Correspondence: Makoto Owhashi, ohashi@ias.tokushima-u.ac.jp
Makoto OWHASHI
Mika FUJINO
Faculty o fIntegrated Arts and Sciences, The University of Tokushima, Tokushima 770, Japan.
Kouki KITAGAWA
Niigata College of Pharmacy, Niigata 950-21, Japan.
Abstract
We previously cloned a cDNA encoding a neutrophil chemotactic factor of Dirofilaria immitis (DiNCF), and showed that Met-Phe-Lys could act as a functional epitope for neutrophil chemotactic activity. In the present study, we showed that recombinant DiNCF showed chemotactic activities for both eosinophils and neutrophils. To identify a novel eosinophil chemotactic oligopeptide derived from DiNCF sequence, we synthesized a formylated tripeptide (fMet-Phe-Lys-OH) and its C-terminus derivatives (fMet-Phe-Lys-OMe, fMet-Phe-Lys-NH2), and their chemotactic activities were examined. fMet-Phe-Lys-OH showed intense chemotactic activity for neutrophils but not for eosinophils. In contrast. fMet-Phe-Lys-OMe or fMet-Phe-LysNH2 showed significant eosinophil chemotactic activity at 10-4 to 10-7 M. The neutrophil chemotactic activity of fMet-Phe-Lys-OMe or fMet-Phe-Lys-NH2 was, however, Iess than 1/1000 of fMet-Phe-Lys-OH in molar basis. These results suggest that Met-Phe-Lys potentially acts as a chemotactic factor for eosinophils as well as for neutrophils. C-terminal negative charge of the peptide likely repels the receptor molecule on eosinophils though it fits the receptor molecule on neutrophils.
Key words: Dirofilaria immitis; eosinophil ; neutrophil ; chemotaxis; peptide.