scholarly journals 697 Tumor-targeted CD28 costimulatory bispecific antibodies enhance T cell activation in solid tumors

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A739-A739
Author(s):  
Michael Hedvat ◽  
Veronica Zeng ◽  
Juan Diaz ◽  
Christine Bonzon ◽  
Kendra Avery ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Solid Tumors ◽  
Cancer Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Bispecific Antibodies ◽  
Anti Tumor Activity

BackgroundT cells in the tumor micro-environment require TCR/MHC engagement and co-stimulatory receptor engagement to achieve complete activation. Solid tumors often lack expression of CD28 ligands, so we hypothesized that activation of CD28 signaling could be beneficial in solid tumors. We designed tumor-associated-antigen (TAA) x CD28 bispecific antibodies that conditionally costimulate CD28 only in the presence of TAA and TCR engagement. Clinical application of this class of antibodies has potential to enhance activity of either anti-PD(L)1 antibodies or TAA x CD3 T cell engagers.MethodsWe designed a stability and affinity optimized anti-CD28 antibody that can be paired with TAA of choice to engage CD28 monovalently using Xencor’s XmAb 2+1 and 1+1 platforms. In vitro T cell activation with these bispecifics was measured by T cell proliferation, cytokine production, and cytotoxicity, in co-cultures of human cancer cell lines mixed with primary human CD3-stimulated T cells. In vitro activity was validated in a CMV recall assay measuring CMV+ T cell proliferation of CMV+ PBMC co-cultured with cancer cell lines ectopically treated with pp65-derived NLV-peptide. In vivo anti-tumor and T cell proliferative activity of B7H3 x CD28 bispecific antibodies were determined in tumor-bearing huPBMC-NSG mice treated simultaneously with TAA x CD3 bispecific antibody. In vivo activity of PDL1 x CD28 antibodies was determined with hCD28 KI mice inoculated with MC38 tumors expressing hPDL1-antigen. Finally, safety and tolerability of B7H3 x CD28 and PDL1 x CD28 was determined in cynomolgus monkeys.ResultsB7H3 x CD28 and PDL1 x CD28 antibodies enhanced T cell degranulation, cytokine secretion, and cancer cell cytotoxicity in concert with CD3 stimulation only in the presence of target antigen. B7H3 x CD28, alone or in combination with anti-PD1 antibody, enhanced proliferation of CMV+ T cells recognizing cancer cells loaded with pp65-derived NLV peptide. PDL1 x CD28 also enhanced CMV+ cell expansion but did not synergize with anti-PD1 antibody treatment. B7H3 x CD28 significantly enhanced in vivo anti-tumor activity of TAA x CD3 antibodies while also promoting greater T cell expansion. In hCD28 mice inoculated with MC38 tumors expressing hPDL1, PDL1 x CD28 antibody inhibited tumor growth greater than an anti-PDL1 antibody alone. B7H3 x CD28 and PDL1 x CD28 were well tolerated in cynomolgus monkeys.ConclusionsB7H3 x CD28 and PDL1 x CD28 bispecific antibodies show promising anti-tumor activity and warrant further development.

scholarly journals 872 PD1 x TGFbR2 and CD5 x TGFbR2 bispecifics selectively block TGFbR2 on target-positive T cells, promote T cell activation, and elicit an anti-tumor response in solid tumors

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A913-A913
Author(s):  
Gregory Moore ◽  
Suzanne Schubbert ◽  
Christine Bonzon ◽  
Kendra Avery ◽  
Rumana Rashid ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Solid Tumors ◽  
T Cell Activation ◽  
Tumor Response ◽  
Bispecific Antibodies ◽  
Nsg Mice ◽  
Anti Tumor Activity

