Effects of the trifunctional antibody catumaxomab (anti-EpCAM x anti-CD3) on proliferation and cytokine secretion of immune cells in malignant pleural effusion

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 3046-3046
Author(s):  
M. Sebastian ◽  
M. Jaeger ◽  
P. Kiewe ◽  
W. Schuette ◽  
R. Wiewrodt ◽  
...  
Keyword(s):  
T Cells ◽  
Pleural Effusion ◽  
Tumor Cells ◽  
Pleural Fluid ◽  
Immune Cells ◽  
Malignant Pleural Effusion ◽  
Cytokine Secretion ◽  
Accessory Cells ◽  
Ifn Γ

3046 Background: The trifunctional antibody catumaxomab specifically binds EpCAM+ tumor cells, CD3+ T lymphocytes and accessory cells via FcγR I/III. Thus the antibody induces tumor specific cell mediated cytotoxicity in vitro and in vivo. Following last years’ ASCO presentation on a phase I/II trial showing safety and efficacy of repetitive intrapleural administration of catumaxomab in patients with EpCAM positive, malignant pleural effusion (MPE), we now present data on the responsiveness of immune cells from pleural fluid to catumaxomab. Methods: Pleural fluid of patients with EpCAM-positive MPE treated with i.pl. catumaxomab was collected before treatment. Cells were harvested from the fluid and cultured ± 100 ng/ml catumaxomab using an in vitro proliferation assay. After 72 h of culture, proliferation of T cells (CD4+ and CD8+) and monocytes (CD11c+) was determined. In addition, cell supernatants after 24h incubation ± catumaxomab were analysed for their TH1/TH2 cytokine profile (IL-2, IL-4, IL-6, IL-10, IFN-γ and TNF- a). Results: Incubation in presence of catumaxomab led to a pronounced increase of CD4+ CD8+ and CD11+ cell numbers indicating a proliferation of these cells, whereas cultures without catumaxomab showed no proliferation of immune cells. Analysis of supernatants after 24 h revealed levels of IL-2, IL-6, IFN-γ and TNF-a, from cells incubated with catumaxomab that were distinctly higher than in cultures without catumaxomab. Conclusions: The immunologic nature of catumaxomab-induced responses in patients with pleural effusion accompanied by a reduction of tumor cells, could be underlined impressively with in vitro data obtained from pleural cells showing catumaxomab-induced proliferation of T cells and accessory cells and TH1-directed cytokine secretion. The data are equivalent to results observed in the peritoneal fluid of ascites patients. [Table: see text]

589 Efficacy of oncolytic vaccinia virus requires infection of suppressive immune cells in the tumor microenvironment leading to their reprogramming and deletion

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A624-A624
Author(s):  
Kristin DePeaux ◽  
Paolo Vignali ◽  
Saumendra Sarkar ◽  
Greg Delgoffe
Keyword(s):  
T Cells ◽  
Vaccinia Virus ◽  
Tumor Cells ◽  
Immune Cells ◽  
Tumor Regression ◽  
Post Treatment ◽  
Oncolytic Viruses ◽  
Phenotypic Change ◽  
Treg Depletion

