MEASUREMENT OF CEROID ACCUMULATION IN MACROPHAGES BY FLOW-CYTOMETRY

The accumulation in macrophages of ceroid, an autofluorescent polymer composed of oxidised protein and lipid, can be monitored semiquantitat ively by staining techniques. However, such methods are crude and give little information about the amount of ceroid within cells. Flow cyto metry, however, can give a quantitative assessment of cellular ceroid accumulation in vitro. Recently, flow cytometry was explored as a meth od for measurement of the accumulation in macrophages of ceroid. The a ccumulation appeared to be diminished in the presence of the antioxida nt, alpha-tocopherol. This is consistent with the role of lipoprotein oxidation in ceroid accumulation. Here the optimum wavelengths of emis sion and excitation, using both conventional fluorescence spectroscopy of cellular ceroid and flow cytometric measurements with a number of optical filters, are determined. The use of optimal wavelengths determ ined in these studies enhances overall sensitivity. The findings are d iscussed in the context of future investigation of cell-mediated lipid oxidation and its potential antagonists. (C) 1994 Wiley-Liss, Inc.