Slow calcium waves imaged in myeloid cells derived from neonatal cord blood

Myeloid cells were derived from neonatal cord blood by culture with granulocyte-macrophage colony-stimulating factor for approximately 8 days. The resultant cell population contained large adherent cells (diameter > or = microns), expressing formylated peptide receptors that were functionally coupled to cytosolic free Ca2+ signaling. Imaging of the cytosolic free Ca2+ changes in these cells revealed initial focal release of Ca2+ from a site from within the cell, with elevated Ca2+ also near the cell edge. Increased cytosolic free Ca2+ moved as a slow oscillating wave across the cell (velocity 1 microns/s). As similar events may occur in mature neutrophils and monocytes but be difficult to resolve because of the small size of these cells, it was concluded that neonatal myeloid cells may provide a useful model system for the investigation of Ca2+ signaling in myeloid cells.