PRODUCTION OF INTERLEUKIN-6 AND GRANULOCYTE-MACROPHAGE COLONY-STIMULATING FACTOR BY MURINE IRIS AND CILIARY BODY EXPLANTS

Purpose. To examine the ability of murine iris-ciliary body explants t o produce cytokines with proinflammatory activities. Methods. Supernat ants derived from murine iris-ciliary body (I-CB) tissue explants cult ured (four per well in 1 ml medium) in the presence of indomethacin we re analyzed for the production of IL-1, IL-2, IL-3, IL-6, tumor necros is factor-alpha/beta (TNF alpha/beta) and granulocyte-macrophage colon y-stimulating factor (GM-CSF). Analysis was performed by thymocyte cos timulation, growth factor-dependent cell proliferation, TGF-beta-sensi tive mink lung epithelial cell proliferation, and enzyme-linked immuno sorbent assays (ELISA). Results. Supernatants from I-CB explants cultu red in vitro for 24 hours contained significant thymocyte costimulator y activity. This activity was fully neutralized by a combination of an tisera to IL-1 and IL-6, and ELISA analysis confirmed that IL-6 was a significant component of the supernatant (402.1 pg/ml). TNF alpha/beta were also found in low concentrations (similar to 2.0 U/ml) by ELISA analysis, whereas IL-2 and IL-4 were not detectable. Significant amoun ts of GM-CSF (15.8 U/ml), but no IL-3, were detected. Conclusions. The se results demonstrate that normal I-CB tissue contains cells capable of producing IL-6, GM-CSF, and IL-1. Because of the proinflammatory na ture of IL-6 and IL 1, and the ability of GM-CSF, IL-1, and IL-6 to en hance functional capabilities of antigen presenting cells, regulation of the production of these cytokines may contribute significantly to t he maintenance of the immunologic status of this regional site.