Abstract
Purpose: :
To determine the quantity of inflammatory cytokines produced by activated cells on the ocular surface in a TH1 disease state using Luminex technology. We previously reported in a mouse model of dry eye that a dry, desiccating environment exposes shared epitopes in the lacrimal functional unit that induce pathogenic CD4+ T cells which are capable of transferring disease to an athymic mouse.
Methods: :
C57BL/6 female euthymic mice were exposed to a dry, desiccating environment (DS) for 10 days. Splenic and superficial cervical lymph node CD4+ T cells from DS mice were adoptively transferred to athymic T-cell deficient mice. Tear samples were collected before and 3 days after adoptive transfer. 1.5 µl of Beadlyte assay buffer was applied to the ocular surface, 1µl tear samples were collected from both eyes of each mouse, placed in 8 µl of Beadlyte assay buffer, and analyzed by Luminex for IFN-γ, TNF-α, IL-12(p70) and IL-1β.
Results: :
In the athymic mice receiving DS CD4+ T cells, IFN-γ tear levels significantly increased from a baseline of 18.87 pg/ml+/-6.66 to 43.53 pg/ml +/-7.87 (*p=0.027) 3 days after adoptive transfer. TNF-α tear levels increased from 38.1+/-9.4 pg/ml to 126.88+/-17.65 pg/ml (*p=0.003). Increases in IL12(p70) (20.8 pg/ml+/-12.81 to 127.28+/-41.2 pg/ml (*p<=0.04)) and IL-1β (125.5+/-29.62 pg/ml to 275.98+/-70.34 pg/ml (*p=0.03)) were also detected.
Conclusions: :
Tears from athymic mice receiving DS CD4+ T cells had a significant increase in IFN-γ, TNF-α, IL-12(p70), and IL-1β, which correlates with the TH1 phenotype found in patients with dry eye. These results further confirm our previous report that CD4+ T cells mediate dry eye disease. Luminex analysis of tear fluid provides a fast, reliable, and quantitative method to measure numerous cytokines in a small volume, thereby providing an additional mechanism for screening the anti-inflammatory effects of potential anti-phlogistic therapeutics in ocular inflammatory diseases.
Keywords: cornea: tears/tear film/dry eye • inflammation • cytokines/chemokines