BackgroundCheckpoint blockade immunotherapy has dramatically changed cancer treatment; however, these therapies depend on the presence of a pre-existing immune infiltrate. Unfortunately, some patients have few to no infiltrating immune cells, highlighting the need for therapies that can generate antigenic stimuli. Oncolytic viruses, which infect and lyse tumor cells while leaving healthy tissue unharmed, are an attractive means to provide these signals, although the mechanisms of action of these engineered viral therapies remain incompletely understood. Virally induced immunogenic death causes an influx of tumor- and virus- specific effector CD8+ T cells. Many oncolytic viruses also decrease tumor-infiltrating suppressive immune populations, such as regulatory T cells (Treg), however the mechanism for this is unknown. Here we show that an oncolytic strain of vaccinia virus (VV) infects tumor infiltrating Tregs, in contrast to the prevailing idea that oncolytic viruses only infect tumor cells. Infection leads to viral-mediated Treg depletion that is required for tumor regression.MethodsUsing a mouse model of head and neck squamous cell carcinoma (MEER), a VV-resistant line was generated through serial treatment of a VV-sensitive MEER line. At varied time points post-intratumoral treatment with VV, tumor infiltrating lymphocytes (TIL) were isolated from both the VV-resistant and VV-sensitive lines and analyzed by flow cytometry.ResultsOne day post-treatment of VV-sensitive MEER tumors, tumor isolated Tregs were infected by VV as determined by viral GFP expression. Infection was confirmed in vitro with purified Tregs. Four days post-treatment, tumor infiltrating Treg counts were reduced, and active caspase 3 staining was increased, suggesting that infection lead to Treg death. At 7 days post-treatment, the remaining Tregs in the VV-sensitive tumors acquired a fragile phenotype (IFN?+ Nrp1-). This was not observed in the VV-resistant MEER line. Fragile Tregs are less suppressive and indeed we observed an increase in pro-inflammatory cytokine production from CD8+ and Tconv (CD4+ Foxp3-) T cells in the VV-sensitive tumors compared to VV-resistant. We then engineered oncolytic VV to be susceptible to Cre mediated inactivation. Infection of various murine transgenic Cre lines confirmed the importance of non-tumoral immune infection for therapeutic efficacy, with a particular emphasis on Treg infection.ConclusionsThese data reveal a previously unappreciated mechanism of action of oncolytic virus immunotherapy, in which new tumor immunity accompanies the viral mediated loss and phenotypic change of regulatory populations. Importantly, as this treatment is delivered intratumorally the loss of Tregs is tumor specific, resulting in targeted Treg deletion without systemic autoimmunity.

TNB-486, a Novel Fully Human Bispecific CD19 x CD3 Antibody That Kills CD19-Positive Tumor Cells with Minimal Cytokine Secretion

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 4070-4070
Author(s):  
Harbani Malik ◽  
Ben Buelow ◽  
Udaya Rangaswamy ◽  
Aarti Balasubramani ◽  
Andrew Boudreau ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Tumor Cells ◽  
Cytokine Secretion ◽  
Employment Equity ◽  
Equity Ownership

