RESUMO
Demonstration of the ability of fresh human hematopoietic cells to engraft severe combined immuno-deficient (scid) mice has provided an in vivo assay for expansion and maturation of early human progenitor cells. However, engraftment of cultured hematopoietic cells has been difficult to achieve. We wished to further develop this model as an in vivo assay for efficiency of retroviral gene transfer and expression in the differentiated progeny of adult human bone marrow progenitor cells. Human bone marrow cells were cultured in vitro for six days under conditions suitable for infection by retroviral vectors prior to transfer to irradiated scid mice. Cultured human bone marrow cells introduced by both intravenous (i.v.) and intraperitoneal (i.p.) injection persisted in the bone marrow, spleen and peritoneum of recipient animals up to four weeks after transfer. Following irradiation scid mice receiving cultured human bone marrow cells by either i.v. or i.p. routes demonstrated engraftment of the bone marrow and spleen as determined by the growth of human hematopoietic progenitors in soft agar. By flow cytometric analysis human cells were also detected in the peritoneum of mice receiving cultured human bone marrow cells i.p. These results suggest that the transfer of cultured human bone marrow cells to scid mice with the subsequent engraftment of these cells in the bone marrow, spleen and peritoneum of recipients can routinely occur. This provides an in vivo model for retroviral gene transfer to human cells.