BackgroundTGFbeta production by solid tumors and their microenvironment is a major mechanism used by tumors to avoid immunosurveillance. Blockade of TGFbeta has been shown to promote an anti-tumor response; however, systemic blockade of TGFbeta has also been associated with toxicity. We hypothesized that a T cell-targeted TGFbR2 bispecific antibody could selectively block the suppressive activity of TGFbeta on T cells and enhance their anti-tumor activity while avoiding toxicity associated with systemic blockade.MethodsWe engineered bispecific antibodies that simultaneously engage PD1 (activated) or CD5 (pan T) and block TGFbR2 using Xencor’s XmAb® platform. The anti-TGFbR2 arm was tuned for optimal activity by introducing affinity-modulating amino acid substitutions. The activity of TGFbR2 bispecifics was evaluated in vitro using a signaling assay to measure phosphorylated SMAD (pSMAD) by flow cytometry with exogenous TGFbeta in unactivated and activated PBMC. In vivo activity was evaluated by monitoring the engraftment of human PBMC in NSG mice (huPBMC-NSG). Anti-tumor activity was assessed in huPBMC-NSG mice engrafted with established human cancer cell lines.ResultsTGFbR2 bispecifics were confirmed to bind PD1 or CD5 and block binding of TGFbeta to TGFbR2. In vitro, we found that T cells from serum-deprived PBMC exhibited robust induction of pSMAD in response to TGFbeta, and TGFbR2 bispecifics selectively inhibited pSMAD induction in target-positive T cells as demonstrated by over a 100-fold potency increase compared to an untargeted anti-TGFbR2 control. Additionally, we saw an enhancement of potency when evaluating activity in target-high T cells versus target-low or -negative immune cells. Intriguingly, CD5-targeted TGFbR2 bispecifics allowed for the targeting of a broader population of T cells compared to PD1-targeting while still conferring potent selectivity against target-negative cells. In vivo, treatment of huPBMC-NSG mice with TGFbR2 bispecifics promoted superior T cell engraftment. Furthermore, TGFbR2 bispecific treatment of huPBMC-NSG mice containing established MDA-MB-231 triple-negative breast cancer tumors promoted an anti-tumor response that was augmented with PD1 blockade.ConclusionsPD1 x TGFbR2 and CD5 x TGFbR2 bispecific antibodies were engineered to selectively block TGFbR2 on target-positive T cells and evaluated in vitro and in vivo. These observations are compelling and suggest that development of these bispecifics is warranted for the treatment of human malignancies.

scholarly journals 714 PD1 x TGFβR2 bispecifics selectively block TGFβR2 on PD1-positive T cells, promote T cell activation, and elicit an anti-tumor response in solid tumors

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A756-A756
Author(s):  
Gregory Moore ◽  
Suzanne Schubbert ◽  
Christine Bonzon ◽  
Kendra Avery ◽  
Rumana Rashid ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Solid Tumors ◽  
T Cell Activation ◽  
Tumor Response ◽  
Nsg Mice ◽  
Pd1 Blockade ◽  
Anti Tumor Activity

BackgroundTGFβ production by solid tumors and their microenvironment is a major mechanism used by tumors to avoid immunosurveillance. Blockade of TGFβ has been shown to promote an anti-tumor response; however, systemic blockade of TGFβ has also been associated with toxicity. We hypothesized that a PD1 x TGFβR2 bispecific antibody could selectively block the suppressive activity of TGFβ on tumor T cells and enhance their anti-tumor activity while avoiding the toxicity associated with systemic blockade.MethodsWe engineered bispecific antibodies that simultaneously engage PD1 and TGFβR2 using Xencor’s XmAb platform. The anti-TGFβR2 arm was tuned for optimal activity by introducing affinity-modulating amino acid substitutions. The activity of PD1 x TGFβR2 bispecifics was evaluated in vitro using a signaling assay to measure phosphorylated SMAD (pSMAD) by flow cytometry with exogenous TGFβ in unactivated and activated PBMC. In vivo activity was evaluated by monitoring the engraftment of human PBMC in NSG mice (huPBMC-NSG). Anti-tumor activity was assessed in huPBMC-NSG mice engrafted with established human cancer cell lines. Antibodies against other T cell targets were also incorporated into TGFβR2 bispecifics, and similarly evaluated in vitro and in vivo.ResultsPD1 x TGFβR2 bispecifics were confirmed to bind PD1 and block binding of TGFβ to TGFβR2. In vitro, we found that T cells from activated, serum-deprived PBMC exhibited robust induction of pSMAD in response to TGFβ, and PD1 x TGFβR2 bispecifics selectively inhibited pSMAD induction in PD1-positive T cells as demonstrated by over a 100-fold potency increase compared to an untargeted anti-TGFβR2 control. Additionally, we saw an enhancement of potency when evaluating blocking activity in activated (PD1-high) vs. unactivated (PD1-low) T cells. Similar selectivity was measured when comparing inhibition of pSMAD induction for activated T cells versus other PD1-negative, TGFβ-responsive immune cells. Intriguingly, TGFβR2 bispecifics incorporating antibodies against other T cell targets allowed for the targeting of a broader population of T cells while still conferring potent selectivity against target-negative cells. In vivo, treatment of huPBMC-NSG mice with TGFβR2 bispecifics promoted superior T cell engraftment and combined additively with PD1 blockade. Furthermore, TGFβR2 bispecific treatment of huPBMC-NSG mice containing established MDA-MB-231 triple-negative breast cancer tumors promoted an anti-tumor response that was also augmented with PD1 blockade.ConclusionsMultiple PD1 x TGFβR2 bispecifics were engineered to selectively block TGFβR2 on PD1-positive T cells and evaluated in vitro and in vivo. Compelling activity, including additivity with PD1 blockade, suggests that clinical development is warranted for the treatment of human malignancies.

