Effect of Schistosoma mansoni infection on offsprings born from infected mothers.

Offsprings C57BL/6 mice (4 weeks old) coming from either moderately infected (40 S. mansoni cercariae) or heavily infected (100 S. mansoni cerariae) mothers, were exposed to 40 S. mansoni cercariae each. Seven weeks post infection (P.I.), Offsprings were sacrificed. In both groups there was significant reduction in the worm load, both hepatic and intestinal tissue egg count. The oogram profile was not altered. Humoral immune response as regards the level of anti S. mansoni SEA Ab was elevated in both groups in comparison to their parallel controls at 2 weeks post delivery and 7 weeks P.I. The level of antibodies was significantly higher in heavily infected Offsprings than that present in offsprings coming from moderately infected mothers. Delayed footpad swelling and hepatic granuloma size were significantly reduced in both groups comparing with their corresponding controls.

Mutual effect of Schistosoma mansoni infection and pregnancy in experimental C57 BL/6 black mice.

Sixty female C57BL/6 mice were infected with 40 Schistosoma mansoni cercariae each. Seven weeks later, they were mated with normal syngeneic males. Uninfected mice (30) were bred in parallel, and both groups were bred several more times with daily records of pregnancy, delivery and number of offsprings. The number of pregnancy was 146, with 50 survived infants (34.2%) in contrast to 121 pregnancy with 93 survived infants (76.8%) in controls. The outcome of pregnancy was 13% abortion, 10.9% maternal death and 41.7% infanticide. The weight of offspring at 2 and 4 weeks of age was significantly less than in controls (P < 0.01). Again, C57BL/6 (40) female mice were mated, then infected with 100 S. mansoni cercariae each. The results showed that, pregnancy had no effect on bilharzial infection as the total worm burden and distribution, hepatic and intestinal tissue egg count and the oogram profile, were not significantly differ from that in the control group (20). Besides, the immediate footpad swelling was significantly higher but the delayed footpad swelling and the level of antibodies against S. mansoni soluble egg antigen were insignificantly differ from that present in the parallel control (infected but not pregnant). As regards histopathological parameters, although there was insignificant difference in the size of hepatic granuloma, yet there was more collagenous fibrous tissue deposition distributed in-between inflammatory cells specially at the periphery of the granuloma.

Production of monoclonal antibodies against target schistosomal antigen secreted in the urine of Schistosoma mansoni-infected patients.

This study was undertaken to develop an immunodiagnostic test of active human schistosomiasis mansoni using a monoclonal antibody which targets urinary schistosomal antigen. Polyclonal antisera raised in rabbits against the processed urine of Schistosoma mansoni-infected patients showed very high and significant reactivity with ES product of ova compared with other different S. mansoni antigens. The monoclonal antibody (4.23) was reactive with repetitive epitopes of S. mansoni soluble egg antigen and ES product of ova with molecular mass range of 65-23 kDa and 80-23 kDa, respectively. It recognised different stages of the parasite life-cycle, with no cross reaction with Fasciola or hydatid antigen. MAbs were characterised by isotyping, immunoelectrophoresis, SDS-PAGE and the enzyme-linked immunoelectrotransfer blot technique, ELISA, and their recognition of carbohydrate or protein antigenic epitopes by periodate oxidation and trichloroacetic acid treatment of the antigen. It was used for detection of circulating schistosomal antigen in an antigen capture antibody sandwich ELISA on sera and urines of 58 S. mansoni-infected patients, 17 S. haematobium-infected patients, 15 parasite-free negative healthy controls and sera from 13 schistosomiasis-free patients harbouring Fasciola or hydatid infections. The percentage sensitivity of the assay in the serum of S. mansoni-infected patients was 98.4% and in urine 94.8%. A positive correlation was found between the number of faecal S. mansoni eggs and the circulating antigen, both in serum and in urine. Antigen circulating in urine correlated with that in the sera of S. mansoni patients. These data provide a sensitive and non-invasive method almost comparable with the use of sera for immunodiagnosis of schistosomiasis and an indirect way to reflect the intensity of infection.

A monoclonal antibody diagnoses active Fasciola infection in humans.

Monoclonal antibodies (MABs) were produced after fusion of spleen cells of Fasciola antigen immunized BALB/c mice and non secreting murine myloma cells (P3x63 Ag8). Six MAbs, showing the highest reactivity with purified Fasciola antigen, were prepared. All 6 MABs were IgG2 with Kappa light chain. Reactive epitopes recognized by the six MAbs were glycoprotein in nature, and each MAb recognized a single epitope of Fasciola antigen. No cros reactions were observed with Schistosomal AWSA, hydatid Ag and Entamoeba Ag. EITB technique showed a specific diagnostic band at 17.5 kDa for each of the six MAbs. Anti-Fasciola MAb (AD2) was conjugated with peroxidase and was used with anti-rabbit anti-Fasciola polyclonal antibody in sandwich-ELISA to detect circulating Fasciola antigen in serum and urine samples of 57 fascioliasis patients, 51 schistosomiasis patients, 45 patients infected with other parasites and 47 healthy controls. Sensitivity of the assay in detection of circulating Fasciola antigen in sera and urines of Fasciola infected patients was 100%. The specificity of the assay was calculated among patients infected with schistosomiasis and other parasites and was 98% in serum and 97% in urine. A positive correlation was found between levels of circulating Fasciola antigen in serum and urine samples of fascioliasis patients (r = 0.825, p < 0.05).

