Presence Of IL-2 Research Articles

Abstract 875: Next generation clonal neoantigen targeting T cells, generated using the PELEUSTM bioinformatics platform and the VELOSTM manufacturing method show superior reactivity and phenotypic characteristics than classical TIL products

Abstract Adoptive transfer of tumor infiltrating lymphocytes (TIL) has generated objective clinical responses in patients with advanced metastatic cancers. Therapeutic exploitation of neoantigens as targets can potentially lead to safer and more effective treatment modalities with reduced toxicities. The Achilles Therapeutics trial NCT03517917 enabled the acquisition of matched tumor specimens and peripheral blood samples from patients undergoing routine surgery and facilitated the development of the proprietary VELOSTM manufacturing process, generating a personalized clonal neoantigen specific T cell product. An in-depth characterization of T cells expanded with the VELOSTM process was performed and compared to a standard TIL product. Samples were obtained from patients with primary NSCLC or metastatic melanoma. TIL were expanded from tumor fragments after dissection in the presence of IL-2. Peptide pools corresponding to the clonal mutations that were identified using the PELEUSTM bioinformatics platform were used to pulse dendritic cells (DC) generated from peripheral blood monocytes from each patient. Clonal neoantigen specific T cells (cNeT) were expanded using the VELOSTM process by co-culture of TIL with the peptide-pulsed autologous DC. As a comparison, TIL were expanded with a rapid expansion protocol (REP-TIL) in the presence of allogeneic feeders, anti-CD3 antibody and high-dose IL-2. Intracellular cytokine staining was performed following rechallenge with individual peptide pools encoding the clonal mutations. Single peptide reactivities were identified using ELISPOT and extended flow cytometric analysis of markers associated with T cell fitness or dysfunction was performed to phenotypically characterize the cNeT, TIL and REP-TIL. Analysis of the immune cell composition showed that cNeT, TIL and REP-TIL have similar CD3+ T cell content (median cNeT 90.2%, TIL 87.3%, REP-TIL 95%, n=6) and are composed of CD4+ and CD8+ T cells (median CD4:CD8 ratio- cNeT 11.1, TIL 2.03 and REP-TIL 4.7, n=6). cNeT showed superior clonal neoantigen specificity compared to TIL or REP-TIL. The proportion of CD3+ T cells responding to clonal neoantigen rechallenge was increased in cNeT (median 24.3%) compared to TIL (median 0.6%) and REP-TIL (median 1.8%) (n=5). The VELOSTM process incorporating the PELEUSTM platform for prediction of clonal neoantigens generates T cell products enriched for clonal neoantigen reactivities and superior phenotypic characteristics compared to conventional TIL. The VELOSTM process is currently being used to manufacture cNeT for two first-in-human studies including NSCLC and melanoma patients (NCT04032847, NCT03997474). Ethical approval: The samples for the study were collected under an ethically approved protocol (NCT03517917). Citation Format: Eleni Kotsiou, Tie Zheng Hou, Joseph Robinson, Sonal Varsani, Theres Oakes, Pablo D. Becker, Shreenal Patel, Jennine Mootien, Andrew Craig, Jane Robertson, Edward Samuel, James Reading, Lyra Del Rosario, Andrew Haynes, Samra Turajlic, Farah Islam, David Lawrence, Mariam Jamal-Hanjani, Martin Foster, Sergio A. Quezada, Katy Newton. Next generation clonal neoantigen targeting T cells, generated using the PELEUSTM bioinformatics platform and the VELOSTM manufacturing method show superior reactivity and phenotypic characteristics than classical TIL products [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 875.

Abstract 4482: Monitoring T cell reactivity to allogeneic placental cell products using multiple lymphocyte reaction and TCR sequencing approaches

Abstract Introduction: Allogeneic stem cell-derived therapies offer patients a readily accessible source of off-the-shelf product. However, allogeneic cells may be recognized by the recipient's immune system thus negatively affecting persistence and efficacy. Among people, allelic differences in human leukocyte antigen (HLA) complex genes are the major source of alloantigen which can elicit immunity. While there are established assays for measuring alloantibodies, monitoring T cell alloreactivity is more challenging. Unique clonal populations vary between individuals and functional assays are difficult to scale and standardize if alloreactive populations are rare/infrequent. Here, we evaluate how alloreactive T cells from patients may be identified using multiple lymphocyte reaction (MLR). Next generation sequencing of the TCR locus permits the subsequent identification and monitoring of allogeneic T cell clones in a patient over time. Methods: Placental leukocytes depleted of CD34 cells or peripheral blood mononuclear cells (PBMC) were enriched for monocytes using magnetic-bead isolation followed by dendritic cell (DC) maturation in the presence of GM-CSF and IL-4 for 5 days. DC were activated with lipopolysaccharide for 16 hours then cultured in the presence of CD3+ T cells isolated from healthy 3rd party PBMC for 5 days in the presence of IL-2. Proliferating alloantigen-specific T cells were observed by flow cytometry. TCR locus sequencing was performed on DNA libraries generated from unstimulated and post-MLR cultures using the Illumina platform. Results: In contrast to monocyte derived DCs from PBMC, monocyte derived DCs from placenta required higher levels of cytokine and lipopolysaccharide stimulation to achieve similar level of maturation. Co-culture of placental-derived DCs with unrelated T cells over 5 days resulted in the outgrowth of T cell colonies visible by brightfield microscopy. Flow cytometry confirmed clonal expansion of CD4 and CD8 T cell populations based upon the expression of Ki-67, CD25, and CD69 on cells with a higher forward scatter. To assess feasibility of performing TCR sequencing in unstimulated and post-MLR T cells, one T cell responder was evaluated in response to 3 different DC donors. For each DC donor, a single T cell clone representing 0.35% of the starting repertoire expanded to become the dominant clone at 44%, 61%, and 66% following MLR with the next most frequent clones represented 4%, 3%, and 2% among total T cells, respectively. Our data demonstrate the feasibility of identifying alloreactive T cell clones for translational research monitoring in patients. This approach could inform correlations with cell persistence and help optimize allogeneic cell delivery and dosage strategies in the context of disease state and lymphodepletion. Citation Format: Bhavani Stout, Tanel Mahlakoiv, Robert Hariri, Xiaokui Zhang, William van der Touw. Monitoring T cell reactivity to allogeneic placental cell products using multiple lymphocyte reaction and TCR sequencing approaches [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4482.

