A Study on the Phagocytosis of Macrophage

Macrophages collected from the rabbit lung by the method of Myrvic showed a high degree of uniformity both morphologically and functionally; more than 95% of the cells consisted of large monocytes and 90 to 95% of the cells had an activity of phagocytosis in vitro.A study on the phagocytosis of these cells against Staphylococcus epidermidis revealed that the phagocytic action required normal rabbit serum as an active component in the reaction mixture, and that when added at the rate of 10%, the serum exhibited a full activity. The active component contained in normal rabbit serum was found to react directly with Staphylococcus epidermidis by opsonization so that the organism might easily be picked up by the macrophages. No washing of the opsonized organism exerted influence on the phagocytic index of the macrophages. The pretreatment of the macrophages with the active component enhanced the phagocytic action of these cells to some extent, but far less than the same treatment of the microorganism.Kinetic experiments made on this system showed that the phagocytic reaction apparently proceeded on the basis of the first order reaction, and that the time required for 50% reaction was 14 minutes in a given condition