A simple procedure for identification of macrophages in peritoneal exudates

Abstract

Identification of peritoneal exudate macrophages by labelling with China ink followed by May-Grünewald Giemsa staining was investigated as a simple and reliable procedure to differentiate these cells from the largest lymphoid cells. This procedure was compared with techniques which reveal acid phosphatase activity and which vitally stain lysosomes (neutral red). The cells were further separated in adherent and nonadherent populations for investigation by the three described techniques. The results showed that all three techniques revealed the same type of cells with a good correlation between enzymatic activity, presence of lysosomes, phagocytic activity and adherence. China ink labelling of peritoneal exudate cells is a simple and reliable method for routine identification of macrophages. It is suggested that functions required for in vitro tests of cellular immunity should be preserved in cells identified in this way.