authors: Gorbacheva Victoria , Fan Ran , Valujskikh Anna 
Published: January 2023

Abstract
As alloreactive antibody (alloAb) mediate allograft rejection we tested how memory CD4 T cells influence alloAb responses in a murine renal transplantation model. While A/J (H-2a) kidney allografts are spontaneously accepted by naïve B6 (H-2b) recipients, donor-reactive memory CD4 T cells induced rapid rejection through induction of alloAb. We compared serum titers and isotypes of donor-reactive alloAb and the numbers of plasma cells secreting Ab against individual donor MHC antigens in B6 recipients with or without transfer of polyclonal A/J-primed memory CD4 T cells. As anticipated, recipients containing memory CD4 T cells developed faster and stronger alloAb responses than non-sensitized recipients. However, the effects of memory CD4 T cell help were not limited to the accelerated kinetics and higher magnitude of alloAb production. Memory CD4 T cells induced high titers of IgG2c, IgG2b and IgG1 Ab reactive to A/J. In contrast, anti-donor Ab in non-sensitized recipients were exclusively IgG2b. High numbers of plasma cells secreting Ab against donor MHC class I molecule H-2Dd were detected in recipients containing memory CD4 T cells, but not in non-sensitized recipients. Thus, donor-reactive alloAb induced by memory and naive CD4 T cells differ not only in quantity but also in isotype distribution and specificity that in turn may influence their pathogenicity. These findings underscore the importance of targeting helper functions of donor-reactive memory CD4 T cells.
Posttransplant inflammation promotes memory T cell recovery following antibody-mediated lymphoablation (TRAN3P.900)
Authors: Ayasoufi Kathy , Wang Xi , Valujskikh Anna 
Published: January 2023

Abstract
Antibody-mediated depletion is commonly used as an induction therapy in recipients of organ transplants subjected to prolonged cold ischemia. We tested how surgery-induced inflammation and ischemia/reperfusion injury affect the recipient T cell recovery after lymphoablation. We previously reported that preexisting memory T cells rapidly expand and mediate rejection in B6 recipients of BALB/c heart allografts treated with murine antithymocyte globulin (mATG). Memory CD8 T cell recovery was not influenced by specificity for donor alloantigens suggesting a role for posttransplant inflammation. In support of this, CD8 T cells recovered faster in B6 isograft recipients than in non-transplanted mice treated with mATG. The increase in cold ischemic time from 0.5 h to 8 h markedly enhanced the post-depletion expansion of memory CD8 T cells in allograft recipients (10 fold increase at d. 10 posttransplant). Treatment with neutralizing anti-TNFα Ab decreased the numbers of donor-reactive IFNγ producing cells in the spleens of mATG treated heart allograft recipient by 60%, but had little effect on the anti-donor responses in control IgG treated recipients suggesting that TNFα facilitates T cell recovery rather than priming. Our data show that posttransplant inflammation facilitates memory T cell reconstitution following antibody-mediated depletion and that neutralizing proinflammatory cytokines may improve the efficacy of induction therapies in sensitized transplant recipients.
Establishing donor specific tolerance in vascularized composite allotransplantation via local enrichment of endogenous regulatory T cells (TRAN3P.865)
Authors: Fisher James , Jhunjhunwala Siddharth , Unadkat Jignesh , Schweizer Riccardo , Komatsu Chiaki , Thomson Angus , Gorantla Vijay , Little Steven 
Published: January 2023

