Leukocyte accumulation in sparganosis: demonstration of eosinophil and neutrophil chemotactic factors from the plerocercoid of Spirometra erinacei in vivo and in vitro.

In order to determine whether the plerocercoid of Spirometra erinacei itself has eosinophil and neutrophil chemotactic factors, in vivo and in vitro examinations were carried out. We could observe large numbers of eosinophils and neutrophils which accumulated at the injection site of normal guinea pig skin following intradermal injection of soluble extract of plerocercoids of S. erinacei. At 1 hour after the injection, neutrophils appeared at the site, and the cell number reached its peak at 4 hours. Eosinophils appeared rather later than neutrophils (at 2-4 hours), and the number of cells reached its peak at 8 hours after the injection. Eosinophil and neutrophil chemotactic activities were also confirmed in an in vitro system by using a blind-well chemotaxis chamber with a Millipore filter in dose dependent fashion. An eosinophil chemotactic factor (ECF) with molecular weight of approximately 15,000, and two different neutrophil chemotactic factors, one of about same molecular weight as the ECF and the other of low molecular weight, were demonstrated by gel filtration on Sephadex G-200. Furthermore, it was confirmed that those factors were released from parasite by the detection of intensive eosinophil and neutrophil chemotactic activities in the culture supernatants containing plerocercoids.