Introduction The restricted expression of CD19 in the B-cell lineage makes it an attractive target for the therapeutic treatment of B-cell malignancies. Many monoclonal antibodies and antibody drug conjugates targeting CD19 have been developed, including bispecific T-cell redirecting antibodies (T-BsAbs). In addition, anti-CD19 chimeric antigen receptor T-cells (CAR-T) have been approved to treat leukemia and lymphoma. However, despite the impressive depth of responses achieved by T-cell redirecting approaches such as T-BsAbs and CAR-T cells, toxicity from over-activation of T-cells remains a substantial limitation for this type of therapy, in particular neurotoxicity. In designing TNB-486, a novel CD19 x CD3 T-BsAb, we endeavored to retain activity against CD19-positive tumor cells while limiting the cytokine secretion thought to underlie toxicity from T-cell redirecting therapies. Utilizing TeneoSeek, a next generation sequencing (NGS)-based discovery pipeline that leverages in silico analysis of heavy chain only/fixed light chain antibody (HCA/Flic, respectively) sequences to enrich for antigen specific antibodies, we made a high affinity αCD19 HCA and a library of αCD3 Flic antibodies that showed a >2 log range of EC50s for T cell activation in vitro. Of note, the library contained a low-activating αCD3 that induced minimal cytokine secretion even at concentrations that mediated saturating T-cell dependent lysis of lymphoma cells (when paired with an αCD19 HCA). We characterized the relative efficacy and potential therapeutic window of this unique molecule, TNB-486, in vitro and in vivo and compared it to two strongly activating bispecific CD19 x CD3 antibodies similar to those currently available and in clinical development. Methods Affinity measurements of the αCD19 moiety were made via Biacore (protein) and flow cytometry (cell surface). Stability measurements were made by subjecting the molecule to thermal stress and the %aggregation was measured by Size Exclusion Chromatography. T-cell activation was measured via flow cytometry (CD69 and CD25 expression) and cytokine was measured by ELISA (IL-2, IL-6, IL-10, INF-ɣ, and TNFα) in vitro. Lysis of B-cell tumor cell lines (Raji, RI-1, and Nalm6) was measured via flow cytometry in vitro. In vivo, NOG mice were engrafted subcutaneously with NALM-6 or SUDHL-10 cells and intravenously with human peripheral blood mononuclear cells (huPBMC), and the mice treated with multiple doses of TNB-486 or negative or positive control antibody. Tumor burden was evaluated via caliper measurement. Pharmacodynamic/Pharmacokinetic (PK/PD) studies were performed in NOG mice. A pharmacokinetic (PK) study was performed in BALB/c mice, and a tolerability and PK study are ongoing in cynomolgus monkeys. Results TNB-486 bound to cell surface CD19 with single digit nanomolar affinity (~3nM). EC50s for cytotoxicity were in the single-digit nanomolar range for TNB-486, and sub-nanomolar for the strongly activating controls; TNB-486 maximum achievable lysis was identical to the positive controls. TNB-486 induced significantly less cytokine release for all cytokines tested compared to the positive controls even at doses saturating for tumor lysis. No off-target activation was observed in the absence of CD19 expressing target cells. In vivo, TNB-486 eradicated all CD19-positive tumors tested (NALM-6 and SUDHL10) at doses as little as 1µg administered every four days after tumors had reached ~200mm3. TNB-486 showed a PK profile consistent with other IgG molecules in mice (T1/2 ~6 days in mice). Conclusions TNB-486 induced comparable lysis of CD19-positive tumor cells as the strongly activating control bispecific antibodies while inducing significantly reduced cytokine secretion, even at doses saturating for tumor lysis in vitro. In vivo TNB-486 eradicated all tested CD19 positive tumor cell lines in established tumor models. No off-target binding was observed. In summary, TNB-486 shows promise as a lymphoma therapeutic differentiated from T-cell targeted therapies currently in the clinic and in clinical trials. Disclosures Malik: Teneobio, Inc.: Employment, Equity Ownership. Buelow:Teneobio, Inc.: Employment, Equity Ownership. Rangaswamy:Teneobio, Inc.: Employment, Equity Ownership. Balasubramani:Teneobio, Inc.: Employment, Equity Ownership. Boudreau:Teneobio, Inc.: Employment, Equity Ownership. Dang:Teneobio, Inc.: Employment, Equity Ownership. Davison:Teneobio, Inc.: Employment, Equity Ownership. Force Aldred:Teneobio, Inc.: Equity Ownership. Iyer:Teneobio, Inc.: Employment, Equity Ownership. Jorgensen:Teneobio, Inc.: Employment, Equity Ownership. Pham:Teneobio, Inc.: Employment, Equity Ownership. Prabhakar:Teneobio, Inc.: Employment, Equity Ownership. Schellenberger:Teneobio, Inc.: Employment, Equity Ownership. Ugamraj:Teneobio, Inc.: Employment, Equity Ownership. Trinklein:Teneobio, Inc.: Employment, Equity Ownership. Van Schooten:Teneobio, Inc.: Employment, Equity Ownership.

