Expression of MHC class I and II molecules by cadaver retinal pigment epithelium cells: optimization of post-mortem HLA typing

Abstract

SUMMARY: The objective of this study was to investigate the expression of MHC antigens by retinal pigment epithelium cells (RPE) after stimulation with interferon-gamma (IFN-γ) and to improve the currently practised technique of cadaver HLA typing. A concentration of 100 U/ml IFN-γ induced expression of class I molecules up to > 90% 3 days after stimulation, whereas 50 U/ml were required for the expression of HLA-DR to > 90%. A concentration of 750 U/ml induced 35–45% expression of HLA-DP and <25% HLA-DQ after 3 days. Cells were serologically typed using the standard lymphocytotoxicity assay 3 days after stimulation with 250 U/ml IFN-γ. Typing of class I specificities was complemented by one-dimensional isoelectric focusing (1D-IEF). We observed high concordance between the results of the RPE typing and the lymphocytotoxicity test on the same donors. Our results show complete typing of class I and II antigens post-mortem, which, in particular, enables graft matching and improvement of graft survival in recipients of organs removed many hours after death such as the cornea.