Abstract LB-390: Intratumoral electroporation of plasmid-encoded IL-12 and membrane-bound anti-CD3 increases tumor immunogenicity and augments the function of T cell subsets

Abstract Intratumoral (IT) delivery of plasmid IL-12 (tavokinogene telseplasmid; tavo) via electroporation (EP), collectively referred as IT-tavo-EP, generates immunologically-relevant levels of localized IL-12, triggering regression of both treated and distant tumors with minimal toxicity in preclinical and clinical studies. Our previous clinical trial data from melanoma patients treated with IT-tavo-EP identified a treatment-related increase of infiltrating T cells and transcripts related to immune activation, as well as a significant increase in the IFN-γ score of patients with a clinical benefit, suggesting that CD3+ tumor-infiltrating lymphocytes (TIL) may be critical in maximizing the anti-tumor effects of IT-tavo-EP. Furthermore, in-house biomarker data have identified an abundance of non-tumor reactive TIL that, if mobilized could additionally contribute to a clinical response. Accordingly, a plasmid-encoded membrane-bound polyclonal T cell-stimulating anti-CD3 (αCD3) hybrid antibody (scFv) was developed and used in combination with tavo (IT-tavo-αCD3-EP) to broaden the scope and depth of the T cell response. We previously demonstrated that membrane expression of αCD3 on neoplastic and stromal cells could activate CD3+ TIL, driving enhanced proliferation and cytotoxicity in a B16-OVA murine model. Here, using immune profiling of the tumor microenvironment (TME), we have demonstrated that this membrane-bound αCD3 therapeutic can significantly upregulate frequencies of CXCR3+CD8+ T cells and short-lived effector T cells, while reducing PD-1 expression on CD8+ T cells in vivo. Critically, naïve T cells, Treg cells, and exhausted T cells (subsets not typically associated with strong anti-tumor responses) displayed enhanced effector function (IFN-γ and granzyme B release) with engagement of membrane-bound αCD3 and IL-12. Furthermore, we found that this therapeutic approach could equally enhance proliferation of T cells regardless of the affinity for their cognate peptide:MHC, suggesting a TCR independent mechanism. Collectively, these observations demonstrate that IT-tavo-αCD3-EP can mobilize broad subsets of T cells beyond dominant anti-tumor effectors demonstrated. Thus, while enhanced cytolytic function is associated with this therapy, inclusion of additional atypical anti-tumor T cell subsets may also promote reshaping of the TME by production of effector cytokines upon engagement of surface-bound αCD3. Moreover, functional restoration of TIL isolated from a melanoma patient with active clinical progression on anti-PD-1 therapy, was possible with engagement of membrane-bound αCD3 in the presence of IL-12. Collectively, these data continue to support the utility of IT-tavo-αCD3-EP as a promising therapeutic approach for patients with melanoma and other accessible solid tumors. Citation Format: Mia Han, Anandaroop Mukhopadhyay, Bianca Nguyen, Jack Y. Lee, Erica Browning, Jon Salazar, Reneta Hermiz, Lauren Svenson, Chris Baker, Daniel O'Connor, Kellie Malloy, David A. Canton, Christopher G. Twitty. Intratumoral electroporation of plasmid-encoded IL-12 and membrane-bound anti-CD3 increases tumor immunogenicity and augments the function of T cell subsets [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr LB-390.

