Partial characterization of a bactericidal system in staphylococcal abscesses.

Since leukocytes comprise a major portion of staphylococcal abscesses, the properties of the bactericidal material in abscess homogenates were compared with those of bactericidal systems associated with leukocyte lysosomes. The bactericidal material in abscess homogenates was distinguished from the myeloperoxidase system by its resistance to heat (100 degrees C, 30 min), lack of solubility in dilute acid (0.005 N HCl), resistance to strong acid (pH 1), and insensitivity to catalase. It was differentiated from the cationic proteins by its lack of solubility in dilute acid, insensitivity to iron (0.1 mM) or trypsin (5 mg/ml), and greater activity in solutions of increased ionic strength. These characteristics, together with its sensitivity to Ca2+ or albumin, suggested that the material might be lipid. Subsequent studies revealed that all the bactericidal activity resided in the lipid fraction recovered after extraction of abscess homogenates by the Dole procedure.