Studies on the locomotory behaviour and adhesive properties of mononuclear phagocytes from blood

Abstract

Mononuclear phagocytes isolated from peripheral blood move slowly on albumin-, collagen- and fibronectin-coated glass, as judged by analysis of time-lapse film, although their movement is stimulated somewhat by serum. When a differential-adhesion method is used to purify monocytes from a crude mononuclear cell fraction it appears to select a particularly slow-moving sub-group. Despite their slow rate of movement (especially in comparison with neutrophils) monocytes move over and penetrate monolayers of endothelial cells, apparently without difficulty; they are, however, restricted to the upper surface of a fibroblast monolayer. Penetration of reconstituted collagen gels by freshly isolated monocytes was not observed but cultured monocytes, which spontaneously detached from the culture substratum over a 48 h period, did invade collagen gels. The adhesive properties of these cultured cells, measured in a flow-chamber assay, did not differ from freshly isolated monocytes purified on serum-coated dishes and detached with EDTA, and their invasive capacity does not seem to be a consequence of altered adhesive properties. The behavioral differences between monocytes and neutrophils are considerable, although both cell types have to leave the circulation and penetrate tissues in vivo.