The number of TH-positive cells was evaluated at four weeks after 6-OHDA lesioning. Normal TH immunoreactivity was detected in the substantia nigra (A) and striatum (C) of all the sham animals. Depletion of TH immunoreactivity was noted in the substantia nigra (B) and striatum (D) at the side treated with 6-OHDA. Immunohistochemical staining was done at 8 weeks after implantation of ES-derived dopaminergic neurons into 6-OHDA lesioned striatum. The M2 mouse-specific antibody (E and F, red) and the nuclear marker DAPI (F, blue) were detected in numerous cells at the implantation site, suggesting that the grafts survived. TH-positive neurons were found within the graft (G, green). All TH-positive profiles coexpressed the M2 mouse-specific antibody (H, yellow), and one cell revealed M2 staining only (arrowhead). The scale bar: A, B: 200 μm; C to H: 50 μm.