X-galactosidase staining confirms engraftment of transplanted stromal cells in multiple hematopoietic organs.

Following transplantation in utero with retrovirally marked stromal cells, sheep were killed and stromal layers established in vitro from their liver, spleen, thymus, and BM. These layers were then evaluated for expression of the vector-encoded LacZ gene by histochemical X-galactosidase staining according to standard procedures. See text for details. The control consisted of a stromal layer derived from the BM of a normal control sheep that was processed and stained identically to the experimental samples.