Protective and Anti-Pathology Effects of Sm Fructose-1,6-Bisphosphate Aldolase-Based DNA Vaccine against Schistosoma mansoni by Changing Route of Injection

This study aimed to evaluate the efficacy of fructose-1,6-bis phosphate aldolase (SMALDO) DNA vaccination against Schistosoma mansoni infection using different routes of injection. The SMALDO has been cloned into the eukaryotic expression vector pcDNA3.1/V5-His TOPO-TA and was used in injecting Swiss albino mice intramuscularly (IM), subcutaneously (SC), or intraperitoneally (IP) (50 microg/mouse). Mice vaccinated with non-recombinant pcDNA3.1 served as controls. Each group was immunized 4 times at weeks 0, 2, 4, and 6. Two weeks after the last booster dose, all mice groups were infected with 80 S. mansoni cercariae via tail immersion. At week 8 post-infection, animals were sacrificed for assessment of parasitological and histopathological parameters. High anti-SMALDO IgG antibody titers were detected in sera of all vaccinated groups (P<0.01) compared to the control group. Both the IP and SC vaccination routes resulted in a significant reduction in worm burden (46.2% and 28.9%, respectively, P<0.01). This was accompanied by a significant reduction in hepatic and intestinal egg counts (41.7% and 40.2%, respectively, P<0.01) in the IP group only. The number of dead eggs was significantly increased in both IP and IM groups (P<0.01). IP vaccination recorded the highest significant reduction in granuloma number and diameter (54.7% and 29.2%, respectively, P<0.01) and significant increase in dead miracidia (P<0.01). In conclusion, changing the injection route of SMALDO DNA vaccination significantly influenced the efficacy of vaccination. SMALDO DNA vaccination via IP route could be a promising protective and anti-pathology vaccine candidate against S. mansoni infection.

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 Freund's 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-gamma, and TNF-alpha, revealed significant decreases (P<0.05). However, the anti-inflammatory cytokine levels, IL-10, TGF-beta, 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.

Clinical value of total HCV core antigen detection and quantification

Recently, the availability of total HCV core antigen assay in peripheral blood gains more interest in clinical evaluation of HCV patients. The aims of the present study were to assess the value of total HCV core antigen as a marker of viral replication, to determine the sensitivity of core antigen assay relative to molecular biology technique and to study the clinical value of HCV core antigen in relation to interferon-based treatment. This study included 150 patients sero-positive for antibodies to HCV. Viral load was assessed by both HCV RNA quantitative assay [bDNA] and HCV core antigen quantitative immunoassay [Ortho trak-C assay]. Spearman rank correlation coefficient was used to determine significant correlations among parameters. Of the 150 studied patients, 128 [85%] were positive to HCV RNA assay [bDNA] and 22 [15%] were negative. Have the 128 patients tested positive for HCV RNA, 125 patients tested positive by HCV core antigen assay with a sensitivity of 98%. All patients tested negative for HCV RNA assay [bDNA] gave negative results by HCV core antigen assay with a specificity of 100%. In the 125 patients that were positive in both assays, HCV RNA and total HCV core antigen were significantly related [r = 0.984; p< 0.001]. The relationship between HCV RNA in IU/ml and total HCV core antigen in pg/ml was given by the following equation: Log HCV core antigen = 0.649 x Log HCV RNA - 2.018. It was found that 1 core pg/ml is equivalent to approximately 8000 HCV RNA IU/ml in clinical samples of the studied patients. The correlation between HCV RNA IU/ml and HCV core antigen pg/ml varied around this average ratio when individual samples were considered, with the majority of the ratios lying between 5000 and 13000 HCV RNA IU/ml per core pg/ml. To evaluate the clinical use of total HCV core antigen quantification in the pretreatment assessment and in monitoring the response; to interferon therapy, sera from ten patients who were treated with a combination therapy of interferon alpha-2a and ribavirin had been studied. Serum samples were collected at baseline, 12 weeks after initiating therapy and at the end of treatment to be tested by both assays. There were significant correlations between log HCV RNA titer [IU/ml] and log HCV core antigen [pg/ml] [r = 0.693. 1.0 and 1.0 for the three comparisons respectively; p< 0.031. 0.003. and 0.017 respectively]. A weak relation had been found between necro-inflammatory changes in liver biopsy and viral load assessed by both assays. No relation could be found with the stage of liver fibrosis. In conclusion, the HCV core antigen assay can be used in confirming HCV infection when antibodies have been detected, in screening of patients, and in monitoring therapeutic interventions