Staphylococcal delta toxin-induced generation of chemiluminescence by human polymorphonuclear leukocytes

Upon exposure to 0.5 hemolytic units of staphylococcal delta toxin, human polymorphonuclear leukocytes repeatedly generated active oxygen, which was detected as luminol dependent chemiluminescence. Gradual loss of the response was, however, observed after repeated exposure to the toxin, and eventually no more chemiluminescence was evoked. On this occasion, if the cells were exposed to another stimulus, such as melittin, chemotactic peptide, phorbol myristate acetate or zymosan, chemiluminescence was again induced. The converse was true if melittin or chemotactic peptide was used as the initial stimulus and delta toxin as a secondary stimulus. These results suggest that there exists a saturable receptor for delta toxin, melittin and other stimuli and that the toxin follows a different transductional pathway to generate chemiluminescence. By using various inhibitors, we found calcium influx, activation of phospholipase A2 and probably lipoxygenase(s) play an important role in delta toxin induced generation of chemiluminescence.