The immunological impact of the RAF inhibitor BMS908662: Preclinical and early clinical experience in combination with CTLA-4 blockade.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. 2521-2521 ◽  
Author(s):  
Margaret Callahan ◽  
Gregg Masters ◽  
Jessica Katz ◽  
Valerie Russell ◽  
Ruth Ann Roman ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Combination Therapy ◽  
T Cell Activation ◽  
Cell Activation ◽  
Mapk Pathway ◽  
Preclinical Studies ◽  
Anti Tumor Activity

2521 Background: Two new approaches to treat advanced melanoma have transformed the standard of care: the CTLA-4 blocking antibody, ipilimumab, and the targeted inhibitor of mutated BRAF, vemurafenib. These agents are mechanistically unique and combination therapy is a promising next step. We evaluated the combination of BMS908662 (662), a pan RAF inhibitor, with CTLA-4 blockade in preclinical studies and report first-in-human clinical experience with this combination. Methods: 1) We tested the impact of 662 on T cells in vitro, using cultured human T cells, and in vivo, using OT-1 transgenic mice. T cell activation and MAPK pathway signaling were assessed in parallel. 2) Preclinical studies measuring the anti-tumor activity of combination therapy were performed in CT-26 and SA1N tumor models. 3) Three pts with BRAF mutant stage IV melanoma were treated at MSKCC on CA206005, an IRB-approved protocol, receiving ipilimumab (3 mg/kg) and 662 (25 mg bid) (NCT01245556). Two pts consented to an IRB-approved protocol permitting immune monitoring. Results: 1) In vitro studies demonstrate that 662 can potentiate T cell activation after stimulation. This corresponds with increased MAPK pathway signaling, consistent with paradoxical activation of the MAPK pathway in wild type cells, a class effect of RAF inhibitors. In vivo, enhanced expansion of OT-1 cells after ovalbumin challenge was seen in mice treated with 662. T cell expansion was greatest in mice treated with a combination of CTLA-4 blockade and 662 (p<0.05). 2) Both preclinical models demonstrate superior anti-tumor activity with combination therapy compared to monotherapy (p<0.05). 3) All pts treated on protocol CA206005 tolerated combination therapy. New keratoacanthomas and SCCs, likely related to 662, were identified. One pt has an ongoing response at 10 mos (-85%), one had stable disease for 24 wks (-19%) and a third had disease progression. Enhanced MAPK signaling in PBMCs after treatment with 662 was detected ex vivo. Conclusions: RAF inhibitors may potentiate T cell activation in vitro and in vivo, offering one explanation for the enhanced anti-tumor activity seen in combination with CTLA-4 blockade in pre-clinical models.

scholarly journals A Novel T Cell-Engaging Bispecific Antibody for Treating Mesothelin-Positive Solid Tumors

Biomolecules ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 399
Author(s):  
Aerin Yoon ◽  
Shinai Lee ◽  
Sua Lee ◽  
Sojung Lim ◽  
Yong-Yea Park ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Solid Tumors ◽  
T Cell Activation ◽  
Target Cell ◽  
Cell Activation ◽  
Cell Killing ◽  
Bispecific Antibodies ◽  
Target Cells

