Quantitation of Immune-Mediated Erythrophagocytosis and Resetting in Developing Macrophages

Abstract

As part of our ongoing investigations of mononuclear phagocytes in health and disease, measurement of antibody-dependent erythrophagocytosis and rosette formation was carried out during human macrophage development in a suspension culture system. Cells derived from 12 normal human subjects were studied at the monocyte (day 0) and macrophage (day 6) stage of development. Analysis of variance demonstrated significant differences between monocytes and macrophages: the mean proportions of cells ( ± SEM) showing erythrophagocytosis were 0.09 ( ± 0.02) and 0.24 ( ± 0.06), respectively, and the average numbers of engulfed red cells ( ± SEM) were 1.12 ( ± 0.02) and 1.38 ( ± 0.11), respectively. No significant difference was detected in rosette formation. It is concluded that (1) immune-mediated activity of developing macrophages can be quantitated; (2) functional changes take place over 6 days of culture; (3) macrophages show more erythrophagocytic activity than monocytes, and (4) the method should be of value in making quantitative comparisons of their functional development in haematological and other disease states.