Bone marrow reactions to E. coli endotoxin or Pseudomonas original endotoxin protein in germ-free mice.

Comparative studies between germ-free and conventional mice were made as to the bone marrow reactions to E. coli endotoxin and Pseudomonas aeruginosa OEP. With the direct smear method of the bone marrow reactions, it was found that conventional mice were more vulnerable than germ-free mice. Conventional mice were more sensitive also as to lethality. With the absolute count method of the bone marrow reactions, conventional mice were more vulnerable than germ-free mice on the increase of red blood cell number in the marrow which reflected damage of the circulation, whereas germ-free mice were more sensitive than conventional mice as to the decrease of nucleated cell number in the marrow which resulted from leukopenia and leukocytosis in the peripheral circulation. This finding as to the nucleated cell number was more remarkable in mice given OEP than in the mice given endotoxin.