As mesothelin is overexpressed in various types of cancer, it is an attractive target for therapeutic antibodies. T-cell bispecific antibodies bind to target cells and engage T cells via binding to CD3, resulting in target cell killing by T-cell activation. However, the affinity of the CD3-binding arm may influence CD3-mediated plasma clearance or antibody trapping in T-cell-containing tissues. This may then affect the biodistribution of bispecific antibodies. In this study, we used scFab and knob-into-hole technologies to construct novel IgG-based 1 + 1 MG1122-A and 2 + 1 MG1122-B bispecific antibodies against mesothelin and CD3ε. MG1122-B was designed to be bivalent to mesothelin and monovalent to CD3ε, using a 2 + 1 head-to-tail format. Activities of the two antibodies were evaluated in mesothelin-positive tumor cells in vitro and xenograft models in vivo. Although both antibodies exhibited target cell killing efficacy and produced regression of xenograft tumors with CD8+ T-cell infiltration, the antitumor efficacy of MG1122-B was significantly higher. MG1122-B may improve tumor targeting because of its bivalency for tumor antigen. It may also reduce systemic toxicity by limiting the activation of circulating T cells. Thus, MG1122-B may be useful for treating mesothelin-positive solid tumors.

scholarly journals 265 CD47xPD-L1 bispecific antibodies for cancer therapy

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A287-A287
Author(s):  
Xavier Chauchet ◽  
Elise Pernarrieta ◽  
Nicolas Bosson ◽  
Sébastien Calloud ◽  
Louis Hellequin ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Xenograft Model ◽  
Bispecific Antibodies ◽  
List Type ◽  
Binding Assays ◽  
Anti Tumor Activity

BackgroundPD-1/PD-L1 blockade can significantly improve survival across many types of cancer, but only in a minority of patients. To broaden its therapeutic efficacy, several combination partners are now being evaluated together with PD-1/PD-L1 blockade. Agents blocking CD47/SIRPα innate immune checkpoint are one such example, and co-targeting PD-1/PD-L1 and CD47 with monoclonal antibody (mAb) combinations showed increased antitumor responses in preclinical studies. However, CD47 mAbs are hindered by ubiquitous CD47 expression leading to rapid target-mediated clearance and safety concerns. Consequently, dual-targeting CD47xPD-L1 bispecific antibodies (bsAbs) enabling preferential inhibition of CD47 on PD-L1-positive cells are being tested as an alternative approach. We compare here two distinct bsAbs, based on a common PD-L1 antibody arm, with differing FcgR-enabling effector functions and CD47-binding arm affinities.MethodsAn array of fully human bsAbs associating a high affinity PD-L1 arm to CD47 arms with varying affinities were generated using the κλ-body platform.1 CD47xPD-L1 bsAbs of human IgG1 isotype (CD47 low affinities) or IgG4 isotype (CD47 high affinities) were screened in various binding assays (including to red blood cells (RBC)) and in receptor-blocking assays, and then tested for their Fc-mediated killing and T-cell activation activity (SEA-stimulated PBMC assay). Selected molecules were evaluated in vivo.ResultsBoth bsAb approaches demonstrated strong blockade of PD-1/PD-L1 interaction and significantly enhanced T-cell activation in vitro. CD47lowxPD-L1 IgG1 bsAbs did not bind to RBC and showed PD-L1-guided inhibition of CD47. ADCP and ADCC experiments with a panel of tumor cell lines expressing various target levels showed superior killing activity with CD47lowxPD-L1 IgG1 bsAbs as compared to the anti-PD-L1 IgG1 mAb, avelumab. On the other hand, CD47highxPD-L1 IgG4 bsAbs showed residual RBC binding and PD-L1-independent blocking of CD47/SIRPα. These CD47high IgG4 bsAbs were able to enhance the anti-tumor activity of anti-tumor-associated antigen (TAA) mAbs in vitro (phagocytosis), and in vivo (Raji lymphoma xenograft model). In addition, anti-tumor activity of mouse CD47xPD-L1 bsAbs in a syngeneic MC38 colon carcinoma model was demonstrated.ConclusionsWith the objective of finding the optimal CD47xPD-L1 bsAb design, two approaches targeting CD47 and PD-L1 inhibition were tested. Both the CD47lowxPD-L1 IgG1 bsAbs and CD47highxPD-L1 IgG4 bsAbs were able to mediate enhanced antitumor responses, the former as a standalone treatment, the latter in conjunction with an anti-TAA mAb. To further characterize the CD47lowxPD-L1 and CD47highxPD-L1 bsAbs, lead candidates will be tested in PK and tolerability studies in non-human primates.ReferencesFischer N, Elson G, Magistrelli G, Dheilly E, Fouque N, Laurendon A, et al. Exploiting light chains for the scalable generation and platform purification of native human bispecific IgG. Nat Commun 2015 May;6(1):6113.

