Abstract
A monoclonal antibody, 8D9, has been obtained that binds to axons in the chick nervous system. Biochemical and immunological experiments indicate that the 8D9 antigen is related to the mouse L1 cell-adhesion molecule. The results of immunohistochemical experiments using monoclonal antibody 8D9 to study the development of the chick visual system are consistent with the 8D9 antigen functioning in axon fasciculation.