Abstract 1068: Tumor infiltrating lymphocytes (TIL) recognize a unique and diverse number of non-synonymous somatic mutations in patients with metastatic breast cancer

Abstract Introduction: Adoptive transfer of tumor infiltrating lymphocytes (TIL) can mediate long-term durable regression in patients with metastatic melanoma, a type of cancer which is characterized by a high number of mutated genes and pronounced lymphocytic infiltrate. In contrast, metastatic breast cancer expresses far fewer somatic mutations and may contain lower levels of TIL. This pilot study investigated the ability to identify immunogenic non-synonymous somatic mutations which can serve as targets for adoptively transferred autologous T cells into patients with metastatic breast cancer, refractory to other treatments. Methods: WES and RNAseq were performed on metastatic lesions resected in the Surgery branch, NCI, NIH from patients with metastatic breast cancer. Non-synonymous somatic mutations were identified and, in parallel, TIL from the same lesions were grown ex vivo in the presence of IL-2. The somatic mutations were tested for recognition by the autologous TIL using previously described functional assays, involving tandem mini-genes (TMG), long peptides or predicted minimal peptide approaches. For some patients, the mutation-reactive T cells were sorted by FACS and the respective TCR was identified by single cell sequencing. Results: Metastatic tumor lesions from 37 patients with breast cancer were studied and all of them were found to contain and express non-synonymous somatic mutations (range: 4-1788, median: 102). TIL were successfully grown ex vivo from the tumors of all patients. Following functional assays (IFN-γ secretion and 4-1BB/OX-40 upregulation), it was found that autologous TIL recognized at least one (range: 1-11, median: 3) mutated product in 25 of 37 patients (68%) tested. Seventy-five percent of those were recognized by CD4+ and 25% by CD8+ T cells. All identified immunogenic tumor mutations (n=88) were unique and not shared by other patients. Sixty-four unique TCR pairs were isolated from the reactive cells and verified to recognize 30 immunogenic tumor mutations (range 1-7 TCRs/neoantigen). Conclusions: Patients with metastatic breast cancer contain a substantial number of non-synonymous somatic mutations and mutation-reactive TIL were found in the majority of those patients. The immunogenicity of tumor-specific mutations in metastatic breast cancer can be the platform for a highly personalized adoptive T cell transfer of selected TIL or mutation-reactive TCR transduced T cells targeting those tumor mutated genes. Citation Format: Nikolaos Zacharakis, Peter Kim, Paul Robbins, Jared Gartner, Todd Prickett, Victoria Hill, Biman Paria, Steven Feldman, Stephanie Goff, Steven Rosenberg. Tumor infiltrating lymphocytes (TIL) recognize a unique and diverse number of non-synonymous somatic mutations in patients with metastatic breast cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1068.

Abstract 874: Adoptive transfer of cytotoxic lymphocytes generated by engineered human dendritic cells for AML treatment

Abstract Introduction: Acute myeloid leukemia (AML) is a devastating blood cancer. The clinical benefit of allogeneic stem cell transplantation (alloSCT) greatly relies on the graft-versus-leukemia (GVL) effect mediated by donor T cells, but it may also cause graft-versus-host disease (GVHD). One strategy to improve GVL without promoting GVHD is to adoptive transfer of cytotoxic T cells (CTLs) against leukemia-associated antigen (LAA). Generating potent CTLs is challenging. Stimulating naïve T cells with monocyte-derived dendritic cells loaded with LAA is commonly used, but it is severely limited due to low efficacy. We have developed a novel DC methodology and established immortalized human primary blood DC lines (ihv-DCs) by transducing human peripheral blood mononuclear cells (PBMCs) with a viral protein Tax. The constitutively activated ihv-DCs expand efficiently in vitro and can potently prime naïve T cells. They can be genetically modified to deliver given tumor antigens and stimulate antigen-specific CTLs in high efficiency. Here, we generate CTLs by stimulating donor PBMCs with ihv-DCs that carry HLA-A2 restrict human telomerase reverse transcriptase (hTERT), a known LAA. We investigate, in vitro and in vivo, the CTL killing efficacy. Methods: ihv-DCs that carry HLA-A2 restrict hTERT was engineered as previously described (Wu et al., PNAS 2018). HLA-A2 restrict hTERT-specific CTLs were generated by co-culturing ihv-DCs in the presence of IL-2 with donor PBMCs. In vitro cytotoxicity was performed by culturing CTLs with target cells that labeled with cell-track dye at different E:T ratio. Cell lysis was tested by flow-cytometry-based cell apoptosis analysis. In vivo cytotoxicity was examined by adoptive transfer CTLs into xenograft AML model. Flow cytometry was used to detect the leukemia burden. Results: Although variable, THP-1 cell line and blasts from all HLA-A2+ AML patients (11/11) in our study express significant intracellular hTERT. CTLs were successfully established by co-culturing ihv-DCs carrying hTERT with PBMCs from HLA-A2+ healthy donors. We observed an increasing proportion of effector memory T cells over time. We observed significant cytotoxic activities of purified CD8 T cells to U2OS that engineered to express hTERT, THP-1 cells, and primary leukemia blasts from AML patients in vitro. The cytotoxicity is predominantly hTERT specific as the killing to the primary U2OS cell line (negative for hTERT) is minimal. In addition, the cytotoxic effect was significantly diminished upon adding blockade antibody against HLA-A2, indicating the killing is through an HLA-A2 restrict manner. To study whether the CTLs can eradicate AML in vivo, we adoptively transferred CTLs into a xenograft AML model generated by engrafting primary AML into NSG mice (n=5), 5 × 106 cells were injected every 5 days for 4 times. Mice injected with PBS were set as control. On day 20, we found significant reduction of leukemia burden in blood and bone marrow from mice treated with CTLs. Importantly, no GVHD was observed. Persistent CTLs were detected in all organs (blood, bone marrow, liver, spleen, and lungs). Conclusion: Using a novel ihv-DC delivering LAA, we established CTLs that are highly efficient in killing primary leukemia blasts derived from AML patients both in vitro and in vivo. Our study provides a proof of principle for applying the novel DC methodology to AML treatment. Citation Format: Chenchen Zhao, Bei Jia, Yixing Jiang, Hiroko Shike, David F. Claxton, W Christopher Ehmann, Todd D. Schell, Hua Cheng, Bei Liu, Hong Zheng. Adoptive transfer of cytotoxic lymphocytes generated by engineered human dendritic cells for AML treatment [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 874.

