MODULATION OF NORMAL HUMAN EOSINOPHIL CHEMOTAXIS IN-VITRO BY HERBIMYCIN-A, ERBSTATIN AND PERVANADATE

Background: The mediators involved in eosinophil accumulation in disea ses such as allergy continue to be an area of interest, even though li ttle is known regarding the signaling involved in the human cell type recruitment. In the present study, we demonstrate a novel modulatory r ole of tyrosine kinase and tyrosine phosphatase activities on normal h uman eosinophil chemotaxis induced by different groups of chemoattract ant. Methods: Purified eosinophils were obtained from normal healthy v olunteers with the CD16-negative procedure. Chemotactic activities aga inst platelet-activating factor (PAF), vasoactive intestinal peptide ( VIP) and eotaxin were assessed using a 48-well microchemotaxis chamber assay. Purified eosinophils were pretreated with herbimycin A, erbast atin or pervanadate to examine the role of tyrosine kinase in chemoatt ractant signaling. Results: Pretreatment of eosinophils with the tyros ine kinase inhibitors herbimycin A and erbstatin significantly blocked chemotaxis induced by eotaxin whilst both inhibitors augmented chemot axis induced by VIP; however, they had no effect on PAF-induced chemot axis. On the other hand, pretreatment of eosinophils with the phosphot yrosine phosphatase inhibitor pervanadate resulted in augmentation of eotaxin-induced chemotaxis and inhibition of VIP-induced chemotaxis, b ut it had no effect on PAF-induced chemotaxis. Conclusions: These resu lts suggest that protein kinase plays a modulatory role in eosinophil chemotaxis induced by various chemoattractants.