Patterns of hemopoietic recovery in irradiated mice.

With the assistance of lb M. Alderman, Ruth E. Gillespie and H. Jeanette Ruth T HE RECENT FINDING that an injection of endotoxin induces hemopoiesis in irradiated mice and hamsters,’ and the observations of Brown, Hirsch and their associates2’3 and of Congdon and Urso4 that homologous and heterologous marrow do not promote thymic regeneration and recovery of lymphatic tissue, have renewed our interest in patterns of hemopoietic recovery in irradiated animals under various conditions which influence their survival. Reports have been made which cover the effect on survival of numerous factors in the administration of bone marrow and spleen homogenate ( e.g.57 ) and in several instances, the course of leukocyte restoration.6’8’9 Quantitative studies to be described here demonstrate several points not previously clear. In this report recovery times of circulating granulocytes and lymphocytes are compared when the following conditions are varied: 1. ) radiation dose; 2. ) spleen homogenate injection, varying radiation dose to recipient, time of injection relative to irradiation, and number of cells injected; 3. ) species of donor for bone marrow injection: isologous vs. heterologous; and 4. ) induction of recovery by an injection of endotoxin or colchicine. In addition, recovery of platelet and of hemoglobin concentrations are compared in experiments with isologous and heterologous bone marrow, endotoxin and colchicine.