bluuebunny/crossref_metadata_2025_split huggingface dataset:
Potential of 131I-anti-TLR5 mAb for noninvasive assessment of monitoring rapamycin treated allograft efficiency (TRAN1P.936)
Authors: hou guihua , sun hukui 
Published: January 2023

Abstract
Background Toll-like receptor 5 (TLR5) is a potentially target related with immunosuppressant rapamycin. Our aim was to evaluate 131I-anti-TLR5 mAb for non-invasive in vivo graft visualization and quantification in rapamycin treated allogeneic transplantation model compared with nonspecific tracer 18F-FDG. Methods Labeling, binding and stability studies were performed. Allografted BALB/c mice were divided into rapamycin-treated and non-treated group, respectively. In vivo dynamic whole-body phosphor-autoradiography and ex vivo biodistribution studies were conducted. Results Phosphor-autoradiography imaging showed clear graft localization from 12 h onward after 131I-anti-TLR5 mAb injection,significantly higher graft uptake in rapamycin-treated group. Pretreatment with anti-TLR5 mAb blocked graft uptake,which were consistent with ex vivo biodistribution studies. As the nonspecific radiotracer, high 18F-FDG uptake was only observed in non-treated allorejection group, not in treated group. The highest allograft skin-to-native skin ratio (A: N) of 131I-anti-TLR5 mAb uptake was significantly higher than the ratio for 18F-FDG (7.68 versus 1.16, respectively) in rapamycin-treated group. Immunohistochemistry analysis confirmed that 131I-anti-TLR5 mAb uptake significantly correlated with TLR5 expression in the allograft. Conclusion Radiolabelled anti-TLR5 mAb is capable of detecting allograft rejection with high target specificity after treatment with the immunosuppresant rapamycin.
The universal donor stem cell: removing the immune barrier to transplantation using CRISPR/Cas9 (TRAN1P.946)
Authors: Meissner Torsten , Strominger Jack , Cowan Chad 
Published: January 2023

Abstract
Recent advances in stem cell biology have made it possible to contemplate the use of a patient’s own cells as an unlimited source for transplantation. Unfortunately, the generation of iPSCs remains a costly, time consuming and highly variable process, with regards to pluripotency, epigenetic status, capacity for differentiation, and genomic stability. Moreover, changes occurring during reprogramming and prolonged culturing have been found to trigger an adaptive immune response, resulting in immune rejection of even autologous stem cell-derived transplants. To overcome this immune barrier, we propose to create a Universal Donor Stem Cell, a source for any transplantable cell type, which will not be rejected by the recipient’s immune system regardless of his/her genetic make-up. For this purpose we are using state-of-the-art genome editing technologies: We have successfully employed the CRISPR/Cas system to delete critical immune genes in human ES cells and iPSCs, rendering them potentially less prone to immune rejection. In a complementary approach, we are introducing well-established tolerance-inducing molecules, such as HLA-G, and PD-L1 into stem cells that can locally suppress the immune system and improve transplant engraftment, thus bypassing the detrimental systemic side effects caused by immunosuppressive drugs. Experiments assessing the immunogenicity of our modified stem cell lines and their derivatives in vivo in humanized mice are currently ongoing.
Antigen-specific killer polylactic-co-glycolic acid microspheres selectively deplete antigen-specific T cells in vitro and in vivo (TRAN1P.924)
Authors: Wang Wei , Li Miaochen , Fang Kun , Wu You , Gu Ning , Shen Chuanlai 
Published: January 2023

Abstract
The strategy of specifically depleting antigen-specific T cells can potentially be used to treat allograft rejection and autoimmunity because it does not suppress the overall immune systems. In this study, we generated killer polylactic-co-glycolic acid (PLGA) microspheres by covalently coupling H-2Kb-Ig and apoptosis-inducing anti-Fas monoclonal antibody (mAb) onto cell-sized PLGA microspheres. The Kb/OVA257-264-Killer PLGAs resulted in a dramatic reduction in the number of OVA257-264-specific CD8+ T cells in an antigen-specific manner in vitro and in vivo, by using a transgenic OT-1 mice model. The bioluminescence imaging revealed that Killer PLGAs dominantly distributed in lung, liver and gut, and was maintained for up to 48 hours in OT-1 mice and a longer time in OT-1 mice than in C57BL/6 mice. Moreover, the Kb-Killer PLGAs were administered intravenously into bm1 mice (H-2Kbm1) that had previously been grafted with ear skin from C57BL/6 mice (H-2Kb). The killer PLGAs selectively decreased the H-2Kb alloantigen-reactive CD8+ T cells infiltrating into the alloskin graft but not CD4+ T cells, and significantly prolonged allograft survival for 41.5 days without the impairment of host overall immune function. Thus, our data highlight the therapeutic potential of this biocompatible and biodegradable killer effectors for the treatment of allograft rejection and autoimmune disease. Keywords: Allograft rejection, PLGA, H-2Kb-Ig
Tumor-derived GM-CSF promotes JAK/STAT3-dependent expression of IDO and PD-L1 in myeloid suppressor cells (TUM6P.954)
Authors: Thorn Mitchell , Cunetta Marissa , Point Gary , Guha Prajna , Espat N , Junghans Richard , Katz Steven 
Published: January 2023

