bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of self antigen specific CD4+ T cell precursor frequency on the anti-tumor immune response: Implications for adoptive T cell therapy (P2040)
Authors: Malandro Nicole , Budhu Sadna , Murphy Judith , Rizzuto Gabrielle , Houghton Alan , Merghoub Taha , Wolchok Jedd 
Published: January 2023

Abstract
Current approaches to cancer immunotherapy aim to enhance the natural T cell response against tumors; however, these treatments may fall short due to the negative selection of tumor antigen specific T cells. To determine how frequency of CD4+ T cells may shape an anti-tumor response we have developed a model in which precursor number can be manipulated in mice bearing implantable melanoma through the adoptive transfer of tumor specific T cells. We have previously shown that lower frequencies of CD8+ T cells specific for melanoma antigen gp100 generate the most productive response due to intraclonal competition at higher concentrations. Unlike CD8+ T cells, the adoptive transfer of greater quantities of CD4+ T cells specific for melanoma antigen TRP-1 results in better tumor regression. The activation and expansion of CD4+ T cells at high precursor frequencies is diminished compared to lower frequencies, which indicates the occurrence of intraclonal competition. We believe the observed differences in tumor eradication are due to increased infiltration of TRP-1 CD4+ T cells into the tumor when present at high precursor frequencies with lower precursor frequencies favoring the preferential accumulation of TRP-1 specific Foxp3+ regulatory T cells both in the tumor and periphery. Further understanding of how antigen specific regulatory T cells develop and shape the effector response may have implications for the use and improvement of CD4+ T cells in adoptive cell therapy.
Characterizing the effects of the BrafV600E inhibitor vemurafenib on CD8 T cell responses to Braf-mutated murine melanoma (P2046)
Authors: Steinberg Shannon , Malik Brian , Zhang Peisheng , Bosenberg Marcus , Turk Mary Jo 
Published: January 2023

Abstract
Vemurafenib, a small molecule inhibitor of the BrafV600E mutation present in 60% of patient melanomas, has lead to promising results in the clinic. Unlike broad spectrum MEK pathway inhibitors, which have significant off-target effects, specific inhibition of BrafV600E does not impair host immunity, raising the interesting idea that vemurafenib may in fact enhance the host immune response to Braf-mutation bearing melanomas. To test this hypothesis, we have utilized the Tyr-CreERT BrafCA Ptenlox/lox (Braf/Pten) mice, an inducible model of BrafV600E-mutated melanoma. These mice provide an immune competent system in which to characterize the effects of BrafV600E-inhibition on the host immune response to melanoma. Our work demonstrates that treating Braf/Pten tumor-bearing mice with vemurafenib completely arrests the growth of established tumors, and significantly enhances the proportion of CD8 T cells infiltrating dermal melanomas. BrafV600E-inhibition also significantly decreases the proportion of immunosuppressive Treg cells infiltrating the tumor, resulting in a more favorable ratio of CD8 effectors to Tregs than in untreated tumors. Furthermore, CD8 T cell depletion studies have confirmed that these CD8 T cells provide potent long-term tumor control even after BrafV600E-inhibition is discontinued. This work serves as a proof-of-principle that vemurafenib, and possibly other targeted molecular therapies, can enhance endogenous anti-tumor immunity.
Panobinostat in combination with azacitidine reduces the frequency of TNFR2+ regulatory T cells in acute myeloid leukemia patients. (P2048)
Authors: Govindaraj Chindu , Tan Peter , Wei Andrew , Spencer Andrew , Plebanski Magdalena 
Published: January 2023

