GRADED DISTRIBUTION OF THE NEURAL 2A10 ANTIGEN IN THE DEVELOPING CHICKEN RETINA

During retinal histogenesis, post-mitotic cells become located in diff erent tissue layers, where they differentiate into distinct cell types . In an attempt to elucidate mechanisms of cell differentiation, we ha ve employed hybridoma technology in conjunction with various in vitro techniques. Here, we present monoclonal antibody 2A10, which binds spe cifically to the cell surface of neurons and outgrowing neurites. With in the retina 2A10 antigen expression is developmentally regulated bei ng most pronounced during the period of tissue layer formation. Elevat ed antigen expression is limited to post-mitotic neurons as revealed b y labeling with bromodeoxyuridine. Retinal ganglion cells, which are t he first neurons to develop, appear not to influence the overall devel opmental regulation of the antigen in the retina, since elimination of these cells by virtue of optic nerve transection in ovo did not alter the antigen expression. The antigen is distributed in a graded fashio n in the radial axis of the retina. Maximal immunoreactivitiy was foun d at the inner surface of the retina (optic fiber layer), whereas only minute reactivity was detected in the outermost layer. This graded di stribution could possibly be involved in a topographic system providin g positional information for differentiating neurons. Operationally, M Ab 2A10 is a useful marker for retinal neurons, and provides a tool fo r establishing pure Muller glia cultures by complement-mediated cytoly sis of retinal neurons.