Cell—substrate adhesion affects intracellular motility of pulmonary macrophages

Abstract

Intracellular motility and cell substrate adhesion has been investigated using magnetic field relaxation of ingested magnetic particles and interference reflection microscopy (IRM). Alveolar macrophages were used in the model cell system. Cell motility for non-stimulated cells was found to be essentially independent of the substrate surface chemistry, as demonstrated by using differing surfaces such as siliconized glass or glass coated with polylysine. Macrophages stimulated by zymosan showed increased adhesion on a variety of surfaces. Reduced intracellular motility was observed and this correlated with cell thinning due to extensive cell spreading. Computerized analysis of IRM images was used to study cell adhesion and the extent of cell spreading continuously for up to 40 min on various substrates in culture dishes with glass coverslip bottoms. The substrates were prepared by coating the glass coverslips with Langmuir—Blodgett bilayers of dipalmitoylphosphatidylcholine (DPPC) from air—water monolayers held at differing surface tensions. Some of the bilayers were further treated with polymeric surfactant Pluronic F68 by allowing this substance to be adsorbed onto the bilayer—water interface. In most cases macrophage adhesion increased with time, reaching a maximum at 12–15 min. The most adhesive surface investigated proved to be a DPPC bilayer that was deposited at a monolayer surface tension of approximately 50 mN m −1. The least adhesive surface was the DPPC bilayer in association with Pluronic F68.