Abstract
Panobinostat (LBH) and azacitidine (Aza) are currently being evaluated in the therapy of AML. The effect of this drug combination on T cells, particularly on regulatory T cells (Tregs) has not been previously investigated. The presence of Tregs in AML is detrimental, as these cells suppress anti-tumor immunity. Tregs expressing Tumor Necrosis Factor Receptor 2 (TNFR2) are associated with maximal immune suppressor activity. Here, we investigated the combined effect of LBH and Aza on effector T cells (Teff), and TNFR2+ and TNFR2- Tregs in newly diagnosed AML patients. Patients were treated with Aza on days 1-5 for each 28-day cycle combined with 7 doses of LBH on days 5-19. T cells within peripheral blood (PB) and bone marrow (BM) were analyzed via flow cytometry, at baseline and at the end of cycle 1 (EOC1). Specifically, TNFR2+ Tregs were present at high levels within patient PB when compared to controls and were significantly reduced by EOC1 of treatment. Interestingly, only patients who responded to treatment had this reduction in their BM. Mechanistic studies adding LBH alone or with Aza to PB cells during T cell activation in vitro indicated LBH might primarily drive the reduction in Tregs. Concomitant with Treg reduction, IFNγ and IL2 production by CD4 Teff and the ratio of CD4 Teff to TNFR2+ Tregs were enhanced by EOC1 in the BM of responder, but not non-responder patients. AML patients who responded to Aza and LBH treatment have a beneficial immunological outcome.
Host conditioning approach and choice of target epitope determine the success of adoptive T cell immunotherapy against oncogene-induced established tumors (P2068)
Authors: Ward-Kavanagh Lindsay , Cooper Timothy , Schell Todd 
Published: January 2023

Abstract
Host conditioning regimens can dramatically enhance adoptive T cell-based therapies for some cancers. We investigated the unique and combined contributions of whole body irradiation (WBI) and agonist anti-CD40 conditioning to successful adoptive immunotherapy in a mouse model of autochthonous cancer. Line Rip1-Tag4 mice develop pancreatic islet cell tumors due to expression of the SV40 large T antigen oncogene from the rat insulin promoter. Using transfer of T cell receptor transgenic CD8+ T cells specific for two unique determinants in T antigen (designated TCR-I or TCR-IV), we demonstrate that successful control of established tumors in these mice is both regimen- and epitope-dependent. WBI conditioning alone minimally enhanced T cell accumulation and persistence, while anti-CD40 alone transiently enhanced the subdominant TCR-I but not the immunodominant TCR-IV response. Combining anti-CD40 with WBI conditioning enhanced the magnitude and duration of both T cell responses, but only TCR-I cells accumulated and persisted at high levels in the pancreas. Mice that received combined conditioning plus TCR-I transfer had an increased life span, and showed histological signs of anti-tumor immunity. Lack of therapeutic impact by TCR-IV T cells was associated with development of an unusual differentiation phenotype following antigen recognition in vivo. The results indicate that target selection and conditioning regimen dramatically influence the efficacy of adoptive T cell therapy.
Chemoimmunotherapy provides protective immunity of murine pancreatic cancer model (P2070)
Authors: Ghansah Tomar , Vohra Nasreen , Kinney Kathleen , Sarnaik Amod , Pilon-Thomas Shari 
Published: January 2023

Abstract
Pancreatic cancer is an aggressive disease with grim prognosis. Immunotherapy is less effective in treating tumors partly due to Myeloid Derived Suppressor Cells (MDSC). In this study we evaluated tumor regression due to MDSC depletion with dendritic cell (DC) vaccination of pancreatic tumor bearing (TB) mice. Flow cytometry results showed a significant increase in the percentage of MDSC in tumors and spleens of TB mice compared to naïve mice. MDSC isolated from TB mice significantly suppressed antigen-specific T cell responses compared to naive mice. Gemcitabine (GM) is a chemotherapeutic drug for cancer therapy. Flow cytometry results showed a significant decrease in the percentage of MDSC in splenocytes from GM-treated TB and naïve mice. To study effects of DC vaccination combined with MDSC depletion on tumor rejection, mice were vaccinated with PANC02 lysate-pulsed DC or PBS, three times at seven-day intervals. One week after final vaccination, mice were challenged with PANC02 tumor cells. Mice in the vaccinated and control groups either received PBS or GM therapy. In vivo depletion of MDSC was performed three days prior to tumor challenge, continued until the end of the experiment and was confirmed using flow cytometry. A significant survival benefit was seen in mice receiving both DC vaccination and MDSC depletion. Results from this study strongly suggest that the depletion of MDSC significantly enhances protective immunity in a murine pancreatic cancer model.
Modulating CXCR3 chemokine expression in the tumor microenvironment as a therapeutic approach for skin cancers. (P2074)
Authors: Gorbachev Anton , Kish Danielle , Fairchild Robert 
Published: January 2023