Mesenchymal Stromal Cells Suppress T-and B-Cells via Galectin-9 in a Donor Dependent Manner

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1248-1248
Author(s):  
Christopher Ungerer ◽  
Patricia Quade-Lyssy ◽  
Reinhard Henschler ◽  
Erhard Seifried ◽  
Heinfried Radeke ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
Immune Suppression ◽  
Immune Cells ◽  
Stromal Cells ◽  
Coagulation Factor ◽  
T And B Cells ◽  
Ifn Γ

Abstract Abstract 1248 Therapeutic approaches using multipotent mesenchymal stromal cells (MSCs) are advancing in regenerative medicine, transplantation and autoimmune diseases. Until now the way of action for MSC-mediated immune suppression is still controversial and relies most probably on a multifactorial mechanism. MSCs have been demonstrated to produce the suppressive molecules hepatocyte growth factor (HGF), tumor growth factor-β (TGF-β), prostaglandin E2 (PGE2) and indoleamine 2,3-dioxygenase (IDO). Furthermore, it has been described that immunosuppression by MSCs is enhanced via stimulation with interferon-γ (IFN-γ). Recently, galectin-1, a β-galactoside binding lectin with immune modulatory properties, has been added to the group of immune modulatory molecules that are responsible for MSC-mediated immune suppression. Here, we identified galectin-9 (Gal-9) as a new molecule involved in MSC-mediated immune modulation. First, we isolated MSCs from bone marrow of randomly selected donors and performed several in vitro experiments regarding their immune modulatory potential (e.g proliferation and IgG production). Interestingly, Gal-9 was the only investigated protein, which was strongly upregulated in MSCs upon activation with IFN-γ. We moreover demonstrate that Gal-9 is a major mediator of the anti-proliferative effect of MSCs on T-cells. Although a B-cell suppressive function of Gal-9 has previously not been reported, we were surprised to detect the same inhibitory effect on isolated B-cells. Proliferation of immune cells was triggered upon either stimulation with either PHA and LPS, or CD40L and PHA. Activation of MSCs with IFN-γ resulted in a major decrease of proliferation of both T-cells and B-cells. In addition, Gal-9 and activated MSCs contribute to the suppression of VZV triggered immunoglobulin release as well. Again activation of MSCs with IFN-γ decreased the IgG release, whereas blocking Gal-9 with lactose, a well characterized inhibitor of Gal-9 function, reversed the effect almost completely. Further, we determined that Gal-9 expression levels (mRNA and protein) distinguish between MSC cultures from different donors after activation. Among donors, we could differentiate between individuals with high Gal-9 levels and higher immune modulatory potential and such with low Gal-9 expression and lower immune modulatory potential. Compared to untreated MSCs we demonstrated a three- to fifty-fold rise in Gal-9 levels after prior activation with IFN-γ. In addition, we demonstrated the upregulation of Gal-9 in MSCs by cell-cell contacts with either T-or B-cells. The upregulation was additionally at least two fold increased by previeously activating MSCs with IFN-γ. Because our group is interested in the therapy of hemophilia A and because of the unxpected suppressive effect of Gal-9 on B-cells and B-cell function, we next tested the effect of MSCs and Gal-9 on the induction of inhibitory antibodies to coagulation factor VIII (FVIII). Mice were immunized with human coagulation factor VIII (FVIII) in the presence or absence of either human MSCs, anti-murine Gal-9 or human Gal-9. As predicted, MSCs suppressed and anti-Gal-9 antibodies anhanced antibody formation. However in contrary to the expected, human Gal-9 co-treatment enhanced the anti-FVIII antibody response. A set of additional experiments revealed, that human Gal-9 suppresses murine regulatory T-cells in vivo. Further, in contrast to human immune cells, murine-derived T- and B-cells did not respond to human recombinant Gal-9 in vitro, but human IFN-γ activated MSCs were able to suppress proliferation of murine immune cells. Because of only 60% homology of murine and human Gal-9 we assume that the murine model cannot predict the function of human Gal-9 and that MSC-mediated immune modulatory functions are exerted via alternative pathways in this setting. Experiments with murine Gal-9 to demonstrate the in vivo function of Gal-9 are ongoing. In conclusion, Gal-9 is novel mediator of MSC immunomodulatory functions and affectsmultiple immune cell types including B-cells. Gal-9 is differentially expressed in MSCs from different donors and may therefore serve as a predictive indicator for clinical MSC functionality. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Single-cell analysis of diverse immune phenotypes in malignant pleural effusion

