Figure 4.

Effect of negatively charged lipid phosphatidylserine (PS)-liposomes on arginase activity of BALB/c macrophages. Peritoneal macrophages were infected with phosphatidylserine- (PS-) liposomes, phosphatidylcholine- (PC-) liposome or glycerol. Amastigotes of Leishmania (L.) amazonensis were used as controls. In parallel, an anti-TGF-β antibody was used in all interaction conditions. Macrophages were lysed and the arginase activity was determined by measuring the urea level. Assays were run in triplicate. The data are presented as the mean ± standard deviation of enzyme activity units (amount of enzyme that catalyzes the formation of 1 μmol urea/min). The results are representative of two similar experiments. ^& P < 0.05 compared with control without liposome (ANOVA and Student Newman-Keuls tests).