36 research outputs found
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Functional characterization of reappearing B cells after anti-CD20 treatment of CNS autoimmune disease.
The anti-CD20 antibody ocrelizumab, approved for treatment of multiple sclerosis, leads to rapid elimination of B cells from the blood. The extent of B cell depletion and kinetics of their recovery in different immune compartments is largely unknown. Here, we studied how anti-CD20 treatment influences B cells in bone marrow, blood, lymph nodes, and spleen in models of experimental autoimmune encephalomyelitis (EAE). Anti-CD20 reduced mature B cells in all compartments examined, although a subpopulation of antigen-experienced B cells persisted in splenic follicles. Upon treatment cessation, CD20+ B cells simultaneously repopulated in bone marrow and spleen before their reappearance in blood. In EAE induced by native myelin oligodendrocyte glycoprotein (MOG), a model in which B cells are activated, B cell recovery was characterized by expansion of mature, differentiated cells containing a high frequency of myelin-reactive B cells with restricted B cell receptor gene diversity. Those B cells served as efficient antigen-presenting cells (APCs) for activation of myelin-specific T cells. In MOG peptide-induced EAE, a purely T cell-mediated model that does not require B cells, in contrast, reconstituting B cells exhibited a naive phenotype without efficient APC capacity. Our results demonstrate that distinct subpopulations of B cells differ in their sensitivity to anti-CD20 treatment and suggest that differentiated B cells persisting in secondary lymphoid organs contribute to the recovering B cell pool
Siponimod Inhibits the Formation of Meningeal Ectopic Lymphoid Tissue in Experimental Autoimmune Encephalomyelitis
Background and ObjectivesTo investigate whether the formation or retention of meningeal ectopic lymphoid tissue (mELT) can be inhibited by the sphingosine 1-phosphate receptor 1,5 modulator siponimod (BAF312) in a murine model of multiple sclerosis (MS).MethodsA murine spontaneous chronic experimental autoimmune encephalomyelitis (EAE) model, featuring meningeal inflammatory infiltrates resembling those in MS, was used. To prevent or treat EAE, siponimod was administered daily starting either before EAE onset or at peak of disease. The extent and cellular composition of mELT, the spinal cord parenchyma, and the spleen was assessed by histology and immunohistochemistry.ResultsSiponimod, when applied before disease onset, ameliorated EAE. This effect was also present, although less prominent, when treatment started at peak of disease. Treatment with siponimod resulted in a strong reduction of the extent of mELT in both treatment paradigms. Both B and T cells were diminished in the meningeal compartment.DiscussionBeneficial effects on the disease course correlated with a reduction in mELT, suggesting that inhibition of mELT may be an additional mechanism of action of siponimod in the treatment of EAE. Further studies are needed to establish causality and confirm this observation in MS
Anti-CD20 Depletes Meningeal B Cells but Does Not Halt the Formation of Meningeal Ectopic Lymphoid Tissue
Objective To investigate whether anti-CD20 B-cell-depleting monoclonal antibodies (alphaCD20 mAbs) inhibit the formation or retention of meningeal ectopic lymphoid tissue (mELT) in a murine model of multiple sclerosis (MS). Methods We used a spontaneous chronic experimental autoimmune encephalomyelitis (EAE) model of mice with mutant T-cell and B-cell receptors specific for myelin oligodendrocyte glycoprotein (MOG), which develop meningeal inflammatory infiltrates resembling those described in MS. alphaCD20 mAbs were administered in either a preventive or a treatment regimen. The extent and cellular composition of mELT was assessed by histology and immunohistochemistry. Results alphaCD20 mAb, applied in a paradigm to either prevent or treat EAE, did not alter the disease course in either condition. However, alphaCD20 mAb depleted virtually all B cells from the meningeal compartment but failed to prevent the formation of mELT altogether. Because of the absence of B cells, mELT was less densely populated with immune cells and the cellular composition was changed, with increased neutrophil granulocytes. Conclusions These results demonstrate that, in CNS autoimmune disease, meningeal inflammatory infiltrates may form and persist in the absence of B cells. Together with the finding that alphaCD20 mAb does not ameliorate spontaneous chronic EAE with mELT, our data suggest that mELT may have yet unknown capacities that are independent of B cells and contribute to CNS autoimmunity
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Intrathecal B-cell activation in LGI1 antibody encephalitis.
