Evaluation of in vivo persistence of T lymphocytes expressing anti-CD19 chimeric antigen receptors

Abstract

Cell therapy using T cells expressing chimeric antigen receptors (CARs) has already revolutionized the treatment of some B-cell leukemias and lymphomas. However, for other hematological malignancies and solid tumors, the long-term clinical response rate is low (~ 20%) or nonexistent. Recent studies indicate that the main causes of these failure cases are the anergy and low persistence of CAR-T cells after transplantation. Even if present below the detection limit of flow cytometry, CAR-T cells are able to keep the patient in clinical remission and cause B cell aplasia. Conversely, CAR-T cells expressing cell surface markers associated with exhaustion have reduced cytolytic capacity. Therefore, developing a monitoring strategy that combines high sensitivity and multiparametric immunophenotypic evaluation is essential to predict, understand and improve the clinical response to CAR-T cell therapies. Thus, this project aims to develop a platform for monitoring the persistence of anti-CD19 CAR-T cells using quantitative PCR and multiparametric flow cytometry. For this, we will generate human T lymphocytes expressing an anti-CD19 CAR by lentiviral transduction. Following confirmation of their in vitro antineoplastic potential against CD19+ neoplastic cells, the therapeutic efficiency and persistence of CAR T cells will be evaluated in vivo in a mouse model of human Burkitt lymphoma. These experiments will allow us to characterize the persistence and phenotype of CAR-T cells that are currently being produced under Good Laboratory Practices (GMP) conditions for clinical application in our laboratory. This is one of the goals of the Cell Therapy Center (project CEPID 013/08135-2). In addition, this project will result in the incorporation of tools to track CAR-T cells after transplantation into clinical protocols currently under development and will contribute to the nucleation and training of human resources in the field of advanced therapies using genetically modified immune cells.