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Zhong-Yin Huang ◽  
Ming-Ming Shao ◽  
Jian-Chu Zhang ◽  
Feng-Shuang Yi ◽  
Juan Du ◽  
...  
Keyword(s):  
Lung Cancer ◽  
T Cells ◽  
B Cells ◽  
Pleural Effusion ◽  
Small Cell Lung Cancer ◽  
Single Cell ◽  
Immune Cells ◽  
Malignant Pleural Effusion ◽  
Small Cell ◽  
Small Cell Lung

AbstractThe complex interactions among different immune cells have important functions in the development of malignant pleural effusion (MPE). Here we perform single-cell RNA sequencing on 62,382 cells from MPE patients induced by non-small cell lung cancer to describe the composition, lineage, and functional states of infiltrating immune cells in MPE. Immune cells in MPE display a number of transcriptional signatures enriched for regulatory T cells, B cells, macrophages, and dendritic cells compared to corresponding counterparts in blood. Helper T, cytotoxic T, regulatory T, and T follicular helper cells express multiple immune checkpoints or costimulatory molecules. Cell-cell interaction analysis identifies regulatory B cells with more interactions with CD4+ T cells compared to CD8+ T cells. Macrophages are transcriptionally heterogeneous and conform to M2 polarization characteristics. In addition, immune cells in MPE show the general up-regulation of glycolytic pathways associated with the hypoxic microenvironment. These findings show a detailed atlas of immune cells in human MPE and enhance the understanding of potential diagnostic and therapeutic targets in advanced non-small cell lung cancer.

The In Vivo Impact of Human Regulatory T Cells on the Graft Versus Tumor Effect.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 349-349 ◽  
Author(s):  
Tuna Mutis ◽  
Henk Rozemuller ◽  
Maarten E. Emmelot ◽  
Tineke Aarts-Riemens ◽  
Vivienne Verweij ◽  
...  
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Tumor Cells ◽  
Cell Reactivity ◽  
Human Pbmc ◽  
Ifn Γ ◽  
T Cell Reactivity ◽  
The Impact

Abstract The curative Graft-vs-Tumor effect (GvT) of allogeneic Stem cell transplantation (SCT) is frequently complicated with life threatening Graft-vs-Host Disease (GvHD). In mice, prevention of GvHD, without abrogation of GvT is possible by co-transplantation of naturally occurring regulatory T cells (Tregs) with SC grafts. Consistent with these murine studies, we recently demonstrated that also human Tregs possess potent GvHD-downregulatory capacities in a xenogeneic(x) model, where x-GvHD is induced by infusion of autologous human T cells in RAG2−/−γc−/− mice (Mutis et al. Clin. Cancer Res.2006, 12: 5520–5525). Towards clinical application of Tregs, we now explored the impact of human Treg-administration on GvT in a bioluminescence imaging (BLI) based human-GvT model in the RAG2−/−γc−/− mice. In this model, mice inoculated with luciferase (LUC)-transduced human myeloma (MM) cell lines developed BLI-detectable, progressive, MM-like multifocal tumors exclusively in the bone marrow (BM). Full blown tumors were effectively eliminated by infusion of allogeneic human PBMC. This treatment also caused lethal x-GvHD as expected. In this setting, co-infusion of human PBMC with autologous, in vitro cultured Tregs at a 1:1 Treg: T effector cell ratio had no adverse effects on the development of GvT while significantly reducing the lethality of x-GvHD. In vitro analyses of sacrificed mice at day 21 revealed that administered Tregs homed to BM and spleen, significantly downregulated the total numbers of IFN-γ-producing CD4+ and CD8+ T cells responding to CD3 mediated signals, but had no downregulatory effect on the frequencies of IFN-γ-producing T cells responding to tumor cells. There was also no downregulation of cytotoxic activity against tumor cells in Treg-treated mice. Conclusively, these results showed that Tregs, at doses which are inhibitory for x-GvHD-inducing T cells, could maintain the GvT effect by allowing T cell reactivity against tumor cells. Human Tregs thus still hold promise as attractive cellular tools for separating GvT from GvHD.

