Expression of B7 Molecules on Corneal Epithelial Cells Infected With Adenovirus

Abstract

Abstract: : Purpose: B7– molecules are a family of proteins that co–stimulate T cell during immune activation; normally the corneal epithelial cells do not have any expression of those molecules on their surface. It has been suggested that the TGF–ß down–regulates B7–molecules on the cellular surface in order to regulate the immune response. The objective of this study is to determine if the corneal epithelial cells express B7–molecules on their cellular surface after a viral infection and to quantify the TGF–ß secretion in culture supernatant from infected cells. Methods: Corneal epithelial cells were isolated from human corneas treated with dispase–II, and grown in the presence of supplemented hormonal epithelial medium at 37ºC and 5% CO₂ until confluence. At passages one or two, the cells were exposed to different doses of adenovirus 5 (Ad5) for 2 h. After infection the cells were washed three times and then cultured at different times. Then, the cells were recovered and stained with PE–conjugated monoclonal antibodies (mAbs)against human CD80 and CD86 and with FITC–conjugated mAbs against human cytokeratin and the results were analyzed by flow citometry. The culture supernatant was also recovered to quantify TGF–ß secretion by ELISA. Results: Non infected corneal epithelial cells did not express at any time CD80 or CD86; however Ad5 infected epithelial cells were positive to CD80 since 24h (40%) raising its maximum level at 72 h (∼90%); CD86 expression on corneal epithelial cells was detected also at 24h (20%) raising its maximum level at 72h (∼70%). When TGF–ß was evaluated, we observed that Ad5 infected corneal epithelial cells only produced 0.25 times more cytokine than the non infected corneal epithelial cells. Conclusions: Our results suggest that corneal epithelial cells express CD80 and CD86 after virus infection independently of TGF–ß concentration.

Keywords: cornea: epithelium • immunomodulation/immunoregulation • immune tolerance/privilege