Abstract
Leukocyte chemotactic activity of Veronal buffered saline (pH 7.2) extract of adult Metastrongylus apri (M. apri) was investigated in vivo and in vitro. The results are as follows; When 0.l ml of the extract containing 50 μg of protein was intradermally injected to guinea pigs, eosinophils and neutrophils began to accumulate at the injected sites in 4 hours after injection and the number of them reached the peak in 8 hours. The facts show that the extract has chemotactic activity over the polymorphs. Also, the activity for guinea pig leukocytes was confirmed by the in vitro assay by the modified Boyden chamber method. The number of migrating eosinophils and neutrophils was in proportion to logarithms of protein concentration of the extract ranging from 5 to 500/μg per ml both in vitro and in vivo. In addition, chemotaxis of macrophages was seen in vitro. The chemotactic activity was heat-labile, non-dialyzable and stable to lyophilization. These findings show that the eosinophil and neutrophil infiltration reported in swine and guinea pigs infected with M. apri are partly due to the chemotactic activity of the component(s) of the adult worms, which may be protein or a related substance.