scholarly journals IRF4 is Correlated With the Conversion to a Th17-like Phenotype in Regulatory T Cells From the Malignant Pleural Effusion

2021 ◽  
Author(s):  
Wen-qing Yu ◽  
Ningfei Ji ◽  
Chengjing Gu ◽  
Juan Yao ◽  
Mingdong Ding ◽  
...  
Keyword(s):  
T Cells ◽  
Pleural Effusion ◽  
Regulatory T Cells ◽  
Protein Expression ◽  
Malignant Pleural Effusion ◽  
Mononuclear Cells ◽  
Double Positive ◽  
Relative Level ◽  
Treg Subset

Abstract Background: RORγt+Foxp3+ (Th17-like) Tregs are a plastic Treg subset implicated in immune-related diseases; however, the mechanism of Treg phenotypic transformation in malignant pleural effusion (MPE) has not been elucidated.Methods: The percentage of CD4+CD25+Foxp3+Helios+ and RORγt+Foxp3+ Tregs from peripheral blood and pleural effusion mononuclear cells were measured. The level of interferon regulatory factor 4 (IRF4) mRNA expression was detected by quantitative real-time reverse transcription polymerase chain reaction. The effects of IRF4 on the induction of Tregs from patients with non-small cell lung cancer (NSCLC) were evaluated in vitro. Correlation assays between IRF4 expression and the frequency of RORγt+Foxp3+ Tregs were performed. Results: The frequency of CD4+CD25+Foxp3+Helios+ Tregs and CD4+RORγt+ Th17 cells were both increased in the MPE of NSCLC patients. The group of double-positive Foxp3+RORγt+ Treg phenotype were identified in the pleural effusion. A significant increase in the frequency of Foxp3+RORγt+ Tregs was found in MPE compared with the non-malignant pleural effusion (NPE). Compared to NPE, the relative level of IRF4 expression was increased in the MPE. IRF4 expression was positively associated with the frequency of Foxp3+RORγt+ Tregs in the PE. In vitro, the level of Helios mRNA and protein expression was reduced in induced Tregs following IRF4 over-expression. Additionally, the level of RORγt protein expression was substantially increased. However, ectopic Helios expression in induced Tregs reversed the effects induced by enhanced IRF4 expression.Conclusion: IRF4 may serve as a potential molecule that promotes the conversion of regulatory T cells from MPE to a Th17-like phenotype by modulating Helios.

scholarly journals 153 Nanoscale, antigen-dependent, IL-12 delivery by CAR T cells plus PD-L1 blockade for cancer treatment

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A162-A163
Author(s):  
Zhifen Yang ◽  
Francesco Marincola
Keyword(s):  
T Cells ◽  
Tumor Growth ◽  
Tumor Cells ◽  
Car T Cells ◽  
Car T ◽  
Ifn Γ ◽  
High Doses ◽  
Fadu Cells

