STAT3-deficient T cells could not traffic into the retina nor induce EAU.

Abstract

<p>(A) WT mice or mice with targeted deletion of STAT3 in T cells (CD4-STAT3KO) were immunized with IRBP in CFA and their eyes were enucleated 21 days post-immunization and histological sections through the retina were stained with H&E. Black arrows indicate presence of inflammatory cells in the vitreous (V) and blue arrows depict pathologic foci characterized by the presence of retinal folds and hemorrhage. Red arrow, choroiditis; White arrow, granuloma; green arrow, retinal vasculitis; OpN, optic nerve; V, vitreous; GCL, ganglion cell layer; INL, inner nuclear layer; ONL, outer nuclear layer. (B) Freshly isolated cells from the draining lymph nodes or spleen of WT unimmunized WT control or EAU mice were analyzed by the intracellular cytokine assay. Plots were gated on CD4⁺ T cells and numbers in quadrants indicate percentage of CD4⁺ T cells expressing IL-17 and/or activated STAT3 (pSTAT3). (C) WT or CD4-STAT3KO mice were immunized with IRBP in CFA and T cells present in retina on day-21 post-immunization were detected and quantified by flow cytometry. Numbers in quadrants indicate percentage of CD3⁺ or CD4⁺ T cells or CD4⁺ T cells expressing IL-17 and/or IFN-γ. Data presented are representative of at least 3 independent experiments.</p