Abstract
Chemokines can inhibit or promote tumor growth through multiple mechanisms such as inhibition or promotion of angiogenesis or recruiting effector or regulatory cells into tumor. Modulation of intra-tumor chemokine expression is considered to be a promising approach of cancer immunotherapy. CXCR3 chemokines (CXCL9/Mig and CXCL10/IP-10) are known as potent tumor suppressors that inhibit tumor angiogenesis and recruit Th1 and NK cells into the tumor. We used murine model of aggressive skin cancer (cutaneous sarcoma or melanoma) to test the induction of Mig expression within tumors as a therapeutic approach. Intra-tumor delivery of Mig DNA by retroviral vector or by plasmid suppressed growth of MCA205 sarcoma and B16 melanoma. This therapeutic effect was T cell-dependent and was mediated through enhancing the activation of tumor-specific T cells by tumor-infiltrating dendritic cells rather than through angiostatic functions of Mig. Surprisingly, the deficiency of tumor hosts in IP-10 resulted in the suppression of tumor growth and increased activation of tumor-specific T cells similar to the therapeutic effects mediated by overexpression of Mig. These results suggest that besides similar angiostatic and chemoattracting functions, Mig and IP-10 impose non-redundant and even antagonistic effects on anti-tumor immunity and that the induction of Mig expression and simultaneous inhibition of IP-10 in tumor hosts might be a potent therapeutic approach to treat aggressive skin cancers.
Combining anti-OX40 with an inhibitor of TGF-β signaling overcomes the immunosuppressive environment in established tumors (P2026)
Authors: Tucker Christopher , Triplett Todd , Garrison Kendra , Sun Lihong , Ling Leona , Akporiaye Emmanuel , Weinberg Andrew 
Published: January 2023

Abstract
OX40 (CD134, TNFRSF4), a member of the tumor necrosis factor receptor (TNFR) superfamily is expressed on activated CD4+ and CD8+ T cells. Engagement of OX40 with cognate ligand or soluble agonist enhances T cell proliferation, survival and cytokine production by memory T cells. Although αOX40 therapy has been effective at controlling incipient tumors in a variety of mouse tumor models, it has been less effective at eradicating large established tumors. Pervasive immunosuppression in the tumor microenvironment has been implicated as a potential mechanism of immune evasion by tumor cells. Here we show that combining agonist antibody (αOX40) with an orally bioavailable small molecule inhibitor of TGF-β signaling, results in complete regression of well-established tumors in ~85% of treated mice. Tumor infiltrating lymphocytes (TIL) from these dual treated mice produce increased levels of Granzyme-B and IFNγ and higher levels of the proliferation marker Ki67. Differences seen in STAT3 expression by the TIL led us to investigate the role of STAT3 in this anti-tumor effect. Using an OX40 promoter-driven CRE model to knock out the STAT3 gene in activated T-lymphocytes, we demonstrated that STAT3 is essential for the therapeutic efficacy of the combination treatment as a 50% drop in tumor cure rate was observed in STAT-3 deficient mice compared to STAT3 sufficient mice. Together these results demonstrate the anti-tumor efficacy of combining OX40 therapy with TGF-β inhibition.
Intra-tumoral administration of tumor membrane vesicles expressing GPI-anchored IL-2 inhibit tumor growth in a murine breast cancer model (P2080)
Authors: Bozeman Erica , Shashidharamurthy Rangaigh , Srivatson Sanjay , Selvaraj Periasamy 
Published: January 2023

