Combined targeting of soluble latent TGF-ß and a solid tumor-associated antigen with adapter CAR T cells.

Solid tumors consist of malignant and nonmalignant cells that together create the local tumor microenvironment (TME). Additionally, the TME is characterized by the expression of numerous soluble factors such as TGF-β. TGF-β plays an important role in the TME by suppressing T cell effector function and promoting tumor invasiveness.

CAR T-cell Entry into Tumor Islets Is a Two-Step Process Dependent on IFNγ and ICAM-1.

Adoptive transfer of T cells expressing chimeric antigen receptors (CAR) has shown remarkable clinical efficacy against advanced B-cell malignancies but not yet against solid tumors. Here, we used fluorescent imaging microscopy and assays to compare the early functional responses (migration, Ca, and cytotoxicity) of CD20 and EGFR CAR T cells upon contact with malignant B cells and carcinoma cells. Our results indicated that CD20 CAR T cells rapidly form productive ICAM-1-dependent conjugates with their targets.

Titratable Pharmacological Regulation of CAR T Cells Using Zinc Finger-Based Transcription Factors.

Chimeric antigen receptor (CAR) T cell therapy has emerged as an attractive strategy for cancer immunotherapy. Despite remarkable success for hematological malignancies, excessive activity and poor control of CAR T cells can result in severe adverse events requiring control strategies to improve safety. This work illustrates the feasibility of a zinc finger-based inducible switch system for transcriptional regulation of an anti-CD20 CAR in primary T cells providing small molecule-inducible control over therapeutic functions.

Anti-CD19 CARs displayed at the surface of lentiviral vector particles promote transduction of target-expressing cells.

Recently, a rare type of relapse was reported upon treating a B cell acute lymphoblastic leukemia (B-ALL) patient with anti-CD19 chimeric antigen receptor (CAR)-T cells caused by unintentional transduction of residual malignant B cells (CAR-B cells). We show that anti-CD19 and anti-CD20 CARs are presented on the surface of lentiviral vectors (LVs), inducing specific binding to the respective antigen. Binding of anti-CD19 CAR-encoding LVs containing supernatant was reduced by CD19-specific blocking antibodies in a dose-dependent manner, and binding was absent for unspecific LV containing supernatant.

Vectofusin-1 Improves Transduction of Primary Human Cells with Diverse Retroviral and Lentiviral Pseudotypes, Enabling Robust, Automated Closed-System Manufacturing.

Cell and gene therapies are finally becoming viable patient treatment options, with both T cell- and hematopoietic stem cell (HSC)-based therapies being approved to market in Europe. However, these therapies, which involve the use of viral vector to modify the target cells, are expensive and there is an urgent need to reduce manufacturing costs. One major cost factor is the viral vector production itself, therefore improving the gene modification efficiency could significantly reduce the amount of vector required per patient.

Induction of a central memory and stem cell memory phenotype in functionally active CD4 and CD8 CAR T cells produced in an automated good manufacturing practice system for the treatment of CD19 acute lymphoblastic leukemia.

Relapsed/refractory B-precursor acute lymphoblastic leukemia (pre-B ALL) remains a major therapeutic challenge. Chimeric antigen receptor (CAR) T cells are promising treatment options. Central memory T cells (Tcm) and stem cell-like memory T cells (Tscm) are known to promote sustained proliferation and persistence after T-cell therapy, constituting essential preconditions for treatment efficacy.

Th17 cells are refractory to senescence and retain robust antitumor activity after long-term ex vivo expansion.

Adoptive immunotherapy for solid tumors relies on infusing large numbers of T cells to mediate successful antitumor responses in patients. While long-term rapid-expansion protocols (REPs) produce sufficient numbers of CD8 T cells for treatment, they also cause decline in the cell's therapeutic fitness. In contrast, we discovered that IL-17-producing CD4 T cells (Th17 cells) do not require REPs to expand 5,000-fold over 3 weeks.

Automated Enrichment, Transduction, and Expansion of Clinical-Scale CD62L T Cells for Manufacturing of Gene Therapy Medicinal Products.

