Detection of human immortalized cells injected into in the tibialis anterior muscle of Rag2-/- γC-/- C5-/- mice. (A) Human nuclei were visualized using an anti-lamin A/C antibody (red) and fibers expressing human proteins were visualized using an anti-human spectrin-specific antibody (green). Nuclei are counterstained with Hoechst. Original magnification × 200. (B) The immortalized cells were present preferentially as myonuclei (top panel), with a small number found in interstitial space (arrow, bottom panel), identified by human lamin expression (laminin staining in green, laminA/C and spectrin staining in red, Hoechst in blue, on the LGMD2B muscle section as an example). Original magnification × 600.