Morphological microassay and kinetics of the cytotoxicity of guinea pig lymphotoxin.

The kinetics of guinea pig lymphotoxin (GLT)-cytotoxicity on three L cell sublines were studied in detail by a micromethod using morphological distinctions between intact cells and dead cells. The reduction of the intact cell number and increase of the dead one concurrently occurred after a lag time, its length depending upon the GLT concentration ([GLT]). Although different patterns of the changes in the survival ratio (S) were discerned with different sublines, under appropriate conditions, --ln S was proportional to [GLT] and the reciprocal of the initial target cells number. Furthermore, it was shown that the S value at 24 hr was dependent upon the absolute amount of GLT.