scholarly journals 798 CDX-585, A bispecific antibody with dual targeting of ILT4 and PD-1 checkpoint pathways

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A833-A833
Author(s):  
Laura Vitale ◽  
Michael Murphy ◽  
Collin Xia ◽  
Zeyu Peng ◽  
Thomas O'Neill ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Clinical Chemistry ◽  
Primary Cultures ◽  
Resistance Mechanism ◽  
Myeloid Cell ◽  
Receptor Activation ◽  
Pilot Studies ◽  
Enhanced Production

BackgroundActivation of the ITIM-bearing ILT4/LILRB2 receptor by its cognate ligands (HLA-G and HLA Class I) has been postulated as a resistance mechanism for checkpoint blockade of PD-1 and CTLA-4. Dual inhibition of receptors that suppress myeloid and T cell compartments through the generation of bispecific antibodies (bsAbs) is a promising strategy to improve outcomes for patients whose tumors are resistant to checkpoint inhibition.MethodsWe describe the discovery and characterization of CDX-585 a bsAb developed from novel ILT4 and PD-1 antagonist mAbs that revert myeloid cell suppression by antagonizing ILT4 and activating T-cell responses through PD-1 inhibition. The bsAb was engineered as a tetravalent molecule using the PD-1 IgG1 mAb linked to scFv of the ILT4 mAb at the C-terminus of the heavy chain. A series of mutations were introduced in the Fc domain to eliminate Fcy receptor binding and increase affinity to the neonatal Fc receptor. CDX-585 has good biophysical characteristics and retains functional properties similar to, or better, than the parental mAbs.ResultsCDX-585 has sub-nanomolar affinity binding to ILT4 and PD-1 and is a potent competitor of their respective ligands. Primary cultures of human macrophages and dendritic cells treated with CDX-585 enhanced production of inflammatory cytokines/chemokines, which was further potentiated in the presence of toll like receptor activation with lipopolysaccharide (LPS). CDX-585 was particularly effective in promoting T cell activation as measured by mixed lymphocyte reactions, and in polarizing macrophages towards M1 based on their cytokine profile. Pilot studies in mice and cynomolgus macaques confirmed a favorable pharmacokinetic profile without adverse effects of treatment noted in clinical observations or clinical chemistry.ConclusionsCDX-585 effectively combines ILT4 and PD-1 blockade into one molecule with favorable biophysical and functional characteristics supporting the initiation of development activities including manufacturing and IND-enabling studies.

IMMU-04. UNVEILING THE TUMOR-METABOLOME-IMMUNITY AXIS OF GLIOMA

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi92-vi92
Author(s):  
Mirco Friedrich ◽  
Lukas Bunse ◽  
Roman Sankowski ◽  
Wolfgang Wick ◽  
Marco Prinz ◽  
...  
Keyword(s):  
T Cell ◽  
Single Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Immune Cell ◽  
Myeloid Cell ◽  
Tumor Evolution ◽  
Large Neutral Amino Acid ◽  
Immune Microenvironment ◽  
Idh Mutations

Abstract The glioma microenvironment orchestrates tumor evolution, progression, and resistance to therapy. In high-grade gliomas, microglia and monocyte-derived macrophages constitute up to 70% of the tumor mass. However, the dynamics and phenotypes of intratumoral myeloid cells during tumor progression are poorly understood. Here we define myeloid cellular states in gliomas by longitudinal single-cell profiling and demonstrate their strict control by the tumor genotype. We report the unexpected and clinically highly relevant finding that human as well as murine gliomas with Isocitrate Dehydrogenase (IDH)1-R132H, a key oncogenic driver mutation of glioma, subdue their innate immune microenvironment by prompting a multifaceted reprogramming of myeloid and T cell metabolism. We employed integrated single-cell transcriptomic, time-of-flight mass cytometry and proteomic analyses of human healthy cortex control and glioma samples to identify myeloid cell subsets with distinct fates in IDH-mutated glioma that diverge from canonical trajectories of antigen-presenting cells as a result of a monocyte-to-macrophage differentiation block. Moving beyond single time point assessments, we now longitudinally describe differential immune cell infiltration and phenotype dynamics during glioma progression that are orchestrated by a fluctuating network of resident microglial cells and educated recruited immune cells. IDH mutations in glioma induce a tolerogenic alignment of their immune microenvironment through increased tryptophan uptake via large neutral amino acid transporter (LAT1)-CD98 and subsequent activation of the aryl hydrocarbon receptor (AHR) in educated blood-borne macrophages. In experimental tumor models, this immunosuppressive phenotype was reverted by LAT1-CD98 and AHR inhibitors. Taken together with direct effects on T cell activation, our findings not only link this oncogenic metabolic pathway to distinct immunosuppressive pathways but also provide the rationale and novel molecular targets for the development of immunotherapeutic concepts addressing the disease-defining microenvironmental effects of IDH mutations.

