Abstract:
BACKGROUND : Spirocerca lupi is a nematode that parasitizes vertebrates in particular canids, by forming nodules in
the thoracic cavity specifically in the oesophagus. In 25% of Spirocerca infections of the domestic dog, nodules
progress from inflammatory to pre-neoplastic to sarcomatous neoplasia. With the mechanism of neoplastic
transformation being incompletely understood, this study investigates if S. lupi parasite proteinaceous secretory/
excretory products (ESPs) play a role in the neoplastic transformation.
METHODS : To facilitate collection of ESPs, we maintained naturally harvested adult parasites in the laboratory under
artificial conditions. Media in which the parasites were grown was subsequently evaluated for the presence of
proteinaceous compounds using a mass spectroscopy library as well as for their ability to be mitogenic in primary
murine fibroblastic cells.
RESULTS : Chromatrography of the ethyl acetate extracted incubation media showed the presence of 9 protein
compounds, of which three were identified as non-specific proteins isolated from Nematostella vectensis,
Caenorhabditis brenneri and Sus scrofa, with the rest being unknown. Acetone, methanol, hexane and ethylacetate
extracted culture media were unable to induce a mitogenic change in primary murine fibroblasts in comparison to
the controls.
CONCLUSION : While no mitogenic effect was evident, further studies are required to understand the role of worm
excretory/secretory products on clastogenesis under chronic exposure. In addition, while not of primary importance
for this study, the observed duration of parasite survival indicates that ex vivo studies on S. lupi are possible. For the
latter we believe that the worm culture method can be further optimized if longer survival times are required.
