ABSTRACT
Recent studies from our laboratory (7) demonstrated the presence of bone marrowderived cells within the normal mouse cornea. Numerous CD45+ cells with pleomorphic and dendriform morphology were found within the pericentral and central region of the corneal stroma (200-300 cells/mm2). Dual-color immunostaining demonstrated that 100% of the CD45+ cells co-expressed CD11b and 50% co-expressed F4/80. Approximately 30% of the totalcells and 50% of the F4/80+ cells co-expressed major histocompatibility complex (MHC) class II antigens. Very small to negligible numbers of cells expressed markers of dendritic cells (CD11c) or granulocytes (Ly6G). Markers for T-cells and NK cells were absent from the corneal stroma, indicating that all the cells identified in the stroma were of the myeloid lineage. Studies by M. Reza Dana (see Chapter 12) also described a network of macrophage-like bone marrow-derived cells in the normal mouse cornea, but their findings conflicted with ours in that they also found cells that expressed the dendritic cell marker CD11c (8,9). Both laboratories found that the majority of bone marrow-derived cells lacked expression of MHC class II, raising interesting questions about the potential role of these corneal cells as immunogenic or tolerogenic APCs.