scholarly journals 704 Preclinical mechanism of action and pharmacodynamic biomarker studies of DuoBody®-CD3x5T4 in vitro and in vivo in solid cancer models

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A746-A746
Author(s):  
Kristel Kemper ◽  
Ellis Gielen ◽  
Mischa Houtkamp ◽  
Peter Boross ◽  
Saskia Burm ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Cells ◽  
T Cell Activation ◽  
Cell Activation ◽  
T Cell Subsets ◽  
Animal Protection ◽  
Anti Tumor Activity

BackgroundThe tumor-associated antigen 5T4 is expressed across a wide range of solid cancers. DuoBody-CD3x5T4 is a bispecific antibody (bsAb) that crosslinks CD3 on T cells with 5T4 on tumor cells, thereby inducing T-cell activation and T-cell mediated cytotoxicity in 5T4-expressing tumor cells. Here, we tested the capacity of DuoBody-CD3x5T4 to engage different T-cell subsets in vitro and investigated the mechanism of action (MoA) in vivo by combining preclinical efficacy studies with exploratory pharmacodynamic (PD) biomarker analysesMethodsImmunohistochemistry was performed on patient-derived tumor tissue-microarrays using a commercial 5T4 monoclonal antibody (EPR5529). The capacity of DuoBody-CD3x5T4 to engage naïve and memory T-cell subsets was assessed in co-cultures of T cells and 5T4-positive tumor cells, using T-cell activation and T-cell mediated cytotoxicity as readouts. Anti-tumor activity in vivo as well as peripheral and intratumoral PD biomarkers were investigated in humanized mice bearing 5T4-expressing cell line-derived xenograft (CDX) or patient-derived xenograft (PDX) tumor models.ResultsHigh prevalence of 5T4 expression (in >86% of biopsies) was observed in NSCLC, SCCHN, TNBC, bladder, esophageal, prostate and uterine cancer. In co-cultures of 5T4+ tumor cells and T cells in vitro, DuoBody-CD3x5T4 induced dose-dependent cytotoxicity, associated with T-cell activation, proliferation, and cytokine, perforin and granzyme production. Crosslinking of T cells with 5T4-expressing tumor cells was essential as no cytotoxicity was observed in CRISPR-Cas9-generated 5T4-knockout tumor cells or with control bsAbs targeting only CD3 or 5T4. Importantly, naïve and memory CD4+ or CD8+ T-cell subsets had equal capacity to mediate DuoBody-CD3x5T4-induced cytotoxicity, although naïve T-cell subsets showed slower kinetics. DuoBody-CD3x5T4 (0.5–20 mg/kg) demonstrated anti-tumor activity in 5T4+ breast and prostate cancer CDX and lung cancer PDX models in humanized mice. Treatment with DuoBody-CD3x5T4 was associated with intratumoral and peripheral T-cell activation as well as elevated cytokine levels, including IFNγ, IL-6 and IL-8, in peripheral blood.ConclusionsDuoBody-CD3x5T4 induced T-cell mediated cytotoxicity in 5T4-expressing tumor cells, associated with T-cell activation and cytokine production in vitro. DuoBody-CD3x5T4 efficiently engaged naïve and memory T cells within both CD4+ and CD8+ T-cell populations to induce T-cell mediated cytotoxicity in 5T4+ tumor cells. In humanized CDX and PDX mouse models, DuoBody-CD3x5T4 showed anti-tumor activity, in addition to PD biomarkers associated with T-cell activation in the tumor and periphery. Currently, DuoBody-CD3x5T4 is being investigated in a first-in-human clinical trial for the treatment of solid tumors (NCT04424641), in which exploratory biomarker analyses to study the clinical MoA and PD are included.Ethics ApprovalThe CDX animal experiments performed are in compliance with the Dutch animal protection law (WoD) translated from the directives (2010/63/EU) and are approved by the Ethical committee of Utrecht. For the PDX models, all patients had given written informed consent, and the animal experiments were carried out in accordance with the German Animal Protection Law (LaGeSoBerlin, A0452/08). The studies were approved by the local Institutional Review Board of Charite University Medicine, Germany.

