A monoclonal antibody that binds to the surface of photoreceptors

A monoclonal antibody (MAB), 7H11, that binds to the surface of photoreceptors has been produced. Using immunoaffinity procedures, proteins with molecular weights of 53, 48 and 42 kDa were found to bind a MAB 7H11 column, although the 48- and 42-kDa proteins may be proteolytic breakdown products of the 53 kDa protein. Electron microscopic-immunohistochemical studies show that the antigen is concentrated on the external surface of inner and outer segments of photoreceptors. It is likely that the 7H11 antigen is a component of the interphotoreceptor matrix and, therefore, may contribute to some aspect of photoreceptor-pigment epithelial interactions. However, the expression of the 7H11 antigen in cell culture suggests that it is expressed independently of direct cell-cell interactions with either pigment epithelial cells, Müller cells or other photoreceptors.