Project description:The optimal T cell attributes for the adoptive immunotherapy of cancer and viral diseases are currently unclear. Recent adoptive transfer clinical trials using ex vivo expanded tumor infiltrating lymphocytes has provided evidence that differentiated effector T cells can mediate durable responses in selected cancer patients. The capacity of these transferred cells to persist in the host was found to strongly correlate with their clinical activity. Thus, there is significant interest in identifying intrinsic markers that define antigen specific effector T cells that can develop into long-lived memory cells rather than undergoing apoptosis after infusion in humans. We recently reported the long term persistence of ex vivo expanded tumor specific CD8+ T effector clones in refractory metastatic melanoma patients after adoptive T cell transfer. By utilizing these highly homogeneous clone populations, we sought to define the pre-infusion cellular and molecular attributes associated with their effector to memory transition. Comparative transcriptional profiling found the pre-infusion clone mRNA expression levels of the IL-7 receptor (IL-7Ra) and the proto-oncogene, c-myc, directly correlated with the level of clonal persistence after adoptive transfer in humans. The predictive value of these markers was further established by utilizing IL-7R protein, induced pSTAT5, and c-myc mRNA expression to prospectively identify human tumor specific effector clones that could engraft after controlled adoptive transfer into highly immunodeficient mice. These findings support that IL-7R and c-myc expression are valuable cell intrinsic markers that can predict the fate of effector CD8+ T cells after adoptive transfer. We used microarrays to compare the pre-infusion gene expression profile of melanoma-specific CD8+ T cell clones that would eventually either persist or not after adoptive transfer in humans. We derived ten melanoma-specific CD8+ T cell clones and determined their degree of persistence after adoptive therapy into patients. We performed microarray on the pre-infusion samples of six persisting and four non-persisting clones to obtain a comparative gene signature profile.

Project description:Neonates are highly susceptible to repeat infection and respond poorly to vaccination; these attributes derive from intrinsic differences between neonatal and adult naïve CD8+ T cells. In contrast to adult cells, naïve neonatal cells exhibit a greatly limited ability to differentiate into memory cells, a fundamental property of their adult counterparts. Here, we describe the role of the miR-29 microRNA in naïve T cells, focusing on age-related differences in miR-29 expression and the consequences of these differences in adult and neonatal cells, from mice and humans. In adults, high expression of miR-29 licenses naïve cells towards eventual memory cell fates; whereas neonatal naïve cells, which lack high expression of miR-29, are predisposed towards effector cell fates in response to an infection. Multiple lines of evidence support this model, including analysis of a mouse model deficient in miR-29, which we examine with adoptive transfer experiments to define the functional consequences of reduction of miR-29, together with genomic assays to define the regulatory impact of miR-29. Adult miR 29 deficient naïve CD8+ T cells cell are primed for activation and therefore secrete elevated levels of cytolytic molecules, and express transcription factors at levels associated with effector cell differentiation; moreover, these cells exhibit an altered CD8+ T cell memory repertoire, akin to that of neonatal CD8+ T cells. Importantly, we use a method that exploits extracellular vesicles as a delivery vehicle with which to modulate levels of miR-29 in neonatal and adult naïve T cells, examining both human and mouse cells. For example, increasing miR 29 expression in mouse naïve neonatal CD8+ T cells significantly improved the memory response during infection, concomitant with alterations to the chromatin landscape characteristic of cells primed for memory differentiation. Delivery of miR-29 antagomirs to human adult naïve CD8+ T cells was sufficient to induce the adult cells to adopt phenotypes and gene expression signatures normally found in cells present in newborns. This study establishes miR-29 as a key conserved regulator in naïve CD8+ T cells, and by adjusting levels of miR-29, has the potential to underlie therapeutic strategies for controlling the balance of effector versus memory fates in human T cells.

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Functionalized nanowires for miRNA-mediated therapeutic programming of naïve T cells

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