CD4+CD126low/− Foxp3+ Cell Population Represents a Superior Subset of Regulatory T Cells in Treating Autoimmune Diseases

CD4+Foxp3+ regulatory T (Treg) cells are crucial for maintaining homeostasis and preventing autoimmune diseases. Nonetheless, we and others have previously reported that natural Treg cells are unstable and dysfunctional in the inflamed environment with a high-salt diet, limiting the Treg function in disease control. In this study, we made an innovative observation showing a high degree of heterogeneity within the Treg pool. We identified that CD126, interleukin (IL)-6 receptor alpha chain, contributed to Treg cell instability. Using a series of invitro and invivo experimental approaches, we demonstrated that CD126Lo/- Treg cells presented greater function and were more stable than CD126Hi nTreg cells, even in the presence ofIL-6 and inflammation. Blockade of programmed death-1 (PD-1) interrupted CD126Lo/- nTreg cell stability. Additionally, CD126Lo/- Treg cells can treat colitis and established collagen-induced arthritis, while the CD126Hi cell population failed to do this. Moreover, we noted that CD126 expression of Treg cells had a positive correlation to rheumatoid arthritis (RA) severity and the stability of Treg cells. Our results strongly suggest that the manipulation of CD126Lo/- nTreg cells could be a novel strategy for the treatment of autoimmune diseases and for other conditions associated with a deficit of Treg cells.

The Effect of a Newly Synthesized Ferrocene Derivative against MCF-7 Breast Cancer Cells and Spheroid Stem Cells through ROS Production and Inhibition of JAK2/STAT3 Signaling Pathway.

Breast Cancer Stem Cells (BCSCs) possess the ability of self-renewal and cellular heterogeneity, and therefore, play a key role in the initiation, propagation and clinical outcome of breast cancer. It has been shown that ferrocene complexes have remarkable potential as anticancer drugs. The present study was conducted to investigate the effects of a novel ferrocene complex, 1- ferrocenyl-3-(4-methylsulfonylphenyl)propen-1-one (FMSP) on MCF-7 breast cancer cell line and its derived mammospheres with cancer stem cell properties. Mammospheres were developed from MCF-7 cells and validated by the evaluation of CD44 and CD24 cell surface markers by flow cytometry as well as of the expression of genes that are associated with stem cell properties by real-time PCR. Cells viability was assessed by a soluble tetrazolium salt (MTS) after the treatment of cells with various concentrations of FMSP. Apoptosis was evaluated by flow cytometry analysis of annexin V and PI labeling of cells. Reactive Oxygen Species (ROS) production was measured using a cellpermeable, oxidant-sensitive fluorescence probe (carboxy-H2DCFDA). The involvement of the JAK2/STAT3 pathway was also investigated by western blotting. FMSP could successfully prevent mammosphere formation from differentiated MCF-7 cells and significantly down-regulated the expression of genes involved in the production of the stem cell properties including Wnt1, Notch1, β -catenin, SOX2, CXCR4 and ALDH1A1. FMSP decreased cell viability in both MCF-7 cells and spheroid cells, although MCF-10A cells were unaffected by this compound. Apoptosis was also dramatically induced by FMSP, via ROS production but independent of CD95 activation. Phosphorylation levels of JAK2 and STAT3 were also found to be significantly attenuated even in the presence of IL-6, the putative activator of the JAK/STAT pathway. FMSP can effectively target BCSCs via ROS production and modulation of major signaling pathways that contribute to the stemness of breast cancer cells, and therefore, might be considered a promising anticancer agent after in vivo studies.

Development and validation of immunoassays for monitoring of guselkumab and anti-guselkumab antibodies in patients with moderate-to-severe psoriasis

