Synthesis of new uracil-5-sulfonamide derivatives and immunostimulatory effect of a chemically modified hemolymph of Biomphalaria alexandrina on Schistosoma mansoni infected mice.

Some N-p-substituted phenyl uracil-5-sulphonamide derivatives have been synthesized to be evaluated as molluscicides against Biomphalanaria alexandrina snails, the intermediate host of Schistosoma mansoni. Schistosoma mansoni infected mice were treated with hemolymph obtained from pre-treated Biomphalana alexandrina snails with the products 4a, 10a, 10b and 4b or obtained from non-treated snails. The selection of the concentration based on the predetermined dose which caused mortality of less than 50% of snails/24 h. LC50 of compounds 4a, 10a, 10b and 4b was 50, 100, 200 and 50 ppm respectively. The result showed that immunostimulatory effect of treated hemolymph with compounds 4a, 10a and 4b was related to significant protective effects (44.4, 34.6 and 50.4% reduction in worm burden respectively). In addition, mean total worm burdens were significantly reduced in non treated hemolymph by 33.8%. The effect of hemolymph obtained from treated or non treated snails on S. mansoni adult worms antigens was studied by indirect immunofluorescence technique using chronic mouse sera (CMS). The results indicated that there was a strong reaction with epitopes in gut epithelium, tubercles, teigument and subtegumental musculature of untreated and treated S. mansoni adult worms antigens. Therefore, treatment of hemolymph obtained from pre-treated snails with compounds 4a, 10a, and 4b can stimulate specific immune response and induce protective effects against S. mansoni infection.

Effect of Daucus carota var. boissieri extracts on immune response of Schistosoma mansoni infected mice.

Isolation and structure elucidation was carried out of flavonoid constituents found in fractionated extracts of the seeds and green leaves of Daucus carota L. var. boissieri (Apiaceae). The flavonoids are mainly apigenin, luteolin, their glycosidic precursors and 2,4,5-trimethoxybenzaldehyde. Fatty acids, hydrocarbons and sterols were identified by GLC. The effect of various carrot extracts on the immune responses of Schistosoma mansoni infected mice was studied. The rate of reduction in worm infestation in mice injected with some fractions indicated a strong protection. Some extracts induced humoral immune response through raising the IgG level at 2, 4 and 6 weeks post-infection as compared with infected control. The phenotypic analysis of the cellular immune response in spleen and mesenteric lymph nodes was accomplished by direct immunofluorescence. The data showed that some extracts stimulated the blastogenesis of CD4(+)-T splenocytes and mesenteric lymph node cells.

Phenotypic analysis of cellular immune response in Swiss albino mice immunized with antigen extract from exposed B. alexandrina subjected to UV-, gamma irradiation and praziquantel treatment.

Mice were immunized (2x) subcutaneously at zero and 21st day with different antigen preparations. Splenocytes and mesenteric lymph nodes (MLN) cells were obtained from both immunized and control groups at 14th 21st and 42nd day post the 2nd immunization. The direct immunofluorescent assay was applied using anti mouse CD3+, D4+, CD8+, and IgG monoclonal antibodies to detect panel T-cells, T-cell subsets and B-cells respectively. The observations revealed that the splenic CD3+ T-cells did not show any considerable interrelation either between experimental groups or different time intervals post-immunization (P.I.). Meanwhile, UV-irradiated and PZQ-treated groups showed slight increase at the 2nd and 4th week P.I. as compared with the control group. The UV- and gamma-irradiated groups showed a significant elevation in CD4+ T-cells when compared with control group throughout the time of experiment, whereas, PZQ-treated group showed a significant increase at the 2nd and 4th week P.I. only. The frequency of CD8+ T-cells was elevated in all the experimental groups as compared with control group at 2nd, 4th and 6th week P.I. The MLN CD3+, CD4+ and CD8+ T-cells did not reveal any considerable changes between the experimental groups and control throughout the time of the experiment. A gradual decrease was observed in all the experimental groups by proceeding the time of the experiment. Splenic and MLN B-cells did not show considerable changes between the experimental groups and control group during the course of the experiment. It is concluded that these antigens could possibly stimulate cellular immune response upon their use as a protective antigens.