Action of T-activin on activity of human natural killer cellsin vitro

Circulating serum interferon andits effect on the activity of human natural killer cells

“…On the other hand, at low effector:target ratios autologous serum produces on NK of sclerotic patients an effect similar to that produced by human leukocyte IFN injected into MNC of healthy donors [6]. During purification this preparation loses some cytokines accompanying IFN [3].…”

“…During purification this preparation loses some cytokines accompanying IFN [3]. In both cases an increase in NK activity was observed in vitro at the effector:target ratio of 12:1 [6]. At the same time, at the effector:target ratio 100:1 the activity of NK preincubated for 4 h with human leukocytic IFN was lowered [6].…”

“…Since the cytoferon dose (2 IU/ml) [3] was the same as the IFN titer in the plasma of patients with multiple sclerosis and the IFN content in the human leukocyte preparation (50 IU/ml) [6], evaluated by the biological activity of the factor, was only two logarithmic units higher than the IFN titer in the patients' autologous serum, the comparable magnitudes of the effects elicited by the a-IFN preparations [3,6], and the extent of changes in the NK activity of patients with multiple sclerosis after treatment with IFN-containing autologous plasma, suggest that in multiple sclerosis serum factors other than IFN are involved in the stimulation of cytotoxicity at high effector :target ratios, whereas at low effector:target ratios the NK activity is regulated by IFN itself.…”