RESUMEN
Th1 cells are critical in experimental autoimmune encephalomyelitis (EAE). Serine protease inhibitor clade E1 (Serpine1) has been posited as an inhibitor of IFN-γ from T cells, although its role in autoimmunity remains unclear. In this study, we show that Serpine1 knockout (KO) mice develop EAE of enhanced severity relative to wild-type (WT) controls. Serpine1 overexpression represses Th1 cell cytokine production and pathogenicity, whereas Serpine1-KO:2D2 Th1 cells transfer EAE of increased severity in comparison with WT 2D2 Th1 cells. Notably, polarized Serpine1-KO Th1 cells display delayed expression of the Th1-specific inhibitory receptor, Tim-3 (T cell Ig and mucin-domain containing-3). Serpine1-KO:Tim-3-Tg Th1 cells, which transgenically overexpress Tim-3, showed increased expression of IFN-γ and reduced expression of the checkpoint molecules Lag-3 and PD-1 relative to WT Tim-3-Tg counterparts. Furthermore, Serpine1 deficiency restored the EAE phenotype of Tim-3-Tg mice that normally develop mild disease. Taken together, we identify Serpine1 as a negative regulator of Th1 cells.
Asunto(s)
Encefalomielitis Autoinmune Experimental , Ratones , Animales , Células TH1 , Receptor 2 Celular del Virus de la Hepatitis A/metabolismo , Inhibidores de Serina Proteinasa , Ratones Noqueados , Ratones Endogámicos C57BL , Células Th17RESUMEN
Multiple sclerosis (MS) is a neurodegenerative disease resulting from an autoimmune attack on central nervous system (CNS) myelin. Although CD4(+) T cell function in MS pathology has been extensively studied, there is also strong evidence that CD8(+) T lymphocytes play a key role. Intriguingly, CD8(+) T cells accumulate in great numbers in the CNS in progressive MS, a form of the disease that is refractory to current disease-modifying therapies that target the CD4(+) T cell response. Here, we discuss the function of CD8(+) T cells in experimental autoimmune encephalomyelitis (EAE), a mouse model of MS. In particular, we describe EAE in non-obese diabetic (NOD) background mice, which develop a pattern of disease characterized by multiple attacks and remissions followed by a progressively worsening phase. This is highly reminiscent of the pattern of disease observed in nearly half of MS patients. Particular attention is paid to a newly described transgenic mouse strain (1C6) on the NOD background whose CD4(+) and CD8(+) T cells are directed against the encephalitogenic peptide MOG[35-55]. Use of this model will give us a more complete picture of the role(s) played by distinct T cell subsets in CNS autoimmunity.
RESUMEN
Interferon (IFN)-ß is a front-line therapy for the treatment of the relapsing-remitting form of multiple sclerosis. However, its immunosuppressive mechanism of function remains incompletely understood. While it has been proposed that IFN-ß suppresses the function of inflammatory myelin antigen-reactive T cells by promoting the release of immunomodulatory cytokines such as IL-27 from antigen-presenting cells (APCs), its direct effects on inflammatory CD4+ Th1 cells are less clear. Here, we establish that IFN-ß inhibits mouse IFN-γ+ Th1 cell function in the absence of APCs. CD4+ T cells express the type I interferon receptor, and IFN-ß can suppress Th1 cell proliferation under APC-free stimulation conditions. IFN-ß-treated myelin antigen-specific Th1 cells are impaired in their ability to induce severe experimental autoimmune encephalomyelitis (EAE) upon transfer to lymphocyte-deficient Rag1-/- mice. Polarized Th1 cells downregulate IFN-γ and IL-2, and upregulate the negative regulatory receptor Tim-3, when treated with IFN-ß in the absence of APCs. Further, IFN-ß treatment of Th1 cells upregulates phosphorylation of Stat1, and downregulates phosphorylation of Stat4. Our data indicate that IFN-γ-producing Th1 cells are directly responsive to IFN-ß and point to a novel mechanism of IFN-ß-mediated T cell suppression that is independent of APC-derived signals.