IDENTIFICATION OF AN N-TERMINALLY TRUNCATED FORM OF THE CHEMOKINE RANTES AND GRANULOCYTE-MACROPHAGE COLONY-STIMULATING FACTOR AS MAJOR EOSINOPHIL ATTRACTANTS RELEASED BY CYTOKINE-STIMULATED DERMAL FIBROBLASTS

Eosinophil (Eo) granule proteins and, rarely, intact Eos represent a c haracteristic histopathologic feature of the dermal part of affected t issue in atopic dermatitis and some allergic reactions, Dermal fibrobl asts are a rich source of cytokines and inflammatory mediators; theref ore, we have investigated whether these cells release Eo chemoattracta nts when stimulated with different stimuli, Eo-chemotactic activity wa s detected after stimulation of cells with TNF-alpha and IL-1, but not when phorbol ester, PHA, or medium alone was used, Biochemical charac terization of Eo-chemotactic activity in supernatants of TNF-alpha-sti mulated cells revealed both heparin-binding and nonbinding activity, H PLC purification with subsequent N-terminal sequencing and mass spectr ometric analysis showed that the heparin-binding Eo-chemotactic peak c orresponded to the chemokine [Tyr-RANTES](66) that also contained [Ser -RANTES](68) as contaminant, whereas the nonheparin-binding activity w as identified as granulocyte-macrophage CSF (CM-CSF) by the use of neu tralizing Abs, [Tyr-RANTES](66) was found to show identical behavior i n the chemotaxis assay system with respect to potency and efficacy as natural [Ser-RANTES](68). These findings support the hypothesis that d ermal fibroblasts can play an important role in the recruitment of Eo by release of the chemokine RANTES together with GM-CSF.