Phagocytosis of Coxiella burneti by macrophages.

Live or killed purified phase I and phase II Coxiella burneti organisms were phagocytized to a similar extent by mouse or guinea pig peritoneal macrophages and polymorphonuclear leukocytes (PMN); phase II was much more susceptible to phagocytosis than phase I. Phagocytosis of phase I was enhanced only by immune sera containing phase I antibodies. Increased in vivo phagocytosis of phase I organisms by macrophages from animals immunized with live phase I C. burneti was lost following their in vitro cultivation and washing.