Are stem cells specific to an individual or mammal? ie, could you take stem cells from an animal and put them in a human and expect them to survive?

Specific, tho doable: Ethical and regulatory issues aside, large animal stem cell sources including transgenic humanized pigs etc are in intense research for regenerative medicine tx for humans. Stem cells, though less immunogenic, may be genetically modified to have similar human HLA type, and could survive, with immunosuppression, in limited settings, ...though i believe most are still experimental.