Figure 3. Confocal immunofluorescence analysis of interphotoreceptor retinoid-binding protein and serum retinol-binding protein in bovine retina

Immunoreactivity for interphotoreceptor retinoid-binding protein (IRBP; red fluorescence) is throughout the interphotoreceptor matrix (IPM). Labeling for serum retinol-binding protein (sRBP; green fluorescence) is associated with the lumen of a choroidal blood vessel (arrows). There is no significant labeling for sRBP in the IPM, as defined by IRBP labeling (red). The dark ovals within the IPM and just above the outer nuclear layer are cone photoreceptor inner segments. Cell nuclei appear blue after DAPI staining. The following abbreviations are used: choroid (CH), retinal pigment epithelium (RPE), outer segment (OS), inner segment (IS), outer nuclear layer (ONL). Top row: Scale bar represents 75 μm; middle and bottom row: Scale bars represents 36 μm.