Related Experiment Video
Updated: Sep 6, 2026
Induction of Maternal Immune Activation in Mice at Mid-gestation Stage with Viral Mimic Poly(I:C)
Published on: March 25, 2016
Monocytosis-inducing activity (MIA) of serum in Corynebacterium parvum treated mice
Abstract:
Intravenous injection of 548 microgram of C. parvum (Lot 0407, Mérieux Laboratories, France) into C57Bl mice produced rapidly appearing monocytopenia which was followed by marked and prolonged monocytosis after the third day. The serum of these animals, collected during the monocytopenic but not the monocytosis phase, showed monocytosis inducing activity (MIA) as was demonstrated by the intravenous injection of the serum into normal test mice. Serum from normal untreated mice or from mice given an intravenous injection of sterile pyrogen-free saline did not cause monocytosis in the test mice. Monocytosis induced in the test animals presented two interesting peaks. The first was observed 2 h after the injection of serum and the second 5 days later. The former was accompanied by a decrease and the latter by an increase in the number of bone marrow monocytes, suggesting that MIA probably represents a releasing activity. The late increase in marrow monocytes is considered as a phenomenon secondary to the initial reduction.
Insights
Cryptosporidium parvum infection in mice induces a serum factor that causes monocytosis. This monocytosis-inducing activity (MIA) likely functions by releasing monocytes from the bone marrow.
Area of Science:
- Immunology
- Hematology
Background:
- Cryptosporidium parvum is a protozoan parasite.
- Immune responses to C. parvum infection are complex.
- Monocyte dynamics are crucial in host defense.
Purpose of the Study:
- To investigate the hematological changes following C. parvum infection.
- To identify serum factors responsible for altered monocyte counts.
Main Methods:
- Intravenous injection of C. parvum into C57Bl mice.
- Collection and injection of mouse serum into naive mice.
- Monitoring of peripheral blood and bone marrow monocyte counts.
Main Results:
- C. parvum infection induced transient monocytopenia followed by prolonged monocytosis.
- Serum from infected mice during the monocytopenic phase exhibited monocytosis-inducing activity (MIA).
- MIA induced biphasic monocytosis in recipient mice, with bone marrow changes suggesting a releasing mechanism.
Conclusions:
- A serum factor (MIA) is generated during C. parvum infection that induces monocytosis.
- MIA appears to act by releasing monocytes from the bone marrow.
- These findings shed light on the host's hematological response to C. parvum.
