Phosphate buffered saline containing calcium and magnesium elicits increased secretion of interleukin-1 receptor antagonist

Abstract

Objective: Phosphate buffered saline (PBS) solutions are commonly used in laboratories for dilutions, washing cell suspensions, and rinsing, as well as additives to cell culture media. In the present study, we evaluated pro- and anti-inflammatory cytokine secretion of peripheral blood mononuclear cells (PBMCs) incubated in medium containing different PBS solutions. Methods: Human PBMCs were incubated in cell culture medium with different concentrations of PBS containing calcium (Ca++) and magnesium (Mg++) (+/+ PBS). Cells in medium alone or in suspensions containing PBS without Ca++ and Mg++ (-/- PBS) served as controls. Results: A dose-dependent increase of interleukin-1 receptor antagonist was found when PBMCs were cultured in medium supplemented with increasing concentrations of +/+ PBS. No significant differences were observed for interleukin-1β, interleukin-4, interleukin-10, or transforming growth factor β. Conclusions: The release of the antiinflammatory cytokine interleukin-1 receptor antagonist in addition to unchanged levels of pro-inflammatory mediators suggests an important modulatory mechanism of heightened extracellular calcium levels.