Phase contrast photomicrographs of IC-21 macrophage morphologies on
Teflon® AF surfaces. (A) Cells commonly exhibit
loosely adherent cell bodies (circle) with numerous filopodia, sometimes in
a circular arrangement. (B) Distinct from cultures on all other surface
chemistries, filopodial extensions are often observed to cross one another
(bold arrows), or to terminate in proximity to attachment sites of other
cells. (C) Cell populations on Teflon® AF surfaces
show a mixture of actin-based cytoskeletal features (filopodia,
lamellipodia, membrane ruffling), often with numerous features on a single
cell, as illustrated by all 3 cells in this field. Note differences in cell
size, shape and features. (D) Filopodia are frequently lengthy, extending
hundreds of μm from the cell body (bold arrows indicate cell
body (right) and filopodium terminus (left)). (E, F) Cells showing
characteristic membrane ruffling, indicative of the ‘lagging
edge’ of a motile cell. (G, H) Less typical morphologies
observed on Teflon® AF include cells with numerous
bulbous attachment sites (G) and tree-trunk-like morphologies (H). (I) This
field illustrates the diversity of the cell population observed: cell
‘1’ has multiple lengthy filopodia that cross over
cell ‘2’, and that are diffuse rather than punctate
at their termini, possibly indicative of active surface probing. Cell
‘2’ has a diffuse cytoplasm, with large areas if
membrane ruffling. Cell ‘3’ has a small well-defined
cell body with one lengthy filopodium. (J) Occasionally, cells with multiple
nuclei (3–5) have been observed on
Teflon® AF without the addition of exogenous
cytokines that promote fusion events. Results are representative of numerous
(>3) experiments.