Assessment of Fasciola hepatica glutathione S-transferase as an antigen for serodiagnosis of human chronic fascioliasis

Abstract

Due to the unsatisfactory performance of parasitological diagnosis of human fascioliasis; the use of immunodiagnosis based on the detection of anti-Fasciola antibodies is traditionally used as a diagnostic alternative using total or purified parasite excretory-secretory products (ESPs). Glutathione S-transferase (GST) protein, one of the F. hepatica ESP components, possesses well-known roles in the detoxification of xenobiotic and endogenously derived toxins within the host bile environment. GST has shown to be a good target for vaccine or drug development against fascioliasis. The current study aimed to evaluate the potential of GST protein purified from a soluble crude extract of adult flukes as an antigen for serodiagnosis of chronic human fascioliasis by indirect ELISA. The study included a panel of 116 serum samples collected from individuals with confirmed fascioliasis, individuals carrying heterologous parasitic infections and healthy subjects. The parasitological examination was used as gold standard and a previously optimized ESP-ELISA was used to compare the performance of the GST-ELISA method. Results demonstrated that GST-ELISA is 94.3% sensitive, 80.2% specific and exhibits a moderate positive correlation (r = 0.555) and substantial agreement (k = 0.786) with the results obtained with the ESP-ELISA method. Moreover, because no sera from patients with early F. hepatica infection were available, GST-ELISA was then tested with sera from rabbits experimentally infected with F. hepatica metacercariae. The assay was able to detect anti-Fasciola antibodies as early as the 3 week of infection (p < 0.0001) with peaks at 4 and 10 week post-infection.

Fasciola hepatica GST downregulates NF-κB pathway effectors and inflammatory cytokines while promoting survival in a mouse septic shock model

“…Our group and others have applied a method based on GSH-affinity chromatography as part of the strategy to identify GST isoforms from a cytosolic extract of F . hepatica 14,16 . In the present study, the protein was purified in active form with an average specific enzymatic activity of ~35 Units/min/mg (two separate batches) and when analyzed by 12.5% SDS-PAGE, it showed a single homogenous polypeptide band of ~25 kDa with a high purity level (96.17%) as demonstrated by the iBAQ value from the nano-LC MS/MS analysis 17 .…”

“…This indicates that the capacity of nFhGST to block the LPS-stimulation of TLR4 is independent of its enzymatic activity, as well as its native secondary/tertiary structure. Additionally, because nFhGST is an immunogenic molecule capable of inducing antibodies during the active infection 16 , we wanted to ascertain whether the presence of high levels of anti-nFhGST antibodies could impact the antagonistic capacity of this molecule on TLR4. To answer this question, THP1-Blue CD14 cells were incubated with different dilutions of an anti-nFhGST serum followed by the addition of nFhGST and the stimulation with LPS.…”

“…F . hepatica GST was purified from a crude soluble extract of adult fluke using 5/5 HP GSTrap column (GE Healthcare) as previously described 16 . The CDNB (1-chloro-2, 4-dinitrobenzene) enzymatic activity assay was used for monitoring the binding efficiency and recovery of the protein during the purification process.…”

Proteomics and bioinformatics analysis of Fasciola hepatica somatic proteome in different growth phases

“…In particular, the liver is an organ of intense metabolic activity and is precisely the place where juvenile and adult stages of F. hepatica localize. Therefore, the parasite may be damaged by the attack of xenobiotics during the normal metabolism of the host, so GST is essential for the survival of F. hepatica in the liver of the host (Vasti et al 2018 ). Our results showed that GST was not only expressed in somatic proteins of JF, IF, and AD of F. hepatica which colonized in the liver of the host, but also expressed in MC which survived in the external water environment.…”

Cold-Adapted Glutathione S-Transferases from Antarctic Psychrophilic Bacterium Halomonas sp. ANT108: Heterologous Expression, Characterization, and Oxidative Resistance

“…Currently, GSTs have been widely used as biomarkers of toxicity [13] and in pharmaceutical industries to scavenge organic hydroperoxides and ROS [14]. Furthermore, GSTs have been used as an indicator of certain diseases, especially hepatic infection [15]. Therefore, GSTs have different biological activities due to the differences of the conserved sequence regions, substrate specificity, and biochemical characterizations.…”