Evaluation of protective immunity of 28KD-GST as a vaccine against experimental Schistosoma mansoni

Schistosoma mansoni GST was purified from adult worm homogenates by affinity chromatography. SDS-PAGE analysis of the purified antigen revealed that SmGST has molecular weight around 28 KD was used as a vaccine in a dose of 25 and 35 microg. Eleven groups of BALB/c mice of 10 mice each were vaccinated by GST. Complete Freund's adjuvant (CFA) and BCG vaccine were used as adjuvant. Booster doses were given after 2 & 4 weeks. Two weeks after the last dose of vaccine, mice were challenged by S. mansoni cercariae. Blood samples were taken 7 weeks post infection for detection of IgGl, IgE and circulating antigens. Then mice were sacrificed for histopathological study of the liver. Highly significant (p > 0.001) increase in the mean optical density of IgGl & IgE in groups vaccinated by 35 microg GST and CFA was demonstrated. On the other hand, highly significant (P < 0.001) decrease in circulating antigen, grnuloma number and size in the same group.

Oxidative stress and immune-suppression in Toxoplasma gondii positive blood donors: implications for safe blood transfusion

The sero-markers of Toxoplasma gondii and oxidative stress (OS) were determined in a group of 260 blood donors attending blood banks in Greater Cairo. Twenty-four blood donors with the highest anti-T. gondii IgG titre were tested for IgG avidity. Of whom 4 (16.6%) had low IgG avidity antibodies, documenting recent infection, 6 (25%) had borderline avidity and 14 (58.3%) showed high avidity, ruling out recent infection. The plasma level of malondialdehyde (MDA) was significantly higher and activity of glutathione peroxidase (GSH-Px) and level of tocopherol (alpha, gamma, & lambda) fractions (P < 0.001) were lower in T. gondii-seropositive than in seronegative blood donors. This significant alteration in redox status between seropositive and seronegative donors suggested a degradation of their antioxidant enzymes caused by OS induced by increased free radicals attributable to toxoplasmosis infection. T. gondii infection also had a prominent influence on the association between OS biomarkers and immune-suppression status in seropositive donors.

Effect of different temperatures on viability of seven encysted metacercariae recovered from freshwater fishes in Qualyobia, Egypt

Encysted metacercariae (EMC) from seven trematod-zoonotic parasites were exposed to different temperature mechanisms. Boiling of the infected fishes was sufficient to kill the EMC, frying of fishes for five minutes was quite sufficient to inhibit the viability of EMC, but frying for 10 minutes killed all EMC. Grilling of infected Tilapia zillii was sufficient to kill EMC after 10 minutes; however five minutes were sufficient only to kill EMC in Clarias gariepinus. Regarding chilling at 5 degrees C, T. zillii EMC showed variation in response. Complete loss of viability of Prohemistomatidae EMC was achieved after 14 days, for Haplorchidae after 11 days, for Diplostomatidae after 12 days, while Clinostomatidae EMC required 15 days. For Cl. gariepinus, Bagrus bajad and Chrysichthys auratus achieved results were similar to those for T. zillii but with fewer days of withstanding chilling. The EMC infecting Tilapia lost their viability by freezing at -5 degrees C & -10 degrees k for Prohemistomatidae after 48 & 40 hours, for Diplostomatidae after 24 & 16 hours and for Clinostomatidae cysts after 48 &32 hours respectively. In infected Clarias gariepinus, Bagrus bajad and Chrysichthys auratus the EMC lost their viability by fireezing at -5 degrees C & -10 degrees C for periods shorter than those of Tilapia sp.