scholarly journals Activation of CD4+ T cells in the presence of a nondepleting monoclonal antibody to CD4 induces a Th2-type response in vitro.

1995 ◽  
Vol 182 (1) ◽  
pp. 5-13 ◽  
Author(s):  
P Stumbles ◽  
D Mason
Keyword(s):  
Monoclonal Antibody ◽  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cd4 T Cells ◽  
Cell Activation ◽  
Primary Cultures ◽  
In Vitro Experiments ◽  
Ifn Gamma

In vitro experiments using purified rat CD4+ T cells in primary and secondary mixed leukocyte cultures (MLC) have been carried out to explore the mechanism of inhibition of cell-mediated autoimmune disease in the rat by a nondepleting monoclonal antibody (mAb) to CD4. Previous work has shown that W3/25, a mouse anti-rat CD4 mAb of immunoglobulin G1 isotype, completely prevents the development of the paralysis associated with experimental allergic encephalomyelitis (EAE) in Lewis rats, but does so without eliminating the encephalitogenic T cells. The in vitro experiments described in this study have shown that when CD4+ T cells were activated in the presence of the anti-CD4 mAb in a primary MLC, the synthesis of interferon (IFN) gamma, but not interleukin (IL) 2, was completely inhibited. After secondary stimulation, now in the absence of the mAb, the synthesis of IL-4 and IL-13 mRNA was greatly enhanced compared with that observed from CD4+ T cells derived from primary cultures in which the mAb was omitted. As IL-4 and IL-13 are known to antagonize cell-mediated immune reactions, and as EAE is cell-mediated disease, the data suggest that the W3/25 mAb controls EAE by modifying the cytokine repertoire of T cells that respond to the encephalitogen. The capacity for the mAb to suppress IFN-gamma synthesis provides, in part, an explanation for this change in cytokine production. These findings are discussed in terms of what is known of the factors that determine which cytokine genes are expressed on T cell activation. Possible implications for the evolution of T cell responses in human immunodeficiency virus infection are also discussed.

scholarly journals Coevolution of TH1, TH2, and TH17 Responses during Repeated Pulmonary Exposure toAspergillus fumigatusConidia

2010 ◽  
Vol 79 (1) ◽  
pp. 125-135 ◽  
Author(s):  
Benjamin J. Murdock ◽  
Andrew B. Shreiner ◽  
Roderick A. McDonald ◽  
John J. Osterholzer ◽  
Eric S. White ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Allergic Bronchopulmonary Aspergillosis ◽  
Myeloid Cell ◽  
Hyphal Growth ◽  
Cell Polarization ◽  
Repeated Exposure ◽  
Invasive Infection ◽  
Pulmonary Exposure

ABSTRACTAspergillus fumigatus, a ubiquitous airborne fungus, can cause invasive infection in immunocompromised individuals but also triggers allergic bronchopulmonary aspergillosis in a subset of otherwise healthy individuals repeatedly exposed to the organism. This study addresses a critical gap in our understanding of the immunoregulation in response to repeated exposure toA. fumigatusconidia. C57BL/6 mice were challenged intranasally withA. fumigatusconidia weekly, and leukocyte composition, activation, and cytokine production were examined after two, four, and eight challenges. Approximately 99% ofA. fumigatusconidia were cleared within 24 h after inoculation, and repeated exposure toA. fumigatusconidia did not result in hyphal growth or accumulation of conidia with time. After 2 challenges, there was an early influx of neutrophils and regulatory T (Treg) cells into the lungs but minimal inflammation. Repeated exposure promoted sustained expansion of the draining lymph nodes, while the influx of eosinophils and other myeloid cells into the lungs peaked after four exposures and then decreased despite continuedA. fumigatuschallenges. Goblet cell metaplasia and low-level fibrosis were evident during the response. Repeated exposure toA. fumigatusconidia induced T cell activation in the lungs and the codevelopment by four exposures of TH1, TH2, and TH17 responses in the lungs, which were maintained through eight exposures. Changes in CD4 T cell polarization or Tregnumbers did not account for the reduction in myeloid cell numbers later in the response, suggesting a non-T-cell regulatory pathway involved in dampening inflammation during repeated exposure toA. fumigatusconidia.

