ORIGINAL RESEARCH article
Front. Immunol.
Sec. Comparative Immunology
This article is part of the Research TopicImmunology of Farm Animals in the Context of One HealthView all articles
Different kinetics of humoral response against individual antigens in the ovine model of Toxoplasma gondii infection and its pathological association
Provisionally accepted
Paula Formigo1Ignacio Gual2
Germán José Cantón2Luisa F. Mendoza Morales1Valeria Scioli2Emiliano Sosa2Agustina Soto Cabrera2Claudia Morsella2
Valeria Analia Sander1
Dadin Prando Moore2
Sergio Oscar Angel1*
LUCIA MARIA CAMPERO2*
Marina Clemente1*- 1CONICET Institute of Biotechnological Research (IIB-INTECH), San Martín, Argentina
- 2Estacion Experimental Agropecuaria Balcarce, Buenos Aires, Argentina
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Background: Toxoplasma gondii is a globally distributed protozoan parasite with major implications for human and animal health. In sheep, infection can cause reproductive failure and represents an important source of zoonotic transmission through contaminated meat. While cell-mediated immunity is the main protective mechanism, the contribution of humoral responses, particularly against individual recombinant antigens (rAGs), remains poorly characterized in ovine toxoplasmosis. Methods: We analyzed the humoral response of lambs experimentally infected with two reference strains of T. gondii (RH and Me49) using different inoculation doses. Recombinant antigens rGra4Gra7, rGra8, rRop2, rCST9, and rBCLA were tested by IgG-ELISA to evaluate their kinetics during infection. Histopathological analyses of brain tissues were performed to assess lesion severity and cyst presence. Additionally, sera from naturally infected sheep were evaluated to test diagnostic performance. Results: An early IgG response against rGra4Gra7 and rGra8 was detected, consistent with markers of acute infections. Anti-rBCLA, rRop2, and rCST9 IgG responses were associated with the chronic phase and correlated with cyst burden. Notably, stronger anti-rGra4Gra7 IgG responses tended to associate with lower lesion scores, suggesting a potential protective role. In naturally infected sheep, IgG-ELISA against rGra4Gra7 and rGra8 demonstrated the highest diagnostic performance, outperforming total lysate antigen (TLA)-based assays. Conclusion: Our findings highlight distinct kinetics of specific antibody responses against selected T. gondii antigens in sheep, suggesting their value as markers of infection stage and pathology. rGra4Gra7 and rGra8 appear particularly promising both as diagnostic candidates and for exploring mechanisms of humoral modulation in ovine toxoplasmosis.
Keywords: Toxoplasmosis, Ovine, humoral response, Recombinant antigen, Pathology
Received: 08 Sep 2025; Accepted: 04 Nov 2025.
Copyright: © 2025 Formigo, Gual, Cantón, Mendoza Morales, Scioli, Sosa, Soto Cabrera, Morsella, Sander, Moore, Angel, CAMPERO and Clemente. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Sergio Oscar Angel, sangel@intech.gov.ar
LUCIA MARIA CAMPERO, campero.lucia@inta.gob.ar
Marina Clemente, mclemente@intech.gov.ar
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