Ibrahim Rabia

OL-037 Effect of treatment with antifibrotic drugs in combination with PZQ in immunized Schistosoma mansoni infected murine model

The main problem in schistosomal hepatic morbidity is fibrosis and extensive scarring induced by living eggs. In this study, we tried to study the effect of treatment using antihelminthic drug (PZQ) and/or antifibrotic drugs (PTX and silymarin) in combination with immunization. The parasitological parameters, the dynamics of serum-specific immunoglobulins and splenic cytokines associated with changes in granuloma diameter were assessed. Naive mice were immunized intravenously with 10 ug of SEA in three doses at 2 days intervals 6 weeks before infection. Animals were infected by tail immersion with 100 cercariae and divided into several groups. Three groups were treated with PZQ, PTX or silymarin administered alone. Another two groups were treated with PZQ combined with PTX or silymarin. All treated animals and respective controls were sacrificed 12 weeks post infection. Immunization did not affect worm reduction , but slight decrease in granuloma diameter, increase in immunoglobulins and cytokines was observed . Reduction in worm burden was associated with reduction in ova count and changes in oogram pattern which were mainly due to PZQ treatment. Increasing reduction in granuloma diameter, elevation of immunogloulins and cytokines levels were observed in the groups treated with PZQ alone or cmbined with PTX or silymarin. In conclusion, in this study, treatment with PZQ complemented with immunization resulted in significant reduction of parasitological parameters and rise of specific Igs. Addition of antifibrotic drugs PTX or silymarin to PZQ, potentiated an antipathology effect which minimized and ameliorated liver fibrosis by inhibition of HSC activation and accentuation of the effect of suppressor Treg cells. (Journal of American Science 2010; 6(5):208-216). (ISSN: 1545-1003). Key word: Schistosoma mansoni, Praziquantel, Pentoxifyllin, silymarin.

Protective Role of Purified Cysteine Proteinases against Fasciola gigantica Infection in Experimental Animals

Fascioliasis is one of the public health problems in the world. Cysteine proteinases (CP) released by Fasciola gigantica play a key role in parasite feeding, migration through host tissues, and in immune evasion. There has been some evidence from several parasite systems that proteinases might have potential as protective antigens against parasitic infections. Cysteine proteinases were purified and tested in vaccine trials of sheep infected with the liver fluke. Multiple doses (2 mg of CP in Freunds adjuvant followed by 3 booster doses 1 mg each at 4 week intervals) were injected intramuscularly into sheep 1 week prior to infect orally with 300 F. gigantica metacercariae. All the sheep were humanely slaughtered 12 weeks after the first immunization. Changes in the worm burden, ova count, and humoral and cellular responses were evaluated. Significant reduction was observed in the worm burden (56.9%), bile egg count (70.7%), and fecel egg count (75.2%). Immunization with CP was also found to be associated with increases of total IgG, IgG1, and IgG2 (P<0.05). Data showed that the serum cytokine levels of pro-inflammatory cytokines, IL-12, IFN-γ, and TNF-α, revealed significant decreases (P<0.05). However, the anti-inflammatory cytokine levels, IL-10, TGF-β, and IL-6, showed significant increases (P<0.05). In conclusion, it has been found that CP released by F. gigantica are highly important candidates for a vaccine antigen because of their role in the fluke biology and host-parasite relationships.

Monoclonal Antibody-Based Dipstick Assay: A Reliable Field Applicable Technique for Diagnosis of Schistosoma mansoni Infection Using Human Serum and Urine Samples

