Studies on the interaction between phagocytes and tubercle bacilli. III. Some metabolic effects in guinea pigs associated with infection with tubercle bacilli

In continuing studies concerning the interactions between phagocytes and tubercle bacilli the effect of tuberculous infection on respiration and glucose utilization was investigated in guinea pigs. Peritoneal exudates rich in polymorphonuclear leucocytes, derived from guinea pigs infected with tubercle bacilli, had a significantly higher rate of respiration than the same cells from normal animals. The difference between cells from normal and infected animals was greater when the animals were infected with a virulent strain (Vallée) than when infected with an attenuated one (R1Rv or BCG). By the use of glucose labelled with C¹⁴ at position 1 or 6, or uniformly labelled glucose, it was established that this difference in oxygen uptake between normal and infected cells was probably not caused by a difference in the pathway of glucose utilization. Similarly, the respiration of liver and kidney slices from normal and infected guinea pigs was compared and it was found that liver slices showed differences similar to those shown by leucocytes, but that the kidney slices did not. The possibility has not been ruled out that the difference in rate of respiration of liver slices due to infection might be caused by tuberculous lesions in the livers of infected animals. The mononuclear cells which invade the liver have a higher rate of oxygen uptake than liver cells. The rate of glucose utilization and the total amount of CO₂ produced was also determined in intact guinea pigs. Both functions were found not to differ significantly in normal and infected animals. The rate of production of CO₂ from C₁ and C₆ of glucose was the same in both groups of animals. The ratio of the rate of production of C¹⁴O₂ from C₁ and C₆ of glucose by the whole animal was found to be about 1.35. It was found to be much higher with polymorphonuclear leucocytes (C₁/C₆ = 8 in the absence of serum). During the process of phagocytosis this ratio increased from about 25 to about 130 (in the presence of 2 per cent serum) indicating an increase in the direct oxidative pathway of glucose utilization during stimulated cellular activity.