Innate-Like T Cells Straddle Innate and Adaptive Immunity by Altering Antigen-Receptor Responsiveness In studies that explain how such cells can straddle innate and adaptive immunity, researchers found that signaling via antigen receptors, whose conventional role is to facilitate clonal T cell activation, was critical for the development of innate-like T cells but then was rapidly attenuated, which accommodated the cells’ innate responsiveness. [Nat Immunol] Abstract Self-Antigen-Driven Activation Induces Instability of Regulatory T Cells during an Inflammatory Autoimmune Response Scientists observed that antigen-driven activation and inflammation in the CNS promoted Foxp3 instability selectively in the autoreactive regulatory T cells that expressed high amounts of Foxp3 before experimental autoimmune encephalitis induction. [ Immunity ] Abstract IL-2 Coordinates IL-2-Producing and Regulatory T Cell Interplay Scientists investigated the regulation of the size of interleukin-2 (IL-2)-producing CD4+ T cell (IL-2p) pool using different IL-2 reporter mice. They found that in the absence of either IL-2 or regulatory CD4+ T cells, the number of IL-2p cells increases. [J Exp Med] Abstract Integrin CD11b Negatively Regulates BCR Signaling to Maintain Autoreactive B Cell Tolerance The authors showed that autoreactive B cells lacking integrin-α-M (CD11b) exhibit a hyperproliferative response to B cell receptor (BCR) crosslinking and enhanced survival. In vivo engagement of BCR in CD11b-deficient mice leads to increased autoAb production and kidney Ig deposition. [Nat Commun] Abstract Etoposide Selectively Ablates Activated T Cells to Control the Immunoregulatory Disorder Hemophagocytic Lymphohistiocytosis Investigators found that the therapeutic mechanism of etoposide in a model system involved potent deletion of activated T cells and efficient suppression of inflammatory cytokine production. This effect was remarkably selective; etoposide did not exert a direct anti-inflammatory effect on macrophages or dendritic cells, and it did not cause deletion of quiescent naive or memory T cells. [J Immunol] Abstract α2β1 Integrin Regulates Th17 Cell Activity and Its Neutralization Decreases the Severity of Collagen-Induced Arthritis The authors examined the role of α2β1 integrin in Th17-mediated destructive arthritis in the murine model of collagen-induced arthritis (CIA). They found that α2β1 integrin is expressed on synovial Th17 cells from CIA mice and its neutralization with a specific mAb significantly reduced inflammation and cartilage degradation, and protected the mice from bone erosion. [J Immunol] Abstract FoxP3 Provides Competitive Fitness to CD4+CD25+ T Cells in Leprosy Patients via Transcriptional Regulation Researchers describe the mechanism of action of FoxP3 in CD4+CD25+ T cells derived from leprosy patients. Increased molecular interactions of FoxP3 with Histone deacetylases in the nucleus of CD4+CD25+ T cells derived from lepromatous leprosy patients were found to be responsible for FoxP3-driven immune suppression activities during the progression of leprosy. [Eur J Immunol] Abstract IgA+ Plasma Cells in Murine Intestinal Lamina Propria as a Positive Regulator of Treg Differentiation Scientists investigated whether IgA+ LP-PCs from murine small intestines had effects on T cell differentiation. Surprisingly, when IgA+ LP-PCs were cocultured with CD4+ T cells, Foxp3 expression was increased significantly in CD4+CD25– T cells. [J Leukoc Biol] Abstract
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