Microbiology and immunology
-
Microbiol. Immunol. · Jan 1998
Kinetical analysis of tumor cell death-inducing mechanism by polymorphonuclear leukocyte-derived calprotectin: involvement of protein synthesis and generation of reactive oxygen species in target cells.
We have previously shown that calprotectin, the most abundant cytosolic protein existing in polymorphonuclear leukocytes (PMNs), induces apoptotic cell death in various tumor cells, suggesting that calprotectin is an effector molecule against tumor cells in PMNs. To explore the cell death-inducing mechanism of the factor, we examined the involvement of target protein synthesis and generation of reactive oxygen species (ROS) in the reaction. Calprotectin induced cell death in MM46 mouse mammary carcinoma cells after a 14-16 hr lag time. ⋯ The addition of NAC even 15 hr later significantly attenuated the calprotectin effect. Flow cytometry analysis showed that calprotectin began to increase the ROS content in MM46 cells after 8-12 hr of culturing, and that the increase was abrogated by the antioxidants. Thus, protein synthesis and ROS generation may be essential elements in the early or later phases of the cell death-inducing reaction of calprotectin, respectively.
-
Microbiol. Immunol. · Jan 1998
Anti-Candida activity of calprotectin in combination with neutrophils or lactoferrin.
The effect of an anti-microbial protein, calprotectin, in combination with neutrophils on the growth of Candida albicans was investigated. The growth inhibition of C. albicans by murine neutrophils was augmented by the addition of a low concentration of calprotectin prepared from rat peritoneal exudate cells. ⋯ Lactoferrin, which is an anti-microbial protein released from neutrophils, strongly inhibited the growth of C. albicans in combination with calprotectin. These results suggest that calprotectin and lactoferrin released from neutrophils may cooperate to inhibit the growth of C. albicans at a local lesion of the infection where there is an accumulation of neutrophils.