In vitro effects of clodronate on macrophages. RAW264.7 cells were incubated with various doses of clodronate, and DNA levels in the media were determined by PicoGreen after 24 hours (A). At that point, heated Jurkat cells were added to the macrophages, and DNA levels in the media were determined after 24 hours (B). Results are presented as nanograms per milliliter DNA as measured by fluorometry.