Abstract
Myeloid suppressor cells (MSC) are a tolerogenic population of immune cells that poses a major obstacle to cancer treatment. Intrahepatic MSC associated with liver metastases (LM) are especially detrimental by enhancing immunosuppression. We have recently found that MSC in a mouse model of LM suppress endogenous T cell function and anti-tumor cell-based immunotherapy. Mice with LM induced by a splenic injection of MC38 tumor cells, showed an expansion of MSC (5-fold, p=0.0005), while GM-CSF blockade reduced MSC frequency and increased the overall survival (6-fold, p=0.03). As MC38 and other tumors overexpress GM-CSF, we wanted to further investigate the importance of GM-CSF in MSC-driven immunosuppression. A significant proportion of MSC in LM co-expressed IDO and PD-L1 (34±5%), while maintaining high levels of pSTAT3, a transcription factor important to MSC function. Ex vivo, MSC in culture with MC38 cells or supplemented with GM-CSF maintained high IDO/PD-L1 expression. Conversely, when MSC were co-cultured with tumor cells supplemented with anti-GM-CSF, IDO/PD-L1 levels were significantly reduced (p=0.03), implicating GM-CSF in promoting IDO/PD-L1 expression in MSC. Small molecule STAT3 and JAK2 inhibitors abolished IDO/PD-L1 expression in MSC (p=0.003 and p=0.002), suggesting the importance of STAT3/JAK2 signaling pathway in IDO/PD-L1 expression. STAT3 and JAK2 pathways represent viable targets for blocking GM-CSF induced immunosuppressive pathways in liver MSC.
Interactions within the tumor microenvironment imprint metastatic traits in cancer cells (TUM6P.1001)
Authors: Sharma Rajesh , Chheda Zinal , Jala Venkatakrishna , Haribabu Bodduluri 
Published: January 2023

Abstract
Metastasis accounts for majority of deaths across cancer types. Tumor microenvironment plays an impotant role in enhancing metastatic propensity of cancer cells. To explore the mechanisms, we herein established a model by in vivo passaging the Lewis lung carcinoma (3LL) cells with 1-2 week of culture in between passages. When injected subcutaneously, 3LL cells have minimal metastasis, while in vivo passaged (p-)3LL cells showed robust metastasis. Sorted p-3LL cells from tumors of the whole body RFP transgenic mice were equally metastatic suggesting that cancer cell intrinsic changes are responsible for the metastatic imprinting. To identify the stromal cell population/s that crosstalk and imprint the metastatic traits in cancer cells, in vivo passages were performed in Rag2-/- mice and WT mice depleted of NK cells that resulted in similar metastatic imprinting excluding the role of adaptive immune and NK cells in this process. Depletion studies in WT mice and/or co-culture of 3LL cells with sorted myeloid cells indicated a critical role for CD11b+Gr1dim myeloid cells in metastatic imprinting. Comparison of gene expression profiles between 3LL and p-3LL cells by microarray showed enhanced expression of claudin-9 in p-3LL cells which was validated at protein levels in mouse and human lung cancers. These results indicate that interaction of CD11b+Gr1dim myeloid cells with cancer cell within tumor microenvironment imprints claudin-9 dependent metastatic traits in cancer cells.
C/EBP homologous protein expression regulates immunosuppressive activity in myeloid derived suppressor cells (TUM6P.1006)
Authors: Thevenot Paul , Sierra Rosa , Raber Patrick , Al Khami Amir , Ochoa Augusto , Rodriguez Paulo 
Published: January 2023