scholarly journals TRPM2 Is Not Required for T-Cell Activation and Differentiation

2022 ◽  
Vol 12 ◽  
Author(s):  
Niels C. Lory ◽  
Mikolaj Nawrocki ◽  
Martina Corazza ◽  
Joanna Schmid ◽  
Valéa Schumacher ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Transient Receptor Potential ◽  
Cell Function ◽  
Intestinal Inflammation ◽  
Activation Markers

Antigen recognition by the T-cell receptor induces a cytosolic Ca2+ signal that is crucial for T-cell function. The Ca2+ channel TRPM2 (transient receptor potential cation channel subfamily M member 2) has been shown to facilitate influx of extracellular Ca2+ through the plasma membrane of T cells. Therefore, it was suggested that TRPM2 is involved in T-cell activation and differentiation. However, these results are largely derived from in vitro studies using T-cell lines and non-physiologic means of TRPM2 activation. Thus, the relevance of TRPM2-mediated Ca2+ signaling in T cells remains unclear. Here, we use TRPM2-deficient mice to investigate the function of TRPM2 in T-cell activation and differentiation. In response to TCR stimulation in vitro, Trpm2-/- and WT CD4+ and CD8+ T cells similarly upregulated the early activation markers NUR77, IRF4, and CD69. We also observed regular proliferation of Trpm2-/- CD8+ T cells and unimpaired differentiation of CD4+ T cells into Th1, Th17, and Treg cells under specific polarizing conditions. In vivo, Trpm2-/- and WT CD8+ T cells showed equal specific responses to Listeria monocytogenes after infection of WT and Trpm2-/- mice and after transfer of WT and Trpm2-/- CD8+ T cells into infected recipients. CD4+ T-cell responses were investigated in the model of anti-CD3 mAb-induced intestinal inflammation, which allows analysis of Th1, Th17, Treg, and Tr1-cell differentiation. Here again, we detected similar responses of WT and Trpm2-/- CD4+ T cells. In conclusion, our results argue against a major function of TRPM2 in T-cell activation and differentiation.

scholarly journals 702 TJ-CD4B (ABL111), a Claudin18.2-targeted 4-1BB tumor engager induces potent tumor-dependent immune response without dose-limiting toxicity in preclinical studies

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A730-A730
Author(s):  
Wenqing Jiang ◽  
Zhengyi Wang ◽  
Zhen Sheng ◽  
Jaeho Jung ◽  
Taylor Guo
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Gene Expression Analysis ◽  
Cell Activation ◽  
Clinical Development ◽  
Cynomolgus Monkeys ◽  
Anti Tumor Activity

Background4-1BB (CD137) is a co-stimulatory receptor that stimulates the function of multiple immune cells. Its ability to induce potent anti-tumor activity makes 4-1BB an attractive target for immuno-oncology. However, clinical development of a monospecific 4-1BB agonistic antibody has been hampered by dose-limiting hepatic toxicities. To minimize systemic toxicities, we have developed a novel Claudin18.2 (CLDN18.2) x 4-1BB bispecific antibody, TJ-CD4B (ABL111) that stimulates 4-1BB pathway only when it engages with Claudin 18.2, a tumor-associated antigen specifically expressed in gastrointestinal cancers. TJ-CD4B (ABL111) is now being evaluated in patients with advanced solid tumors in a first-in-human trial (NCT04900818).MethodsTJ-CD4B (ABL111) was evaluated in vivo using the human 4-1BB knock-in mice bearing CLDN18.2 expressing MC38 tumor cells. Pharmacodynamic effects upon treatment were characterized in tumor tissue and blood. Immunophenotyping of the tumor microenvironment (TME) and peripheral blood was performed by flow cytometry. Soluble biomarkers were measured using Luminex-based multiplex assay. In-depth gene expression analysis was performed on primary human CD8+ T cells that were co-cultured with CLDN18.2 expressing cells in the presence of anti-CD3 using NanoString nCounter®. Pharmacokinetic (PK) and toxicity study were performed in cynomolgus monkeys.ResultsTJ-CD4B (ABL111) elicited complete tumor regression in 13 out of 18 MC38 tumor bearing mice given at a dose above 2 mg/kg. Dose-dependent anti-tumor activity was associated with enhanced T cell activation in TME and expansion of memory T cells in the peripheral blood. Increased CD8+ T cells number and proliferation were observed in both tumor nest and surrounding stroma while the level of soluble 4-1BB in the serum was also elevated in response to the treatment. In vitro gene expression analysis by Nanostring revealed TJ-CD4B(ABL111) effectively activated immune pathways characterized by IFN?-signaling and T cell inflammation. Preclinically, TJ-CD4B was well tolerated at the repeated doses up to 100 mg/kg/wk in cynomolgus monkeys without the adverse influence on the liver function which is generally affected by 4-1BB activation. Besides, no cytokine release or immune activation was observed in the periphery.ConclusionsTJ-CD4B (ABL111) is a novel CLDN18.2 dependent 4-1BB bispecific agonist antibody that induced T cell activation and memory response in tumor with CLDN18.2 expression, leading to a strong anti-tumor activity in vivo. TJ-CD4B did not induce systemic immune response nor hepatic toxicity due to the CLDN18.2 dependent 4-1BB stimulation. These data warrant the current clinical development in phase I trial to validate the safety properties and tumor specific responses.

