Changes in the Titre of Serum Opsonins and Phagocytic Properties of Mouse Peritoneal Macrophages following Injection of Endotoxin

A study has been made of the changes in the opsonic properties of mouse serum and bactericidal activity of mouse peritoneal macrophages at different times following the injection of various doses of lipopolysaccharide. It has been found that changes in the percentage of bacteria phagocytosed and killed within the mouse peritoneal cavity in a given time could be correlated with changes in the opsonic titre of the serum. Macrophages harvested from the peritoneal cavities of mice injected with endotoxin appear to be more efficient in phagocytosing bacteria in the presence of serum opsonins than macrophages obtained from normal mice. The relative importance of these changes in determining an animal's resistance to infection is discussed.