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Antibody-based therapeutics have experienced a rapid growth in recent years and are now utilized in various modalities spanning from conventional antibodies, antibody-drug conjugates, bispecific antibodies to chimeric antigen receptor (CAR) T cells. Many next generation antibody therapeutics achieve enhanced potency but often increase the risk of adverse events. Antibody scaffolds capable of exhibiting inducible affinities could reduce the risk of adverse events by enabling a transient suspension of antibody activity. To demonstrate this, we develop conditionally activated, single-module CARs, in which tumor antigen recognition is directly modulated by an FDA-approved small molecule drug. The resulting CAR T cells demonstrate specific cytotoxicity of tumor cells comparable to that of traditional CARs, but the cytotoxicity is reversibly attenuated by the addition of the small molecule. The exogenous control of conditional CAR T cell activity allows continual modulation of therapeutic activity to improve the safety profile of CAR T cells across all disease indications. Many next-generation antibody therapeutics have enhanced potency but the risk of adverse events. Here the authors develop a conditionally activated, single-module CAR. [ABSTRACT FROM AUTHOR]

One of the most important factors that limit the potency of CD8+cytotoxic T lymphocyte (CTL) responses is the tumor microenvironment (TME). Here, we provide evidence that miR-26a is a negative regulator of CTL function in the TME. Specifically, we identified miR-26a as a crucial suppressor gene in CTLs from the TME, as we found that, miR-26a expression was elevated in CTLs to respond to TME secretome stimulation. CTLs from miR-26a-transgenic mice showed impaired IFNγ and granzyme B production in response to their cognate antigen. Conversely, we found that miR-26a inhibition in CTLs could effectively increase the cytotoxicity and suppress tumor growth. Mechanically, we identified EZH2 as a direct target of miR-26a. miR-26a and EZH2 expression were found to be inversely correlated in CTLs, and the inhibition of EZH2 in CTLs impairs CTL function. These functional correlations were validated in a cohort of non-small cell lung cancer patients, indicating that the miR-26a-EZH2 axis is clinically relevant. Our findings suggested that miR-26a silencing as a novel strategy to improve the efficacy of CTL-based cancer immunotherapy. [ABSTRACT FROM AUTHOR]

T-cell receptor (TCR)-mediated cross-recognition is a major mechanism in the pathogenesis of drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome. However, the characteristics of the TCR repertoire and the clinical significance of repertoire reformation throughout the course of DRESS are unknown. Here, we isolated CD4+ and CD8+ T-cells from peripheral blood of 8 DRESS patients at 10-day intervals and, sequenced CDR3-regions of the TCRB chain by high-throughput sequencing to analyze the dynamic reformation in the T-cell repertoire hierarchy. Compared with healthy donors, T-cell expanded in peripheral repertoires from DRESS patient. The extent of fluctuation of dominant CD8+ T-cell clones, but not of CD4+ counterparts, correlated positively with the clinical severity and helped classify the enrolled subjects into 'fluctuant' and 'flat' repertoire groups. The anti-herpesvirus response, which was measured using anti-EBV/HHV antibodies, and the proportion of the homologous CD8+ EBV-specific clonotypes, in the 'fluctuant' group was substantial higher than that in the 'flat' group. Furthermore, autoimmune sequelae were observed in a cured 'fluctuant' patient. Collectively, the clinical relevance of the fluctuant CD8+ T-cell repertoires supports the notion that herpes virus-mediated continuously de novo priming of newly pathogenic CD8+ T-cell clones is an alternate mechanism responsible for the pathogenicity of DRESS. [ABSTRACT FROM AUTHOR]

A characteristic immunopathology of human cancers is the induction of tumor antigen-specific T lymphocyte responses within solid tumor tissues. Current strategies for immune monitoring focus on the quantification of the density and differentiation status of tumor-infiltrating T lymphocytes; however, properties of the TCR repertoire ‒ including antigen specificity, clonality, as well as its prognostic significance ‒ remain elusive. In this study, we enrolled 28 gastric cancer patients and collected tumor tissues, adjacent normal mucosal tissues, and peripheral blood samples to study the landscape and compartmentalization of these patients’ TCR β repertoire by deep sequencing analyses. Our results illustrated antigen-driven expansion within the tumor compartment and the contracted size of shared clonotypes in mucosa and peripheral blood. Most importantly, the diversity of mucosal T lymphocytes could independently predict prognosis, which strongly underscores critical roles of resident mucosal T-cells in executing post-surgery immunosurveillance against tumor relapse. [ABSTRACT FROM PUBLISHER]

In adoptive T cell transfer therapy (ACT), the antitumor efficacy of cytotoxic CD8+T lymphocytes (CTLs) has been limited by tumor-induced immunosuppression. We have demonstrated that miR-23a blockade in tumor-specific CTLs conferred resilience to TGFβ-mediated immunosuppression, resulting in superior tumor control. Our studies highlight miR-23a in tumor-specific CTLs as a clinically relevant target to enhance ACT. [ABSTRACT FROM PUBLISHER]