Harnessing antibody-mediated recognition of the intracellular proteome with T cell receptor-like specificity.

The clinical success of cancer immunotherapy has driven ongoing efforts to identify novel targets that can effectively guide potent effector functions to eliminate malignant cells. Traditionally, immunotherapies have focused on surface antigens; however, these represent only a small fraction of the cancer proteome, limiting their therapeutic potential. In contrast, the majority of proteins within the human proteome are intracellular, yet they are represented on the cell surface as short peptides presented by MHC class I molecules.

Antigen-specific modulation of chronic experimental autoimmune encephalomyelitis in humanized mice by TCR-like antibody targeting autoreactive T-cell epitope.

The development and application of human TCR-like (TCRL) antibodies recognizing disease-specific MHC-peptide complexes may prove as an important tool for basic research and therapeutic applications. Multiple sclerosis is characterized by aberrant CD4 T-cell response to self-antigens presented by MHC class II molecules. This led us to select a panel of TCRL Abs targeting the immunodominant autoantigenic epitope MOG derived from myelin oligodendrocyte glycoprotein (MOG) presented on HLA-DR2, which is associated with multiple sclerosis (MS).

The Intracellular Proteome as a Source for Novel Targets in CAR-T and T-Cell Engagers-Based Immunotherapy.

The impressive clinical success of cancer immunotherapy has motivated the continued search for new targets that may serve to guide potent effector functions in an attempt to efficiently kill malignant cells. The intracellular proteome is an interesting source for such new targets, such as neo-antigens and others, with growing interest in their application for cell-based immunotherapies. These intracellular-derived targets are peptides presented by MHC class I molecules on the cell surface of malignant cells.

Artificial Antigen Presenting Cells for Detection and Desensitization of Autoreactive T cells Associated with Type 1 Diabetes.

Autoimmune diseases and in particular type 1 diabetes rely heavily on treatments that target the symptoms rather than prevent the underlying disease. One of the barriers to better therapeutic strategies is the inability to detect and efficiently target rare autoreactive T-cell populations that are major drivers of these conditions. Here, we develop a unique artificial antigen-presenting cell (aAPC) system from biocompatible polymer particles that allows specific encapsulation of bioactive ingredients.

Serologic Status and Toxic Effects of the SARS-CoV-2 BNT162b2 Vaccine in Patients Undergoing Treatment for Cancer.

Importance: The efficacy and safety profile of SARS-CoV-2 vaccines have been acquired from phase 3 studies; however, patients with cancer were not represented in these trials. Owing to the recommendation to prioritize high-risk populations for vaccination, further data are warranted.

Objective: To evaluate the use and safety of the BNT162b2 vaccine in patients undergoing treatment for cancer.

Shaping Functional Avidity of CAR T Cells: Affinity, Avidity, and Antigen Density That Regulate Response.

Chimeric antigen receptors (CARs) are immunoreceptors that redirect T cells to selectively kill tumor cells. Given their clinical successes in hematologic malignancies, there is a strong aspiration to advance this immunotherapy for solid cancers; hence, molecular CAR design and careful target choice are crucial for their function. To evaluate the functional significance of the biophysical properties of CAR binding (i.

Phenotypic Models of CAR T-Cell Activation Elucidate the Pivotal Regulatory Role of CAR Downmodulation.

Adoptive cell immunotherapy with chimeric antigen receptor (CAR) showed limited potency in solid tumors, despite durable remissions for hematopoietic malignancies. Therefore, an investigation of ways to enhance the efficacy of CARs' antitumor response has been engaged upon. We previously examined the interplay between the biophysical parameters of CAR binding (i.

Multi-center nationwide comparison of seven serology assays reveals a SARS-CoV-2 non-responding seronegative subpopulation.

Background: An Israeli national taskforce performed a multi-center clinical and analytical validation of seven serology assays to determine their utility and limitations for SARS-CoV-2 diagnosis.

Methods: Serology assays from Roche, Abbott, Diasorin, BioMerieux, Beckman-Coulter, Siemens, and an in-house RBD ELISA were included. Negative samples from 2391 individuals representative of the Israeli population, and 698 SARS-CoV-2 PCR positive patients, collected between March and May 2020, were analyzed.

SS1P Immunotoxin Induces Markers of Immunogenic Cell Death and Enhances the Effect of the CTLA-4 Blockade in AE17M Mouse Mesothelioma Tumors.

