Heterotopically induced bone marrow formation: morphology and transplantation

Following heterotopic osteogenesis by implantation of xenogeneic epithelia, established human amnion cell lines FL and WISH, and isolated transitional epithelium of dogs in mice, biogenesis of hematopoietic tissue among the induced bone ossicles was observed. Precursors and mature forms of erythroid, granuloid, lymphoid and megakaryocytic series were found in the induced bone marrow. The concentration of lymphocytes in the induced marrow was higher and that of erythropoietic cells lower as compared with orthotopic femur bone marrow. The yield of myeloid cells varied from 0.31 to 14.5 X 10(6) per induced bone nodule, and was higher when uroepithelium was used as an inductor. The induced bone marrow contained hemopoietic stem cells in concentration similar to that of medullar bone marrow and the induced bone marrow protected lethally irradiated syngeneic recipients when used in the same doses as orthotopic bone marrow.