Schistosoma mansoni: the immune response against cercarial glycocalyx.

Schistosoma mansoni cercarial glycocalyx was separated and purified by Sephacryl-300 SR. It was found to stimulate the humoral immune response in mice injected with it. Antiglycoalyx antibodies raised in CD/1 mice were found to be cytotoxic to schistosomula in vitro. But conversely, no protective effect was demonstrated in vivo. Eosinophil-mediated cytotoxicity was found to have no effector function in the murine immune response against schistosomes. A monoclonal antiglycocalyx IgM was prepared during our study. It was found to have no cytotoxic effect on schistosomules in vitro. However, it was found to have an inhibitory activity blocking the cytotoxic effect of other antiglycocalyx isotypes in the immune mouse. The contradiction between the result of antiglycocalyx antibody-mediated cytotoxicity obtained in vivo and that obtained in vitro is in itself revealing and suggests that the effect is crucially dependent upon factors as yet poorly understood.

Host and parasite determinants of morbidity in Egyptian children with schistosomiasis.

The relation of morbidity due to schistosomiasis in Egyptian children to egg count, eosinophilic count, antibodies mediating eosinophil damage to schistosomula, total immunoglobulins and specific antischistosomal antibodies IgG and IgM anti-cercarial antigen preparation (CAP), anti-soluble worm antigen preparation (SWAP) and anti-soluble egg antigen preparation (SEA) were evaluated. The behavior of the immune parameters after treatment was also determined. The studied children were 78 males, aged 9-11 years. They were classified to control (14), simple intestinal (26) and hepatosplenic schistosomiasis (38) groups according to the clinical, parasitological and sonographic basis. The egg count was found higher in hepatosplenic schistosomiasis compared to that in simple group. Eosinophilic count did not differ between the two groups. Studies of immune responses revealed that antibodies mediating eosinophil adherence and damage to schistosomula rose in both groups particularly in hepatosplenic group. The levels of total and specific immunoglobulins were not significantly differed in both groups. The immune response was measured 2 months after treatment. The level of total IgA was increased in simple and decreased in hepatosplenic group. Total IgG and IgM were not affected by treatment in simple but IgM increased in hepatosplenic after treatment. Total IgE was decreased after treatment in both groups. This denotes that the behavior of the two groups after treatment was similar as regards the levels of IgG and IgE and differed as regards IgA and IgM. IgG anti-CAP and anti-SEA were declined after treatment but IgG- anti SWAP was elevated after treatment in both groups. The treatment has no effect on the levels of specific IgM against all used antigens. The antibodies mediating eosinophil adherence and damage to schistosomula rose in both groups after treatment. These indicated consistency of specific immune responses after treatment in schistosomal children. It is concluded that high intensity of infection may be one of the determinants of morbidity due to Schistosoma mansoni infection in Egypt. The elevated response of antibodies mediating adherence and damage to schistosomula may be associated or play a role with morbidity. Eosinophilic count, total IgA, IgG, IgM, IgE and specific antischistosomiasis IgG and IgM (Anti-CAP, anti-SWAP and anti-SEA) are not related to morbidity.

Identification and characterization of specific hydatid antigen fraction(s).

A specific hydatid antigen was prepared in this study from Echinococcus granulosus cyst in livers and lungs of camels. Elimination of host "camel" protein from crude hydatid fluid was achieved by two methods: Salting out using ammonium sulfate precipitation method and immunoaffinity purification using coupled anticamel antibody to cyanogenbromide activated sepharose 4B gel. Testing the prepared hydatid antigen against anticamel serum, using immunodiffusion method, indicated that the affinity purified hydatid antigen was almost completely purified from camel protein. Characterization of the affinity purified hydatid antigen, using immunoelectrophoresis, showed positive arc 5 precipitation when tested against known positive antihydatid sera. Further characterization with gradient gel electrophoresis, showed with silver stain that the dominant and most consistently demonstrable proteins occurred as a complex in the 52/62 KDa region. Strong reaction with the 52/62 KDa complex was consistently observed when the affinity purified hydatid antigen was probed with known positive reference antihydatid sera. The identified hydatid antigen fraction(s) with 52/62 KDa complex can provide promising non-invasive parameter for diagnosis of Hydatidosis.