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Induction of MHC class II antigen in cultured bovine ciliary epithelial cells
H Helbig1, R C Gurley, R J Reichl
1Laboratory of Immunology, National Eye Institute, NIH, Bethesda, Md.
Insights
Bovine ciliary epithelial cells express major histocompatibility complex (MHC) class II antigens upon stimulation with gamma-interferon (IFN-G). This expression is modulated by other factors, with implications for understanding anterior uveitis.
Area of Science:
- Immunology
- Ophthalmology
- Veterinary Science
Background:
- Major histocompatibility complex (MHC) class II antigens play a crucial role in immune responses.
- The expression of MHC class II in ocular tissues, particularly the bovine ciliary epithelium, is not fully understood.
- Anterior uveitis involves inflammation within the eye, where immune cells and antigen presentation are critical.
Purpose of the Study:
- To investigate the expression of MHC class II antigens in cultured bovine ciliary epithelial cells.
- To determine the effects of gamma-interferon (IFN-G) and other cytokines on MHC class II expression in these cells.
- To compare the sensitivity of different intraocular tissues to IFN-G-induced MHC class II expression.
Main Methods:
- Indirect immunohistochemistry and immunocytofluorometry were used to detect MHC class II antigens.
- Bovine ciliary epithelial cells and other intraocular tissues were cultured in vitro.
- Cells and tissues were incubated with varying concentrations of bovine gamma-interferon (IFN-G) and other modulatory agents.
Main Results:
- Cultured bovine ciliary epithelial cells did not express MHC class II antigens without stimulation.
- Incubation with bovine gamma-interferon (IFN-G) induced significant MHC class II expression in nearly all ciliary epithelial cells.
- Tumor necrosis factor enhanced IFN-G-induced expression, while dexamethasone, prostaglandin E2, and alpha-interferon reduced it.
- All tested intraocular tissues, including retinal pigment epithelium, corneal endothelium, and lens epithelium, responded to IFN-G with MHC class II expression, albeit with varying sensitivities.
Conclusions:
- Bovine ciliary epithelial cells can be induced to express MHC class II antigens by IFN-G.
- The expression of MHC class II on ciliary epithelium is modulated by several factors, suggesting a complex regulatory mechanism.
- The differential sensitivity of various intraocular tissues to IFN-G warrants further investigation in the context of ocular inflammation and anterior uveitis.
Abstract:
The expression of major histocompatibility complex (MHC) class II antigens in cultured bovine ciliary epithelial cells was investigated by means of indirect immunohistochemistry and immunocytofluorometry. Ciliary epithelial cells grown in control tissue-culture medium did not express MHC class II. However, after incubation with bovine gamma-interferon (IFN-G) in concentrations as low as 0.3 units/ml, nearly all cells stained for MHC class II. Tumor necrosis factor increased IFN-G-induced MHC class II expression. A reduction in IFN-G-induced MHC class II expression was observed with dexamethasone, prostaglandin E2 and alpha-interferon. To test whether MHC class II expression in response to IFN-G was specific for the ciliary epithelium, several intraocular tissues were grown in culture and incubated with IFN-G. MHC class II expression was observed in all tissues tested for response to IFN-G, but at different sensitivities. Retinal pigment epithelium and ciliary epithelium exhibited the highest sensitivity, followed by corneal endothelium and lens epithelium; the lowest sensitivity was observed for retinal vascular pericytes. The results are discussed in the context of MHC class II expression on the ciliary epithelium in anterior uveitis.