SS1P is an anti-mesothelin immunotoxin composed of a targeting antibody fragment genetically fused to a truncated fragment of Pseudomonas exotoxin A. Delayed responses reported in mesothelioma patients receiving SS1P suggest that anti-tumor immunity is induced. The goal of this study is to evaluate if SS1P therapy renders mesothelioma tumors more sensitive to cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) immune checkpoint blockade.

Combining Local Immunotoxins Targeting Mesothelin with CTLA-4 Blockade Synergistically Eradicates Murine Cancer by Promoting Anticancer Immunity.

Immune checkpoint blockade using antibodies to cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) benefits a limited number of cancer patients. SS1P and LMB-100 are immunotoxins that target mesothelin. We observed delayed responses to SS1P in patients with mesothelioma suggesting that antitumor immunity was induced.

Major-histocompatibility complex harnessing and lymphocytic recruitment: a new tool for glioblastoma multiforme immunotherapy.

Glioblastoma multiforme (GBM) is the most common malignant primary brain neoplasm, notorious for being able to evade and suppress the immune-system. We present a new immunotherapeutic approach that can potentially overcome or circumvent many of the GBM laden obstacles for an efficient antitumor immune response. In this molecular construct, a soluble major-histocompatibility complex (MHC), presenting an immunogenic peptide is directed towards GBM cells.

Recruitment of Oligoclonal Viral-Specific T cells to Kill Human Tumor Cells Using Single-Chain Antibody-Peptide-HLA Fusion Molecules.

Tumor progression is often associated with the development of diverse immune escape mechanisms. One of the main tumor escape mechanism is HLA loss, in which human solid tumors exhibit alterations in HLA expression. Moreover, tumors that present immunogenic peptides via class I MHC molecules are not susceptible to CTL-mediated lysis, because of the relatively low potency of the tumor-specific CLTs.

A novel host-proteome signature for distinguishing between acute bacterial and viral infections.

Bacterial and viral infections are often clinically indistinguishable, leading to inappropriate patient management and antibiotic misuse. Bacterial-induced host proteins such as procalcitonin, C-reactive protein (CRP), and Interleukin-6, are routinely used to support diagnosis of infection. However, their performance is negatively affected by inter-patient variability, including time from symptom onset, clinical syndrome, and pathogens.

Functional comparison of engineered T cells carrying a native TCR versus TCR-like antibody-based chimeric antigen receptors indicates affinity/avidity thresholds.

Adoptive transfer of Ag-specific T lymphocytes is an attractive form of immunotherapy for cancers. However, acquiring sufficient numbers of host-derived tumor-specific T lymphocytes by selection and expansion is challenging, as these cells may be rare or anergic. Using engineered T cells can overcome this difficulty.

On the limited recognition of inorganic surfaces by short peptides compared with antibodies.

The vast potential applications of biomolecules that bind inorganic surfaces led mostly to the isolation of short peptides that target selectively specific materials. The demonstrated differential affinity toward certain surfaces created the impression that the recognition capacity of short peptides may match that of rigid biomolecules. In the following, we challenge this view by comparing the capacity of antibody molecules to discriminate between the (100) and (111A) facets of a gallium arsenide semiconductor crystal with the capacity of short peptides to do the same.

HLA-DRα1 constructs block CD74 expression and MIF effects in experimental autoimmune encephalomyelitis.

CD74, the cell-surface form of the MHC class II invariant chain, is a key inflammatory factor that is involved in various immune-mediated diseases as part of the macrophage migration inhibitory factor (MIF) binding complex. However, little is known about the natural regulators of CD74 in this context. In order to study the role of the HLA-DR molecule in regulating CD74, we used the HLA-DRα1 domain, which was shown to bind to and downregulate CD74 on CD11b(+) monocytes.

Antigen-dependent integration of opposing proximal TCR-signaling cascades determines the functional fate of T lymphocytes.

T cell anergy is a key tolerance mechanism to mitigate unwanted T cell activation against self by rendering lymphocytes functionally inactive following Ag encounter. Ag plays an important role in anergy induction where high supraoptimal doses lead to the unresponsive phenotype. How T cells "measure" Ag dose and how this determines functional output to a given antigenic dose remain unclear.

Antigen-specific immunomodulation for type 1 diabetes by novel recombinant antibodies directed against diabetes-associates auto-reactive T cell epitope.