A field applicable diagnostic technique, the dipstick assay, was evaluated for its sensitivity and specificity in diagnosing human Schistosoma mansoni infection. A monoclonal antibody (mAb) against S. mansoni adult worm tegumental antigen (AWTA) was employed in dipstick and sandwich ELISA for detection of circulating schistosome antigen (CSA) in both serum and urine samples. Based on clinical and parasitological examinations, 60 S. mansoni-infected patients, 30 patients infected with parasites other than schistosomiasis, and 30 uninfected healthy individuals were selected. The sensitivity and specificity of dipstick assay in urine samples were 86.7% and 90.0%, respectively, compared to 90.0% sensitivity and 91.7% specificity of sandwich ELISA. In serum samples, the sensitivity and specificity were 88.3% and 91.7% for dipstick assay vs. 91.7% and 95.0% for sandwich ELISA, respectively. The diagnostic efficacy of dipstick assay in urine and serum samples was 88.3% and 90.0%, while it was 90.8% and 93.3% for sandwich ELISA, respectively. The diagnostic indices of dipstick assay and ELISA either in serum or in urine were statistically comparable (P>0.05). In conclusion, the dipstick assay offers an alternative simple, rapid, non-invasive technique in detecting CSA or complement to stool examinations especially in field studies.

PP-198 Comparison between different immunological techniques for detection of circulating Fasciola antigen in sheep

The detection of Fasciola antigen in serum or stool could be more valuable in diagnosis, hence early treatment before irreparable damage. In this study, fresh adult Fasciola gigantica worms were collected, then incubation in culture medium and collected medium was used to extract crude excretory-secretory (E/S) antigen. E/S was used to immunize rabbits to raise specific antibodies against Fasciola spp. Purified antibodies are further used as primary capture to coat ELISA plates. The secondary capture of antibodies was by conjugation with horse reddish peroxidase. Sandwich ELISA and DOT-ELISA were performed to detect Fasciola antigens in both serum and stool samples collected from a total of 152 sheep. After slaughtering, gross inspection of liver and parasitological stool examination, sheep were divided into Fasciola positive group (97 sheep), other helminthic infection group (30 sheep) and healthy control group (30 sheep). Fasciola antigen detected in serum of sheep by ELISA showed 94.8 % sensitivity and 95 % specificity. Copro-antigen detected by ELISA showed 96.9% sensitivity and 96.7% specificity. The sensitivity and specificity of coproantigen by ELISA in stool sample were higher than that recorded by Sandwich ELISA for serum. Dot ELISA sensitivity was found to be 98.9% and specificity 98.3%. In conclusion the Dot ELISA gives better sensitivity and specificity than sandwich ELISA for serum and coproantigen in stool by ELISA. (New York Science Journal 2010;3(7):34-39). (ISSN: 1554-0200).

HPLC-ESI-MS Characterization of Certain Polyphenolic Compounds of Carica papaya L. Fruit Extracts and Evaluation of Their Potential Against Murine Schistosomiasis mansoni

The in vivo antischistosomal activities of Carica papaya L. extracts were evaluated and the characterization of the active secondary metabolites of the defatted methanolic extract was performed using HPLC-ESI-MS. The plant fruit powders were extracted with 85% methanol and fractionated using organic solvents. The in vivo antischistosomal effects of the methanolic extracts and its fractions, as well as the assessment of the relationship between the antischistosomal activity of these plant extracts and oxidative stress, was determined. In addition, the defatted methanolic extract was characterized by HPLC-ESI-MS analysis. The number of worms, ova, and the Oogram pattern displayed typical Schistosoma mansoni pathology 8 weeks after infection in mice. Treatment of the infected group with the defatted methanolic extracts significantly decreased worm burden, immature ova and mature ova, while increasing the percentage of dead ova in vivo. The butanol fraction was the most effective fraction reducing worm burden by 77%, ova count in the intestine by 76% and in the liver by 80%, and significantly decreased immature and mature ova (P<0.001) compared to the infected group. Additionally, the defatted methanolic extracts improved the reduced glutathione and malondialdehyde levels in hepatic tissues in the treated groups compared to the infected group. The HPLC-ESI-MS analysis of the Carica papaya defatted methanolic extract revealed the presence of several polyphenolic compounds. Carica papaya fruit extracts are rich with phenolic acids and flavonoids and show a significant effect against S. mansoni infections which may be used alternative to PZQ as anti-schistosomal drug against schistosomiasis.