scholarly journals Three-Dimensional Model of Sub-Plasmalemmal Ca2+ Microdomains Evoked by the Interplay Between ORAI1 and InsP3 Receptors

2021 ◽  
Vol 12 ◽  
Author(s):  
Diana Gil ◽  
Andreas H. Guse ◽  
Geneviève Dupont
Keyword(s):  
T Cells ◽  
Cell Adhesion ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Three Dimensional ◽  
Receptor Activation ◽  
Reaction Diffusion Model ◽  
Activated State ◽  
T Cell Adhesion

Ca2+ signaling plays an essential role in T cell activation, which is a key step to start an adaptive immune response. During the transition from a quiescent to a fully activated state, Ca2+ microdomains characterized by reduced spatial and temporal extents are observed in the junctions between the plasma membrane (PM) and the endoplasmic reticulum (ER). Such Ca2+ responses can also occur in response to T cell adhesion to other cells or extracellular matrix proteins in otherwise unstimulated T cells. These non-TCR/CD3-dependent Ca2+ microdomains rely on d-myo-inositol 1,4,5-trisphosphate (IP3) signaling and subsequent store operated Ca2+ entry (SOCE) via the ORAI/STIM system. The detailed molecular mechanism of adhesion-dependent Ca2+ microdomain formation remains to be fully elucidated. We used mathematical modeling to investigate the spatiotemporal characteristics of T cell Ca2+ microdomains and their molecular regulators. We developed a reaction-diffusion model using COMSOL Multiphysics to describe the evolution of cytosolic and ER Ca2+ concentrations in a three-dimensional ER-PM junction. Equations are based on a previously proposed realistic description of the junction, which is extended to take into account IP3 receptors (IP3R) that are located next to the junction. The first model only considered the ORAI channels and the SERCA pumps. Taking into account the existence of preformed clusters of ORAI1 and STIM2, ORAI1 slightly opens in conditions of a full ER. These simulated Ca2+ microdomains are too small as compared to those observed in unstimulated T cells. When considering the opening of the IP3Rs located near the junction, the local depletion of ER Ca2+ allows for larger Ca2+ fluxes through the ORAI1 channels and hence larger local Ca2+ concentrations. Computational results moreover show that Ca2+ diffusion in the ER has a major impact on the Ca2+ changes in the junction, by affecting the local Ca2+ gradients in the sub-PM ER. Besides pointing out the likely involvement of the spontaneous openings of IP3Rs in the activation of SOCE in conditions of T cell adhesion prior to full activation, the model provides a tool to investigate how Ca2+ microdomains extent and interact in response to T cell receptor activation.

scholarly journals B cell depletion reduces the development of atherosclerosis in mice

2010 ◽  
Vol 207 (8) ◽  
pp. 1579-1587 ◽  
Author(s):  
Hafid Ait-Oufella ◽  
Olivier Herbin ◽  
Jean-David Bouaziz ◽  
Christoph J. Binder ◽  
Catherine Uyttenhove ◽  
...  
Keyword(s):  
T Cell ◽  
B Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Density Lipoprotein ◽  
Protective Role ◽  
Cell Depletion ◽  
B Cell Depletion ◽  
B Cell Activation ◽  
Enhanced Production

