EFFECT OF PH AND TEMPERATURE ON CELL RE-AGGREGATION.

Abstract

THE successful re-aggregation of cells has been used widely as a test for their adhesiveness1,2. Moscona1 observed that the re-aggregation of chick embryonic cells does not occur at temperatures at or below 15° C. Steinberg2 found that re-aggregated cells did not deadhere at low temperatures and re-interpreted Moscona's results by suggesting that the initial adhesions of cells alone were prevented below such temperatures. Both authors interpreted their results to indicate that the adhesion of cells in re-aggregation involves a temperature-dependent mechanism. Similarly, Steinberg3 argued that since amphibian embryonic cells could not re-aggregate at pH 4.0, carboxyl ionization and calcium-linked binding between cell surfaces are probably involved in cell adhesion. It remains possible that the failure of re-aggregation in these systems was due to the particular conditions of re-aggregation used, and that low temperature or pH values do not of themselves generally impede the adhesiveness of normal viable cells. Successful re-aggregation of cells at low temperatures or pH values will demonstrate that low temperature and pH do not in themselves necessarily affect cell adhesion. The following tests show that this suggestion is probably correct and that other conclusions can be drawn about the modes of cell adhesion.