Human stem cells ( forming a  teratoma) in mouse host.

Mouse nuclei are negative ( stained blue by Gill’s III Haemalum) . Abcam state that this ab is anti nucleoli: to me, the nuclei are positive. If positivity  was localised to nucleoli, the nuclei would be stained blue and show brown dot/s within them ( nucleoli).

Abcam datasheet images show positive nuclei, not nucleoli.