B cell depletion significantly reduces the burden of several immune-mediated diseases. However, B cell activation has been until now associated with a protection against atherosclerosis, suggesting that B cell–depleting therapies would enhance cardiovascular risk. We unexpectedly show that mature B cell depletion using a CD20-specific monoclonal antibody induces a significant reduction of atherosclerosis in various mouse models of the disease. This treatment preserves the production of natural and potentially protective anti–oxidized low-density lipoprotein (oxLDL) IgM autoantibodies over IgG type anti-oxLDL antibodies, and markedly reduces pathogenic T cell activation. B cell depletion diminished T cell–derived IFN-γ secretion and enhanced production of IL-17; neutralization of the latter abrogated CD20 antibody–mediated atheroprotection. These results challenge the current paradigm that B cell activation plays an overall protective role in atherogenesis and identify new antiatherogenic strategies based on B cell modulation.

scholarly journals Beta-1,3 Oligoglucans Specifically Bind to Immune Receptor CD28 and May Enhance T Cell Activation

2021 ◽  
Vol 22 (6) ◽  
pp. 3124
Author(s):  
Jeffrey Comer ◽  
Molly Bassette ◽  
Riley Burghart ◽  
Mayme Loyd ◽  
Susumu Ishiguro ◽  
...  
Keyword(s):  
Free Energy ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Binding Free Energy ◽  
Receptor Activation ◽  
Free Energy Calculations ◽  
Mrna Levels ◽  
Immunostimulatory Activity ◽  
Immune Receptor

Beta glucans are known to have immunomodulatory effects that mediated by a variety of mechanisms. In this article, we describe experiments and simulations suggesting that beta-1,3 glucans may promote activation of T cells by a previously unknown mechanism. First, we find that treatment of a T lymphoblast cell line with beta-1,3 oligoglucan significantly increases mRNA levels of T cell activation-associated cytokines, especially in the presence of the agonistic anti-CD3 antibody. This immunostimulatory activity was observed in the absence of dectin-1, a known receptor for beta-1,3 glucans. To clarify the molecular mechanism underlying this activity, we performed a series of molecular dynamics simulations and free-energy calculations to explore the interaction of beta-1,3 oligoglucans with potential immune receptors. While the simulations reveal little association between beta-1,3 oligoglucan and the immune receptor CD3, we find that beta-1,3 oligoglucans bind to CD28 near the region identified as the binding site for its natural ligands CD80 and CD86. Using a rigorous absolute binding free-energy technique, we calculate a dissociation constant in the low millimolar range for binding of 8-mer beta-1,3 oligoglucan to this site on CD28. The simulations show this binding to be specific, as no such association is computed for alpha-1,4 oligoglucan. This study suggests that beta-1,3 glucans bind to CD28 and may stimulate T cell activation collaboratively with T cell receptor activation, thereby stimulating immune function.

scholarly journals Antibodies to ILT3 abrogate myeloid immunosuppression and enable tumor killing

2021 ◽  
Author(s):  
Philip E Brandish ◽  
Anthony Palmieri ◽  
Gulesi Ayanoglu ◽  
Jeanne Baker ◽  
Raphael Bueno ◽  
...  
Keyword(s):  
T Cell ◽  
Tumor Microenvironment ◽  
T Cell Activation ◽  
Cell Activation ◽  
Suppressor Cells ◽  
Myeloid Cell ◽  
Soluble Form ◽  
Myeloid Suppressor Cells ◽  
Wide Range ◽  
Tumor Killing

Tumor myeloid suppressor cells impede response to T cell checkpoint immunotherapy. Immunoglobulin-like transcript 3 (ILT3, gene name, LILRB4) expressed on dendritic cells (DCs) promotes antigen-specific tolerance. Circulating monocytic MDSCs that express ILT3 have been linked to clinical outcomes and a soluble form of ILT3 is elevated in certain cancers. We find that LILRB4 expression is correlated with Gene Expression Profile of T-cell inflamed tumor microenvironment shown to be significantly associated with response to the anti-PD1 antibody pembrolizumab across several tumor types. A potent and selective anti-ILT3 mAb effectively antagonized IL-10 polarization of DCs and enabled T cell priming. In an MLR assay anti-ILT3 combined with pembrolizumab afforded greater CD8+ T cell activation compared to either agent alone. Anti-ILT3 antibodies impaired the acquisition of a suppressive phenotype of monocytes co-cultured with SK-MEL-5 cancer cells, accompanied by a reduction in surface detection of peptidase inhibitor 16, a cis interaction candidate for ILT3. Growth of myeloid cell-abundant SK-MEL-5 tumors was abrogated by ILT3 blockade and remodeling of the immune tumor microenvironment was evident by CyTOF. These data support the testing of anti-ILT3 antibodies for the treatment of a wide range of solid tumors replete with myeloid cells.

