Bactericidal properties of group IIA and group V phospholipases A2

Group V phospholipase A2 (PLA2) is a recently characterized 14-kDa secretory PLA2 of mammalian heart and macrophage-derived cells. Group IIA PLA2, which is structurally close to group V PLA2, has been shown to kill Gram-positive bacteria in vitro and to prevent symptoms of Gram-positive infection in vivo. We studied the antibacterial properties of fully active recombinant rat group IIA and V PLA2s. Both group IIA and V PLA2s were highly bactericidal against Gram-positive bacteria, including methicillin-resistant staphylococci and vancomycin-resistant enterococci. Only high concentrations of group IIA PLA2 showed some bactericidal effect against the Gram-negative bacterium Escherichia coli. Our results confirm that group IIA PLA2 is a potent antibacterial enzyme against Gram-positive bacteria. Moreover, we show here that group V PLA2 is a novel antibacterial mammalian protein, but is less potent than group IIA PLA2. Both enzymes may be considered as future therapeutic agents against bacterial infection