Abstract
Purpose:
In recent years, evidence has emerged demonstrating a unique stratification of antigen-presenting cells (APC) within the normal murine cornea, an immune-privileged site once thought to be devoid of such cells. In this study, we investigated the phenotype and distribution of APC within normal human donor corneas.
Methods:
Human corneas were obtained from the Center for Organ Recovery and Education (CORE). Fluorescence confocal microscopy was used to image corneal whole mounts. Only corneas without abnormalities noted on slit lamp examination by CORE were utilized.
Results:
CD11c+ dendritic cells (DC) were identified in the basal aspect of the epithelium as well as in the anterior stroma. A significant population of Langerin+ cells (LC) was found confined to the basal epithelium. The density of CD45+ DC diminished from peripheral to central cornea. CD68+ macrophages were identified mostly within the anterior stroma. The majority of CD45+ cells within the epithelium express MHC class II (HLA-DR) on at least portions of their dendrites.
Conclusions:
Our results reveal a unique stratification of APC within the normal human cornea with DC and LC situated more anteriorly than macrophages, suggesting progression from APC to barrier function. These findings are strikingly similar to the distribution of APC previously described in mice thus confirming the relevance of the murine model for study of corneal APCs. Flow cytometry is currently being employed to further phenotype the APC population within normal human corneas.
Keywords: 480 cornea: basic science •
423 antigen presentation/processing •
599 microscopy: light/fluorescence/immunohistochemistry