Abstract
Cancer is the second leading cause of death in the US with breast cancer being among the most common cancers. Tumor membrane vesicles (TMVs) used a vaccine will present a variety of tumor antigens to the immune system. TMVs due to their size and particulate nature are likely to be processed and presented by dendritic cells. To enhance their immunogenicity, TMVs were prepared from homogenized 4T07 mouse breast cancer cell transfectants expressing GPI-IL-2 Expression of GPI-IL-2 was verified by flow cytometry analysis. To ensure functionality, IL-2 expressing TMVs were co-cultured with CTLL-2 cells, an IL-2 dependent cytotoxic T cell line, for 48hrs and proliferation of the CTLL-2 cells was assessed by thymidine incorporation. Mice were then challenged with live wild-type 4T07 cells and administered 50ug of TMVs intra-tumorally on days 10 and 17 post tumor challenge. We observed that GPI-IL-2 expressing TMVs are functionally active and capable of inducing proliferation of CTLL-2 cells. More importantly, intra-tumoral injection of GPI-IL-2 expressing TMVs is capable of significantly reducing overall tumor burden in a therapeutic setting. These studies provide evidence that intra-tumoral vaccination with TMVs expressing GPI-IL-2 could potentially be a viable immunotherapeutic strategy for breast cancers that cannot be surgically removed.
Sorafenib induces apoptosis through reactive oxygen species production, JNK/p38 MAPK activation, and suppression of Akt/NF-kB signaling in EBV-transformed B cells (P2088)
Authors: Choi Yunock , Park Ga Bin , Kim Ja Young , Kim Hae Jin , Kim Seonghan , Kim Yeong-Seok , Lee Hyun-Kyung , Cho Dae-Ho , Lee Wang Jae , Bae Ki Won , Hur Dae Young 
Published: January 2023

Abstract
Sorafenib (SRF), the multiple tyrosine kinase inhibitor, is known as a potential targeted drug that may have antitumor activity against various cancers, but the roles of SRF in EBV-transformed B cells remain unclear. Here, we investigated the in vitro cytotoxic effects of SRF on EBV-transformed B cells and the underlying mechanism such as the changes in oxidative stress and MAPKs signaling, which are closely associated with cell death-signaling transduction pathways, in EBV-transformed B cells treated with SRF. We first observed that SRF significantly decreased the cell viability of EBV-transformed B cells in a dose-dependent manner. SRF induced the generation of reactive oxygen species (ROS), translocation of Bax into mitochondria, disruption of mitochondrial membrane potential, activation of caspase-9, -3, and PARP, and subsequent apoptosis. Moreover, we found that SRF exposure activated the phosphorylation of JNK and p38 MAPK and suppressed the phosphorylation of PI3K p85 and Akt. In particular, SRF diminished nuclear localization of NF-κB in EBV-transformed B cells. These results demonstrate that SRF induces apoptosis through ROS production, ER stress, and mitochondrial-dependent pathway in EBV-transformed B cells. Taken together, these findings provide an overview of the molecular signaling pathway driving SRF-mediated cell death in EBV-transformed B cells and suggest SRF could be a potential therapeutic drug for the treatment of EBV-transformed B cells.
Human antigen-specific invariant NKT cells generated by the TIL 1383I T cell receptor gene transfer (P2098)
Authors: Nagato Kaoru , Scurti Gina , Moxley Kelly , Wang Xinxin , Seetharaman Aravind , Simms Patricia , Motohashi Shinichiro , Yoshino Ichiro , Nakayama Toshinori , Nishimura Michael 
Published: January 2023

