STUDIES ON THE INTERACTION BETWEEN PHAGOCYTES AND TUBERCLE BACILLI

Abstract

Tubercle bacilli were labeled with C14 by growing them in an atmosphere containing C14O2, in a medium with C14-glycerol or C14-acetate. These bacilli were used for a study of their metabolic fate after phagocytosis by polymorphonuclear leukocytes and by monocytes. It was compared with the fate of equally labeled saprophytic Mycobacteria and Bacillus subtilis. Leukocytes cannot break down bacillary material from tubercle bacilli to CO2 nor to other detectable small molecules, whereas the other organisms tested were broken down at a detectable rate. Tubercle bacilli maintain when phagocytized a rate of respiration (O2 consumption and release of endogenous C14O2) equal to the rate of respiration prior to phagocytosis. This was in sharp contrast to the reduction of respiration of the other organisms after phagocytosis. If tubercle bacilli are disintegrated by supersonic vibration, bacillary components are attacked by leukocytic enzymes. The CO2 production of tubercle bacilli which were heat-treated for 60 minutes at 56o C and which were not viable upon cultivation was greatly activated when phagocytized.