Peritoneal Macrophage Activation Indicated by Enhanced Chemiluminescence

A number of studies have demonstrated the ability of various bacterial preparations, protozoa, and chemicals to activate macrophages and concomitantly to enhance host resistance to both tumors and infections. Recently, viral infections have been shown to have a similar effect upon macrophage function. To better define the metabolic state of activated macrophages, we have evaluated the ability of peritoneal cells (PC) from vaccinia virus- or murine cytomegalovirus-infected or Corynebacterium parvum-treated mice to emit chemiluminescence (CL) during phagocytosis of zymosan particles or yeasts. PC from C. parvum-treated mice (1,400 microgram intraperitoneally) emitted enhanced CL over controls on days 3, 6, 14, and 21 after treatment, thereby establishing the emission of CL as a correlate of metabolic activation. Previous evidence for activation of PC from vaccinia virus-infected mice (10(8) plaque-forming units) was confirmed by demonstration of enhanced levels of CL on days 3, 6, and 13 after murine infection. Likewise, PC from mice infected with murine cytomegalovirus (10(5) plaque-forming units) 3, 6, or 13 days previously demonstrated augmented levels of CL over controls. Opsonized virus particles (vaccinia virus or murine cytomegalovirus) failed to induce the emission of CL with PC from mice infected with the isologous virus. Our data further demonstrate the immunomodulationinduced by virus infections and suggest that the detection of CL is an easily quantitated correlate of macrophage activation which may be helpful in defining metabolic alterations induced during activation.