Evaluation of purified 27.5 kDa protoscolex antigen-based ELISA for the detection of circulating antigens and antibodies in sheep and human hydatidosis.

Hydatidosis is a zoonotic disease caused by the larval stage of Echinococcus granulosus, and the diagnosis of hydatidosis to date remains unresolved despite the development of many serological techniques. The present study aimed to develop an antigen-based enzyme-linked immunosorbent assay (ELISA) using IgG anti-27.5 kDa protoscolex antigen (27.5 PA) for measuring circulating protoscolex antigen (CPA), for comparison with an antibody detection assay, in sera of naturally infected sheep and humans in highly endemic areas in Egypt. In sheep, the sensitivity of ELISA in detecting anti-27.5 PA IgG and CPA was 75.0 and 60.0%, respectively, and the recorded specificity was 80.0 and 88.0%, respectively. In humans, the sensitivity of ELISA in detecting anti-27.5 PA IgG and CPA was 62.5 and 52.5%, respectively, while the specificity of the assay was 66.7 and 75.0%, respectively. In conclusion, an antibody detection assay is still superior and is more sensitive than an antigen detection assay, especially in diagnosing an active infection in which hydatid cysts are predominant. An antigen detection assay may be a useful approach to assessment of the efficacy of treatment, especially after removal of the cyst. Further studies are recommended to improve the diagnostic efficacy of an antigen-based ELISA method by using a highly purified recombinant antigen.

Overview on cysteine protease inhibitors as chemotherapy for Schistosomiasis mansoni in mice and also its effect on the parasitological and immunological profile.

The present study evaluated the use of 3 types of Cysteine Protease Inhibitors (CPIs) with praziquantel (PZQ) as chemotherapy against schistosomiasis mansoni in mice. All groups were going to assessment of fluromethylketone (FMK), Vinyl Sulfone (VS) and Sodium Nitro Prussid (SNP) by measurement of parasitological, immunological and histological parameters. In our study, The ova count/gm liver or intestine on with PZQ treatment showed 99.1 and 95.2% Percent Reduction (PR), respectively compared to control group. The most effective CPI was FMK when combined with PZQ recording 99.8 and 99.6% PR for liver and intestine, respectively. Regarding to the oogram pattern, FMK, VS and SNP treatment either at 3 or 5 wk PI revealed marked decrease in the immature and mature ova counts and an increase of the dead ova percentages. The effect of CPIs was studied on the PR of Mean Granuloma Diameter (MGD) and Mean Granuloma Number (MGN) of infected treated groups compared to infected control and PZQ treated groups. FMK treatment proved to be highly was effective against S. mansoni in mice disintegrating ova and reduction in granulomatous size and numbers. The microscopic examination of liver sections of infected mice showed a large cellular granuloma with living central ova. sections of Infected mice liver treated with FMK or VS alone or combined with PZQ showed a great reduction in granuloma size as small cellular granuloma with central degenerated ova. We observed that these CPIs alone or combined with PZQ could effectively block schistosomal activity and prevented its growth and differentiation. Briefly, the best schistosomicidal effect of CPIs, that gained by drug administration orally in a dose of 50 mg kg(-1) mouse, was observed with FMK. This was followed by VS and lastly with SNP. These results gave evidence that CPIs can selectively arrest parasite replication without untoward toxicity to the host.

Fasciola gigantica fatty acid binding protein (FABP) as a prophylactic agent against Schistosoma mansoni infection in CD1 mice.

Although schistosomicidal drugs and other control measures exist, the advent of an efficacious vaccine remains the most potentially powerful means for controlling this disease. In this study, native fatty acid binding protein (FABP) from Fasciola gigantica was purified from the adult worm's crude extract by saturation with ammonium sulphate followed by separation on DEAE-Sephadex A-50 anion exchange chromatography and gel filtration using Sephacryl HR-100, respectively. CD1 mice were immunized with the purified, native F. gigantica FABP in Freund's adjuvant and challenged subcutaneously with 120 Schistosoma mansoni cercariae. Immunization of CD1 mice with F. gigantica FABP has induced heterologous protection against S. mansoni, evidenced by the significant reduction in mean worm burden (72.3%), liver and intestinal egg counts (81.3% and 80.8%, respectively), and hepatic granuloma counts (42%). Also, it elicited mixed IgG(1)/IgG(2b) immune responses with predominant IgG1 isotype, suggesting that native F. gigantica FABP is mediated by a mixed Th1/Th2 response. However, it failed to induce any significant differences in the oogram pattern or in the mean granuloma diameter. This indicated that native F. gigantica FABP could be a promising vaccine candidate against S. mansoni infection.