Protected environment and its utility in experimental allogeneic and xenogeneic bone marrow transplantation.

: Allogeneic bone marrow (BM) chimerism can be established in germfree (GF) rats and mice without the manifestations of graft vs host (GvH) disease that develop in conventional counterpart animals. This procedure has been applied with prophylactic and therapeutic benefits in mice predestined to develop leukemia and reticulum cell sarcoma. Xenogeneic BM chimerism has been accomplished in rats with mouse bone marrow cells, without evidence of GvH disease; and over long periods they produce blood cells with characteristics of mouse species. A critical factor in allogeneic and xenogeneic BM chimerism is the microbial status of the animals.