BackgroundInterleukin(IL)-12 activates T cells pivoting the switch that turns lingering inflammation into acute inflammation and cancer rejection. However, its clinical utilization is limited by severe systemic toxicity. IL-12 is a potent inducer of PD-1 expression in T cells. Here, we present a conditional, antigen-dependent, non-editing CRISPR-activation (CRISPRa) circuit (RB-312) that delivers nanoscale doses of IL-12 for autocrine activation of CAR-T cells. RB-312 was also tested in combination with PD-L1 blocking antibody (atezolizumab).MethodsRB-312 is a CAR T cell engineered to express the IL-12 heterodimer via conditional transcription of its two endogenous subunits p35 and p40. The circuit includes two lentiviral constructs with one encoding HER2-specific chimeric antigen receptor and two sgRNAs targeting IL-12A or IL-12B and the other encoding linker for activation of T cells, complexed to dead Cas9 (dCas9)-VP64-p65-Rta transcriptional activator (VPR) (LdCV). Activation of CAR allows the release of dCas9 for nuclear localization and hence conditionally and reversibly induces the secretion of IL-12 p70 heterodimer.ResultsRB-312 induced low concentrations of IL-12 upon exposure to HER2+ FaDu cancer cells engineered to overexpress PD-L1 and this resulted in significantly enhanced production of IFN-γ, cytotoxicity and CAR-T proliferation (figure 1A). These effects were comparable to co-culturing conventional HER2 CAR with FaDu cells modified to express high doses of IL-12 (figure 1B). In vivo administration of RB-312 significantly enhanced survival of mice carrying FaDu xenografts compared to mice treated with the respective conventional HER2 CAR or cRB-312 (control lacking the IL-12 sgRNAs, figure 2A). RB-312 induced a strong upregulation of PD-1 in CAR-T cells in vivo (figure 2B). The critical role of the PD-1/PD-L1 interaction was demonstrated in vitro by comparing RB-312 proliferation when exposed to FaDu overexpressing PD-L1 or PD-L1 knock out cells (figure 3A). Indeed, combined treatment of RB-312 and atezolizumab resulted in significant reduction in tumor growth (figure 3B and C) and significantly enhanced survival (figure 3D).Abstract 153 Figure 1Conditional autocrine release of nanoscale-dose p70/IL-12 by RB-312 resulting in enhanced IFN-γ production in vitro after three days of exposure to HER2+ FaDu cells (figure 1A), and the level of IFN-γ production was comparable to co-culturing conventional HER2-specific CAR-T cells with a modified FaDu cell line engineered to constitutively express high doses of IL-12 (FaDu/IL-12, figure 1B)Abstract 153 Figure 2Intra-tumoral administration of RB-312 extended survival in mice carrying FaDu xenografts compared to NT (non-transduced T cells), HER2 CAR (conventional HER2 CAR-T cells) and cRB-312 CAR-T cells missing the sgRNAs for the two IL-12 subunits (figure 2A). Analysis of necropsy material demonstrated that PD-1 expression was dramatically increased in RB-312 compared with the respective control cRB-312 (figure 2B)Abstract 153 Figure 3RB-312 cellular function in vivo. PD-L1 expression by FaDu cell lines is a critical mechanism of repression of RB-312 function. In vitro CAR-T proliferation of RB-312 upon stimulation with FaDu tumor cells (orange solid lines) or FaDu/PD-L1 knockout tumor cells (orange dashed lines) over 6-day time course (figure 3A). In vivo efficacy of intra-tumoral RB-312 against FaDu tumor cells with (orange solid lines) or without (orange dashed lines) addition of PD-L1 blocking antibody atezolizumab (administered intravenously at 5 mg/kg twice per week), as shown by tumor growth followed till day 29 and scatter plot at day 29 (figure 3B), tumor growth spider plots (figure 3C) and Kaplan-Meier survival curve (figure 3D)ConclusionsWe concluded that addition of a Th1 polarizing component such as IL-12 exponentially increases the efficacy of reprogrammed CAR-T cells by combining enhancement of effector functions to cellular fitness. The autocrine effects of nanoscale IL-12 production limit the risk of off-tumor leakage and systemic toxicity. Here, we tested the combination of PD-1/PD-L1 blockade with IL-12-induced CAR-T cell activation demonstrated dramatic synergistic effects. We are currently evaluating the intrinsic combination of IL-12 delivery and PD-L1 resistance for the next generation of RB-312 product eliminating the need for systemic checkpoint blockade.

scholarly journals Characterization of the Therapeutic Effects of Novel Chimeric Antigen Receptor T Cells Targeting CD38 on Multiple Myeloma

2021 ◽  
Vol 11 ◽  
Author(s):  
Xiaorui Li ◽  
Yaru Feng ◽  
Fengqin Shang ◽  
Zhuoying Yu ◽  
Tieshan Wang ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
T Cells ◽  
Tumor Cells ◽  
Chimeric Antigen Receptor ◽  
Second Generation ◽  
Antigen Receptor ◽  
Car T Cells ◽  
Car T ◽  
Ifn Γ