ObjectiveTo study intrathecal B-cell activity in leucine-rich, glioma-inactivated 1 (LGI1) antibody encephalitis. In patients with LGI1 antibodies, the lack of CSF lymphocytosis or oligoclonal bands and serum-predominant LGI1 antibodies suggests a peripherally initiated immune response. However, it is unknown whether B cells within the CNS contribute to the ongoing pathogenesis of LGI1 antibody encephalitis.MethodsPaired CSF and peripheral blood (PB) mononuclear cells were collected from 6 patients with LGI1 antibody encephalitis and 2 patients with other neurologic diseases. Deep B-cell immune repertoire sequencing was performed on immunoglobulin heavy chain transcripts from CSF B cells and sorted PB B-cell subsets. In addition, LGI1 antibody levels were determined in CSF and PB.ResultsSerum LGI1 antibody titers were on average 127-fold higher than CSF LGI1 antibody titers. Yet, deep B-cell repertoire analysis demonstrated a restricted CSF repertoire with frequent extensive clusters of clonally related B cells connected to mature PB B cells. These clusters showed intensive mutational activity of CSF B cells, providing strong evidence for an independent CNS-based antigen-driven response in patients with LGI1 antibody encephalitis but not in controls.ConclusionsOur results demonstrate that intrathecal immunoglobulin repertoire expansion is a feature of LGI1 antibody encephalitis and suggests a need for CNS-penetrant therapies
Anti-CD20 B-cell depletion enhances monocyte reactivity in neuroimmunological disorders
<p>Abstract</p> <p>Background</p> <p>Clinical trials evaluating anti-CD20-mediated B-cell depletion in multiple sclerosis (MS) and neuromyelitis optica (NMO) generated encouraging results. Our recent studies in the MS model experimental autoimmune encephalomyelitis (EAE) attributed clinical benefit to extinction of activated B-cells, but cautioned that depletion of naïve B-cells may be undesirable. We elucidated the regulatory role of un-activated B-cells in EAE and investigated whether anti-CD20 may collaterally diminish regulatory B-cell properties in treatment of neuroimmunological disorders.</p> <p>Methods</p> <p>Myelin oligodendrocyte glycoprotein (MOG) peptide-immunized C57Bl/6 mice were depleted of B-cells. Functional consequences for regulatory T-cells (Treg) and cytokine production of CD11b<sup>+ </sup>antigen presenting cells (APC) were assessed. Peripheral blood mononuclear cells from 22 patients receiving anti-CD20 and 23 untreated neuroimmunological patients were evaluated for frequencies of B-cells, T-cells and monocytes; monocytic reactivity was determined by TNF-production and expression of <it>signalling lymphocytic activation molecule </it>(SLAM).</p> <p>Results</p> <p>We observed that EAE-exacerbation upon depletion of un-activated B-cells closely correlated with an enhanced production of pro-inflammatory TNF by CD11b<sup>+ </sup>APC. Paralleling this pre-clinical finding, anti-CD20 treatment of human neuroimmunological disorders increased the relative frequency of monocytes and accentuated pro-inflammatory monocyte function; when reactivated ex vivo, a higher frequency of monocytes from B-cell depleted patients produced TNF and expressed the activation marker SLAM.</p> <p>Conclusions</p> <p>These data suggest that in neuroimmunological disorders, pro-inflammatory APC activity is controlled by a subset of B-cells which is eliminated concomitantly upon anti-CD20 treatment. While this observation does not conflict with the general concept of B-cell depletion in human autoimmunity, it implies that its safety and effectiveness may further advance by selectively targeting pathogenic B-cell function.</p
Monitoring retinal changes with optical coherence tomography predicts neuronal loss in experimental autoimmune encephalomyelitis.