Multiple clinical studies have demonstrated that adaptive immunotherapy using redirected T cells against advanced cancer has led to promising results with improved patient survival. The continuously increasing interest in those advanced gene therapy medicinal products (GTMPs) leads to a manufacturing challenge regarding automation, process robustness, and cell storage. Therefore, this study addresses the proof of principle in clinical-scale selection, stimulation, transduction, and expansion of T cells using the automated closed CliniMACS Prodigy system.

Automated manufacturing of chimeric antigen receptor T cells for adoptive immunotherapy using CliniMACS prodigy.

Novel cell therapies derived from human T lymphocytes are exhibiting enormous potential in early-phase clinical trials in patients with hematologic malignancies. Ex vivo modification of T cells is currently limited to a small number of centers with the required infrastructure and expertise. The process requires isolation, activation, transduction, expansion and cryopreservation steps.

Toll-like receptor agonist therapy can profoundly augment the antitumor activity of adoptively transferred CD8(+) T cells without host preconditioning.

Background: Lymphodepletion enhances adoptive T cell transfer (ACT) therapy by activating the innate immune system via microbes released from the radiation-injured gut. Microbial components, such as LPS, are key mediators of total body irradiation (TBI) enhancement, but our ability to strategically use these toll-like receptor (TLR) agonists to bolster the potency of T cell-based therapies for cancer remains elusive. Herein, we used TLR4 agonist LPS as a tool to address how and when to use TLR agonists to effectively improve cancer immunotherapy.

Mimicking homeostatic proliferation in vitro generates T cells with high anti-tumor function in non-lymphopenic hosts.

CD8(+) T cells undergoing homeostatic proliferation (HP) in a lymphopenic environment acquire a central memory-like phenotype (CD44(+) CD62L(+) Ly6c(+)). Such cells are readily functional in vitro, with a strong capacity to secrete IFNγ and IL-2 and to lyse target cells upon antigen recognition. In vivo, these memory-like T cells display potent anti-tumor reactivity.

Reduced tumor-antigen density leads to PD-1/PD-L1-mediated impairment of partially exhausted CD8⁺ T cells.

Clinical progression of cancer patients is often observed despite the presence of tumor-reactive T cells. Co-inhibitory ligands of the B7 superfamily have been postulated to play a part in this tumor-immune escape. One of these molecules, PD-L1 (B7-H1, CD274), is widely expressed on tumor cells and has been shown to mediate T-cell inhibition.

Overall survival and PD-L1 expression in metastasized malignant melanoma.

Background: Cancers are known to elude the immune system, for example, by MHC loss, FAS up-regulation, or increased secretion of TGF-beta. Recently, ligands of coinhibitory receptors like programmed cell death ligand-1 (PD-L1, B7-H1) have come to attention for their role in tumor immune escape. Various tumors have been tested for PD-L1 expression, and conflicting results were obtained regarding its correlative impact on patient survival.

Genetic engineering of murine CD8+ and CD4+ T cells for preclinical adoptive immunotherapy studies.

T-cell receptor (TCR) gene therapy enables for the rapid creation of antigen-specific T cells from mice of any strain and represents a valuable tool for preclinical immunotherapy studies. Here, we describe the superiority of γ-retroviral vectors compared with lentiviral vectors for transduction of murine T cells and surprisingly illustrate robust gene-transfer into phenotypically naive/memory-stem cell like (TN/TSCM; CD62L(hi)/CD44(low)) and central memory (TCM; CD62L(hi)/CD44(hi)) CD8+ T cells using murine stem cell-based γ-retroviral vectors (MSGV1). We created MSGV1 vectors for a major histocompatibility complex-class I-restricted TCR specific for the melanocyte-differentiation antigen, glycoprotein 100 (MSGV1-pmel-1), and a major histocompatibility complex-class II-restricted TCR specific for tyrosinase-related protein-1 (MSGV1-TRP-1), and found that robust gene expression required codon optimization of TCR sequences for the pmel-1 TCR.

Lethal graft-versus-host disease in mouse models of T cell receptor gene therapy.

The transfer of T cell receptor (TCR) genes can be used to induce immune reactivity toward defined antigens to which endogenous T cells are insufficiently reactive. This approach, which is called TCR gene therapy, is being developed to target tumors and pathogens, and its clinical testing has commenced in patients with cancer. In this study we show that lethal cytokine-driven autoimmune pathology can occur in mouse models of TCR gene therapy under conditions that closely mimic the clinical setting.