Endogenous Nur77 is a specific indicator of antigen receptor signaling in human T and B cells

JF Ashouri, A Weiss - The Journal of Immunology, 2017 - journals.aai.org
JF Ashouri, A Weiss
The Journal of Immunology, 2017journals.aai.org
Distinguishing true Ag-stimulated lymphocytes from bystanders activated by the
inflammatory milieu has been difficult. Nur77 is an immediate early gene whose expression
is rapidly upregulated by TCR signaling in murine T cells and human thymocytes. Nur77-
GFP transgenes serve as specific TCR and BCR signaling reporters in murine transgenic
models. In this study, we demonstrate that endogenous Nur77 protein expression can serve
as a reporter of TCR and BCR specific signaling in human PBMCs. Nur77 protein amounts …
Abstract
Distinguishing true Ag-stimulated lymphocytes from bystanders activated by the inflammatory milieu has been difficult. Nur77 is an immediate early gene whose expression is rapidly upregulated by TCR signaling in murine T cells and human thymocytes. Nur77-GFP transgenes serve as specific TCR and BCR signaling reporters in murine transgenic models. In this study, we demonstrate that endogenous Nur77 protein expression can serve as a reporter of TCR and BCR specific signaling in human PBMCs. Nur77 protein amounts were assessed by immunofluorescence and flow cytometry in T and B cells isolated from human PBMCs obtained from healthy donors that had been stimulated by their respective Ag receptors. We demonstrate that endogenous Nur77 is a more specific reporter of Ag-specific signaling events than the commonly used CD69 activation marker in both human T and B cells. This is reflective of the disparity in signaling pathways that regulate the expression of Nur77 and CD69. Assessing endogenous Nur77 protein expression has great potential to identify Ag-activated lymphocytes in human disease.
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