Isolation of a Thy-1-like glycoprotein from cat brain: distribution in retina and brain defined by monoclonal antibodies.

Thy-1 is a glycoprotein primarily expressed in the nervous system of a large number of vertebrate species. A concanavalin-A binding glycoprotein with a molecular weight of 25,000 daltons has been isolated from cat brain, which corresponds to the Thy-1 molecule isolated in other species. Monoclonal antibodies were generated against this cat Thy-1 molecule, and immunohistochemical staining on adult cat brain frozen sections demonstrated a localisation of the molecule to regions rich in synapses. In the cerebellum, the immunoperoxidase staining with the antibodies was intense in the molecular layer, the fibres of the granular layer, and the Purkinje cell bodies. This distribution of Thy-1 is consistent with that seen with the rodent and chicken Thy-1 molecule. In the retina, one antibody (WEHY-MS-1) detected the cat Thy-1 molecule in the ganglion cell layer and on fibres of the inner plexiform and inner nuclear layers. Another antibody (WEHY-MS-2) produced a similar retinal staining pattern except that the ganglion cell layer was devoid of Thy-1. Although the Thy-1 molecule in the rodent and chicken retina have been reported in the ganglion cell and inner plexiform layers, there have been no consistent reports of Thy-1 in the inner nuclear layer. This suggests that this putative cat Thy-1 molecule may have a retinal distribution pattern different from that seen in other species.