Phagocytosis of Francisella tularensis by Rhesus monkey peripheral leukocytes.

Phagocytosis of Francisella tularensis by rhesus monkey peripheral neutrophils (PMN, was assessed by autoradiography, electron microscopy, and biochemical techniques. PMN, in contrast to mononuclear phagocytes, were unable to phagocytize F. tularensis in vitro in the absence of immune serum. It is postulated that in the nonimmune host the innate inability of PMN to phagocytize F. tularensis deletes one of the possible mechanisms of host defense to bacterial infection and thus permits the early dissemination of F. tularensis to intracellular sites of specific target tissues.