Effect of phospholipase C on lymphocyte responses to mitogen

Peripheral lymphocytes treated with phospholipase C (phosphatidylcholine cholin phosphohydrolase E [3.1.4.3]) were examined for their response to mitogen and rosette formations. High levels of phospholipase C (greater than 0.01 unit) showed significant toxic effects on the peripheral lymphocytes as examined by the trypan blue exclusion test. This was attributable to "impurities" in the Cl. perfringens phospholipase C preparation since recovery of the mitogen responses were incomplete after heat inactivation of the enzyme. Active phospholipase C at 0.005 unit significantly (50%) suppressed the PHA response with little or no effect on the PWM stimulation. Similarly, a significant suppression of E rosette formation occurred with phospholipase C (0.005 u) treated lymphocytes. Suppression of similarly treated lymphocytes to EAC rosette was slight. It is suggested that the removal of phosphorylated amines from membrane surfaces affects T-cells more than B-cells and that the use of phospholipase C is a useful means of examining membrane functions of the lymphoid system.