الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The present study aimed to assess the efficacy of CCA DNA vaccine to protect against schistosomiasis mansoni. The immunological, histological and ultrastructural consequences of vaccination were tested using ELISA, paraffin sectioning and ultrathin sectioning, respectively. Female C57 BL/6 mice aged from 45 weeks were vaccinated with 50<U+00B5>g of CCA DNA vaccine/mouse divided into three equal doses and administered at monthly intervals in the quadriceps muscles. Mice groups included; Naive, received no immunization; Naivechallenged, challenged with 200 normal S. mansoni cercariae; Wild immunized with empty plasmids; CCA, immunized with fulllength CCA. Mice of all groups were sacrificed one month after last immunization. Except those of CCA group, where some animals were left for estimating the regeneration process. Sera and livers were collected for immunological, histological and ultrastructural assays. The immunosuppressive efficacy of CCA DNA was noticed in an elevation of antiCCA DNA SWAP IgM in all groups, as compared to Naive controls. Furthermore, decreasing levels of IgG in CCA and Wild groups as compared to Naive controls. In previous studies, it was noticed that, antibodyantigen reaction raises the collagenase and proteases activities. This elevation plays an important role in the digestion of collagen fibers and the extracellular skeleton process. This lead to the degradation of the hepatic cytoplasm and the changeable of blood sinusoids. Which make this vaccine important for the control of fibrotic liver during the infection with Schistosoma. In general, the liver has high capacity for regeneration and return to its normal feature because it is constituted from the epithelial tissues which have the ability to regenerate following exposure to some factors effecting negatively on its cells. And the present study showed the ability of liver cells to regeneration. It could be concluded that vaccination with CCA DNA vaccine is favorable concerning its efficacy in developing appropriate immune responses and aavoiding deleterious histological and ultrastructural consequences of vaccination. This preliminary study gave some evidence that may help in developing new strategies for vaccination against schistosomiasis mansoni.