Multiple myeloma (MM) is a tumor type characterized by the unregulated proliferation of clonal plasma cells in the bone marrow. Immunotherapy based on chimeric antigen receptor T cell (CAR-T) therapy has achieved exciting success in the treatment of hematological malignant tumors. CD38 is highly and evenly expressed in MM and is an attractive target for MM treatment. Here, we successfully constructed two novel second-generation CAR-T cells targeting CD38 by retroviral vector transduction. CD38 CAR-T cells could be activated effectively after stimulation with CD38-positive tumor cells and secrete cytokines such as IFN-γ and TNF-α to promote tumor cell apoptosis in in vitro experiments. Real-time fluorescence monitoring experiments, luciferase detection experiments and flow cytometry experiments revealed the efficient and specific killing abilities of CD38 CAR-T cells against CD38-positive tumor cells. The proliferation ability of CD38 CAR-T cells in vitro was higher than that of untransduced T cells. Further antitumor experiments in vivo showed that CD38 CAR-T cells could be quickly activated to secrete IFN-γ and eliminate tumors. Thus, novel CD38-targeted second-generation CAR-T cells have efficient and specific antitumor activity and may become a novel therapy for the clinical treatment of MM.

Immunomonitoring results of a pivotal phase II/III study with the trifunctional antibody catumaxomab (anti-EpCAM x anti-CD3) in ovarian cancer patients with malignant ascites

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 3020-3020
Author(s):  
M. J. Jaeger ◽  
A. M. Schoberth ◽  
M. M. Heiss ◽  
A. Lahr ◽  
H. Lindhofer
Keyword(s):  
Ovarian Cancer ◽  
T Cells ◽  
Tumor Cells ◽  
Cd8 T Cells ◽  
Malignant Ascites ◽  
Accessory Cells ◽  
Target Ratio ◽  
Effector Target

3020 Background: Malignant ascites is a symptom of late-stage tumor disease and associated with a poor prognosis. The trifunctional antibody catumaxomab specifically binds to EpCAM+ tumor cells and redirects CD3+ T lymphocytes and FcγR I/III+ accessory cells simultaneously to the tumor site. Methods: 129 (85 catumaxomab; 44 control paracentesis) EpCAM-positive ovarian cancer patients with symptomatic malignant ascites were compared in an open-label, multicenter, randomized study for efficacy and tolerability of intraperitoneally given catumaxomab. Various in vivo and in vitro immunological and pharmacodynamic parameters were measured directly from ascites cell preparations. Results: During the course of catumaxomab treatment in the ascites fluid tumor cells dramatically decreased and leukocytes increased. Accordingly, the in vivo effector/target ratio (CD45+/EpCAM+) showed an drastic increase from a baseline of 6:1 to 10,000:1 already after the first infusion (all median). Leukocyte expansion was accompanied by in vivo upregulation of T cell activation marker CD69 on CD4+ and CD8+ T cells in the ascites fluid and an increase of IL-6 in serum at 24 hours after each infusion indicating systemic effects of catumaxomab. In vitro pharmacodynamic studies were carried out with screening samples to further validate the in vivo results. Similarly, the in vitro experiments showed efficient EpCAM+ tumor cell elimination, leukocyte expansion, drastical improvement of the effector/target ratio and activation of T cells. Additionally, a strong upregulation of activating cytokines IL-2 and IFN-γ (TH1 cytokine profile) and proliferation of CD4+, CD8+ T cells and CD11c+ accessory cells were demonstrated in the samples with catumaxomab compared to controls. Conclusions: Intraperitoneal catumaxomab treatment triggers activation and proliferation of different immune cells and leads to elimination of tumor cells within malignant ascites. These data confirm the postulated mode of action of trifunctional catumaxomab in vivo and correlate with clinical efficacy in patients with malignant ascites. [Table: see text]

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