[Quantitative evaluation of the phagocytic activity of endothelial cells in culture]

The phagocytic activity of endothelial cells (EC) from human umbilical vein was analysed quantitatively in primary culture. EC were incubated with fluorescent carboxylated microspheres (FCM) and the intensity of fluorescence was measured on spectrofluorimeter. It was found that EC phagocyted actively only FCM of limited diameter (not more than 0.26 mu). The most intensive phagocytosis occurred in the first 60 min of the experiment, the following incubation with FCM did not influence significantly the number of phagocyted particles but increased nonspecific binding. High doses of FCM stimulated phagocytosis within EC. The phagocytic activity of EC depended on the growth stage: it was maximum in proliferated cells and sharply decreased in confluent cultures. This method may be useful for the comparison of phagocytic activity of different cell types, as well as for drug testing.