Eotaxin-2 activates chemotaxis-related events and release of reactive oxygen species via pertussis toxin-sensitive G proteins in human eosinophils

LeukoSite Inc., Cambridge, USAEosinophils play an important role in allergic and autoimmune diseases. They are activatedby distinct chemokines, leading to the immigration into the inflamed tissue, and mediate tis-sue damage by releasing reactive oxygen species. Recently, eotaxin was found to have thebroadest spectrum of activities of all eosinophil-activating CC chemokines. In this study weinvestigated the effect of the novel CC chemokine, eotaxin-2, on eosinophil effector func-tions and compared its activity with eotaxin. Using nitrobenzoxadiazole-phallacidin stainingand flow cytometry, we show that eotaxin-2 induced rapid and transient actin polymeriza-tion, a prerequisite for cell migration and modulation of the respiratory burst, in eosinophilsin the same range of efficacy as observed for eotaxin. Eotaxin-2 induced the release of reac-tive oxygen species in a dose-dependent manner; half maximal and maximal release werefound at 50 ng/ml and 500 ng/ml, respectively. Surprisingly, the efficacy of eotaxin-2 wascomparable to that of eotaxin and C5a. Release of reactive oxygen species was inhibited bypertussis toxin, indicating the involvement of G