Culture in vitro Modulation of Human Leukocyte Antigen Molecules and Costimulatory Molecules on Human Retinal Pigment Epithelium

Abstract

Purpose: To determine the potential of culture in vitro to alter the human leukocyte antigen (HLA) molecules and costimulatory molecules on human retinal pigment epithelium (RPE). Methods: Pure RPE were isolated and cultured. Two sets of RPE (normal and activated) were used. Activated RPE were obtained by incubating primary cultures of RPE with recombinant human interferon-γ. The expression of HLA molecules and costimulatory molecules on human RPE at different passages after culture in vitro were analyzed quantitatively by flow cytometry. Results: In the process of routine culture on culture flask, the duration of culture in vitro was significantly correlated with the expression of HLA-ABC molecules on the normal RPE and the activated RPE (r = –0.893, p < 0.001 and r = –0.964, p < 0.001 respectively), HLA-DR molecule on the activated RPE (r = –0.901, p < 0.001) and intercellular adhesion molecule-1 on the normal RPE (r = 0.961, p < 0.001). There were no correlations between the duration of culture in vitro andthe expression of HLA-DR molecule on the normal RPE, intercellular adhesion molecule-1 on the activated RPE, B7-1 and B7-2 molecules on the normal RPE and the activated RPE. Conclusions: The chronic rejection is the major immunological rejection following RPE allogeneic graft. Culture in vitro modulation of HLA molecules and costimulatory molecules on RPE may increase lymphocyte infiltration and activation and promote the chronic rejection following allograft RPE transplantation.