Characteristics of the granulocyte chemiluminescence reaction following an interaction between human neutrophils and Salmonella typhimurium bacteria.

The production of reactive oxygen metabolites by neutrophils is thought to play a key role in the host defence against invading microorganisms. The production of these oxidative metabolites can be measured as chemiluminescence. In this study, two strains of Salmonella typhimurium were used as stimuli, and the opsonin-independent CL response from neutrophils challenged with these bacteria was investigated. The strains used, S. typimurium 395 MS and a rough (Rd Epi-2) mutant 395 MR 10, differ with respect to physicochemical surface characteristics. When neutrophils were exposed to the phagocytic prey, only the MR 10 bacteria induced a CL response. The response induced by the MS bacteria was less than 2% of that induced by MR 10. In order to study the relation between intra and extracellularly generated CL, systems were used which selectively inhibit the intra and extracellular CL, respectively. Using these systems it was found that a predominant part of the response was of intracellular origin. When the neutrophils were treated with cytochalasin B (5ug) before the addition of the bacteria, the CL response was reduced to around 37% of the value obtained from untreated cells, and the relation between the extra and the intracellular parts of the response was changed. The mechanism(s) and biological consequences of the extracellular and intracellular generation of oxygen metabolites, respectively, are discussed.