Campero Lucía M, Gual Ignacio, Sander Valeria A, Morales Luisa F Mendoza, Duarte Victor A Ramos, Formigo Paula M, Sosa Emiliano, Lázaro Fermín, Scioli María Valeria, Atela Agustín, Legarralde Ariel, Hozbor Federico A, Cantón Germán J, Angel Sergio O, Moore Dadín P, Clemente Marina
Instituto de Innovación para la Producción Agropecuaria y el Desarrollo Sostenible (IPADS Balcarce), Instituto Nacional de Tecnología Agropecuaria Estación Experimental Agropecuaria Balcarce (CONICET-INTA), Balcarce, Buenos Aires, Argentina.
Facultad de Ciencias Agrarias, Universidad Nacional de Mar del Plata, Balcarce, Buenos Aires, Argentina.
Acta Trop. 2025 Feb;262:107540. doi: 10.1016/j.actatropica.2025.107540. Epub 2025 Jan 31.
Toxoplasma gondii is a protozoan parasite causing toxoplasmosis, a principal concern for public health and livestock industries. Effective vaccination strategies are crucial for controlling toxoplasmosis, particularly in the lamb, which are significant reservoirs of T. gondii. In addition, ovine toxoplasmosis also causes economic losses due to abortions and reproductive complications. In this study, we evaluated two immunization strategies to elucidate the immune protective potential of T. gondi major surface protein SAG1 fused to the plant heat shock proteins 90-kDa (pHsp90) adjuvant against experimental toxoplasmosis in lambs. We performed an oral administration of fresh leaves homogenate infiltrated with a B- and T-cell antigenic epitope-containing surface protein SAG1 (SAG1HC) fused to Arabidopsis thaliana Hsp90 (AtHsp81.2-SAG1HC) (Plant Vaccine) and a subcutaneous administration of recombinant SAG1HC fused to Nicotiana benthamiana Hsp90 (NbHsp90.3-SAG1HC) produced in Escherichia coli (Recombinant Vaccine). Our results showed that only the Recombinant Vaccine significantly increased anti-rSAG1 total IgG values (∼ 4-fold more than the Vehicle and Control groups). In addition, only lambs immunized with the Plant Vaccine showed a significant increase (∼ 3-fold more than the Vehicle and Control groups) in IFN-γ serum levels after the experimental infection (evaluated 8 days post-challenge). On the other hand, we also observed a statistically significant decrease (∼ 80 % less) in histopathological lesions (injury score) in challenged vaccinated lambs compared to challenged but not vaccinated animals (Vehicle and Control groups). Previously, we showed that the chimera recombinant Gra4-Gra7 protein is an acute marker of human infection. Since Gra4-Gra7 is not connected to the SAG1 immunogen, this chimera allows us to monitor infection in challenged lambs early. All lambs from the Control and Vehicle groups showed higher rates of serological reactivity than lambs from the vaccinated groups, concurrently with increased severity of lesions. These results suggest that the Plant-based and Recombinant Vaccines are promising candidates for controlling T. gondii infection in lambs, with potential benefits for enhancing public health and animal welfare.
刚地弓形虫是一种导致弓形虫病的原生动物寄生虫，这是公共卫生和畜牧业主要关注的问题。有效的疫苗接种策略对于控制弓形虫病至关重要，尤其是在作为刚地弓形虫重要宿主的羔羊中。此外，绵羊弓形虫病还会因流产和生殖并发症造成经济损失。在本研究中，我们评估了两种免疫策略，以阐明与植物热休克蛋白90 kDa（pHsp90）佐剂融合的刚地弓形虫主要表面蛋白SAG1对羔羊实验性弓形虫病的免疫保护潜力。我们对用融合了拟南芥热休克蛋白90（AtHsp81.2-SAG1HC）（植物疫苗）的含B细胞和T细胞抗原表位的表面蛋白SAG1（SAG1HC）浸润的新鲜叶片匀浆进行口服给药，并对在大肠杆菌中产生的与本氏烟草热休克蛋白90（NbHsp90.3-SAG1HC）融合的重组SAG1HC进行皮下给药（重组疫苗）。我们的结果表明，只有重组疫苗显著提高了抗rSAG1总IgG值（比载体组和对照组高约4倍）。此外，只有用植物疫苗免疫的羔羊在实验感染后（攻毒后8天评估）血清IFN-γ水平显著升高（比载体组和对照组高约3倍）。另一方面，我们还观察到，与攻毒但未接种疫苗的动物（载体组和对照组）相比，攻毒接种疫苗的羔羊的组织病理学损伤（损伤评分）在统计学上显著降低（减少约80%）。此前，我们表明嵌合重组蛋白Gra4-Gra7是人类感染的急性标志物。由于Gra4-Gra7未与SAG1免疫原相连，这种嵌合体使我们能够在攻毒羔羊中早期监测感染情况。对照组和载体组的所有羔羊血清反应率均高于接种疫苗组的羔羊，同时病变严重程度增加。这些结果表明，基于植物的疫苗和重组疫苗有望用于控制羔羊的刚地弓形虫感染，对促进公共卫生和动物福利具有潜在益处。
