Plasticity and lineage commitment of individual T1 cells are determined by stable T-bet expression quantities.

T helper 1 (T1) cell identity is defined by the expression of the lineage-specifying transcription factor T-bet. Here, we examine the influence of T-bet expression heterogeneity on subset plasticity by leveraging cell sorting of distinct in vivo-differentiated T1 cells based on their quantitative expression of T-bet and interferon-γ. Heterogeneous T-bet expression states were regulated by virus-induced type I interferons and were stably maintained even after secondary viral infection.

Dissecting the dynamic transcriptional landscape of early T helper cell differentiation into Th1, Th2, and Th1/2 hybrid cells.

Selective differentiation of CD4+ T helper (Th) cells into specialized subsets such as Th1 and Th2 cells is a key element of the adaptive immune system driving appropriate immune responses. Besides those canonical Th-cell lineages, hybrid phenotypes such as Th1/2 cells arise , and their generation could be reproduced . While master-regulator transcription factors like T-bet for Th1 and GATA-3 for Th2 cells drive and maintain differentiation into the canonical lineages, the transcriptional architecture of hybrid phenotypes is less well understood.

Effect of Secukinumab on Traditional Cardiovascular Risk Factors and Inflammatory Biomarkers: Post Hoc Analyses of Pooled Data Across Three Indications.

Background: Psoriasis, psoriatic arthritis (PsA), and axial spondyloarthritis (axSpA) are chronic immune-mediated inflammatory diseases (IMIDs) associated with cardiovascular (CV) disease. High-sensitivity C-reactive protein (hsCRP) and, more recently, the neutrophil-lymphocyte ratio (NLR) are important inflammatory biomarkers predictive of CV disease and CV disease-associated mortality. Here, we report the effect of interleukin (IL)-17A inhibition with secukinumab on CV risk parameters in patients with psoriasis, PsA, and axSpA over 1 year of treatment.

IL-33 in T Cell Differentiation, Function, and Immune Homeostasis.

Recent studies have highlighted a role for the alarmin interleukin (IL)-33 in CD4(+) and CD8(+) T cell activation and function, and have also revealed important distinctions. The IL-33 receptor ST2 is constitutively and abundantly expressed on T-helper-2 (Th2) and GATA-3(+) regulatory T cells in a GATA-3- and STAT5-dependent manner. Upon activation, Th1 and cytotoxic T cells express ST2 transiently, driven by T-bet and/or STAT4.

T-bet- and STAT4-dependent IL-33 receptor expression directly promotes antiviral Th1 cell responses.

During infection, the release of damage-associated molecular patterns, so-called "alarmins," orchestrates the immune response. The alarmin IL-33 plays a role in a wide range of pathologies. Upon release, IL-33 signals through its receptor ST2, which reportedly is expressed only on CD4(+) T cells of the Th2 and regulatory subsets.

Individual T helper cells have a quantitative cytokine memory.

The probabilistic expression of cytokine genes in differentiated T helper (Th) cell populations remains ill defined. By single-cell analyses and mathematical modeling, we show that one stimulation featured stable cytokine nonproducers as well as stable producers with wide cell-to-cell variability in the magnitude of expression. Focusing on interferon-γ (IFN-γ) expression by Th1 cells, mathematical modeling predicted that this behavior reflected different cell-intrinsic capacities and not mere gene-expression noise.

Stable T-bet(+)GATA-3(+) Th1/Th2 hybrid cells arise in vivo, can develop directly from naive precursors, and limit immunopathologic inflammation.

Differentiated T helper (Th) cell lineages are thought to emerge from alternative cell fate decisions. However, recent studies indicated that differentiated Th cells can adopt mixed phenotypes during secondary immunological challenges. Here we show that natural primary immune responses against parasites generate bifunctional Th1 and Th2 hybrid cells that co-express the lineage-specifying transcription factors T-bet and GATA-3 and co-produce Th1 and Th2 cytokines.

In-vitro-induced Th17 cells fail to induce inflammation in vivo and show an impaired migration into inflamed sites.

Recently, IL-17 produced by Th17 cells was described as pro-inflammatory cytokine with an eminent role in autoimmune diseases, e.g. rheumatoid arthritis.

Interferons direct Th2 cell reprogramming to generate a stable GATA-3(+)T-bet(+) cell subset with combined Th2 and Th1 cell functions.

Current T cell differentiation models invoke separate T helper 2 (Th2) and Th1 cell lineages governed by the lineage-specifying transcription factors GATA-3 and T-bet. However, knowledge on the plasticity of Th2 cell lineage commitment is limited. Here we show that infection with Th1 cell-promoting lymphocytic choriomeningitis virus (LCMV) reprogrammed otherwise stably committed GATA-3(+) Th2 cells to adopt a GATA-3(+)T-bet(+) and interleukin-4(+)interferon-gamma(+) "Th2+1" phenotype that was maintained in vivo for months.