Therapeutic drug monitoring, which is the measurement of drug concentrations in the blood, is a useful tool to guide clinical decision-making and treatment adjustments, on the condition that drug concentrations are correlated with treatment response. For guselkumab, an anti-IL-23 monoclonal antibody for the treatment of moderate-to-severe psoriasis, such a concentration-response relationship could not yet be determined as no commercial assays for the quantification of this drug or antibodies against this drug are available. Therefore, the aim of this study was to develop and validate immunoassays for the quantification of guselkumab and anti-guselkumab antibodies according to the guidelines of the European Medicines Agency (EMA). A diverse panel of 20 highly specific anti-guselkumab monoclonal antibodies (MA-GUS) was generated of which eight revealed a neutralizing capacity of ≥65 %. At least seven different antibody clusters were identified based on their epitope binning profile. Using MA-GUS9F6 as the capture antibody and MA-GUS12G12 as the detection antibody, an ELISA was developed with a dose-response curve ranging from 0.08 to 5 ng/mL. The assay was specific, selective and could accurately and precisely quantify guselkumab concentrations in spiked healthy control serum and serum from guselkumab-treated psoriasis patients with a cut-off for quantification of 0.014 μg/mL. The presence of IL-23 in physiological concentrations or of non-neutralizing antibodies did not impact the quantification of guselkumab, while the presence of neutralizing antibodies did. Using MA-GUS12A9 as a calibrator, two anti-guselkumab antibody assays were developed to detect anti-guselkumab antibodies, which differ in the threshold for detection and quantification and the tolerance to the presence of guselkumab. Together, these validated immunoassays are essential to establish a concentration-response relationship and will allow the future implementation of therapeutic drug monitoring in moderate-to-severe psoriasis patients receiving guselkumab treatment.

Sialylation of Human Natural Killer (NK) Cells is Regulated by IL-2.

Sialic acids are terminal sugars on the cell surface that are found on all cell types including immune cells like natural killer (NK) cells. The attachment of sialic acids to different glycan structures is catalyzed by sialyltransferases in the Golgi. However, the expression pattern of sialyltransferases in NK cells and their expression after activation has not yet been analyzed. Therefore, the present study determines which sialyltransferases are expressed in human NK cells and if activation with IL-2 changes the sialylation of NK cells. The expression of sialyltransferases was analyzed in the three human NK cell lines NK-92, NKL, KHYG-1 and primary NK cells. NK-92 cells were cultured in the absence or presence of IL-2, and changes in the sialyltransferase expression were measured by qPCR. Furthermore, specific sialylation was investigated by flow cytometry. In addition, polySia and NCAM were measured by Western blot analyses. IL-2 leads to a reduced expression of ST8SIA1, ST6GAL1 and ST3GAL1. α-2,3-Sialylation remained unchanged, while α-2,6-sialylation was increased after IL-2 stimulation. Moreover, an increase in the amount of NCAM and polySia was observed in IL-2-activated NK cells, whereas GD3 ganglioside was decreased. In this study, all sialyltransferases that were expressed in NK cells could be identified. IL-2 regulates the expression of some sialyltransferases and leads to changes in the sialylation of NK cells.

In vitro treatment of CD8+ T cells with interleukin-7 enhances their in vivo anti-tumor capabilities against an animal model of Ehrlich ascites carcinoma

Background: Developing optimal strategies for generating T cells capable of effectively controlling tumors is one of the most important prerequisites for the clinical application of adoptive cell therapies in cancer patients. However, the generation of sufficient numbers of tumor-reactive T cells capable of efficient tumor regression and long-term persistence remains a significant impediment to widespread clinical implementation. Aim: The main aim of the present study was to evaluate the beneficial anti-tumor effects of a simplified combinatorial approach that involves a short activation of naive CD8+ T cells with the T cell mitogen concanavalin A (CON-A; 4 ug/mL) and the survival cytokine IL-7 (10 ng/mL), after a single intraperitoneal injection of cyclophosphamide (CTX; 4 mg/mouse) after their adoptive transfer into Ehrlich ascites carcinoma (EAC) tumor-bearing CD1 mice. Results: We found that adoptive transfer of in vitro IL-7-conditioned T cells into EAC-bearing (3-day) mice previously treated with a single dose of CTX induced a delay in the progression of EAC, and the establishment of long-term immunological memory, which has the efficiency to provide full protection for mice against cancer. Our results indicated that in the presence of IL-7, the short-term T-cell receptor signaling mediates promiscuous qualities in naive cytotoxic CD8+T cells. Conclusion: The data indicate that upon the adoptive transfer of IL-7 conditioned T cells into lymphopenic hosts, they were able to eradicate tumors and also to generate long-term tumor-specific memory.

Generation of dendritic cells using viral lysate of tumor cells in vitro.