Abstract
Myeloid-derived suppressor cell (MDSC) suppression of anti-tumor T cell responses is a significant barrier in cancer immunotherapy. Although pathways controlling MDSC regulatory activity have been characterized, therapies to globally and specifically inhibit MDSC function are limited. Targeting central mediators of MDSC-regulatory activity may overcome T cell suppression and increase the efficacy of T cell-based immunotherapy. We investigated the role of the stress sensor C/EBP homologous protein (Chop) on MDSC function. Elevated Chop expression in tumor-bearing mice was restricted to malignant cells and tumor MDSCs. Chop elevation was also detected in tumor MDSCs from colon carcinoma patients. Interestingly, increased CD8+ T cell-mediated anti-tumor effects were found in both systemic Chop -/- and Chop -/- bone marrow chimeric mice bearing s.c. Chop-competent tumors, suggesting the importance of MDSC-Chop in tumor-induced T cell anergy. MDSCs from Chop -/- mice showed a decreased expression of major MDSC-inhibitory pathways, reduced inhibitory activity on T cells, and a surprising ability to prime T cell proliferation and induce anti-tumor effects. The reduced regulatory activity in Chop -/- MDSCs was caused by decreased IL-6 production, resulting from decreased C/EBPb activity. Altogether the results demonstrate a central role of Chop in MDSC inhibitory activity and suggest targeting Chop to restore protective immunity in cancer.
Tumor-derived osteopontin suppresses antitumor immunity by accumulating myeloid progenitor cells and myeloid-derived suppressor cells (TUM6P.1012)
Authors: Song Boyeong , Kim Eun Kyung , Jeon Insu , Seo Hyungseok , Park Youngjun , Chung Yeonseok , Kang Chang-Yuil 
Published: January 2023

Abstract
Extramedullary myelopoiesis occurs commonly in tumor-bearing animals and is known to lead to accumulation of peripheral myeloid-derived suppressor cells (MDSC), which play an important role in immune escape. However, the cellular and molecular mechanisms by which tumors induce extramedullary myelopoiesis are poorly understood. In this study, we found that osteopontin expressed by tumor cells enhances extramedullary myelopoiesis in a CD44-dependent manner through the Erk1/2-MAPK pathway. Osteopontin-mediated extramedullary myelopoiesis was directly associated with increased MDSCs in tumor-bearing hosts. More importantly, osteopontin silencing in tumor cells delayed both tumor growth and extramedullary myelopoiesis, while the same treatment did not affect tumor growth in vitro. Finally, treatment with an antibody against osteopontin inhibited tumor growth and synergized with cell-based immunotherapeutic vaccines in mediating antitumor immunity. Our findings unveil a novel immunosuppressive role for tumor-derived osteopontin and offer a rationale for its therapeutic targeting in cancer treatment.
Progressive loss of differentiated effector CD8 T cells infiltrating melanoma (TUM7P.1021)
Authors: Stevens Aaron , Bullock Timothy 
Published: January 2023

Abstract
CD8 tumor infiltrating lymphocytes (TIL) are critical for tumor control and their presence is a positive prognostic factor. Understanding CD8 TIL dysfunction is vital for developing cancer immunotherapies. Here, using a Granzyme B Cre ROSA YFP reporter system, we characterized the differentiation of CD8 T cells over the course of tumor growth using a murine melanoma model. At early stages of the CD8 T cell response (day 10 after tumor injection), the majority of the cells had differentiated to express Granzyme B (YFP+). However, over a period of four days, most of these effector cells were replaced by CD8+ T cells that had no evidence of effector differentiation. Concurrently, we found an increase in expression of the inhibitory receptor PD-1 in differentiated (YFP+) relative to non-differentiated (YFP-) CD8 TIL in late stage tumors. This suggests that there is both a loss of differentiated CD8 TIL and that the differentiated CD8 T cells that remain are more dysfunctional in late stage tumors. To provide insight into the cause and effect of this fluctuation in differentiation, we present data establishing the contribution of checkpoint inhibitory molecules and dendritic cell activation state in the loss of effector characteristics, and whether cytokine production and other effector activities correlate with the shift in effector differentiation status.
Chronic cold-stress suppresses chemokine production and CD8+ T cell infiltration in the tumor microenvironment (TUM7P.1024)
Authors: Alexander Matthew , Kokolus Kathleen , Costa Amanda , Clancy-Thompson Eleanor , Repasky Elizabeth , Mullins David 
Published: January 2023