scholarly journals 268 KVA 12.1 a novel fully human anti-VISTA antibody: clinical trial design in monotherapy and in combination with an anti-PD1 antibody

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A291-A291
Author(s):  
Thierry Guillaudeux ◽  
Shawn Iadonato ◽  
Eric Tarcha ◽  
Craig Philips
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Immune Checkpoint ◽  
Cell Activation ◽  
Checkpoint Inhibitors ◽  
Clinical Chemistry ◽  
T Cell Response ◽  
Fixed Dose ◽  
List Type ◽  
Cytokine Levels

BackgroundV-domain Ig Suppressor of T cell Activation (VISTA) is an immune-suppressive checkpoint inhibitor of T cell response. VISTA is expressed in the immuno-suppressive tumor microenvironment, mostly by cells of the myeloid lineage, and its blockade can restore an efficient antitumor immune response especially in hard-to-treat tumors.1 In addition, an increase in VISTA expression has been described after treatment by the current immune checkpoint inhibitors, anti-CTLA-4 or anti-PD1-(L),1 especially in patients refractory to these treatments.2 3 Therefore, VISTA may be involved in a compensatory resistance mechanism to checkpoint inhibitors.MethodsKineta has selected a lead candidate anti-VISTA monoclonal antibody, KVA12.1, after a deep screen of 107 fully human and highly diverse antibodies directed against the extracellular domain of VISTA.ResultsKVA12.1 exhibits high potency and binds to a unique epitope. It restores T cell activation and induces a pro-inflammatory response in in vitro assays. In vivo, in human VISTA knock-in mice, KVA12.1 treatment mediates strong single-agent antitumor activity in multiple syngeneic tumor models and shows enhanced efficacy in combination with either anti-PD-(L)1 or anti-CTLA-4 treatment. Finally, our anti-VISTA antibody was well-tolerated in exploratory toxicology studies in cynomolgus monkey, where hematology and clinical chemistry evaluations as well as clinical observations including monitoring of body weight revealed no indicators of toxicity. Safety endpoints, including the monitoring of cytokine levels related to cytokine release syndrome (CRS), clinical pathology and immunogenicity were evaluated. Cytokine levels associated with CRS (e.g., TNF-alpha, IL-6, IL-1β) were assessed, and none were elevated to levels associated with CRS. These studies provided drug exposures (AUC) well over the expected exposures required for clinical efficacy, and KVA12.1 exhibits a good half-life consistent with other monoclonal check-point inhibitors. We are currently engaged in pre-IND studies and manufacturing of KVA12.1.ConclusionsHere we are presenting the design of a phase 1/2 multicenter, open label, dose escalation and dose expansion study of intravenous infusion of KVA12.1 as a monotherapy and in combination with a fixed dose of an anti-PD1 antibody in patients with advanced refractory or metastatic solid tumors.ReferencesElTanbouly MA, Schaafsma E, Noelle RJ, Lines JL. VISTA: Coming of age as a multi-lineage immune checkpoint. Clin Exp Immunol 2020;200(2):120–130.Kuklinski LF, Yan S, Li Z, Fisher JL, Cheng C, Noelle RJ, Angeles CV, Turk MJ, Ernstoff MS. VISTA expression on tumor-infiltrating inflammatory cells in primary cutaneous melanoma correlates with poor disease-specific survival. Cancer Immunol Immunother 2018 July;67(7):1113–1121.Kakavand H, Jackett LA, Menzies AM, Gide TN, Carlino MS, Saw RPM, Thompson JF, Wilmott JS, Long GV, Scolyer RA. Negative immune checkpoint regulation by VISTA: a mechanism of acquired resistance to anti-PD-1 therapy in metastatic melanoma patients. Mod Pathol 2017 December;30(12):1666–1676.

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