Previously, we reported the presence of group II-like phospholipase A2 activity in the soluble fraction of rat gingiva. In the present study, we found that treatment of rat gingival cells with human recombinant interleukin- 1β resulted in dose-dependent stimulation of intracellular and extracellular phospholipase A2 activity. Antisera against group II phospholipase A2 totally blocked the interleukin-1β-induced phospholipase A2 activity, but antisera against group I phospholipase A2 did not. Moreover, immunoblot analysis showed that the induced phospholipase A2 was group II phospholipase A2. These findings suggest that the induced enzyme belongs to the group II phospholipase A2 family of proinflammatory enzymes.
