Efficiency of immunization of mice with irradiated antigen against schistosoma mansoni infection in comparison with praziquantel

The present study is an attempt to evaluate the protective effect of schistosomula antigen and the current antischistosomal drug praziquantel [PZQ] as a reference drug on mice infected with S. mansoni. Mice were vaccinated by irradiated or non-irradiated schistosomula antigen, both at a dose of 100 ug protein/mice once weekly for 3 weeks, before infection with a live cercariae and compared with the treatment with i.m. injection of praziquantel at a dose, of 40 mg/kg b.wt. 4 times once weekly for 4 weeks after infection. The degree of resistance or protection induced by immunization and chemotherapy was assessed 45 days post-infection and evaluated by physiological, parasitological, immunological as well as histological parameters. The results indicated that immunization with lambda irradiated antigen at 20 Krad or the treatment with PZQ resulted in significant reduction in ova count in liver and intestine tissues more than those vaccinated with non-irradiated antigen compared with infected group. Immunized group with irradiated antigen and the group treated with PZQ showed a significant decrease in liver enzymes activity [ALT, AST and lambda -GT], while in immunized group with non-irradiated antigen, there was a significant increase in AST and lambda -GT as compared to infected group. The level of alkaline phosphatase enzyme was significantly increased in all investigated groups compared to infected one. Treatment with PZQ or immunization with irradiated or non-irradiated schistosomula antigen induced amelioration in serum IL-10 and TNF-alpha. Scanning electron microscope demonstrated normal mature worms in infected group after 45 days from infection. In contrast, many changes were detected in the rest groups as alterations in the tegument, implosion of tubercles which appeared pealed and sloughed off and most of the spines were detached and separated. Histological examination of liver sections of infected mice revealed lobular cellular infiltration and cloudy swelling in hepatocytes with occurrence of necrotic foci. Also, granuloma of infiltrating cells was noticed around the portal structures and inbetween the degenerated cells. Congested portal vein could be seen lodged with adult worms and the portal tracts showed fibrous thickening. Whereas, the lung revealed destructed bronchioles which appeared surrounded by intense inflammatory foci. Thickened interalveolar septae were also marked, however many alveoli appeared with shed destroyed epithelium. Moreover, peribronchiolar and perivascular fibrosis was quite prominent. Gross pathological alterations were observed in both liver and lung of immunized groups with non-irradiated antigen. In controversy, immunization with irradiated antigen can reduce the granulomatous reaction and collagen deposition. There are also little inflammation and less congestion, however the hepatic and pulmonary architectures appeared otherwise normal. The present histological findings proved that PZQ has a valuable schistosomicidal effect but some pathological changes are still detectable. On the whole, it could be concluded that irradiated antigen produced marked protection against S.mansoni infection and this may reflect its possible beneficial effect on the diseased liver and lung

Physiological and histological studies on glucan as modulator of hazardous effects in rats treated with cyclophosphamide and exposed to gamma radiation

beta-glucan which is known as biological response modifiers and immunostimulator was investigated in this study to minimize the toxicity of chemo-and radiotherapy induced by cyclophosphamide [CYP] and radiation exposure in rats. beta-glucan was orally administered in a dose of 10 mg/kg b.wt. daily against the hazardous impacts of gamma-irradiation [1 Gy daily up to 10 Gy] and/or CYP [50 mg/kg b.wt. every other day for 2 weeks]. Determination of some biochemical analysis was carried out including calcium, alkaline phosphatase, creatine kinase, lactate dehydrogenase. Hematological analysis was performed on leucocytes and platelets counts. Additionally, histological study was also done on both lung and testis tissues. The experimental rats being sacrificed 1, 7 and 21 days post-treatment. Treatment with CYP induced significant decrease in WBCs, platelets counts and alkaline phosphatase activity and significant increase of creatine kinase and LDH activities accompanied by a significant increase in Ca level only at the end of experimental period. Similar results were recorded with irradiated group accompanied with a non significant change in Ca level allover the experimental periods. Combined treatment with both gamma-radiation and CYP intensified the effect of each other on most of the investigated parameters. Microscopic examination of the lung revealed that both gamma-irradiation and CYP showed disturbed structure of bronchioles, thickened alveolar walls together with scattered haemorrhagic areas. Signs of pneumonia and compensatory emphysema were also seen. Meanwhile, in testis, irregular seminiferous tubules with reduction in their sizes were observed. Besides, the intertubular spaces were fibrotic and devoid of Leyding cells. Bizarre-shaped spermatogenic cells were also prominent. In combined treatment, these lesions became much more progressed. However, glucan administration prior to treatment with CYP or gamma-radiation led to an improvement in most of biochemical, hematological and histological parameters under investigation. beta-glucan has a good protective role against the toxic effects associated with chemo-and radiotherapy