B cells orchestrate tolerance to the neuromyelitis optica autoantigen AQP4.

Neuromyelitis optica is a paradigmatic autoimmune disease of the central nervous system, in which the water-channel protein AQP4 is the target antigen. The immunopathology in neuromyelitis optica is largely driven by autoantibodies to AQP4. However, the T cell response that is required for the generation of these anti-AQP4 antibodies is not well understood.

The glioblastoma multiforme tumor site promotes the commitment of tumor-infiltrating lymphocytes to the T17 lineage in humans.

Although glioblastoma multiforme (GBM) is not an invariably cold tumor, checkpoint inhibition has largely failed in GBM. In order to investigate T cell-intrinsic properties that contribute to the resistance of GBM to endogenous or therapeutically enhanced adaptive immune responses, we sorted CD4 and CD8 T cells from the peripheral blood, normal-appearing brain tissue, and tumor bed of nine treatment-naive patients with GBM. Bulk RNA sequencing of highly pure T cell populations from these different compartments was used to obtain deep transcriptomes of tumor-infiltrating T cells (TILs).

Ly6DSiglec-H precursors contribute to conventional dendritic cells via a Zbtb46Ly6D intermediary stage.

Plasmacytoid and conventional dendritic cells (pDC and cDC) are generated from progenitor cells in the bone marrow and commitment to pDCs or cDC subtypes may occur in earlier and later progenitor stages. Cells within the CD11cMHCIISiglec-HCCR9 DC precursor fraction of the mouse bone marrow generate both pDCs and cDCs. Here we investigate the heterogeneity and commitment of subsets in this compartment by single-cell transcriptomics and high-dimensional flow cytometry combined with cell fate analysis: Within the CD11cMHCIISiglec-HCCR9 DC precursor pool cells expressing high levels of Ly6D and lacking expression of transcription factor Zbtb46 contain CCR9B220 immediate pDC precursors and CCR9B220 (lo-lo) cells which still generate pDCs and cDCs in vitro and in vivo under steady state conditions.

Formation and immunomodulatory function of meningeal B cell aggregates in progressive CNS autoimmunity.

Meningeal B lymphocyte aggregates have been described in autopsy material of patients with chronic multiple sclerosis. The presence of meningeal B cell aggregates has been correlated with worse disease. However, the functional role of these meningeal B cell aggregates is not understood.

Dendritic Cell Accumulation in the Gut and Central Nervous System Is Differentially Dependent on α4 Integrins.

Homing of pathogenic CD4 T cells to the CNS is dependent on α4 integrins. However, it is uncertain whether α4 integrins are also required for the migration of dendritic cell (DC) subsets, which sample Ags from nonlymphoid tissues to present it to T cells. In this study, after genetic ablation of in DCs and monocytes in mice via the promoters of and (also known as LysM), respectively, the recruitment of α4 integrin-deficient conventional and plasmacytoid DCs to the CNS was unaffected, whereas α4 integrin-deficient, monocyte-derived DCs accumulated less efficiently in the CNS during experimental autoimmune encephalomyelitis in a competitive setting than their wild-type counterparts.

Myeloid-derived suppressor cells control B cell accumulation in the central nervous system during autoimmunity.

Polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) have been characterized in the context of malignancies. Here we show that PMN-MDSCs can restrain B cell accumulation during central nervous system (CNS) autoimmunity. Ly6G cells were recruited to the CNS during experimental autoimmune encephalomyelitis (EAE), interacted with B cells that produced the cytokines GM-CSF and interleukin-6 (IL-6), and acquired properties of PMN-MDSCs in the CNS in a manner dependent on the signal transducer STAT3.

The Insulin Receptor Plays a Critical Role in T Cell Function and Adaptive Immunity.

T cell activation is an energy-demanding process fueled by increased glucose consumption and accompanied by upregulation of the insulin receptor (INSR). In this article, we report that silencing the INSR in inducible knockdown rats impairs selective T cell functions but not thymocyte development. Glucose transport and glycolysis in activated CD4 T cells were compromised in the absence of the INSR, which was associated with alterations in intracellular signaling pathways.

Dendritic cells in central nervous system autoimmunity.

Dendritic cells (DCs) operate at the intersection of the innate and adaptive immune systems. DCs can promote or inhibit adaptive immune responses against neuroantigens. While DC intrinsic properties, i.

IL-27 and IL-12 oppose pro-inflammatory IL-23 in CD4+ T cells by inducing Blimp1.

Central nervous system (CNS) autoimmunity is regulated by the balance of pro-inflammatory cytokines and IL-10. Here we identify the transcriptional regulator Blimp1 as crucial to induce IL-10 in inflammatory T helper cells. Pre-committed Th17 cells respond to IL-27 and IL-12 by upregulating Blimp1 and adopt a Tr-1-like phenotype characterized by IL-10 and IFN-γ production.

Th17 cells in central nervous system autoimmunity.

Multiple sclerosis (MS) is the most important autoimmune disease of the central nervous system (CNS). Its animal model experimental autoimmune encephalomyelitis (EAE) has been instrumental in defining the features of the novel T helper cell subset Th17. Conversely, the broad characterization of Th17 immune responses has substantially advanced our understanding of organ-specific autoimmunity and inspired almost a decade of immunological research.

T cells become licensed in the lung to enter the central nervous system.

The blood–brain barrier (BBB) and the environment of the central nervous system (CNS) guard the nervous tissue from peripheral immune cells. In the autoimmune disease multiple sclerosis, myelin-reactive T-cell blasts are thought to transgress the BBB and create a pro-inflammatory environment in the CNS, thereby making possible a second autoimmune attack that starts from the leptomeningeal vessels and progresses into the parenchyma. Using a Lewis rat model of experimental autoimmune encephalomyelitis, we show here that contrary to the expectations of this concept, T-cell blasts do not efficiently enter the CNS and are not required to prepare the BBB for immune-cell recruitment.

Cellular and cytokine-dependent immunosuppressive mechanisms of grm1-transgenic murine melanoma.

Grm1-transgenic mice spontaneously develop cutaneous melanoma. This model allowed us to scrutinize the generic immune responses over the course of melanoma development. To this end, lymphocytes obtained from spleens, unrelated lymph nodes and tumor-draining lymph nodes of mice with no evidence of disease, and low or high tumor burden were analyzed ex vivo and in vitro.