The expression of class I major histocompatibility antigens by human retinal pigment epithelium in vitro.

Since the expression of class I major histocompatibility antigens by the retinal pigment epithelium (RPE) may be important with regard to ocular immune responses, we investigated this using flow cytometry and compared the RPE cells with the colon carcinoma cell line SW742. Six cultured RPE cell lines were examined. All showed strong basal expression of class I antigen. However, this expression was not maximal, and all the RPE lines tested showed a marked capacity for up-regulation of expression by culture in the presence of interferon-alpha, interferon-gamma, or tumour necrosis factor alpha, cytokines involved in immunological responses.