e15202 Background: The purpose of the study was to investigate the effect of a new unclassified rotavirus on the effectiveness of maturation of dendritic cells (DC) and their activation of lymphocytes in vitro. Methods: Strain No.100 of the RVK virus was isolated by S.A. Kolpakov and characterized as rotavirus. U87MG cell lysate (glioblastoma) was obtained by incubation with 108 RVK particles in the DMEM medium with L-glutamine for 72 hours; a cytopathic effect was observed. Immature DCs were cultured for 7 days in the presence of IL-4 and GM-CSF. For antigen loading of DCs, we used the following options for 48 h: a) U87MG lysate obtained by repeated freeze-thaw cycles (TL); b) U87MG lysate obtained by co-cultivation with RVK (VTL); c) RVK. To assess the DC ability to activate autologous lymphocytes, they were co-cultured for 5 days in a 3:1 ratio. Results: The use of VTL culture for DC loading caused an increase in the expression of mature DC (mDC) markers compared to TL: the number of CD83+/CD86+ cells increased by more than 2 times, CD83+/CD80+ by 1.2 times, CD83+HLA-DR - by 5.5 times. With VTL, expression of markers of immature DCs (CD1a, CD14) was minimal. The use of RVK as an antigen induced the generation of DCs from monocytes, but their maturation was much less pronounced: a significant increase in the membrane expression of CD86, but not CD83, was determined. These DCs demonstrated a higher expression of markers of immature DCs, compared to stimulation with cell lysates (both TL and VTL): CD1a and CD14; CD80+/CD86+ level was the highest among all options. Analysis of the DC effect on co-cultivated lymphocytes showed that DCs loaded with RVK, both alone and as part of VTL, stimulated predominantly the NKT subpopulation. The same samples contained more T lymphocytes, activated CD4+ and CD8+ compared to samples stimulated by TL. However, the samples co-cultivated with VTL contained the maximal amount of CD4+/CD25+/CD127dim phenotypically corresponding to Tregs. Conclusions: The antigen loading of immature DCs with RVK alone causes their activation, but not maturation, which is not realized in typical terms of the DC generation from blood monocytes. The presence of RVK, including in VTL, has a stimulating effect on NKT lymphocytes suggesting the possible generation of specific highly active cytotoxic lymphocytes.

CD28.OX40 co-stimulatory combination is associated with long in vivo persistence and high activity of CAR.CD30 T-cells.

The prognosis of many patients with chemotherapy-refractory or multiply relapsed CD30+ non-Hodgkin lymphoma (NHL) or Hodgkin lymphoma (HL) still remains poor, and novel therapeutic approaches are warranted to address this unmet clinical need. In light of this consideration, we designed and pre-clinically validated a chimeric antigen receptor (CAR) construct characterized by a novel anti-CD30 single- chain variable-fragment cassette, linked to CD3ζ by the signaling domains of two co-stimulatory molecules, namely CD28.4-1BB or CD28.OX40. We found that CAR.CD30 T cells exhibit remarkable cytolytic activity in vitro against both HL and NHL cell lines, with sustained proliferation and pro-inflammatory cytokine production, even after multiple and sequential lymphoma-cell challenges. CAR.CD30 T cells also demonstrated anti-lymphoma activity in two in vivo xenograft immune-deficient mouse models of metastatic HL and NHL. We observed that administration of CAR.CD30 T cells, incorporating the CD28.OX40 co-stimulatory domains and manufactured in the presence of interleukin 7 and interleukin 15, were associated with the best overall survival in the treated mice, along with establishment of a long-term immunological memory able to protect mice from further tumor re-challenge. Our data indicate that, in the context of in vivo systemic metastatic xenograft mouse models, the co-stimulatory machinery of CD28.OX40 is crucial for improving persistence, in vivo expansion and proliferation of CAR.CD30 T cells upon tumor encounter. The CD28.OX40 co-stimulatory combination is ultimately responsible for the anti-tumor efficacy of the approach, paving the way to translate this therapeutic strategy into clinical use for patients with CD30+ HL and NHL.

CD126 negative regulatory cells represents a superior Treg subset in treating autoimmune diseases

Abstract Treg cells play an important role in maintaining immunologic homeostasis. Abnormal Treg were found in some autoimmune diseases. Infusion of natural Treg (nTreg) prevents some autoimmune disease but usually fails to treat established diseases. Several studies demonstrated nTreg could be transdifferentiated into Th17 cells and lost its function under inflammatory condition. Given IL-6 is an important inflammatory cytokine and it binds to its receptor (CD126) to exert functional role, whereas nTreg express CD126, we hypothesize that CD126− Foxp3+ cell subsets could be more stable and functional in the inflammatory condition. CD126+ and CD126− nTreg were sorted from collagen-induced arthritis (CIA) and then were analyzed for transcript difference via RNA-sequence. They were cultured in the presence of IL-6 to determine the stability and function following a colitis model in vivo. Compared to normal mice, the proportion of CD126+ nTreg in CIA was significantly higher. CD126− nTreg express higher immunosuppressive molecules and present stronger function than CD126+ nTreg in both normal condition and presence of IL-6. Moreover, CD126− nTreg was stable while CD126+ nTreg lost Foxp3 expression and trans-differentiated into Th17 in the presence of IL-6. In addition, CD126− nTreg exhibited reduced Hif-1a and glucose transporter 1(Slc2a1) expression, which are two key regulators of glycolytic metabolism and play an important role in the balance of Th17 and Treg. Finally, CD126− Treg more potent treat colitis compared to control. We show CD126− nTreg present stronger function and stability under inflammatory conditions Our results suggest that manipulation of CD126− nTreg might be a novel strategy for the treatment of autoimmune diseases.