scholarly journals Modulating p56Lck in T-Cells by a Chimeric Peptide Comprising Two Functionally Different Motifs of Tip fromHerpesvirus saimiri

2015 ◽  
Vol 2015 ◽  
pp. 1-12
Author(s):  
Jean-Paul Vernot ◽  
Ana María Perdomo-Arciniegas ◽  
Luis Alberto Pérez-Quintero ◽  
Diego Fernando Martínez
Keyword(s):  
T Cells ◽  
T Cell ◽  
Lipid Rafts ◽  
T Cell Activation ◽  
Cell Activation ◽  
Jurkat Cells ◽  
Chimeric Peptide ◽  
Vector Targeting

The Lck interacting protein Tip ofHerpesvirus saimiriis responsible for T-cell transformation bothin vitroandin vivo. Here we designed the chimeric peptide hTip-CSKH, comprising the Lck specific interacting motif CSKH of Tip and its hydrophobic transmembrane sequence (hTip), the latter as a vector targeting lipid rafts. We found that hTip-CSKH can induce a fivefold increase in proliferation of human andAotussp. T-cells. Costimulation with PMA did not enhance this proliferation rate, suggesting that hTip-CSKH is sufficient and independent of further PKC stimulation. We also found that human Lck phosphorylation was increased earlier after stimulation when T-cells were incubated previously with hTip-CSKH, supporting a strong signalling and proliferative effect of the chimeric peptide. Additionally, Lck downstream signalling was evident with hTip-CSKH but not with control peptides. Importantly, hTip-CSKH could be identified in heavy lipid rafts membrane fractions, a compartment where important T-cell signalling molecules (LAT, Ras, and Lck) are present during T-cell activation. Interestingly, hTip-CSKH was inhibitory to Jurkat cells, in total agreement with the different signalling pathways and activation requirements of this leukemic cell line. These results provide the basis for the development of new compounds capable of modulating therapeutic targets present in lipid rafts.

T cell-T cell activation in multiple sclerosis

1997 ◽  
Vol 3 (4) ◽  
pp. 238-242 ◽  
Author(s):  
JW Lindsey ◽  
RH Kerman ◽  
JS Wolinsky
Keyword(s):  
Multiple Sclerosis ◽  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Viral Infections ◽  
Activated T Cells ◽  
In Vitro Proliferation

Activated T cells are able to stimulate proliferation in resting T cells through an antigen non-specific mechanism. The in vivo usefulness of this T cell-T cell activation is unclear, but it may serve to amplify immune responses. T cell-T cell activation could be involved in the well-documented occurrence of multiple sclerosis (MS) exacerbations following viral infections. Excessive activation via this pathway could also be a factor in the etiology of MS. We tested the hypothesis that excessive T cell-T cell activation occurs in MS patients using in vitro proliferation assays comparing T cells from MS patients to T cells from controls. When tested as responder cells, T cells from MS patients proliferated slightly less after stimulation with previously activated cells than T cells from controls. When tested as stimulator cells, activated cells from MS patients stimulated slightly more non-specific proliferation than activated cells from controls. Neither of these differences were statistically significant We conclude that T cell proliferation in response to activated T cells is similar in MS and controls.

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