Graphic analysis of superoxide secretion by phagocytic leukocytes at different cell concentrations

Superoxide secretion by monocytes, macrophages and neutrophils becomes less efficient in a non-linear manner as the cell concentration is increased. This relation holds for cells in suspension or attached to a substrate, elicited into the peritoneum with various agents or from the peripheral circulation, acutely stimulated with particulate or soluble agents, and in experimental animals and in man. The significant observation of this study is that in all these systems, of data from our own studies as well as from the literature, plots of the logarithm of superoxide secreted per cell per unit of time versus the logarithm of the cell concentration were linear with correlation coefficients better than 0.98. The common practice of comparing data on superoxide secretion from experiments performed at different cell concentrations is clearly unsatisfactory. It is suggested that superoxide secretion be expressed in terms of both the slope of the log log plot and the secretion rate at a given cell concentration.