In Vitro Expanded CD4+CD25+Foxp3+ Regulatory T Cells Maintain a Normal Phenotype and Suppress Immune-Mediated Ocular Surface Inflammation.
Invest Ophthalmol Vis Sci. 2008 Jul 24. [Epub ahead of print]
Siemasko KF, Gao J, Calder VL, Hanna R, Calonge M, Pflugfelder SC, Niederkorn JY, Stern ME
Purpose: To determine if in vitro expanded CD4+CD25+Foxp3+ regulatory T cells can suppress immune-mediated ocular surface inflammation in a mouse model of dry eye.
Methods: C57BL/6 or BALB/c mice were exposed to a dry, desiccating environment produced by maintaining low humidity (<40%), injections of scopolamine, and air flow produced by a fan. CD4+CD25+ regulatory T cells were isolated and expanded in vitro in the presence of rmIL-2 and beads coated with anti-CD28 and anti-CD3. In vitro expanded regulatory T cells were phenotypically compared to freshly isolated regulatory T cells by flow cytometry and immunofluorescence. T cell-deficient nude mice were reconstituted with CD4+ T-effector cells from donor mice exposed to a desiccating environment for 5 days in combination with or without freshly isolated or in vitro expanded regulatory T cells. Tear cytokine levels were determined by multiplex bead-based immunoassay (Luminex).
Results: In vitro regulatory T cells maintained normal levels of CD4+, CD25+, and intracellular Foxp3+ as determined by flow cytometry and immunohistochemistry. Freshly isolated and in vitro regulatory T cells were titrated in the presence of CD4+ pathogenic T cells (CD4+Path T cells) in reconstitution experiments and most efficiently ablated tear cytokine levels and conjunctival cellular infiltration at a ratio of 1:1 (T Regs: CD4+Path).
Conclusions: Regulatory T cells expressed CD4+, CD25+, and intracellular Foxp3+ at normal levels and retained their inhibitory function after in vitro expansion, providing a useful tool to determine the mechanism regulatory T cells use to sustain a homeostatic environment on the ocular surface.
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