Abstract
Purpose: :
Previously we have demonstrated that retinal pigmented epithelial cells (RPE) and cells of the neuroretina (NR) contribute factors into the ocular microenvironment that promote anti–inflammatory activity in activated macrophages. Therefore, we investigated whether there is a change in this anti–inflammatory activity by RPE and NR from eyes with experimental autoimmune uveitis (EAU).
Methods: :
RPE eyecups and NR from healthy B10.RIII mice or from B10.RIII mice with EAU were prepared, placed into culture, and incubated for 48 hours. The conditioned media of each culture was transferred to cultures of resting or LPS–activated macrophages (J774A.1 cell line). After 48 hours of incubation, the cytokines in the supernatants (SN) were quantified by multianalyte bead profiling (Luminex) for IL–1ß, IL–6, Il–10, TNF–α, G–CSF, GM–CSF. Also, the RPE–CM and NR–CM were analyzed by the multianalyte analysis.
Results: :
Factors from both RPE and NR of healthy eyes suppressed IL–1ß and TNF–α production, and induced significant IL–10 production by LPS–activated macrophages. In contrast, the RPE and NR factors from eyes of mice near the peak of clinical EAU, day 14, no longer suppressed IL–1ß and TNF–α production, but promoted GM–CSF production, and still induced IL–10 production. There was no affect on IL–6 and G–CSF production. The factors of EAU RPE and NR did not induce any cytokine production in resting macrophages, nor did we detect any inflammatory cytokines in the RPE and NR conditioned media. Similar to healthy retinal tissues, RPE and NR from eyes of mice that have recovered from EAU, day 40, suppressed IL–1ß and TNF–α production and induced IL–10 production by activated macrophages.
Conclusions: :
The results indicate that there are at least two mechanisms of retinal immunoregulation, one to suppress the production of proinflammatory cytokines, and one to promote anti–inflammatory cytokine production by activated macrophages. In EAU there is a temporary loss of the suppressor of inflammatory cytokine production, while the retinal tissues retained their ability to induce immunosuppression during uveitis, which maybe a mediator of the spontaneous resolution of EAU.
Keywords: uveitis-clinical/animal model • immunomodulation/immunoregulation • retina