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Mast cell degranulation is the major mechanism influencing establishment and survival of the abomasal nematode Teladorsagia circumcincta and probably many other gastrointestinal nematodes. Host galectins-3 and -9 have been shown to bind IgE and positively and negatively influence mast cell degranulation. As incoming nematodes produce large amounts of galectin, we hypothesised that nematode galectin competes with host galectin and inhibits mast cell degranulation. ELISA was used to show that nematode galectin reduced total IgE activity. Galectin also reduced the binding of sheep IgE to the surface of a mast cell line and decreased the release of LCT-4 and Beta hexosaminidase but not MMP-9. These results indicate that nematode galectin influences mast cell degranulation and identify a potential immunomodulatory mechanism used by nematodes to enhance their establishment and survival.

Avena sativa L., 1753 (Poaceae) is used as feed for livestock and as a crop rotation agent. The purpose of the study was to examine the molecular mechanisms behind the antihelminth activity of the oat saponins avenacoside B (AveB) and 26-desglucoavenacoside B (26DGAveB) by evaluating their effect on Heligmosomoides bakeri, a parasitic nematode of mice. The avenacosides AveB and 26DGAveB were separated and purified from A. sativa green leaves, and their mycotoxic activity was confirmed against the fungus Trichoderma harzianum. The anti-nematode activity of the avenacosides was measured by egg hatching assay. In the surviving L3 larvae exposed to avenacosides, the expression of CED-9, a protein of the apoptosis pathway, was identified by Western blotting. The protein profile of L3 larvae was monitored by High Performance Liquid Chromatography (HPLC). The action of saponins on glycoprotein pump (Pgp) activity in L3 larvae was compared to that of the pump blocker Verapamil (VPL). A mouse model was used to measure the infectivity of L3 larvae exposed to AveB and 26DGAveB, and the outcome of the immune response. Both compounds induced morphological changes in larvae and blocked Pgp activity; however, only 26DGAveB provoked expression of CED-9. The infected mice displayed changes in the molecular pattern of larval proteins and enhanced IL-4 production, indicating that avenacosides reduced the infectivity of H. bakeri larvae. In avenacosides, the residue without glucose at the C26 position demonstrated greater anti-nematode activity. Our findings indicate that A. sativa compounds are natural products with anti-parasitic activity.

Current study was designed to evaluate in vivo and in vitro anthelmintic activity of Artemisia vestita Wall ex DC. and Artemisia maritima L. against Haemonchus contortus in comparison with ivermectin to investigate the effect of plant extracts on survival of infective L3 and adults under in vitro condition. Plant extracts were given to H. contortus infected sheep orally and it was infected with L3 stage of H. contortus at dose of 5000 larvae/sheep. Total of 25-30 larvae were incubated with plant extracts in PBS alone and ivermectin at different concentration used as positive control. It was recorded that there is a significant decrease in fecal egg count (FEC) after post-treatment period for both plants. The highest fecal egg count reduction for A. vestita was 87.2% at 100mg/kg while for A. maritima it was 84.5% on day 28 post-treatment. Investigated extracts indicated significant activity against larvae and adult worms.