Expression of protease and protease-inhibitory activity in human mononuclear leukocyte cultures. Effect of conA stimulation

Trypsin-activated protease activity was observed in the supernatants of conA-treated unfractionated or monocyte-depleted cultures at 1 h of incubation and trypsin-inhibitory activity was detected at 24 h. In contrast, supernatants from wheat germ agglutinin (WGA)-treated cultures or untreated cultures exhibited trypsin-inhibitory activity at 1 h and trypsinactivated protease activity after 24 h. The expression of proteases and protease inhibitors may be early events that occur during the activation of quiescent lymphocytes to a proliferative state.