a higher level of cytolytic activity was achieved when pbl were separated by means of percoll density gradient ( 1.077 ; 1.067 and 1.056 g/ml ) centrifugation and the cells of fraction ii ( 1.077-1.067 g/ml ) were employed in the experiment , the level of cytotoxicity being elevated in all cases ( 1.7-fold elevation in donors and 2-fold elevation in patients on the average ) .
C1536403
cytolytic
C0007634
the cells