Impairment of Macrophage Presenting Ability and Viability by Echinococcus granulosus Antigens.

BACKGROUND: Despite advances toward an improved understanding of the evasive mechanisms leading to the establishment of cystic echinococcosis, the discovery of specific immunosuppressive mechanisms and related factors are of great interest in the development of an immunotherapeutic approach. OBJECTIVE: To elucidate immunosuppressive effects of bioactive factors contained in chromatographic fractions from hydatid cystic fluid (HCF) of Echinococcus granulosus. METHODS: Hydatid cystic fluid was fractionated by reverse phase chromatography. Non-specific Concanavalin A-driven proliferation of spleen cells was used to determine specific inhibitory fractions. Trypan blue exclusion test and flowcytometry analysis were performed to check whether highly inhibitory fractions of HCF have apoptotic effect on peritoneal macrophages. Western blot analysis was used to determine proteolytic effects of parasitic antigens on major histocompatibility complex (MHC) class II (I-a) contained in membrane proteins extract from macrophages. RESULTS: High concentrations of HCF and few of chromatographic fractions suppressed spleen cells proliferation. Fractions 7 and 35 were the highest inhibitory fractions. Specifically fraction 35 and to a lesser extent HCF induced apoptosis in peritoneal naive macrophages. However, HCF and the fraction 7 proteolytically altered the expression of MHC class II molecules on peritoneal macrophages. The proteolytic molecule was identified to be a serine protease. Macrophages taken at the chronic and end phase from cystic echinococcosis-infected mice were able to uptake and process C-Ovalbumine-FITC. These cells expressed a drastically reduced level of (I-a) molecules. CONCLUSION: Our study present new aspects of immune suppression function of E. granulosus. Further molecular characterization of apoptotic and proteolytic factors might be useful to develop immunotherapeutic procedure to break down their inhibitory effects.

Chemodiversity of volatile oils in Thapsia garganica L. (Apiaceae).

The chemical composition of the volatile oils obtained from the roots, leaves, flowers, and stems of Thapsia garganica of Tunisian origin was investigated by GC-FID and GC/MS analyses. Sesquiterpene hydrocarbons and oxygenated monoterpenes were predominant in the oils of all plant parts. Bicyclogermacrene (21.59-35.09%) was the main component in the former compound class, whereas geranial (3.31-14.84%) and linalool (0.81-10.9%) were the most prominent ones in the latter compound class. Principal-component (PCA) and hierarchical-cluster (HCA) analyses revealed some common constituents, but also significant variability amongst the oils of the different plant parts. This organ-specific oil composition was discussed in relation to their biological and ecological functions. For the evaluation of the intraspecific chemical variability in T. garganica, the composition of the flower volatile oils from four wild populations was investigated. Bicyclogermacrene, linalool, and geranial were predominant in the oils of three populations, whereas epicubenol, ß-sesquiphellandrene, and cadina-1,4-diene were the most prominent components of the oil of one population. PCA and HCA allowed the separation of the flower oils into three distinct groups, however, no relationship was found between the volatile-oil composition and the geographical distribution and pedoclimatic conditions of the studied populations.