Figure 4

CD31 immunofluorescence of EC-neurosphere co-cultures after 5 days culture. Mouse brain EC were plated onto mouse neurospheres, as described in Methods. Five days later, CD31 immunohistochemistry was performed on frozen sections using Hoechst to label all cell nuclei (A) and CD31 (Cy-3 conjugated secondary antibody, (B) to identify EC. Merged channels (C). Scale bar = 50 μm. Note that after 5 days co-culture, CD31-positive structures were observed that resembled early vascular structures.