Related Experiment Videos
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 behavioural differences between monocytes and neutrophils are considerable, although both cell types have to leave the circulation and penetrate tissues in vivo.
Insights
Mononuclear phagocytes (monocytes) exhibit slow movement but can penetrate endothelial cells. Cultured monocytes invade collagen gels, unlike freshly isolated ones, suggesting altered behavior, not adhesion changes.
Area of Science:
- Cell Biology
- Immunology
- Biophysics
Background:
- Mononuclear phagocytes, including monocytes, are crucial immune cells involved in tissue repair and pathogen clearance.
- Understanding monocyte migration is vital for comprehending inflammatory and immune responses in vivo.
Purpose of the Study:
- To investigate the migratory behavior and invasive capacity of human peripheral blood monocytes.
- To compare the movement and tissue penetration abilities of monocytes with neutrophils.
Main Methods:
- Time-lapse microscopy was used to analyze monocyte movement on various substrates (albumin, collagen, fibronectin).
- Differential-adhesion methods were employed for monocyte purification.
- Monocyte interaction with endothelial and fibroblast cell monolayers was assessed.
- Invasion assays using reconstituted collagen gels were performed on freshly isolated and cultured monocytes.
- Flow-chamber assays measured cell adhesion properties.
Main Results:
- Monocytes displayed slow movement on coated glass surfaces, with some stimulation by serum.
- Purification methods appeared to select for slower-moving monocyte subpopulations.
- Despite slow movement, monocytes effectively traversed endothelial cell monolayers but were restricted by fibroblast monolayers.
- Freshly isolated monocytes did not penetrate collagen gels, whereas cultured monocytes did.
- Invasive capacity of cultured monocytes was not linked to altered adhesive properties.
Conclusions:
- Monocyte migration is characterized by slow لیکن effective movement, enabling them to penetrate certain biological barriers like endothelial cells.
- The ability of monocytes to invade collagen gels appears to be acquired during culture, independent of changes in cell adhesion.
- Significant behavioral differences exist between monocytes and neutrophils, impacting their respective roles in vivo immune surveillance and tissue penetration.