BACKGROUND:Retinal optical coherence tomography (OCT) is a clinical and research tool in multiple sclerosis, where it has shown significant retinal nerve fiber (RNFL) and ganglion cell (RGC) layer thinning, while postmortem studies have reported RGC loss. Although retinal pathology in experimental autoimmune encephalomyelitis (EAE) has been described, comparative OCT studies among EAE models are scarce. Furthermore, the best practices for the implementation of OCT in the EAE lab, especially with afoveate animals like rodents, remain undefined. We aimed to describe the dynamics of retinal injury in different mouse EAE models and outline the optimal experimental conditions, scan protocols, and analysis methods, comparing these to histology to confirm the pathological underpinnings. METHODS:Using spectral-domain OCT, we analyzed the test-retest and the inter-rater reliability of volume, peripapillary, and combined horizontal and vertical line scans. We then monitored the thickness of the retinal layers in different EAE models: in wild-type (WT) C57Bl/6J mice immunized with myelin oligodendrocyte glycoprotein peptide (MOG35-55) or with bovine myelin basic protein (MBP), in TCR2D2 mice immunized with MOG35-55, and in SJL/J mice immunized with myelin proteolipid lipoprotein (PLP139-151). Strain-matched control mice were sham-immunized. RGC density was counted on retinal flatmounts at the end of each experiment. RESULTS:Volume scans centered on the optic disc showed the best reliability. Retinal changes during EAE were localized in the inner retinal layers (IRLs, the combination of the RNFL and the ganglion cell plus the inner plexiform layers). In WT, MOG35-55 EAE, progressive thinning of IRL started rapidly after EAE onset, with 1/3 of total loss occurring during the initial 2 months. IRL thinning was associated with the degree of RGC loss and the severity of EAE. Sham-immunized SJL/J mice showed progressive IRL atrophy, which was accentuated in PLP-immunized mice. MOG35-55-immunized TCR2D2 mice showed severe EAE and retinal thinning. MBP immunization led to very mild disease without significant retinopathy. CONCLUSIONS:Retinal neuroaxonal damage develops quickly during EAE. Changes in retinal thickness mirror neuronal loss and clinical severity. Monitoring of the IRL thickness after immunization against MOG35-55 in C57Bl/6J mice seems the most convenient model to study retinal neurodegeneration in EAE
Repetitive Pertussis Toxin Promotes Development of Regulatory T Cells and Prevents Central Nervous System Autoimmune Disease
Bacterial and viral infections have long been implicated in pathogenesis and progression of multiple sclerosis (MS). Incidence and severity of its animal model experimental autoimmune encephalomyelitis (EAE) can be enhanced by concomitant administration of pertussis toxin (PTx), the major virulence factor of Bordetella pertussis. Its adjuvant effect at the time of immunization with myelin antigen is attributed to an unspecific activation and facilitated migration of immune cells across the blood brain barrier into the central nervous system (CNS). In order to evaluate whether recurring exposure to bacterial antigen may have a differential effect on development of CNS autoimmunity, we repetitively administered PTx prior to immunization. Mice weekly injected with PTx were largely protected from subsequent EAE induction which was reflected by a decreased proliferation and pro-inflammatory differentiation of myelin-reactive T cells. Splenocytes isolated from EAE-resistant mice predominantly produced IL-10 upon re-stimulation with PTx, while non-specific immune responses were unchanged. Longitudinal analyses revealed that repetitive exposure of mice to PTx gradually elevated serum levels for TGF-β and IL-10 which was associated with an expansion of peripheral CD4+CD25+FoxP3+ regulatory T cells (Treg). Increased frequency of Treg persisted upon immunization and thereafter. Collectively, these data suggest a scenario in which repetitive PTx treatment protects mice from development of CNS autoimmune disease through upregulation of regulatory cytokines and expansion of CD4+CD25+FoxP3+ Treg. Besides its therapeutic implication, this finding suggests that encounter of the immune system with microbial products may not only be part of CNS autoimmune disease pathogenesis but also of its regulation
Sunlight exposure exerts immunomodulatory effects to reduce multiple sclerosis severity
Multiple sclerosis (MS) disease risk is associated with reduced sun-exposure. This study assessed the relationship between measures of sun exposure (vitamin D [vitD], latitude) and MS severity in the setting of two multicenter cohort studies (n(NationMS) = 946, n(BIONAT) = 990). Additionally, effect-modification by medication and photosensitivity-associated MC1R variants was assessed. High serum vitD was associated with a reduced MS severity score (MSSS), reduced risk for relapses, and lower disability accumulation over time. Low latitude was associated with higher vitD, lower MSSS, fewer gadolinium-enhancing lesions, and lower disability accumulation. The association of latitude with disability was lacking in IFN-β-treated patients. In carriers of MC1R:rs1805008(T), who reported increased sensitivity toward sunlight, lower latitude was associated with higher MRI activity, whereas for noncarriers there was less MRI activity at lower latitudes. In a further exploratory approach, the effect of ultraviolet (UV)-phototherapy on the transcriptome of immune cells of MS patients was assessed using samples from an earlier study. Phototherapy induced a vitD and type I IFN signature that was most apparent in monocytes but that could also be detected in B and T cells. In summary, our study suggests beneficial effects of sun exposure on established MS, as demonstrated by a correlative network between the three factors: Latitude, vitD, and disease severity. However, sun exposure might be detrimental for photosensitive patients. Furthermore, a direct induction of type I IFNs through sun exposure could be another mechanism of UV-mediated immune-modulation in MS