Production of singlet oxygen by eosinophils activated in vitro by C5a and leukotriene B4

Using the trans-methoxyvinylpyrene analogues of benzo[a]pyrene-7,8-dihydrodiol (MVP) as a singlet oxygen ((1)O2) chemiluminescence probe, we have demonstrated that guinea pig eosinophils release (1)O2 when activated with the physiological agonists C5a and leukotriene B4. This release, which occurs at agonist concentrations as low as 10(-7) M, occurs more rapidly than activation with phorbol ester (10(-6) M), is similar in level, but is more transitory. In addition, the release of (1)O2 occurs in the absence of added bromide ions and represents, we propose, an important feature of eosinophil-mediated inflammatory damage.