Interleukin 7 regulates naive T cell metabolism to promote motility of T cells

Abstract Interleukin-7 (IL-7) is a key cytokine that drives the survival and maintenance of naïve T cells in lymph nodes. Naïve T cells continuously move throughout lymph nodes in order to interact with dendritic cells (DCs) to become activated and promote an effective immune response. As IL-7 is highly expressed in lymph nodes, we investigated whether IL-7 might regulate T cell movement potentiating T-DC interaction. Using two photon microscopy, we show IL-7 promotes T cell motility in vitro and in vivo. Downstream of IL-7, JAK3 and STAT5 signaling are important to regulate T cell speed. To understand the mechanism underlying IL-7 effects on T cell movement, we investigated whether IL-7 might change the metabolic profile of naïve T cells. Using the Seahorse analyzer, we show that IL-7 can affect the metabolic profile of naïve T cells, particularly CD8 T cells. The chemokine CCL21 has previously been shown to drive T cell motility. We then asked whether IL-7 and CCL21 might combine to modulate effects on T cell metabolism. We find that CCL21 decreases ATP production and this decrease in ATP production persists even in the presence of IL-7. Our results suggest that IL-7 is a novel regulator of T cell motion in lymph nodes via changes in T cell metabolism, leading efficient T cell responses.

T cell-intrinsic expression of HIC1 links retinoic acid to tissue residency

Abstract The interaction between micronutrients and the immune system is emerging as a key control point in immune cell function in homeostasis and disease. For example, the vitamin A metabolite all-trans retinoic acid (atRA) has established roles in immune cell migration and effector function. Vitamin A deficiency results in a significant reduction in intestinal immune cells, which is thought to be associated with a lack of intestinal homing receptor expression and reduced migration to the intestine. However, the precise molecular pathways controlling intestinal immune cell homeostasis remains unclear. Here, we show that the atRA-inducible BTB-POZ transcriptional repressor Hypermethylated in cancer 1 (HIC1, ZBTB29) controls intestinal T cell residency. Mice with a T cell-intrinsic deletion of HIC1 (Hic1ΔT mice) have reduced numbers of CD69+ CD103+ tissue resident memory T (TRM) cells in the intestine, demonstrating that the atRA/HIC1 axis is critical for establishing and maintaining TRM cells. Further, following influenza A virus infection, numbers of TRM cells in the lungs are significantly reduced in Hic1ΔT mice, as well as in mice treated with the pan-retinoic acid receptor inhibitor BMS493, or in mice with a T cell-specific deletion of RARa (RaraΔT mice). Consistent with this, activation of naive CD8+ T cells from mice or humans in the presence of IL-2, IL-15, TGFβ and atRA results in the generation of CD69+ CD103+ ‘TRM-like’ cells that share the transcriptional profile of bona fide TRM cells. Taken together, these results identify atRA as a critical regulator of T cell tissue residency, acting by inducing expression of HIC1 and promoting the tissue residency gene program.

IL-27-producing B cells are key regulators of anti-viral immunity and antibody responses

Abstract Emerging evidence indicates that B lymphocytes regulate immunity by producing antibodies, presenting antigens and secreting cytokines that provide signals to other cells to modulate both humoral and cellular immunity. Here, we show that B cells produce IL-27 upon activation by TLR4 and CD40 in the presence of IL-21 in vitro. Using Lymphocytic choriomeningitis virus (LCMV) Clone 13 as a model of a persistent viral infection, we identify plasma B cells as major source of IL-27. Further, we show that IL-27-producing B cells are key players in the regulation of immunity. Mice with conditional B cell–specific IL-27p28 knockout were unable to control persistent LCMV infection and failed to respond to anti-IFNAR1 immunotherapy. The impaired immunity found in these mice was associated with reduced virus-specific IgG2a/2c. In addition, these mice displayed reduced virus-specific CD4+ T cells and T follicular helper (Tfh) cells, suggesting that B-cell-derived cytokines regulate immunity by providing signals to T cells. The effects of Il27ra deletion from T cells mirrors the phenotypes observed in mice lacking B-cell-derived IL-27. In addition, IL-27ra deficient (KO) Tfh cells lost their ability to produce IL-21, resulting in aberrant production of virus-specific antibodies to LCMV clone 13 in IL-27ra KO mice. Finally, RNA-sequencing of virus-specific CD4+ T cells identified IL-27R-dependent genes during persistent LCMV infection. Collectively, our data reveal a central role of plasma cell-derived IL-27 in the regulation of T cell functions. Importantly, our study describes cellular interactions between T and B cells and highlights the importance of virus-specific IgG2a/2c during persistent LCMV infection.

TLR7/8 and TLR9 ligands induce phenotypic and transcriptional changes in human transitional B cells

Abstract The maturation of human transitional B cells into mature, naïve follicular or marginal zone B cells is a key step in B cell development. Transitional B cells are a prominent B cell population in newborns and very young children who receive many vaccines during early childhood. Pattern recognition receptor (PRR) ligands are attractive candidate vaccine adjuvants due to their targeted mechanisms of action. However, the effects of PRR ligands on transitional B cell fate are not fully understood. We have demonstrated that human cord blood transitional B cells predominantly mature into follicular-like B cells when stimulated in vitro with R848 (TLR7/8 ligand) or CpG (TLR9 ligand) in the presence of IL-4. Additionally, we have profiled the transcriptome of human transitional, follicular and marginal zone-like B cells and identified genes uniquely associated with each B cell subset. Several of the genes identified during our transcriptome analysis were expressed in our in vitro-stimulated transitional B cells. These gene expression changes following PRR ligand stimulation indicate that differing stimuli can skew transitional B cell fate. Our characterization of PRR ligand-induced phenotypic and transcriptional changes associated with mature follicular and marginal zone B cell development may influence the rational approach for vaccine adjuvant development, especially for newborns and very young children.