Abstract
Human invariant NKT cells (iNKT cells) are a novel lymphocyte population characterized by an invariant T-cell receptor (Vα24/Vβ11). iNKT cells activated with αGalCer and IL-2 have been shown to produce large amounts of cytokines such as IFN-γ and also have potent killing activity against various tumor cell lines. One major hurdle to studying the anti-tumor activity of iNKT cells is they don’t recognize antigens presented by classical MHC molecules and their tumor antigen specificity is unknown. Therefore, we expressed the MHC class I restricted TIL 1383I TCR into iNKT cells to better study their biology and anti-tumor activity. The 1383I TCR is a high affinity TCR that recognizes the melanoma antigen tyrosinase presented by HLA-A2. In this study, we report the production and function of the TIL 1383I TCR transduced human iNKT cells. iNKT cells were activated and expanded from normal PBMCs by stimulating them with αGalCer in the presence of IL-2 and IL-15. The iNKT cells were isolated using iNKT magnetic beads and transduced using retroviral vectors encoding the TIL 1383I TCR. The TIL 1383I TCR transduced iNKT expression was measured by flow cytometry (FACS) and their anti-tumor activity by intracellular cytokine staining. The TIL 1383I TCR transduced iNKT cells specifically produced IFN-γ in response to tyrosinase peptide loaded T2 cells and HLA-A2+/tyrosinase+ human melanomas. These results indicate that iNKT cells can be engineered to recognize normal tumor antigens.
Characterization of polyclonal type II NKT cells and their role in CpG oligodeoxynucleotides-mediated anti-tumor response (P2112)
Authors: Zhao Jie , Weng Xiufang , Bagchi Sreya , Wang Chyung-Ru 
Published: January 2023

Abstract
CD1d-restricted NKT cells are innate-like T cells with potent immunomodulatory function via rapid production of both Th1 and Th2 cytokines. NKT cells comprise well-characterized type I NKT cells which can be detected by α-GalCer (α-galactosylceramide) loaded CD1d tetramer and less-studied type II NKT cells which do not recognize α-GalCer. Here we characterized type II NKT cells on a polyclonal level by using an IL-4 reporter mouse model. We found type II NKT cells, like type I NKT cells, exhibit an activated phenotype and are dependent on the transcriptional regulator PLZF (promyelocytic leukemia zinc finger) and the adaptor molecule SAP (signaling lymphocyte activation molecule-associated protein) for their development. Compared to type I NKT cells, type II NKT cells produce lower levels of IFN-γ but comparable amounts of IL-13 in response to polyclonal TCR stimulation, suggesting they may play different roles in regulating immune responses. However, type II NKT cells can be activated by CpG oligodeoxynucletides to produce IFN-γ, but not IL-4 or IL-13. Importantly, CpG-activated type II NKT cells contribute to the anti-tumor effect of CpG in the B16 melanoma model. Taken together, our data reveal the characteristics of polyclonal type II NKT cells and their potential role in anti-tumor immunotherapy.
Potential roles of human chorionic gonadotropin in tumorigenesis and the development of novel vaccination strategies (P2116)
Authors: Khare Priyanka , Javed Saleem , Jain Swatantra , Singh Om , Pal Rahul 
Published: January 2023

Abstract
Human chorionic gonadotropin (hCG) is associated with poor prognosis in several cancers, but causative molecular events remain inadequately described. In this study, tumor cells were found to express message for both hormonal subunits. Along with increasing cell viability, exogenous hCG enhanced several key tumor-promoting mechanisms. It induced the transcriptional activation and secretion of the angiogenic factors VEGF and IL8. Matrix-degrading enzymes associated with invasion (MMP2 and MMP9) were also enhanced, as was invasiveness. hCG up-modulated secretion of the proteoglycan versican and the consequent secretion of the inflammatory cytokines IL6 and TNFα from macrophages. hCG up-regulated FOXP3 in tumor cells, leading to the increased secretion of the immunosuppressive cytokines IL10 and TGFβ and up-modulation of CTLA-4; co-culture hCG-stimulated tumor cells with mature BMDCs heightened the secretion of the tryptophan catabolizing enzyme indoleamine 2,3-dioxygenase. Anti-hCG antibodies restricted the growth of human tumor xenografts, and immunization with a novel anti-hCG vaccine formulation (βhCG-TT + Mycobacterium indicus pranii) synergistically attenuated tumor development and prolonged survival in syngeneic mice. By preventing autocrine and subsidiary paracrine hCG-induced effects on multiple pathways, new generation anti-hCG vaccines may therefore hold considerable promise as adjunct therapy in patients of gonadotropin-sensitive tumors.
Adoptively transferred TCR-engineered cytotoxic human T lymphocytes use TRAIL apoptotic pathway in killing melanomas: Pivotal role of DR5 and regulation of resistance by SAHA (P2124)
Authors: Jazirehi Ali , Economou James 
Published: January 2023

