CD4 + and CD8 + regulatory T cell characterization in the rat using a unique transgenic Foxp3-EGFP model

• Published in: BMC biology 2023-01, Vol.21 (1), p.8-8, Article 8
• Main Authors: Ménoret, Séverine, Tesson, Laurent, Remy, Séverine, Gourain, Victor, Sérazin, Céline, Usal, Claire, Guiffes, Aude, Chenouard, Vanessa, Ouisse, Laure-Hélène, Gantier, Malika, Heslan, Jean-Marie, Fourgeux, Cynthia, Poschmann, Jeremie, Guillonneau, Carole, Anegon, Ignacio
• Format: Article
• Language: English
• Subjects: Analysis; Animals; Candidiasis; Care and treatment; CD4+ Treg; CD8+ Treg; CD8-Positive T-Lymphocytes - metabolism; Diagnosis; Forkhead Transcription Factors - genetics; Forkhead Transcription Factors - metabolism; Foxp3; Gene knockin; Genetic engineering; Genome editing; Immune tolerance; Interleukin-2 - genetics; Interleukin-2 - metabolism; Life Sciences; Methods; Rats; RNA sequencing; T cells; T-Lymphocytes, Regulatory - metabolism; Transforming Growth Factor beta - metabolism; Transforming growth factors
• ISSN: 1741-7007; 1741-7007
• DOI: 10.1186/s12915-022-01502-0

Regulatory T cells (Treg) in diverse species include CD4 and CD8 T cells. In all species, CD8 Treg have been only partially characterized and there is no rat model in which CD4 and CD8 FOXP3 Treg are genetically tagged. We generated a Foxp3-EGFP rat transgenic line in which FOXP3 gene was expressed and controlled EGFP. CD4 and CD8 T cells were the only cells that expressed EGFP, in similar proportion as observed with anti-FOXP3 antibodies and co-labeled in the same cells. CD4 EGFP Treg were 5-10 times more frequent than CD8 EGFP Treg. The suppressive activity of CD4 and CD8 Treg was largely confined to EGFP cells. RNAseq analyses showed similarities but also differences among CD4 and CD8 EGFP cells and provided the first description of the natural FOXP3 CD8 Treg transcriptome. In vitro culture of CD4 and CD8 EGFP cells with TGFbeta and IL-2 generated induced EGFP Treg. CD4 and CD8 EGFP Treg were expanded upon in vivo administration of a low dose of IL-2. This new and unique rat line constitutes a useful model to identify and isolate viable CD4 and CD8 FOXP3 Treg. Additionally, it allows to identify molecules expressed in CD8 Treg that may allow to better define their phenotype and function not only in rats but also in other species.