Abstract
Vascularized composite allotransplantation (VCA)—encompassing transplantation of hands/limbs and face is an emerging field with potential to restore the appearance and function of damaged tissue. Clinically, the process of rejection is suppressed via systemic immunosuppression, which is associated with a host of deleterious side effects. An alternative approach to prevent rejection is to harness the homeostatic mechanisms intrinsic to the immune system. To this end our group has recently developed controlled release microparticle (MP) systems capable of enriching Tregs at given location via synthetic cell constructs referred to as Expansion MP. Accordingly, we hypothesized that Treg enriching systems that release key cytokines, and immunosuppressive agents, can promote long term graft survival in preclinical VCA models. Following fabrication, Expansion MP was tested in an allogeneic rat hind limb transplant model and then in a swine gracilis myocutaneous flap allotransplant model. Following subcutaneous injection of microparticles, rodent hind limbs survived indefinitely (&gt;200 days) and swine allografts survived until the end of the study period (4 weeks) with no signs of rejection. Secondary skin grafts and MLRs in both models demonstrate that ExpansionMP treatment appears to confer donor specific tolerance to recipients. Given these promising results, we believe this technology has the potential to dramatically impact the field of VCA and reconstructive transplantation.
Combination of ATG and rapamycin prolongs the persistence of ex vivo expanded allogeneic Treg transferred in cynomolgus monkeys (TRAN3P.904)
Authors: Zhang Hong , Ezzelarab Mohamed , Lu Lien , Zahorchak Alan , Cooper David , Thomson Angus 
Published: January 2023

Abstract
It has been shown that ex vivo-expanded regulatory T cells (Treg) can promote transplant tolerance in small animal models as well as in phase I clinical trials of hematopoietic stem cell transplantation. The issue has been raised of establishing Treg banks for cell therapy of organ transplant rejection and autoimmune disease. However, little is known about the persistence, stability and fate of infused Treg, especially third-party allogeneic Treg. In this study, we massively expanded flow-sorted monkey Tregs using artificial APCs. The expanded Tregs maintained expression of Treg signature markers, in vitro suppressive capacity, and demethylation status at the Treg-Specific Demethylation Region. When autologous (auto) and allogeneic (allo) ex vivo expanded Tregs were simultaneously transferred into monkeys, the number of auto-Treg was up to 100 per ml blood for at least 6 days in both control and ATG/rapamycin-treated (IS) monkeys. In contrast, by day 3 after their infusion, allo-Treg could not be detected in control monkeys, while they were maintained up to 100 cells per ml blood for at least 15 days in IS monkeys with the expression of Foxp3 and CD25. The finding that allo-Treg can survive in IS-treated monkeys and maintain Treg phenotype supports the concept and potential utility of Treg banks for clinical application in transplantation and autoimmune disease.
Defining the mechanism involved in the inhibition of GvHD by azacitidine in vivo through the use of FoxP3 diphtheria toxin receptor (Foxp3DTR) donor T cells. (TRAN3P.911)
Authors: Cooper Matthew , Choi Jaebok , Ritchey Julie , DiPersio John 
Published: January 2023

Abstract
Azacitidine (AzaC) can mitigate GvHD in both murine preclinical transplant models and in human clinical trials while maintaining a robust GvL effect. Two mechanisms have been proposed to explain how AzaC reduces GvHD: 1) the generation of suppressive regulatory T cells (Tregs, CD4+CD25+Foxp3+) through the in vivo conversion of alloreactive donor T effectors (FoxP3-) into suppressive regulatory T cells (Tregs, CD4+CD25+Foxp3+), or 2) the direct anti-proliferative and pro-apoptotic effects of AzaC on allogeneic T cells. To determine the importance of AzaC generated Tregs, we designed an MHC-mismatched model of allogeneic bone marrow transplantation in which Tregs could be specifically depleted by Diphtheria toxin (DT) following treatment of mice with AzaC. Mice depleted of nTreg prior to infusion, and treated with AzaC alone had significantly less GvHD and increased overall survival than mice treated with AzaC and depleted of AzaC generated Tregs with DT, indicating an important role of AzaC generated Tregs in GvHD amelioration. Furthermore, mice treated with both AzaC and DT had less GvHD and survived longer than PBS treated control mice suggesting direct cytotoxicity of effector T cells induced by AzaC leads to enhanced survival and reduced GvHD. Our data suggests that increasing FOXP3+ Tregs and AzaC induced cytotoxicity towards allogeneic T cells are both important mechanisms involved in the mitigation of GvHD in vivo.
Pharmacological inhibition of MyD88 prevents dendritic cell maturation and synergizes with CTLA4-Ig to promote transplant survival (TRAN3P.918)
Authors: Raimondi Giorgio , Khalifian Saami , Oh Byoung , Lee W.P. Andrew , Brandacher Gerald , Olson Mark , Saikh Kamal 
Published: January 2023

