Thy-1 antigen: a ganglion cell specific marker in rodent retina.

A monoclonal antibody, 2G12 , has been produced against a rat cerebral cortex glycoprotein fraction. It interacts with Thy-1 based on both the tissue distribution of its reactivity and the blocking of its binding by pretreatment with a rabbit anti-Thy-1 serum. In rat retina this antibody labels only cell bodies in the ganglion cell layer, optic nerve fibres and the inner plexiform layer. That the cell-body labelling was confined to ganglion cells was confirmed by double-labelling experiments. Ganglion cells were distinguished by retrograde transport of fluorescent markers injected into the superior colliculi. The retinas were dissociated into single cells and the cell suspension was labelled with 2G12 . There was almost complete coincidence of the two labels. A monoclonal antibody against mouse Thy-1.2 gave an essentially identical pattern of labelling. In both rats and mice Thy-1 was also found on the vitreal surface of the inner limiting membrane in a pattern reminiscent of that formed by the Müller cell endfeet, although these cells do not express Thy-1.