Corneal epithelial-specific cell surface antigen recognized by a monoclonal antibody

Monoclonal antibodies, specific against cell surface differentiation antigens of human corneal epithelial cells, were developed using epithelial cells resected from human corneas as the immunogens. One of these antibodies reacted specifically with corneal epithelial cells and not with epithelial cells of other tissues when tested by an indirect immunoperoxidase technique. Nonidet P-40 extracts of different subcellular fractions of human corneal epithelial cells were tested for their reactivity against this antibody using an enzyme-linked immunosorbent assay. The results indicated that the antigen recognized by this antibody is associated with the plasma membrane. This was further verified by immuno-electron-microscopic analysis using ferritin-conjugated anti-mouse IgG antibody. This antigen was not detectable in the corneal epithelial cells in primary cultures nor in the epithelial cells from early stages of developing cornea (12 to 18 weeks in utero ) but was present in the epithelial cells in the corneas of an 8-month-old infant. Therefore, this surface-associated antigen identified in the present study is a developmentally regulated marker of human corneal epithelium.