Characterization of retinal expression of vascular cell adhesion molecule (VCAM1) during experimental autoimmune uveitis

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Abstract Purpose Leukocyte adhesion to the blood retinal barrier is a critical step in the pathogenesis of autoimmune uveitis and is mediated through adhesion molecule expression. Here, we have investigated the retinal expression of VCAM1 in an adoptive transfer model of experimental autoimmune uveitis (EAU). Methods C57Bl6 mice were immunized with interphotoreceptor retinoid‐binding protein (IRBP) peptide 1–20. Activated IRBP‐specific T cells were prepared from their draining lymph nodes and spleens, cultured with IRBP peptide 1‐20 and adoptively transferred in C57BL/6 mice. The animals were sacrified after 3 weeks and the eyes processed for immunohistology. The severity of the disease was determined by histological grading. The expression of VCAM1 was analysed by immunofluorescence. Co‐labelling with GFAP (glial cells markers) and endoglin (endothelial cell marker) were also performed in order to determine which cell type expressed VCAM1. Results In eyes with low grade uveitis, VCAM1 was only expressed at certain location of the internal limiting membranes and epithelial cells of the ciliary body. In correlation with disease severity, the staining extend to all the limiting membranes, vasculitis lesions, Muller cells extension, the outer limiting membranes and RPE cells. VCAM1 expression on the inner limiting membrane and Müller cells extension co stained with GFAP. On vasculitis lesions, VCAM1 expression co localized with either GFAP or endogline. Conclusion VCAM1 is expressed on blood retinal cells during EAU. Moreover, the intensity and extension of its expression correlates with disease severity. Those data suggest that VCAM1 plays an important role in EAU development.