Prolonged effect of Corynebacterium parvum stimulation on granulopoiesis

An intravenous injection of 548 microgram of killed Corynebacterium parvum (C. parvum) into C57BL mice led to a significant increase in the number of both committed stem cells (GM-CFC) and proliferating cells of bone marrow granulocytic series. This increase appeared 24 h after the injection of the bacterium, persisted in varying levels until the 4th week and was accompanied by a marked and prolonged granulocytosis. The proportion of GM-CFC in DNA synthesis was found to be increased 1, 2, and 5 d after injection of C. parvum. Increased serum lysozyme levels were observed on the 9th and 15th d. These findings suggest that C. parvum can stimulate granulopoiesis in the animal system. This property of the bacterium should be considered when a combined chemo-immunotherapy schedule has to be applied.