Human PGLYRP1, PGLYRP3, and PGLYRP4 are directly bactericidal for both Gram-positive and Gram-negative bacteria. Mouse and bovine PGLYRP1 also have antibacterial activity, and bovine PGLYRP1 has also antifungal activity. These human PGRPs kill bacteria by simultaneously inducing three synergistic stress responses: oxidative stress, thiol stress, and metal stress. Bacterial killing by these PGRPs does not involve cell membrane permeabilization, cell wall hydrolysis, or osmotic shock, but is synergistic with lysozyme and antibacterial peptides.
