NOVEL EXPRESSION AND CHARACTERIZATION OF LYMPHATIC VESSEL ENDOTHELIAL HYALURONATE RECEPTOR (LYVE–1) BY OCULAR SURFACE CELLS.

Abstract

Abstract: : Purpose: Lymphatic vessel endothelial hyaluronic acid receptor (LYVE–1) is a newly discovered lymphatic–specific marker; to date there is no report of its expression on corneal or ocular surface cells. The purpose of this study was to investigate its expression by different cell types in both the cornea and conjunctiva. Methods: Normal and inflamed corneas and conjunctivae were harvested from BALB/c mice (6–8 weeks of age) for immunofluorescent confocal microscopic studies. As a control, cross sections of the skin were studied. Results: In addition to its expected expression on lymphatic vessels, LYVE–1 expression was also detected on a population of cells in both the ocular surface and skin. In the skin, the expressional patterns of LYVE–1⁺ cells changed during inflammation, with more staining found on the superficial layers of the dermis as compared to the normal condition. In the normal ocular surface, LYVE–1⁺ cells were present in both the corneal and conjunctival stroma. These cells are CD45⁺, CD11b⁺, and CD31^– indicating a monocytic lineage. Further studies were undertaken to investigate a) the expressional changes of LYVE–1 during corneal inflammation, and b) the possible interaction between LYVE–1 and the other lymphatic markers including VEGFR–3 using a VEGFR–3 blockade strategy. Conclusions: A new population of monocytic cells has been found to express LYVE–1 in both the ocular surface and the skin. These cells are CD45⁺, CD11b⁺, and CD31^– indicating their bone marrow lineage. These data suggest that the cells that normally express LYVE–1 might act as a reservoir for new lymphatic vessel development and dendritic or inflammatory cell recruitment when the immune system is challenged.

Keywords: immunomodulation/immunoregulation • transplantation • cornea: basic science