Specific cell types transduced by intravitreal AAV2 in TgIGF-I retinas.

<p>(A) Retinal flat-mount immunostained for GFP showing transduction of cells located on the surface of the retina. Arrows indicate GFP signal in axons, demonstrating transduction of ganglion cells. (B) GFP detection in paraffin-embedded eye sections. Besides transduction of cells in the ganglion cell layer (GCL), there was, to a lesser extend, transduction of cells of the Inner Nuclear layer (INL) <i>(inset, arrows)</i>. (C) Double immunostaining for GFP and calretinin (amacrine neurons) showed that amacrine cells located both in the surface of the retina as well as in the INL were transduced by AAV2-GFP. Bipolar cells, stained with an antibody against PKC-α, do not show colocalization with GFP nor in the cell bodies localized in the INL <i>(right inset)</i> nor in the neuronal projections ending at the GCL <i>(left inset)</i>. Immunohistochemistry for calbindin, expressed in horizontal cells of the INL outmost layer <i>(left inset)</i> and in a subtype of amacrine cells located in the INL and GCL <i>(right inset)</i>, showing that both cell types are transduced by AAV2-GFP. (D) Double immunostaining for GFP and Glutamine synthetase (Müller cells). No expression of GFP was observed in the Müller cells' end feet processes at the retinal surface <i>(right panel)</i> or in the cell bodies in the INL <i>(left panel)</i>. Astrocytes (S100+), localized in the most superficial retinal layer and around blood vessels, were not transduced by AAV2-GFP. Original magnification: 10× (A), 2× (B). Scale bar: 33 µm (C, <i>left and central panel</i>); 74 µm (C, <i>right panel</i>); 74 µm (D, <i>left panel</i>); 18 µm (D, <i>right panel</i>).