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Leukocyte activation by malarial pigment.
Nguyen Tien Huy1, Dai Thi Xuan Trang, Tohru Kariu
1Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
Parasitology International
|December 1, 2005
Summary
Malarial pigment, hemozoin, activates immune cells like monocytes and neutrophils. This suggests hemozoin may play a role in severe malaria pathology by stimulating leukocytes.
Area of Science:
- Immunology
- Parasitology
- Biochemistry
Background:
- Malarial pigment, or hemozoin, is a heme dimer crystal found in leukocytes.
- It can persist in macrophages for extended periods.
Purpose of the Study:
- To investigate the effects of hemozoin on macrophages and neutrophils.
- To understand hemozoin's role in immune cell activation.
Main Methods:
- Used beta-hematin (BH), a synthetic hemozoin analog.
- Conducted in vitro studies on whole blood and isolated macrophages.
- Performed in vivo experiments involving peritoneal cavity injections in mice.
- Assessed neutrophil migration and myeloperoxidase activity.
Main Results:
- BH upregulated tumor necrosis factor-alpha in monocytes and macrophages.
- BH stimulated neutrophils to express macrophage inflammatory protein-2 (MIP-2).
- BH induced dose-dependent neutrophil migration and increased myeloperoxidase activity in vivo.
- BH directly promoted neutrophil chemotaxis in vitro.
Conclusions:
- Malarial pigment (hemozoin) activates monocytes and neutrophils.
- Hemozoin can stimulate leukocytes, suggesting a potential role in severe malaria pathogenesis.