Th2 Lymphoproliferative Disorder of Lat Y136F Mutant Mice Unfolds Independently of TCR-MHC Engagement and Is Insensitive to the Action of Foxp3+ Regulatory T Cells

Abstract

Mutant mice where tyrosine 136 of linker for activation of T cells (LAT) was replaced with a phenylalanine (LatY136F mice) develop a fast-onset lymphoproliferative disorder involving polyclonal CD4 T cells that produce massive amounts of Th2 cytokines and trigger severe inflammation and autoantibodies. We analyzed whether the LatY136F pathology constitutes a bona fide autoimmune disorder dependent on TCR specificity. Using adoptive transfer experiments, we demonstrated that the expansion and uncontrolled Th2-effector function of LatY136F CD4 cells are not triggered by an MHC class II-driven, autoreactive process. Using Foxp3EGFP reporter mice, we further showed that nonfunctional Foxp3+ regulatory T cells are present in LatY136F mice and that pathogenic LatY136F CD4 T cells were capable of escaping the control of infused wild-type Foxp3+ regulatory T cells. These results argue against a scenario where the LatY136F pathology is primarily due to a lack of functional Foxp3+ regulatory T cells and suggest that a defect intrinsic to LatY136F CD4 T cells leads to a state of TCR-independent hyperactivity. This abnormal status confers LatY136F CD4 T cells with the ability to trigger the production of Abs and of autoantibodies in a TCR-independent, quasi-mitogenic fashion. Therefore, despite the presence of autoantibodies causative of severe systemic disease, the pathological conditions observed in LatY136F mice unfold in an Ag-independent manner and thus do not qualify as a genuine autoimmune disorder.

Alloantigen‐specific de novo‐induced Foxp3+ Treg revert in vivo and do not protect from experimental GVHD

“…De novo induction of Foxp3 1 T cells MACS-enriched (Miltenyi) CD4 1 T cells were sorted into GFP 1 (nTreg) and GFP À cells from C57BL/6 knock-in mice expressing enhanced GFP under the control of an IRES element in the 3 0 -untranslated region of the Foxp3 gene (Foxp3EGFP) [26]. GFP À cells were then co-cultured for 6 days with either cluster disrupted [9] (CD) or LPS-matured, BM-derived DC from BALB/c mice (H-2 d ) in complete RPMI supplemented with 10 ng/mL rh-TGF-b (PeproTech), 5 nM retinoic acid (RA) (Sigma) and 333 IU/mLl rh-IL2 (Roche).…”

Highly self-reactive naive CD4 T cells are prone to differentiate into regulatory T cells

“…C57BL/6 Marilyn TCR-transgenic RAG2 À / À mice were provided by Dr Emmanuel Donnadieu, Institut Cochin, Paris, France. C57BL/6 Foxp3-GFP CD45.2 52 and C57BL/6 DEREG 26 mice were initially obtained from Dr Bernard Malissen, Centre d'Immunologie de Marseille-Luminy, France, and Dr Tim Sparwasser, Institute of Infection Immunology, TWINCORE, Hannover, Germany, respectively. C57BL/6 Foxp3-GFP CD45.2 mice were then crossed with C57BL/6 CD45.1 mice to generate C57BL/6 Foxp3-GFP CD45.1 mice.…”

IL-2 and IL-7 Determine the Homeostatic Balance between the Regulatory and Conventional CD4+ T Cell Compartments during Peripheral T Cell Reconstitution

“…C57BL/6 CD3ε 2/2 mice (26) were crossed with MHC II D/D mice (27) to obtain CD3ε/MHC II double-deficient mice (CD3ε 2/2 II D/D mice) (13). C57BL/6 Foxp3-GFP reporter mice were initially provided by Dr. Bernard Malissen (Centre d'Immunologie de Marseille-Luminy, Marseille, France) (28,29) and maintained in our own animal facilities. Experiments were carried out in accordance with the guidelines of the French Veterinary Department.…”