A possible function in cell-substrate adhesion of a metabolic product of L-M cells.

Tms work developed from an observation made during experiments designed to compare the metabolism of cells in suspension and in monolayer culture respectively. Cells from a suspension culture were spun down and resuspended in fresh medium; they were then distributed as suspension cultures, and as monolayer cultures on plastic, for comparison of glucose utilization and lactate and pyruvate production, per lo6 cells, after different periods of incubation. This comparison necessitated the harvesting of the cells from sample monolayers, after 24, 48 and 72 hr incubation, by scraping from the plastic. Routine checks of viability on the resulting suspensions indicated that, by comparison with cells grown in suspension for a comparable period, the 24 hr monolayer, after being scraped from the plastic, had a low viability. On succeeding days, the viability of the cells obtained from the monolayers increased. These findings suggested that some substance, produced by the cells during prolonged growth in monolayer culture, protected them from trauma on removal by scraping; and that this substance was either not produced by cells grown in suspension, or, if produced, was not attached to the surfaces of the cells and so did not protect them. Further experiments were made to test this hypothesis, and to see if similar findings were obtained for cells grown for short periods on glass.