en Radiation Biology Radiation Biology تحقيق بديع Original Research <div style="text-align: justify;">Background: Gamma radiation-attenuated vaccine has a very promising value in controlling schistosomiasis. The objective of this study is to investigate the effects of vaccination with gamma radiation-attenuated schistosomules regarding histopathological and immunohistochemical changes in mice model of human Schistosoma mansoni infection. Materials and Methods: The study is conducted upon 40 mice, divided into four groups of 10 each: uninfected control group A (normal control),&nbsp;Schistosoma mansoni infected group B (infected control), Group C subcutaneously injected with 200 Gy gamma radiation&ndash;attenuated schistosomules (vaccine control) and group D injected with the same dose of gamma radiation-attenuated schistosomules then challenged after 4 weeks by S. mansoni&nbsp;cercariae (vaccinated-challenged). Parts of liver tissues stained with Masson&#39;s trichrome (MT) stain for classifying the granulomas into cellular, fibrocellular or fibrous according to the amount of collagens; stained bluish green. Immunohistochemistry assay was then done on the other portion through expression of Smad2/3 protein and CD8+ in the extracellular matrix (ECM). Results: Compared to control infected group, mild histopathological changes with decrease of egg granulomas mainly cellular is detected in vaccinated-challenged group. This is accompanied with moderate immunohistochemical expression of Smad2/3 and CD8+ proteins in vaccine-control group and mild expression in vaccinated-challenged group. Conclusion: The The results indicate that vaccination with 200 Gy gamma-irradiated schistosomules could reduce histopathological and immunohistochemical changes induced due to infection which represents an effective strategy in disease control.</div> Schistosoma mansoni, vaccination, immunohistochemistry, histochemistry. 579 586 http://ijrr.com/browse.php?a_code=A-10-1-820&slc_lang=en&sid=1 E.N. Hafez eman_naser612@hotmail.Com 7900319475328460013911 7900319475328460013911 Yes Department of Health Radiation Research, National Centre for Radiation Research and Technology (NCRRT), Egyptian Atomic Energy Authority, Cairo, Egypt M.M. Amin 7900319475328460013912 7900319475328460013912 No Department of Health Radiation Research, National Centre for Radiation Research and Technology (NCRRT), Egyptian Atomic Energy Authority, Cairo, Egypt