title: Bacterial clearance reverses a skewed T-cell repertoire induced by Salmonella infection.
abstract: Salmonella typhimurium invades the spleen, liver, and peripheral lymph nodes and has recently been detected in the bone marrow and thymus, resulting in a reduced thymic size and a decline in the total number of thymic cells. A specific deletion of the double-positive cell subset has been characterized, yet the export of mature T cells to the periphery remains normal. We analyzed Salmonella pathogenesis regarding thymic structure and the T-cell maturation process. We demonstrate that, despite alterations in the thymic structure, T-cell development is maintained during Salmonella infection, allowing the selection of single-positive T-cell clones expressing particular T-cell receptor beta chains (TCR-Vβ). Moreover, the treatment of infected mice with an antibiotic restored the normal thymic architecture and thymocyte subset distribution. Additionally, the frequency of TCR-Vβ usage after treatment was comparable to that in non-infected mice. However, bacteria were still recovered from the thymus after 1 month of treatment. Our data reveal that a skewed T-cell developmental process is present in the Salmonella-infected thymus that alters the TCR-Vβ usage frequency. Likewise, the post-treatment persistence of Salmonella reveals a novel function of the thymus as a potential reservoir for this infectious agent.
authors.affiliation: Doctorado en Ciencias Biomédicas Facultad de Medicina, UNAM Mexico City, CP 045510, Mexico ; Departamento de Biomedicina Molecular, Centro de Investigación y Estudios Avanzados del Instituto Politecnico Nacional (CINVESTAV) Mexico City.
authors.forename: Jessica P
authors.initials: JP
authors.lastname: Leyva-Rangel
authors.affiliation: Hospital General la Raza, Instituto Mexicano del Seguro Social (IMSS) Mexico City.
authors.forename: Maria
authors.initials: M
authors.lastname: de Los Angeles Hernández-Cueto
authors.affiliation: Departamento de Biomedicina Molecular, Centro de Investigación y Estudios Avanzados del Instituto Politecnico Nacional (CINVESTAV) Mexico City.
authors.forename: Carlos-Samuel
authors.initials: CS
authors.lastname: Galan-Enriquez
authors.affiliation: Departamento de Biomedicina Molecular, Centro de Investigación y Estudios Avanzados del Instituto Politecnico Nacional (CINVESTAV) Mexico City.
authors.forename: Marcela
authors.initials: M
authors.lastname: López-Medina
authors.affiliation: Departamento de Biomedicina Molecular, Centro de Investigación y Estudios Avanzados del Instituto Politecnico Nacional (CINVESTAV) Mexico City.
authors.forename: Vianney
authors.initials: V
authors.lastname: Ortiz-Navarrete
keywords: Negative selection; Salmonella; T-cell repertoire; positive selection; thymus