Abstract
TLRs-induced maturation of dendritic cells (DC) and accumulation of inflammatory cytokines are important contributors to alloreactive T cell activation. We aimed to characterize two new MyD88-specific small molecule inhibitors, EM-163 (EM) and T923 (T9), and determine their synergism with CTLA4-Ig in a mouse skin transplant model. Both EM and T9 reduced upregulation of costimulatory molecules on DC in response to LPS. They also reduced the accumulation of IL-6 in supernatants, though the inhibition was stronger with T9 at equimolar level. Interestingly, both inhibitors promoted high MHC II expression - a favorable scenario for delivery of “Signal 1” with low “Signal 2-3” that could promote induction of T cell tolerance. In vivo analysis in a fully mismatched skin transplantation mouse model (BALB/c to B6) showed that transient administration of T9 (d0-10) combined with CTLA4-Ig doubled skin allograft survival (MST untreated: 9.5d, CTLA4-Ig only: 13d, CTLA4+T9: 19d). Overall, our results demonstrate that pharmacological inhibition of MyD88 is possible and potentiates the protective effect of costimulation blockade. Further elucidation of the mechanisms underlying this synergism and optimization of the protocol in multiple transplant models are underway. These encouraging results also suggest the use of pharmacological inhibition of MyD88 as replacement of CD154 blockade in protocols of costimualtion blockade to promote long term transplant acceptance.
Pediatric liver transplant recipients with operational tolerance exhibit features of immune activation and exhaustion (TRAN3P.869)
Authors: Ramaswami Balathiripurasundari , Yoshida Osamu , Ippolito Renee , Metes Diana , Zeevi Adriana , Thomson Angus , Mazariegos George , Chalasani Geetha 
Published: January 2023

Abstract
Experimental models describe immune exhaustion in liver transplant tolerance. It is not known if immune exhaustion is also occurs in clinical operational tolerance. We tested this in a cross-sectional cohort of pediatric liver transplant recipients with stable allograft function in the absence of immunosuppression (Operationally Tolerant, OT) in comparison to those Weaned off Immunosuppression (WI), continued on Maintenance Immunosuppression (MI) and Healthy Controls (HC). Results: In OT recipients, B cell frequencies (p &lt;0.05) were increased and were enriched in both unswitched (p&lt;0.005) and switched memory B cells (CD19+ IgM+ CD27+ and CD19+ IgG+ CD27+) (p&lt;0.05) compard to MI. CD8 T cells in OT showed an increase in effector memory compared to MI (p&lt;0.05). CD4 Treg frequencies were increased in OT compared to MI (p&lt;0.0005). Both CD4 and CD8 T cells in OT showed an increase in cells expressing CD57, indicative of replicative senescence and these were enriched within CD4 central memory and CD8 effector memory when compared to MI (p&lt;0.05). CD57+ T cells upregulated PD1 and 2B4, markers of exhaustion in OT compared to MI (p&lt;0.05). Upon stimulation, IFNγ expression in CD4 T cells and IL-2 expression in CD8 T cells in OT were decreased compared to MI consistent with exhaustion. Moreover, OT showed decreased CD8 frequencies (p&lt;0.05) and high PDL1 expression on monocytes (p&lt;0.0005) suggesting that this population might contribute to T cell exhaustion in these recipients.
IRF-8 regulates MMP3-dependent mechanisms of tumor progression to metastasis (TUM7P.929)
Authors: Banik Debarati 
Published: January 2023

