Quantitative studies of increased cell-to-substratum adhesion at low temperature

The cell-to-substratum adhesion of an established epithelial cell line cultured for 24 h on glass coverslips was determined at 4 degrees C, 8 degrees C and 37 degrees C using a miniaturised parallel-plate shearing apparatus. The measurements of the minimum shear necessary to dislodge the cells (minimum distraction force, MDF) demonstrated a three- to fourfold increase in the adhesion of the cells at 4 degrees C (6.17 Pa) compared to that at 37 degrees C (1.36 Pa). At 8 degrees C the MDF was 2.31 pascals. Part of the adhesion was resistant to mild trypsinisation. Trypsin-resistant adhesion (TRA) was stabilised by low temperature, and by treatment with concanavalin A (50 micrograms ml-1) or colchicine (200-400 microM). The effects of con A (140 micrograms ml-1) and low temperature (4 degrees C) were additive, giving a combined MDF of greater than 9.27 pascals. On the basis of their different temperature and protease susceptibility it is suggested that trypsin-sensitive adhesion (TSA) and TRA represent separate functional classes of cell-to-substratum attachment corresponding to 'frictional' and 'tractional' adhesion, respectively.