Regeneration of transplanted allogeneic hemopoietic progenitor cells in mouse spleen organ cultures.

The capacity of CBA, C57BL/6 and BALB/c mouse bone marrow cells to repopulate lethally-irradiated syngeneic or allogeneic recipients was monitored by measuring hemopoietic progenitor cell (colony forming cell, CFC) levels in the bone marrow and spleen from 0-7 days after transplantation. Bone marrow cells (10(7)/mouse) injected into allogeneic recipients failed to repopulate the spleen in vivo whereas regeneration was possible in spleen organ cultures. In contrast, the repopulation of the bone marrow by injected hemopoietic cells was successful in both allogeneic and syngeneic recipients. The observed absence of allogeneic CFC growth inhibition in organ cultured spleens provides an unique in vitro model for further dissecting the mechanism(s) responsible for allogeneic rejection.