Abstract
Recently it was reported that maintenance of mice at thermoneutral temperatures (TT, the temperature at which basal metabolism is sufficient to maintain body temperature, 30oC) enhanced antitumor immune responses and reduced tumor growth, relative to standard vivarium temperatures (ST, 22oC). We hypothesized that mice maintained at ST may have impaired production of T cell chemoattractant cytokines and subsequent T cell infiltration. In mice bearing breast tumors or solid or metastatic-like melanomas, intratumoral expression of CXCL9 and CXCL10 (CXCR3-cognate chemokines) was enhanced by maintenance of hosts in TT conditions. Further, tumors of TT-housed mice contained increased numbers of CD8+ T cells. We further hypothesized that the effect of temperature on T cell chemokine pathways may be a result of chronic cold stress, which may induce norepinephrine (NE) production and subsequent activation of β-adrenergic signaling pathways. We observed that pharmacologic blockade of β-adrenergic receptors in mice bearing solid or metastatic-like melanomas recapitulated the increased intratumoral expression of CXCL9 and CXCL10 and increased CD8+ T cell numbers. Because melanoma cells express β-adrenergic receptors, we suggest that chronic cold stress may induce systemic NE production, leading to tumor local activation of receptors and inhibition of tumor-derived chemokine production. These studies suggest potential interventions to improve existing T cell-based immunotherapies.
Novel kinetic live cell imaging assays for T cell killing of tumor cells (TUM7P.1031)
Authors: APPLEDORN DANIEL , Bevan Nicola , Szybut Clare , O'Callaghan Tim , Dale Tim , Trezise Del 
Published: January 2023

Abstract
Cancer immunotherapy offers the potential for specific eradication of tumor cells and the prevention of cancer recurrence. In this study we describe fully kinetic live cell imaging assays designed to quantify T cell mediated killing of tumor cells in co-culture. RFP-nuclear labelled tumor cells were seeded overnight in 96 or 384 well plates. Peripheral Blood Mononuclear Cells (PBMCs) or isolated CD8+ T cells were then added to the wells in combination with various activators and a non-perturbing green fluorescence caspase-3/7detection reagent. Phase and 2-colour fluorescence images were captured every 2h for 4-7 days using IncuCyte ZOOM™. Tumor cell numbers were quantified by direct nuclear object counting (RFP). The number of apoptotic tumor cells were measured using green object counting and size/brightness filtering to remove dying T cells. This method is illustrated and validated with anti CD3, IL-2 and CD28 mediated cell killing, and a study on the impact of target/effector cell ratios. These validation data demonstrate that live cell imaging can be used to discern the full time course and specificity of T cell killing, without the need to lift cells, use Ab labels or radioisotopes (e.g. 51Cr). HD images and time-lapse movies facilitate a clear understanding and compelling verification of the underlying biology.
Metabolic competition in the tumor microenvironment determines cancer progression (TUM7P.1016)
Authors: Chang Chih-Hao , Qiu Jing , Pearce Erika 
Published: January 2023

Abstract
T cells produce cytokines that are critical for tumor immunity. However, during cancer, T cells often experience a decline in function preventing tumor regression. Why T cell hyporesponsiveness develops is unclear, but it is thought to result from lack of dominant epitope-specificity, continuous antigen exposure, and suppression by other immune cells. Previously we have shown that T cells need to engage aerobic glycolysis to optimally produce IFN-γ. Using a well-characterized mouse sarcoma model we show here that tumor mediated glucose consumption metabolically restricts tumor-infiltrating T cells (TILs), which dampens their mTOR activity, decreases their glycolytic capacity and therefore, limits their IFN-γ production, leading to tumor progression. We show that anti-CTLA-4, anti-PD-1, or anti-PD-L1 blockade therapy, which induces regression of progressing sarcomas, restores glucose in the tumor microenvironment and rescues glycolysis in TILs. Moreover, we demonstrate that blocking PD-L1 directly on tumor cells dampens tumor glycolysis and glucose uptake. Finally, we show that an antigenic sarcoma that normally is rejected can turn into a progressing tumor when its glycolytic rate is enhanced. Our data show that metabolic competition in the tumor microenvironment dictates T cell function and that this influences cancer progression. Combining therapies that blunt tumor cell metabolism with those that promote glycolysis in TILs could provide new effective treatments for cancer.
Ex vivo co-stimulatory 4-1BBL enhances the antitumor capacity of antigen specific CD8+ T cells after adoptive transfer in NSG mice (VAC7P.1042)
Authors: Srivastava Abhishek , Paria Biman , Chandran Smita , Kammula Udai 
Published: January 2023