The trimolecular complex composed of autoreactive T-cell receptor, MHC class II, and an autoantigenic peptide plays a central role in the activation of pathogenic Islet-specific CD4+ T cells in type 1 diabetes (T1D). We isolated and characterized novel antibodies against autoreactive T-cell epitopes associated with T1D. Our antibodies mimic the specificity of the T-cell receptor (TCR), while binding MHC class II/peptide complexes in an autoantigen peptide specific, MHC-restricted manner.

MUC1 is a potential target for the treatment of acute myeloid leukemia stem cells.

Acute myeloid leukemia (AML) is a malignancy of stem cells with an unlimited capacity for self-renewal. MUC1 is a secreted, oncogenic mucin that is expressed aberrantly in AML blasts, but its potential uses to target AML stem cells have not been explored. Here, we report that MUC1 is highly expressed on AML CD34(+)/lineage(-)/CD38(-) cells as compared with their normal stem cell counterparts.

Immunoglobulin-like transcript receptors on human dermal CD14+ dendritic cells act as a CD8-antagonist to control cytotoxic T cell priming.

Human Langerhans cells (LCs) are highly efficient at priming cytolytic CD8(+) T cells compared with dermal CD14(+) dendritic cells (DCs). Here we show that dermal CD14(+) DCs instead prime a fraction of naïve CD8(+) T cells into cells sharing the properties of type 2 cytokine-secreting CD8(+) T cells (TC2). Differential expression of the CD8-antagonist receptors on dermal CD14(+) DCs, the Ig-like transcript (ILT) inhibitory receptors, explains the difference between the two types of DCs.

A novel regulatory pathway for autoimmune disease: binding of partial MHC class II constructs to monocytes reduces CD74 expression and induces both specific and bystander T-cell tolerance.

Treatment with partial (p)MHC class II-β1α1 constructs (also referred to as recombinant T-cell receptor ligands - RTL) linked to antigenic peptides can induce T-cell tolerance, inhibit recruitment of inflammatory cells and reverse autoimmune diseases. Here we demonstrate a novel regulatory pathway that involves RTL binding to CD11b(+) mononuclear cells through a receptor comprised of MHC class II invariant chain (CD74), cell-surface histones and MHC class II itself for treatment of experimental autoimmune encephalomyelitis (EAE). Binding of RTL constructs with CD74 involved a previously unrecognized MHC class II-α1/CD74 interaction that inhibited CD74 expression, blocked activity of its ligand, macrophage migration inhibitory factor, and reduced EAE severity.

Mixed alkanethiol monolayers on submicrometric gold patterns: a controlled platform for studying cell-ligand interactions.

Nanoscale organization of surface ligands often has a critical effect on cell-surface interactions. We have developed an experimental system that allows a high degree of control over the 2-D spatial distribution of ligands. As a proof of concept, we used the developed system to study how T-cell activation is independently affected by antigen density and antigen amount per cell.

Melanoma cells present high levels of HLA-A2-tyrosinase in association with instability and aberrant intracellular processing of tyrosinase.

Short-lived protein translation products are proposed to be a major source of substrates for major histocompatibility complex (MHC) class I antigen processing and presentation; however, a direct link between protein stability and the presentation level of MHC class I-peptide complexes has not been made. We have recently discovered that the peptide Tyr((369-377)) , derived from the tyrosinase protein is highly presented by HLA-A2 on the surface of melanoma cells. To examine the molecular mechanisms responsible for this presentation, we compared characteristics of tyrosinase in melanoma cells lines that present high or low levels of HLA-A2-Tyr((369-377)) complexes.

T-cell-receptor-like antibodies - generation, function and applications.

Tumour and virus-infected cells are recognised by CD8+ cytotoxic T cells that, in response, are activated to eliminate these cells. In order to be activated, the clonotypic T-cell receptor (TCR) needs to encounter a specific peptide antigen presented by the membrane surface major histocompatibility complex (MHC) molecule. Cells that have undergone malignant transformation or viral infection present peptides derived from tumour-associated antigens or viral proteins on their MHC class I molecules.

Electrically controlled molecular recognition harnessed to activate a cellular response.

Seamless embedment of electronic devices in biological systems is expected to add the outstanding computing power, memory, and speed of electronics to the biochemical toolbox of nature. Such amalgamation requires transduction of electronic signals into biochemical cues that affect cells. Inspired by biology, where pathways are directed by molecular recognition, we propose and demonstrate a generic electrical-to-biological transducer comprising a two-state electronic antigen and a chimeric cell receptor engineered to bind the antigen exclusively in its "on" state.