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DeBarge, R.

Publications and source records attributed to DeBarge, R..

3 recordsLinked to original sources

A mass cytometry approach to track the evolution of T cell responses during infection and immunotherapy by paired T cell receptor repertoire and T cell differentiation state analysis

T cell receptor (TCR) recognition followed by clonal expansion is a fundamental feature of adaptive immune responses. Here, we developed a mass cytometric (CyTOF) approach combining antibodies specific for different TCR V- and V{beta}-chains with antibodies against T cell activation and differentiation proteins to identify antigen-specific expansions of T cell subsets and assess aspects of cellular function. This strategy allowed for the identification of expansions of specific V{beta} and V chain expressing CD8+ and CD4+ T cells with varying differentiation states in response to Listeria monocytogenes, tumors, and respiratory influenza infection. Expanded V{beta} chain expressing T cells could be directly linked to the recognition of specific antigens from Listeria, tumor cells, or influenza. In the setting of influenza infection, we showed that the common therapeutic approaches of intramuscular vaccination or convalescent serum transfer altered the clonal diversity and differentiation state of responding T cells. Thus, we present a new method to monitor broad changes in TCR specificity paired with T cell differentiation during adaptive immune responses.

immunology↗

T cell-instructed inflammation drives immune checkpoint inhibitor therapy resistance

Resistance to immune checkpoint inhibitors (ICIs) is common, even in tumors with T cell infiltration. We thus investigated consequences of ICI-induced T cell infiltration in the microenvironment of resistant tumors. T cells increased in ICI-resistant tumors following treatment as did neutrophils, in contrast to ICI-responsive tumors. Resistant tumors were distinguished by high expression of IL-1 Receptor 1 (IL1R1), enabling a synergistic response to IL-1 and TNF to induce G-CSF, CXCL1, and CXCL2 via NF-{kappa}B signaling, supporting neutrophils. Perturbation of this inflammatory resistance circuit sensitized tumors to ICIs. Paradoxically, T cells drove this resistance circuit via TNF both in vitro and in vivo. Evidence of this inflammatory resistance circuit and its impact also translated to human cancers. These data support a novel mechanism of ICI resistance, wherein treatment-induced T cell activity can drive resistance in tumors responsive to IL-1 and TNF, with important therapeutic implications. Statement of SignificanceAlthough T cell-infiltrated cancers are frequently resistant to immune checkpoint inhibitor therapies, mechanisms of resistance beyond T cell exhaustion remain unclear. Here, we reveal the functional significance of tumor- infiltrating T cells in resistant tumors, which surprisingly instruct immunosuppressive inflammation in mouse and human cancers responsive to IL-1 and TNF.

immunology↗

The Development, Function, and Plasticity of the Immune Macroenvironment in Cancer

Harnessing immune defense mechanisms has revolutionized cancer therapy, but our understanding of the factors governing immune responses in cancer remains incomplete, limiting patient benefit. Here, we use mass cytometry to define the organism-wide immune landscape in response to tumor development across five tissues in eight tumor models. Systemic immunity was dramatically altered across mouse models and cancer patients, with changes in peripheral tissues differing from those in the tumor microenvironment and taking place in phases during tumor growth. This tumor-experienced immune system mounted dampened responses to orthogonal challenges, including reduced T cell activation during viral or bacterial infection. Disruptions in T cell responses were not cell-intrinsic but rather due to reduced responses in antigen-presenting cells (APCs). Promoting APC activation was sufficient to restore T cell responses to orthogonal infection. All systemic immune changes were reversed with surgical tumor resection, revealing remarkable plasticity in the systemic immune state, which contrasts with terminal immune dysfunction in the tumor microenvironment. These results demonstrate that tumor development dynamically reshapes the composition and function of the immune macroenvironment.

immunology↗