Anti-inflammatory activity of PAS-1, a protein component of Ascaris suum

Abstract.

Background: Recently, we identified a 200 kDa protein (PAS-1) from Ascaris suum worms, that suppresses the humoral immune response. Here, the effect of PAS-1 on inflammatory leukocyte migration induced by bacterial lipopolysaccharide (LPS) was investigated.

Methods: Cellular migration and cytokine release, stimulated by LPS or LPS+PAS-1, were analyzed in air pouches induced in the shaved back of BALB/c mice. Cytokines were determined by ELISA and RT-PCR on air pouch exudates and in vitro stimulated peritoneal macrophages.

Results: The significant cellular influx induced by LPS, consisting predominantly of neutrophils, was highly suppressed in the presence of PAS-1, but not a non-related protein. PAS-1 led also to a marked reduction of TNF-α, IL-1 β and IL-6 levels in both LPS-stimulated air pouches and peritoneal macrophage cultures. In contrast, PAS-1 induced a significant increase of IL-10 and TGF-β production.

Conclusions: These results demonstrate that PAS-1 has a potent anti-inflammatory activity, probably due to the stimulation of regulatory cytokines in macrophages, thus leading to the inhibition of pro-inflammatory cytokine production.