Mem Inst Oswaldo Cruz, Rio de Janeiro, VOLUME 121 | 2026
Research Articles

Retinal pigment epithelium drives macrophage migration during Toxoplasma gondii infection in vitro

Alex Martins Nasaré1, Roberto Carlos Tedesco2, Paula Andrea Faria Waziry3, Lorena de Paula Pantaleon4, Esther Lopes Ricci4, Luís Antônio Baffile Leoni5, André Rinaldi Fukushima6,+, Andres Jimenez Galisteo Junior1

1Universidade de São Paulo, Faculdade de Medicina, Hospital das Clínicas, Laboratório de Investigação Médica em Protozoologia, Bacteriologia e Resistência Antimicrobiana-LIM-49, São Paulo, SP, Brasil
2Universidade Federal de São Paulo, São Paulo, SP, Brasil
3Florida Atlantic University, Schmidt College of Science, Boca Raton, FL, USA
4Universidade Presbiteriana Mackenzie, São Paulo, SP, Brasil
5Universidade Santo Amaro, São Paulo, SP, Brasil
6Universidade de São Paulo, Faculdade de Ciências da Saúde, São Paulo, SP, Brasil

DOI: 10.1590/0074-02760250141
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ABSTRACT

BACKGROUND Ocular toxoplasmosis is a leading cause of infectious posterior uveitis worldwide. The retinal pigment epithelium (RPE), a key barrier and immunomodulatory layer in the eye, is directly targeted by Toxoplasma gondii during infection. However, its role in orchestrating the local immune response remains unclear.
OBJECTIVES To investigate whether RPE cells actively drive macrophage migration during T. gondii infection in vitro, and to identify associated cytokine profiles.
METHODS Adult retinal pigment epithelial cells (ARPE)-19 and primary RPE cells were exposed to tachyzoites, soluble antigens or conditioned supernatants. Macrophage migration was assessed using Transwell® and under-agar assays. Cytokines were quantified by cytometric bead array.
FINDINGS Both ARPE-19 and primary RPE exhibited chemotaxis toward parasite antigens (0.12 - 0.5 μg), and enhanced interleukin-6 (IL-6), IL-10 and tumor necrosis factor-α (TNF-α) secretion. Co-culture with RAW 264.7 macrophages further amplified cytokine production. Primary RPE from infected animals occluded 90% of Transwell® pores within 24h. IL-6 and IL-10 levels strongly correlated with migratory activity (r = 0.82 and 0.77, respectively).
MAIN CONCLUSIONS RPE cells are not passive targets but active participants in the ocular immune response to T. gondii. By secreting IL-6 and IL-10, they establish a chemotactic environment that recruits macrophages. These insights identify the RPE-cytokine-macrophage axis as a potential therapeutic target in ocular toxoplasmosis.

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Financial support: CAPES.
AJGJ received financial support from the FAPESP (grant 2014/26782-8). Additional financial and infrastructure support was provided by LIM-49 - Laboratório de Protozoologia, Bacteriologia e Resistência Antimicrobiana.
+ Corresponding author: fukushima@alumni.usp.br | ORCID https://orcid.org/0000-0001-6026-3054
Received 29 May 2025
Accepted 23 December 2025

HOW TO CITE
Nasaré AM, Tedesco RC, Waziry PAF, Pantaleon LP, Ricci EL, Leoni LAB, et al. Retinal pigment epithelium drives macrophage migration during Toxoplasma gondii infection in vitro. Mem Inst Oswaldo Cruz. 2026; 121: e250141.

HANDLING EDITOR
Adeilton Alves Brandão | ORCID https://orcid.org/0000-0001-5877-607X

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