El Shanawany Eman E, Younis Salwa Sami, Nemr Waleed A, Hassan Soad E, Zalat Rabab S, Desouky Hassan M, Shaapan Raafat M, Abdel-Rahman Eman H
Parasitology and Animal Diseases Department, Veterinary Research Institute, National Research Centre, Dokki, Giza, Egypt.
Medical Parasitology Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt.
Parasite Immunol. 2024 Dec;46(12):e13077. doi: 10.1111/pim.13077.
Gamma irradiation was applied to the tachyzoites Toxoplasma gondii virulent strain at doses of 0.25, 0.5, 1, 1.5 and 2 KGy. Radiation's effects were assessed both in vivo and in vitro. In vitro, the modest dosage of radiation, 0.25 KGy, showed 97% tachyzoites viability with only slight surface abnormalities and a normal crescent form using a scanning electron microscope. Protein analysis by SDS-PAGE demonstrated that while higher doses of radiation altered the protein banding profile, the 0.25 KGy irradiated tachyzoites showed no significant changes compared to the control (non-irradiated tachyzoites). While, tachyzoites exposed to the higher dose of irradiation (1, 1.5 and 2 KGy) resulted in the appearance of a new protein band as the molecular weights detected were 60, 30 and 10 kDa for antigens prepared from tachyzoites exposed to 1 kDa, and 1.5 and 60, 28 kDa for antigen prepared from tachyzoites exposed to 2 KGy. The immunogenicity of the tachyzoites exposed to radiation did not reveal any significant change in comparison with no irradiated tachyzoites when tested by ELISA using sheep-infected sera. A study conducted in vivo evaluated the infectivity of irradiation tachyzoites by inoculating mice with a 2500 tachyzoites virulent strain/mouse. There are six groups of mice, each with twelve animals, for the six doses of radiation. Mice harbouring irradiation tachyzoites remained viable until 40 days post-inoculation. On the other hand, the mice of control group had a mean survival time of 6.5 ± 0.22 days, and none of them survived past 7 dpi. Comparing the attenuated T. gondii tachyzoites at 0.25 KGy to the control group and other groups injected with irradiated tachyzoites, the results showed statistically significant increases in total IgG. Compared to other irradiation groups, the group injected with 0.25 KGy irradiated tachyzoites had a considerably higher level of IFN γ and IL17 (p < 0.000001). The groups which received 0.25 and 0.5 KGy irradiated tachyzoites as an injection showed no discernible variation in their higher levels of IL12. The findings imply that gamma irradiation was successful in reducing the pathogenicity of the T. gondii virulent strain while preserving the potential of the irradiated tachyzoites to induce an immunological reaction. An investigation into this immune response's immunoprotective potential is advised.
将剂量为0.25、0.5、1、1.5和2千戈瑞（KGy）的伽马辐射应用于刚地弓形虫强毒株速殖子。在体内和体外评估辐射的效果。在体外，适度剂量的辐射，即0.25 KGy，显示97%的速殖子具有活力，使用扫描电子显微镜观察仅表面有轻微异常且月牙形正常。通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）进行蛋白质分析表明，虽然较高剂量的辐射改变了蛋白条带图谱，但与对照（未辐照的速殖子）相比，0.25 KGy辐照的速殖子没有显著变化。而暴露于较高剂量辐照（1、1.5和2 KGy）的速殖子出现了一条新的蛋白条带，因为从暴露于1 KGy的速殖子制备的抗原检测到的分子量为60、30和10 kDa，从暴露于2 KGy的速殖子制备的抗原检测到的分子量为60、28 kDa。当使用绵羊感染血清通过酶联免疫吸附测定（ELISA）测试时，与未辐照的速殖子相比，暴露于辐射的速殖子的免疫原性没有显示出任何显著变化。在体内进行的一项研究通过给小鼠接种2500个强毒株速殖子/只来评估辐照速殖子的感染性。有六组小鼠，每组十二只动物，对应六种辐射剂量。携带辐照速殖子的小鼠在接种后40天内仍存活。另一方面，对照组小鼠的平均存活时间为6.5±0.22天，且无一存活超过感染后7天（dpi）。将0.25 KGy的减毒刚地弓形虫速殖子与对照组以及注射辐照速殖子的其他组进行比较，结果显示总IgG有统计学上的显著增加。与其他辐照组相比，注射0.25 KGy辐照速殖子的组干扰素γ（IFN γ）和白细胞介素17（IL17）水平显著更高（p＜0.000001）。接受0.25和0.5 KGy辐照速殖子注射的组在较高的白细胞介素12（IL12）水平上没有明显差异。这些发现表明伽马辐射成功降低了刚地弓形虫强毒株的致病性，同时保留了辐照速殖子诱导免疫反应的潜力。建议对这种免疫反应的免疫保护潜力进行研究。
