Bacterial clearance reverses a skewed T‐cell repertoire induced by Salmonella infection

摘要

AbstractSalmonella 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.