Assisted Relaxation Therapy for Insomnia in Older Adults With Mild Cognitive Impairment: A Pilot Study.

Insomnia symptoms are prevalent in older adults with mild cognitive impairment (MCI) and can pose treatment challenges. We tested the feasibility, acceptability, and preliminary efficacy of assisted relaxation therapy (ART) to improve insomnia symptoms in community-dwelling older adults with MCI. In this pilot RCT, 25 participants were assigned to intervention or control groups for 2 weeks. The final sample (n = 20) consisted of all Black, primarily female (70%) older adults (mean age 69.10; SD = 7.45) with mean Montreal Cognitive Assessment scores of 21.10 (SD = 2.49). Recruitment was timely; attrition was low (80%). Participants were able to use ART (average use 7.00; SD = 5.07 days). Participants in the ART group improved on Insomnia Severity Index (ISI) (- 7.10; 95% CI [-11.63, -2.55]; p = .004) compared to baseline. There were clinically meaningful mean change scores on ISI for the intervention group compared to the control (- 7.10 vs. - 4.33). Results provide justification for testing ART in a fully powered clinical trial.

Treatment of pemphigus vulgaris and foliaceus with efgartigimod, a neonatal Fc receptor inhibitor: a phase II multicentre, open-label feasibility trial.

BACKGROUND: Pemphigus vulgaris and pemphigus foliaceus are potentially life-threatening autoimmune disorders triggered by IgG autoantibodies against mucosal and epidermal desmogleins. There is an unmet need for fast-acting drugs that enable patients to achieve early sustained remission with reduced corticosteroid reliance. OBJECTIVES: To investigate efgartigimod, an engineered Fc fragment that inhibits the activity of the neonatal Fc receptor, thereby reducing serum IgG levels, for treating pemphigus. METHODS: Thirty-four patients with mild-to-moderate pemphigus vulgaris or foliaceus were enrolled in an open-label phase II adaptive trial. In sequential cohorts, efgartigimod was dosed at 10 or 25 mg kg-1 intravenously with various dosing frequencies, as monotherapy or as add-on therapy to low-dose oral prednisone. Safety endpoints comprised the primary outcome. The study is registered at ClinicalTrials.gov (identifier NCT03334058). RESULTS: Adverse events were mostly mild and were reported by 16 of 19 (84%) patients receiving efgartigimod 10 mg kg-1 and 13 of 15 (87%) patients receiving 25 mg kg-1 , with similar adverse event profiles between dose groups. A major decrease in serum total IgG and anti-desmoglein autoantibodies was observed and correlated with improved Pemphigus Disease Area Index scores. Efgartigimod, as monotherapy or combined with prednisone, demonstrated early disease control in 28 of 31 (90%) patients after a median of 17 days. Optimized, prolonged treatment with efgartigimod in combination with a median dose of prednisone 0·26 mg kg-1 per day (range 0·06-0·48) led to complete clinical remission in 14 of 22 (64%) patients within 2-41 weeks. CONCLUSIONS: Efgartigimod was well tolerated and exhibited an early effect on disease activity and outcome parameters, providing support for further evaluation as a therapy for pemphigus.

Selective Depletion of Antigen-Specific Antibodies for the Treatment of Demyelinating Disease.

Current treatments for antibody-mediated autoimmunity are associated with lack of specificity, leading to immunosuppressive effects. To overcome this limitation, we have developed a class of antibody-based therapeutics for the treatment of autoimmunity involving antibodies that recognize the autoantigen, myelin oligodendrocyte glycoprotein (MOG). These agents ("Seldegs," for selective degradation) selectively eliminate antigen (MOG)-specific antibodies without affecting the levels of antibodies of other specificities. Seldeg treatment of mice during antibody-mediated exacerbation of experimental autoimmune encephalomyelitis by patient-derived MOG-specific antibodies results in disease amelioration. Consistent with their therapeutic effects, Seldegs deliver their targeted antibodies to Kupffer and liver sinusoidal endothelial cells that are known to have tolerogenic effects. Our results show that Seldegs can ameliorate disease mediated by MOG-specific antibodies and indicate that this approach also has the potential to treat other autoimmune diseases where the specific clearance of antibodies is required.

The addition of respiratory muscle strength training to facilitate swallow and pulmonary rehabilitation following massive tissue loss and severe deconditioning: A case series.

