Characterization of Excretory-Secretory Antigens of Toxoplasma gondii in the Acute and Chronic Phase of Toxoplasmosis in a Murine Model

Abstract

Purpose: The excretory-secretory antigen (ESA) of Toxoplasma gondii has been classified as a good diagnostic marker for the acute and chronic phases of toxoplasmosis. The objective of this study was to determine an antigenic pattern that allows distinguishing both acute and chronic phases of toxoplasmosis. Methods: T. gondii RH ESA cultured in the LLC-MK2 cell line was used and challenged with sera from Swiss mice infected experimentally with T. gondii RH (group I), T. gondii Me49 (group II) tachyzoites and a control group of uninfected mice (group III) by Western blot (WB) test. The success of the proliferation of both strains was confirmed by microscopy and quantified by qPCR, which corroborated the acute and chronic phases with the RH and Me49 strains, respective. Results: In WB, no bands were detected with ESA against mice from group I. Antigenic bands were obtained in the range of 10–129 kDa in the mice from group II at 60 days post infection (dpi). On the other hand, bands of 28 kDa and 33 kDa were evident in all mouse sera 56–165 dpi. Conclusion: Although, in this study, the use of ESA did not allow obtaining an antigenic profile to distinguish both the acute and chronic phases of toxoplasmosis, an antigenic profile was found that could be useful to identify the chronic phase and monitor the clinical evolution of patients with toxoplasmosis. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025.