THE CHEMOKINE, EOTAXIN, ACTIVATES GUINEA-PIG EOSINOPHILS IN-VITRO AND CAUSES THEIR ACCUMULATION INTO THE LUNG IN-VIVO

Eotaxin is a novel C-C chemokine purified from the bronchoalveolar lavage (BAL) fluid of actively sensitised guinea-pigs after aerosol allergen challenge. In this study we show that eotaxin induced a dose-dependent increase in both intracellular-free calcium concentration ([Ca2+](i)) and aggregation of guinea-pig eosinophils in vitro. Intradermally injected eotaxin induced the accumulation of [111In]eosinophils in naive guinea- pig skin in vivo, without oedema-inducing activity; the latter emerging in separate BAL fluid HPLC fractions. Aerosol exposure of naive guinea-pigs to eotaxin in vivo caused a selective increase in eosinophils in BAL fluid. Thus, eotaxin activates guinea-pig eosinophils in vitro and causes a selective eosinophil accumulation in the lung in vivo. Eotaxin and related molecules are potentially important endogenous signalling substances in allergic reactions in vivo. © 1993 Academic Press, Inc.