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Effect of Corynebacterium parvum on hemopoietic stem-cell kinetics
Abstract:
The intravenous administration of 548 microgram of killed Corynebacterium parvum (C. parvum) into C57BL mice leads to a significant decrease in the number of bone-marrow colony-forming-units in spleen (CFUs) as early as 12 h after the injection of the bacterium. This decrease persisted in varying degrees for 3 weeks. After an initial fall at 24 h, the splenic CFUs exhibited a rapid expansion and reached values 10 times higher than the control range on the ninth day. A significant rise in the number of circulating CFUs, reaching a first peak at 2 h and a second one on the fifth day, was also observed. The proliferative status of femoral CFUs was increased at 48 and 72 h, while that of splenic CFUs presented a significant increase only 48 h after the injection of C. parvum. The sequence of events which were observed in these experiments indicates that an accelerated migration of hemopoietic stem cells from bone marrow to spleen via the blood circulation has to take place.
Insights
Intravenous Corynebacterium parvum (C. parvum) injection in mice initially reduced bone marrow colony-forming units in spleen (CFUs). CFUs then rapidly expanded in the spleen, indicating accelerated stem cell migration.
Area of Science:
- Immunology
- Hematology
- Microbiology
Background:
- Corynebacterium parvum (C. parvum) is an immunomodulatory agent.
- Hematopoietic stem cells (HSCs) are crucial for blood cell production.
- The spleen plays a role in hematopoiesis and immune responses.
Purpose of the Study:
- To investigate the effects of C. parvum on hematopoietic stem cells (HSCs) in mice.
- To determine the migration patterns of colony-forming units in spleen (CFUs) after C. parvum administration.
- To understand the temporal dynamics of HSCs in bone marrow and spleen.
Main Methods:
- Intravenous administration of killed C. parvum to C57BL mice.
- Quantification of colony-forming units in spleen (CFUs) in bone marrow, spleen, and blood over time.
- Assessment of the proliferative status of femoral and splenic CFUs.
Main Results:
- A significant decrease in splenic CFUs was observed within 12 hours post-injection, persisting for 3 weeks.
- Splenic CFUs showed a rapid expansion, reaching 10 times control levels by day 9.
- Circulating CFUs peaked at 2 hours and on day 5, with increased proliferation noted in femoral and splenic CFUs.
Conclusions:
- C. parvum administration induces a transient decrease followed by a significant expansion of splenic CFUs.
- The observed changes suggest an accelerated migration of hematopoietic stem cells from bone marrow to the spleen via circulation.
- This study elucidates the dynamic response of hematopoiesis to C. parvum, highlighting stem cell mobilization.