Cholesterol content and heat sensitivity of nine mammalian cell lines

Abstract

The cholesterol, phospholipid and protein contents of nine mammalian cell lines, three lymphoid and six attached cell lines, were measured, along with the sensitivity of the cells to hyperthermia at 42° and 44°C.

The free cholesterol content and the protein content per cell correlated positively with the time required to kill 99 per cent of the cells at 44°C. The phospholipid content showed a less significant positive correlation whilst the cholesterol ester content and the cholesterol:phospholipid molar ratio did not correlate with heat sensitivity. There were no correlations observed when the levels of these cell components were compared to heat survival at 42°C.

As the three lymphoid lines are small, very heat sensitive cells, the six monolayer lines were analysed separately. In this case, only the protein and the free cholesterol content maintained a significant correlation (at the 5 per cent level).

It is concluded that the levels of cholesterol or phospholipid cannot be used as reliable indicators of the heat sensitivity of a cell.

Key Words:

• heat sensitivity
• cholesterol
• membranes