Abstract
Interferon regulatory factor (IRF-8), originally identified as a tumor suppressor gene in leukemia, was also shown to regulate malignant behavior in solid tumor models. Our previous data revealed that IRF-8 influenced tumor growth, in part, by regulating Fas-mediated signaling. Gene expression profiling further revealed an inverse relationship between IRF-8 and MMP3 expression. Although MMP3 has been implicated in early tumorigenesis, the role of MMP3 beyond the stage of tumor initiation has remained largely unknown. Here, we hypothesized that MMP3 governs later stages of the neoplastic process, namely progression to metastasis, and that MMP3 does so through a novel IRF8-MMP3 regulatory axis. To test this hypothesis, we employed loss- and gain-of-function approaches in multiple tumor models. Overall, we showed that: 1) silencing MMP3 expression in tumor cells reduced their primary growth rate and propensity for lung metastases even in a post-surgical setting; 2) overexpressing MMP3 expression in tumor cells increased their primary tumor growth rates; 3) MMP3 expression impacted malignant behavior at multiple levels, e.g., invasive ability and the generation of active MMP9; 4) IRF-8 downregulated MMP3 expression by binding to an ISRE site within the MMP3 promoter; and 5) modulating IRF8 levels inversely regulated MMP3 expression and, consequently, malignant behavior. Thus, our data define a previously unrecognized role of an IRF8-MMP3 axis in regulating tumor progression.
Immune enhancing effects of fucoidan-agaricus mix under treatment of an immunosuppressive anti-cancer agent (TUM7P.939)
Authors: Miyazaki Yoshiyuki , Nakamizo Masaji , Shibasaki Tetsuya , Kirino Tomomi , Kawahara Kazuhiro , Otsuka Ken , Tachibana Hirofumi , Yamada Koji , Tachikawa Daisuke 
Published: January 2023

Abstract
Fucoidan is a series of sulfated polysaccharides derived from brown algae that mainly consist of L-fucose. Fucoidan have various biological activities, and our investigation with experimental animal models and a healthy human trial demonstrated fucoidan from Cladosiphon okamuranus and Undaria pinnatifida effectively augmented anti-tumor immunity in combination with agaricus mycelium extract. In this context, we have reported that feeding of the fucoidan-agaricus mix (FAM) protected mice from immunosuppressive effect of 5-fluorouracil (5-FU). In current study, we confirmed dose-dependent immunoprotective effects of the dietary FAM (at 20 and 40 mg/day) by observing recovery in spleen weight, NK cell activity and IFN-γ production in 5-FU-treated mice. Furthermore, we investigated in vitro effects of FAM against 5-FU on growth and function of primary cultured immune-related cells. As the results with thioglycollate-induced peritoneal exudates cells (PEC), 5-FU dose-dependently suppressed the growth whereas FAM exerted no effects. However, production of cytokines such as IL-12p40 and TNF-α in PEC were stimulated by FAM treatment even in the presence of 5-FU. In the case of bone marrow derived cells differentiated with GM-CSF and M-CSF, FAM markedly enhanced the growth and IL-12 production of these cells. From these results, it was suggested that FAM contributed to amelioration of decline in anti-tumor immune function by 5-FU treatment through activation of innate immune cells.
Activation of innate and adaptive immunity by a TLR5 agonist to prevent and suppress liver metastasis (TUM7P.947)
Authors: Brackett Craig , Kojouharov Bojidar , Veith Jean , Gollnick Sandra , Abrams Scott , Burdelya Lyudmila , Gudkov Andrei 
Published: January 2023

Abstract
Colorectal cancer (CRC) liver metastases are a major cause of mortality of CRC patients providing incentive to develop systemic therapies to prevent and treat this condition. We are exploring the use of a TLR5 agonist Entolimod™ (CBLB502) for immunotherapy against CRC liver metastases. Entolimod is a pharmacologically optimized Salmonella flagellin derivative that is at advanced stage of clinical development as a medical radiation countermeasure. We found that liver is the major primary Entolimod target organ. Entolimod rapidly triggers a TLR5-elicited response in hepatocytes that activates NF-kB and quickly mobilizes immunity to the liver. This includes short-term neutrophilic infiltrate and long-term NK cell accumulation that coordinate CD8 and CD4 T cell immunity against CRC liver metastases. As a result, Entolimod administration dramatically improved long-term survival in a mouse model that mimicked clinically occurring development of post-surgery liver metastases in CRC patients. Importantly, Entolimod induces durable, tumor-specific T cell memory. Unlike other TLR agonists, systemic administration of Entolimod does not induce septic shock-like syndrome due to lack of production of cytokine storm-inducing cytokines upon TLR5 activation. These safe and long-lasting TLR5-elicited changes within liver provide important groundwork for further clinical development of Entolimod, which is currently in clinical trials as a potential immunotherapy against CRC liver metastases.