Vg9Vd2 T cell activation leads to broad functional activities against tumors. Tumor-infiltrating γδ T cells are the most significant favorable cancer-wide prognostic signature. Anti-tumoral response of Vg9Vd2 T cells requires sensing of phosphoantigens accumulated through binding of butyrophilin 3A(BTN3A) expressed in tumors. We identified butyrophilin 2A (BTN2A) as a requirement for BTN3A-mediated Vg9Vd2 T cell cytotoxicity against cancer cells.

Vγ9Vδ2-T cells constitute the largest γδ-T cell subset in human peripheral blood and are powerful anti-tumor immune effector cells that can be identified in many different tumor types. This presentation will discuss bispecific antibodies designed to engage Vγ9Vδ2-T cells and their use for cancer immunotherapy.

In the current study, we generated novel bispecific proteins to mediate the interaction between APCs and CAR T cells. We termed these bispecifics “Bispecific Engagers of APCs and T Cells (BEATs)”. CAR T cell proliferation and function was significantly enhanced by BEATs in the presence of APCs in vitro and in vivo. Importantly, murine syngeneic and human xenograft solid tumor growth was significantly inhibited when CAR T cells were administered in combination with BEATs.

The treatment of malignancies with adoptive cell therapy is largely limited to patient-derived, autologous alpha beta T cells. This approach comes with challenges (toxicities, relapse, production costs, lack of migration) and a requirement for gene editing to avoid graft vs. host disease in allogeneic settings. In contrast, V delta 1 T cells innately recognise malignant cells, are not MHC-restricted, and facilitate broader immunological responses. Thus, they are an ideal vehicle for immunotherapy.

ImCheck Therapeutics is developing the first activating humanized antibody to butyrophilin3A (BTN3A). ICT01 binds to BTN3A that specifically activates human gamma9delta2 T cells and has entered into Phase I studies in solid and hematological malignancies. Additionally, therapeutic antibodies against multiple novel butyrophilins are currently developed. These novel antibodies have a clearly differentiated mode of action from ICT01 by functional effects on other immune cells critical in the immune responses to tumours. This opens a completely new space clearly different from the current B7/CD28 superfamily targets and has the potential to become the next generation therapeutic immune modulators.

Intra-tumoural blood derived gamma delta T cells correlate strongly with superior outcome across a range of cancer types. However, immunotherapy with blood-derived gamma delta T cells has largely proven ineffective. We have found that when these cells are expanded in the presence of TGF-beta, they acquire a fitter, less differentiated phenotype, enabling these cells to elicit improved anti-tumour activity. In this presentation, we will illustrate the anti-tumour activity of TGF-b-supplemented, blood-derived gamma delta T cells across a spectrum of solid and haematological malignancies. Moreover, we will present our experience with CAR targeting of these cells.

Emerging data suggest that approximately 25% of therapeutic MAbs in development are polyspecific and can result in severe or even life-threatening adverse events. We developed the Membrane Proteome Array (MPA) to de-risk MAb safety by specificity testing across an array of 6,000 native membrane proteins. Having tested hundreds of molecules, we will discuss the importance of specificity testing during discovery, and case studies of clinical MAb and CAR T safety failures that could have been averted.

Clinical responses to checkpoint inhibitors used for cancer immunotherapy seemingly require the presence of αβT cells that recognize tumour neoantigens and are therefore primarily restricted to tumours with high mutational load. Approaches that could address this limitation by engineering αβT cells, such as chimeric antigen receptor T (CAR T) cells, are being investigated intensively, but these approaches have other issues, such as a scarcity of appropriate targets for CAR T cells in solid tumours. Consequently, there is renewed interest among translational researchers and commercial partners in the therapeutic use of γδT cells and their receptors. Overall, γδT cells display potent cytotoxicity, which usually does not depend on tumour-associated (neo)antigens, towards a large array of haematological and solid tumours, while preserving normal tissues. However, the precise mechanisms of tumour-specific γδT cells, as well as the mechanisms for self-recognition, remain poorly understood. In this review, we discuss the challenges and opportunities for the clinical implementation of cancer immunotherapies based on γδT cells and their receptors.

Gamma delta (γδ) T cells are essential to protective immunity. In humans, most γδ T cells express Vγ9Vδ2⁺ T cell receptors (TCRs), which respond to phosphoantigens (pAg) produced by cellular pathogens and overexpressed by cancers. However, the molecular targets recognized by these γδTCRs are unknown. Here, we identify butyrophilin 2A1 (BTN2A1) as a key ligand that directly binds to the Vγ9⁺ TCR γ-chain. We found that BTN2A1 is highly expressed on a variety of cancer tissues and cell lines and associates with BTN3A1, which act together to initiate responses to pAg. This unique mode of MHC-independent T cell activation was essential for γδ T cell cytokine expression as well as γδ T cell-mediated killing of tumor cells. Knockout studies in melanoma cells confirmed the absolute requirement for BTN2A1 and BTN3A1 in this process. While most current immunotherapy approaches rely on (re)-activation of conventional alpha-beta (aß) T cells, this finding creates additional opportunities for the development of γδ T cell-based immunotherapies utilizing a different part of the immune system.

Cell microarray screening of plasma membrane and tethered secreted proteins that are expressed in human cells enables rapid discovery of primary receptors, as well as potential off-targets for a variety of biologics including: peptides, antibodies, proteins, CAR T, and other cell therapies. Case studies will demonstrate the utility of the technology in identifying novel, druggable targets, as well as in specificity screening to aid safety assessment and provide key data to support IND submissions.

Despite the remarkable results of CAR T cells in patients with hematologic malignancies, the success of CAR T cells in treating patients with solid tumors has been poor. A major obstacle for the field is the limited ability of CAR T cells to persist and maintain their functions in the tumour microenvironment. New approaches to enhance the persistence and efficacy of CAR T  cells will be presented, focusing on the treatment of solid tumors. 

Chimeric antigen receptor (CAR) T cells have enabled remarkable advances in cancer therapy, but unexpected toxicity and other adverse side effects remain an important issue. To engineer safety, we computationally designed a synthetic chemically disruptable heterodimer (CDH) featuring a high-affinity protein interface with minimal amino acid deviation from wild-type, which self-assembles but can be disrupted by a small molecule. The CDH was incorporated into a synthetic heterodimer receptor, dubbed STOP-CAR, featuring an antigen-recognition chain and a CD3z- and CD28-containing endodomain signaling chain. STOP-CAR-T cells exhibited similar activity to classic second-generation (2G) CAR-T cells in vitro and in vivo against tumors, while timed administration of the small-molecule drug disruptor dynamically inactivated the STOP-CAR-T cells. We propose that STOP-CARs hold important clinical promise, and our work highlights the potential for rational, structure-based design to implement novel, controllable elements into synthetic cellular therapies.

Metabolic competition in the tumour microenvironment is a limiting factor in cancer immune therapy. T cell efficacy and phenotypic changes are dependent on shifts in metabolic pathways within individual cells. I will explore approaches to target a putative tumour-associated antigen is a key role in metabolic solute availability, as well as methods to adapt CAR T cells to be armed to better manage the competitive cancer microenvironment.

Immunotherapeutic antibodies and cell therapies have proven to be highly effective cancer therapy for solid tumors, leukemia and lymphomas.  The immunotherapy acts in part by stimulating and redirecting the immune system to attack cancer cells, and cytokines can be released during the process.