Cytotoxic effects of canine nk cells on canine mammary tumor cells

Background & Aim Natural killer (NK) cells play a crucial role in immune responses against various pathogens. NK cells are innate lymphocytes that rapidly provide defenses against tumors and viral infections allowing pathogen elimination or limiting viral spread. Their fast responses mainly rely on the expression of multiple germ-line encoded activating receptors among which natural cytotoxic receptors (NCRs) and NKG2D play the most relevant role in the recognition and killing of infected cells. NK cells have been characterized in a variety of mammals, but canine NK cells remain incompletely characterized. Mammary tumors account for ∼30% of all tumors in the female canine and approximately 50% of the tumors are malignant. Canine mammary gland tumor cell lines are excellent experimental models for identification of cancer-associated genes and understanding cancer biology and progression. In this study, we isolated canine peripheral blood-derived NK cells and defined their immunophenotype and cytotoxic effects on canine mammary tumor cells. In this study, we compared characteristics of canine NK cells against two canine mammary carcinoma cell lines, REM134 and CF41.Mg. Methods, Results & Conclusion Canine NK cells are proliferated and activated in CD5 negative population under specific culture condition. We peripheral blood mononuclear cells (PBMCs) were isolated from female beagle dogs (n=3). Subsequently, CD5 negative cells were isolated by immunomagnetic separation from PBMCs. For activation and expansion of NK cells, CD5 negative cells and co-cultured K562 cells in the presence of IL-2, IL-15, and IL-21 for 21 days. We found that expression markers of activated NK cells such as NKp30, NKp44, NKp46, NKG2D, CD244, perforin, granzyme B, and tumor necrosis factor alpha were highly upregulated. In addition, we found upregulated production of interferon gamma of activated NK cells against target cells such as REM134 and CF41.Mg. Also, we observed that cytotoxicity of activated NK cells against target cells more sensitively reacted to CF41.Mg than REM134. Taken together, we recommend the development of an experimental application of CF41Mg, which has not been reported in canine mammary carcinoma research.

Self-reactive T cells induce and perpetuate chronic relapsing arthritis

BackgroundCD4+ T cells play a central role during the early stages of rheumatoid arthritis (RA), but to which extent they are required for the perpetuation of the disease is still not fully understood. The aim of the current study was to obtain conclusive evidence that T cells drive chronic relapsing arthritis.MethodsWe used the rat pristane-induced arthritis model, which accurately portrays the chronic relapsing-remitting disease course of RA, to examine the contribution of T cells to chronic arthritis.ResultsRats subjected to whole-body irradiation and injected with CD4+ T cells from lymph nodes of pristane-injected donors developed chronic arthritis that lasted for more than 4 months, whereas T cells from the spleen only induced acute disease. Thymectomy in combination with irradiation enhanced the severity of arthritis, suggesting that sustained lymphopenia promotes T cell-driven chronic inflammation in this model. The ability of T cells to induce chronic arthritis correlated with their expression of Th17-associated transcripts, and while depletion of T cells in rats with chronic PIA led to transient, albeit significant, reduction in disease, neutralization of IL-17 resulted in almost complete and sustained remission.ConclusionThese findings show that, once activated, self-reactive T cells can sustain inflammatory responses for extended periods of time and suggest that such responses are promoted in the presence of IL-17.

Mesenchymal Stem Cells Could Be Considered as a Candidate for Further Studies in Cell-Based Therapy of Alzheimer's Disease via Targeting the Signaling Pathways.

Mesenchymal stem cells (MSCs) are of particular interest because of their potential in regenerative medicine. Stem cell-based therapies cast a new hope for neurodegenerative disease treatment as a regeneration strategy, including treatment for Alzheimer's disease (AD). A multitude of cytokines and factors secreted from MSCs are known to give such multifunctional properties, but associated mechanisms of these factors have yet to be entirely understood. To better understand the in vitro effect of MSCs on a neurodegenerative disorder, we treated primary cortical and hippocampal neural cells with amyloid β (Aβ) as an in vitro cell line model for AD. For this purpose, bone marrow-derived MSCs (BMSCs) were cocultured with Aβ-treated neural cells, collected at day 3, and subjected to absolute telomere length measurement and telomerase activity assay. Next, the gene and protein expression levels of mTOR, p-mTOR, AMPK, p-AMPK, GSK-3β, p-GSK-3β, Wnt3, and β-catenin were investigated. Also, after 3 days of coculture treatment, the supernatant was collected from both groups for cytokine measurement. It was found that telomere length as a biomarker in neurodegenerative disorder as well as telomerase activity had significantly increased in the experimental group, and the presence of IL-6, IL-10, and TGF-β was obviously significant in the cocultured media. Also, BMSCs significantly changed the gene and protein expression of mTOR, AMPK, GSK-3β, and Wnt3/β-catenin signaling pathways components. It was concluded that the mentioned effects of MSCs on neural cells as an in vitro cell line model for AD as a therapeutic agent can be related to the signaling network.