Localization of CD15 immunoreactivity in the rat retina

Using immunocytochemistry, we have investigated the localization of CD15 in the rat retina. In the present study, two types of amacrine cell in the inner nuclear layer (INL) and some cells in the ganglion cell layer were labeled with anti-CD15 antisera. Type 1 amacrine cells have large somata located in the INL, with long and branched processes ramifying mainly in stratum 3 of the inner plexiform layer (IPL). Type 2 cells have a smaller soma and processes branching in stratum 1 of the IPL. A third population showing CD15 immunoreactivity was a class of displaced amacrine cells in the ganglion cell layer. The densities of type 1 and type 2 amacrine cells were 166/mm² and 190/mm² in the central retina, respectively. The density of displaced amacrine cells was 195/mm². Colocalization experiments demonstrated that these CD15-immunoreactive cells exhibit γ-aminobutyric acid and neuronal nitric oxide synthase (nNOS) immunoreactivities. Thus, the same cells of the rat retina are labeled by anti-CD15 and anti-nNOS antisera and these cells constitute a subpopulation of GABAergic amacrine cells.