Hematopoietic Recovery Induced by Bacterial Endotoxin in Irradiated Mice

Abstract

Mice given an intraperitoneal injection of Salmonella typhosa endotoxin 24 hours before irradiation showed an advance in the recovery of granulocytes, platelets and hemoglobin, with the effect on lymphocyte counts relatively small. Differences in bone marrow cellularity and in ability to mobilize granulocytes were particularly striking. Effects of an injection given after irradiation although significant were less pronounced. The induction of hemopoiesis is thought to be responsible for the increase in survival previously observed with this treatment. It is not known whether the action of endotoxin upon the precursor cells is direct or indirect.