Abstract
Adoptive transfer of ex vivo engineered autologous lymphocytes encoding high-affinity MART-1/ A*0201-specific TCRα/β chains (F5 CTL), densely infiltrate into metastatic sites, mediating dramatic but partial responses in metastatic melanoma patients. We hypothesized that down-modulation of death receptors and aberrant apoptotic signaling confer resistance to F5 CTLs. To test this, we established a preclinical model of resistance from sensitive parental lines under serial F5 CTL-selective pressure. While surface peptide/MHC complex remains intact (F5 CTLs efficiently recognize and engage melanomas), R lines downregulate surface DR5 expression, exhibit constitutive NF-κB activation and overexpress resistant factors. The HDACi SAHA blocked antiapoptotic pathway, reduced expression of resistance factors, restored DR5 expression, and sensitized R lines to F5 CTL. At concentrations used, SAHA didn’t affect functionality and viability of F5 CTLs. Using blocking Abs, rhTRAIL and murine CTL hybridoma line, we found that TCR-engineered F5 CTLs mainly utilize TRAIL apoptosis pathway. Further, using Drozitumab (αDR5 mAb), pivotal role of DR5 and its regulation by SAHA was confirmed. These studies identify molecular determinants of resistance to TCR engineered CTL and suggest that adjuvant therapy with SAHA in immune-resistant tumors imposes a proapoptotic milieu by regulating apoptotic machinery and inducing death-receptor expression, thus, overcoming melanoma immunotherapy resistance.
The autoantibody-inducing CD4 T cell causing systemic lupus erythematosus belongs to CCR4+CD45RBlo122lo CD4 subpopulation (P4125)
Authors: Miyazaki Yumi , Tsumiyama Ken , Shiozawa Shunichi 
Published: January 2023

Abstract
Objective: We have shown that repeated immunization of mice with any antigen reproducibly led to development of SLE, in which a novel T cell type which we term an autoantibody-inducing CD4 T (aiCD4 T) cell was generated via TCR revision at periphery. The aiCD4 T cell induces varieties of autoantibodies and also help full maturation of CTL to induce lupus tissue injuries. We are trying tried to assign CD number on this aiCD4 T cell. Methods: BALB/c mice were repeatedly immunized with 12x OVA, KLH or SEB, and the expression of effector / memory markers on CD4 T cell was studied. CD4 T cells were isolated referring to CD45RB, CD27 and CD122 markers, and these cells were adoptively transferred into naïve mice. Autoantibodies in sera of recipient mice were measured 2 weeks after transfer. Microarray analyses were also performed using CD45RBlo122lo CD4 T cell immunized 12x with OVA. Results: The CD45RBlo, CD27lo and CD122hi CD4 T cells were significantly expanded in mice immunized 12x with either OVA, KLH or SEB. Adoptive transfer of CD45RBlo122lo CD4 T cells of mice immunized 12x with OVA showed that autoantibodies were significantly increased in naïve recipients. In microarray analysis, chemokine (C-C motif) receptor 4 (Ccr4) was increased &gt;x4 in CD45RBlo122lo CD4 subset after 12x immunization with OVA. Conclusion: The aiCD4 T cell that induces SLE belongs to CCR4+CD45RBlo122lo CD4 subpopulation.