Antigens from Ascaris suum trigger in vitro macrophage NO production

Abstract

SUMMARY We investigated the in vitro effect of total excretory/secretory and somatic antigens from Ascaris suum adults (ESA and SA) and larvae 3 (ESL3 and SL3), and of 10 purified protein fractions from ESA components on rat alveolar macrophage nitric oxide (NO) production. Our results showed that in vitro incubation of macrophages with SA and SL3 antigens of A. suum did not result in NO release from cells, whereas incubation with ESA or ESL3 antigens resulted in the stimulation of NO production by these cells, both in a specific (inhibited by L-NAME and L-canavanine) and dose-dependent manner. In addition, we could demonstrate that a purified ESA fraction consisting of three Coomassie-stained bands of approximately 37, 44 and 46 kDa is involved in the in vitro triggering of NO production by host cells. These three bands were subjected to MALDI-peptide mass fingerprint, showing similarities with phosphoglycerate kinase, elongation factor Tu and enolase molecules, respectively. Future studies will focus on the characterization of these parasite-derived molecules.

Comparative Proteomics of Excretory-Secretory Proteins Released by the Liver Fluke Fasciola hepatica in Sheep Host Bile and during in Vitro Culture ex Host

“…Enolase has been found on the surface of many other pathogenic species, i.e. bacteria, fungi, and protozoa (32) with immune modulating properties (33), and has been predicted on the surface of the nematode worm Onchocerca volvulus (34) and found in in vitro culture studies in other nematodes, Ascaris suum (35) and Haemonchus contortus (36).…”

Nitric Oxide and Respiratory Helminthic Diseases

“…Finally, we have studied the effect of different antigens, somatic and excretory/secretory of larval and adult worms of nematodes, on NO production from rat alveolar macrophages. We have observed that somatic antigens from the third stage larvae and excretory/secretory antigens from adult worms in Toxocara canis and Strongyloides venezuelensis stimulated the NO production from alveolar macrophages ([30]; unpublished data ); similar data were found with Ascaris suum antigens [31]. …”

“…We also analyzed different parasite proteins to define the specific Dirofilaria immitis somatic adult-worm antigens involved in host cell NO secretion. We identified a parasitic specific component (DiID35.3) which does not belong to the endosymbiont Wolbachia and which is intimately related to proteins of the Immunoglobulin Superfamily (ISP) group, triggering NO release from macrophages in a dose-dependent and specific manner [31]. …”

Transcriptome profiling of gene expression during immunisation trial against Fasciola hepatica: identification of genes and pathways involved in conferring immunoprotection in a murine model

“…Significant alteration in IL-8 signalling was observed after mice were immunised with our vaccine candidate, involving up-regulation of receptors for IL-8, MMP9 and CXCR2. Nitric oxide production has been studied in vitro in infection caused by helminths involving Trichinella spp, Dirofilaria immitis and Ascaris suum antigens; a correlation has been found between antigen-dependent stimulation and nitric oxide levels [63–65]. Nitric oxide could regulate inflammation produced by egg release, prevent hepatic cell damage, the spread of damage in the liver and reduce granuloma formation by S. mansoni [66].…”