[Hematopoietic reconstitution in the allogeneic bone marrow chimeric mice].

Hematopoietic reconstitution in the allogeneic chimera is an important issue because its failure causes fatal infection in the host. Although graft-versus-host disease (GVHD) often occurs and is a major obstacle for successful bone marrow transplantation (BMT), it does not always play an unfavorable role in the host. It has been suggested that GVHD may show some effects on the hematopoietic reconstitution. In order to elucidate mechanism of the influence of GVHD on the hematopoiesis, I have studied kinetics of the hematopoietic progenitor cells in the bone marrow chimeric mice and the effects of spleen cells on it using in vitro CFU-GM assay. The number of CFU-GM in the bone marrow obtained from the allogeneic chimeras were reduced in the very early phase after BMT compared to that of syngeneic bone marrow chimeras. After then, the CFU-GM number in the allogeneic chimeras increased rapidly, especially in the chimeras showing a sign of severe GVHD. Addition of spleen cells from syngeneic chimeras to the bone marrow cell cultures showed no influence on the CFU-GM number observed. However, addition of spleen cells from allogeneic chimeras at 14 days after BMT to the bone marrow cells increased the CFU-GM number. By contrast, the chimeric spleen cells at 21 days after BMT decreased the number. These biphasic effects of spleen cells from allogeneic chimeras on the CFU-GM were considered to be mediated by some kinds of colony stimulating and inhibiting factors. Intraperitoneal injections of recombinant granulocyte-colony stimulating factors into bone marrow chimeras increased the number of granulocyte.(ABSTRACT TRUNCATED AT 250 WORDS)