Abstract
Adoptive T cell therapy (ACT) using tumor infiltrating lymphocytes (TIL) can result in durable complete cancer remission in select patients with metastatic melanoma. These clinical responses have strongly correlated with the ability of the transferred cells to engraft and persist in these patients. Preclinical murine studies have further supported that T cells with superior anti-tumor efficacy have higher proliferative capacity, reduced AICD and enhanced in vivo persistence. Thus, in an effort to further improve ACT, we sought to exploit ex vivo 4-1BB co-stimulation to generate T cells with enhanced in vivo anti-tumor activity. We used an artificial APCs genetically engineered to express costimulatory 4-1BBL (eAPC-4-1BBL) to human tumor specific CD8+ T cell clones. The use of clones allowed us to precisely define the impact of the 4-1BB on the in vivo fate and function of a genetically distinct mono-specific T cell population without the ambiguity of subset outgrowth. Our results demonstrate that ex vivo eAPC-4-1BBL enhanced proliferative capacity and reduced AICD of the CD8+ T cell clones without loss of functional tumor avidity. The eAPC-4-1BBL further restored the ability of the clones to persist and survive after adoptive transfer in NSG mice and resulted in improved survival of established tumor bearing NSG mice. Similarly, eAPC-4-1BBL provided significant improvement in the in vivo persistence and antitumor capacity of human TIL after adoptive transfer in NSG mice.
Adoptive T cell therapy using rejuvenated antigen-specific T cells from induced pluripotent stem cells (VAC7P.1044)
Authors: Saito Hidehito , Ito Fumito 
Published: January 2023

Abstract
Current approaches to adoptive T cell therapy for cancer and chronic viral infection are limited by the difficulty of obtaining sufficient numbers of antigen-specific T cells with optimized therapeutic features. We hypothesized that this limitation of adoptive T cell therapy could be overcome by using induced pluripotent stem cells (iPSCs) that self-renew, maintain pluripotency, and provide an unlimited source of phenotypically defined, functional, and expandable autologous T cells against targeted antigens for immunotherapy. We established iPSCs from pmel-1 T cell receptor (TCR) transgenic CD8+ T cells specific for the gp100 melanocyte differentiation antigen as a preclinical model of evaluating antitumor reactivity of rejuvenated antigen-specific T cells from iPSCs. Stably TCR retained pmel-1 T cell-derived iPSCs (pmel-1 iPSCs) were then differentiated into CD4+CD8+ double positive (DP) T cells in vitro. Stimulation of pmel-1 iPSC-derived DP T cells with the gp100 antigen generated a large number of CD8+ T cells with high antigen-specific cytokine production and cytolytic activity in vitro. Furthermore, adoptive transfer of pmel-1 iPSC-derived cytotoxic CD8+ T cells significantly delayed tumor progression and improved survival in mice with established subcutaneous B16 melanoma expressing gp100. These findings suggest that rejuvenated antigen-specific T cells from iPSCs may be useful for adoptive T cell therapy.
Targeting of a fixed bacterial immunogen to Fc receptors reverses the anti-inflammatory properties of the gram negative bacterium, Francisella tularensis, during the early stages of infection (VAC8P.1055)
Authors: Bitsaktsis Constantine 
Published: January 2023

Abstract
Production of pro-inflammatory cytokines by innate immune cells at the early stages of bacterial infection is important for host protection. Many intracellular bacteria, such as Francisella tularensis, utilize the anti-inflammatory cytokine IL-10 to evade the host immune response, mainly by suppressing antigen presentation. In the current study, we hypothesized that F. tularensis polarizes antigen presenting cells during the early stages of infection towards an anti-inflammatory status characterized by increased synthesis of IL-10, and decreased production of IL12p70 and TNFa, in an IFN-γ-dependent fashion. In addition, F. tularensis drives the alternative activation of alveolar macrophages at the early stages of infection, thus allowing the bacterium to avoid protective immunity. Furthermore, for the first time, we demonstrate that targeting inactivated F. tularensis (iFt) to Fcγ receptors via intranasal immunization with mAb-iFt complexes, reverses the anti-inflammatory effects of the bacterium on macrophages by down-regulating production of IL-10. More specifically, we observed that targeting of iFt to FcγRs enhances the classical activation of macrophages in the respiratory mucosa, as well as systemically, at the early stages of infection. These results provide important insight for further understanding the protective immune mechanisms generated when targeting immunogens to Fc receptors.