INTRODUCTION: Impaired respiratory and swallow function in patients with intensive care unit-acquired deconditioning, such as associated with massive tissue loss, is not uncommon and can require prolonged rehabilitation. AIM: The aim of the study was to examine the effect of combined inspiratory and expiratory respiratory muscle strength training (RMST) on respiratory and swallow function in two critical care patients with marked deconditioning after massive tissue loss. METHODS: Case 1 was a 19-year-old male patient with 80% body surface area burns; case 2 was a 45-year-old man with group A streptococcus myositis necessitating quadruple amputation. Both required prolonged intensive care and mechanical ventilation. Both received routine intensive pulmonary and swallow rehabilitation before the trial; however, chronic aspiration and poor secretion clearance remained. At 25 and 26 weeks after initial injury, RMST was performed using EMST150 (expiratory) and Threshold IMT (inspiratory) devices, respectively. At baseline and throughout treatment, data collected included peak expiratory flow (PEF), anthropometry measures, aspiration risk (Penetration-Aspiration Scale [PAS]), pharyngeal clearance (Yale Pharyngeal Residue Scale), secretions (New Zealand Secretion Scale [NZSS]), and functional diet (Functional Oral Intake Scale [FOIS]) via endoscopy. RESULTS/DISCUSSION: At baseline, the PEF score of case 1 was 41% (predicted age-height norm) and the PEF score of case 2 was 14%, indicating severe expiratory compromise. Both had extreme energy requirements (3300 kcal/day; 3500 kcal/day). The baseline swallowing scores of case 1 and 2 were as follows: PAS, 8 and 8; Yale, 9 and 10; NZSS, 4 and 7; and FOIS, 1 and 1, respectively, indicating profound dysphagia. At week 3 of 7 of RMST, swallow function improved to allow both to commence oral intake, followed by tracheostomy decannulation. At weeks 10 and 11, full dysphagia resolution was achieved (FOIS = 7; PAS = 1, Yale = 2, NZSS = 0), with PEF at 70% and 48% predicted respectively. Both patients continued RMST, and at discharge from the acute facility, PEF was 84% and 80% predicted respectively. CONCLUSION: The addition of RMST assisted swallow and pulmonary rehabilitation in both cases and was clinically viable to deliver. Controlled validation trials are now required.

Microscope calibration protocol for single-molecule microscopy.

Single-molecule microscopy allows for the investigation of the dynamics of individual molecules and the visualization of subcellular structures at high spatial resolution. For single-molecule imaging experiments, and particularly those that entail the acquisition of multicolor data, calibration of the microscope and its optical components therefore needs to be carried out at a high level of accuracy. We propose here a method for calibrating a microscope at the nanometer scale, in the sense of determining optical aberrations as revealed by point source localization errors on the order of nanometers. The method is based on the imaging of a standard sample to detect and evaluate the amount of geometric aberration introduced in the optical light path. To provide support for multicolor imaging, it also includes procedures for evaluating the geometric aberration caused by a dichroic filter and the axial chromatic aberration introduced by an objective lens.

Whiplash-Associated Dysphagia and Dysphonia: A Scoping Review.

Swallowing and voice complaints after a whiplash injury have been observed and reported in several studies; however, variability in study design complicates current understanding of whether dysphagia and dysphonia should be recognised as potential adverse outcomes. A scoping review was conducted across six databases from 1950 to March 2019. A total of 18 studies were included for review. Data regarding study purpose, design, outcome measures, participant characteristics and outcomes reported were extracted. Level of evidence (LOE) was assessed by the American Speech-Language Language Association (ASHA)'s LOE system. All studies were exploratory, with 68% rated as poor (< 3) on quality ratings. Nearly half (n = 6) were single case reports. Only three studies investigated some type of swallow-related outcome specifically within the study aim/s. Incidence of swallow-related problems ranged from 2 to 29%, with unspecified complaints of "swallowing difficulty", "dysphagia" and fatigue and pain whilst chewing reported. Neither swallowing biomechanics nor the underlying pathophysiology of swallow or voice complaints was investigated in any study. Four case studies presented post-whiplash voice complaints; two of which described loss of pitch range. Others described hoarseness, loss of control and weak phonation. Most studies only mentioned swallow- or voice-related deficits when reporting a wider set of post-injury symptomatology and six did not describe the outcome measure used to identify the swallow and voice-related problems reported. The existing literature is limited and of low quality, contributing to an unclear picture of the true incidence and underlying mechanisms of whiplash-related dysphagia and dysphonia.

Self-reported Dysphagia and Pharyngeal Volume Following Whiplash Injury.

Difficulty swallowing has been reported following whiplash injury; however, the reasons remain poorly understood. A possible factor may be the observed changes in pharyngeal volume. The current exploratory study was designed to examine the prevalence of self-reported dysphagia after whiplash and the relationship with recovery status and change in pharyngeal volume. Data were available from a longitudinal study of adults with whiplash. Data included magnetic resonance imaging (MRI) of the cervical spine, the Dysphagia Handicap Index (DHI), and Neck Disability Index (NDI) collected over four timepoints (< 1 week, 2 weeks, 3 months, and 12 months post-injury). Initial cross-sectional analysis examined 60 patients with DHI data from at least one timepoint. A second, longitudinal analysis was conducted on 31 participants with MRI, NDI, and DHI data at both early (< 1-2 weeks) and late (3-12 months) timepoints. The pharynx was contoured on axial T2-weighted MRI slices using OsiriX image processing software and pharyngeal volume (mm3) was quantified. In the 60-patient cohort, prevalence of self-reported dysphagia (DHI ≥ 3) was observed in 50% of participants at least once in 12 months (M = 4.9, SD 8.16, range 0-40). In the longitudinal cohort (n = 31), mean total DHI significantly (p = 0.006) increased between early and late stages. There was no relationship (p = 1.0) between dysphagia and recovery status, per the NDI% score. Pharyngeal volume remained stable and there was no relationship between dysphagia and pharyngeal volume change (p = 1.0). This exploratory study supports the need for further work to understand the nature of dysphagia, extent of functional compromise, and the underlying pathophysiology post-whiplash.

Phagocytosis of antibody-opsonized tumor cells leads to the formation of a discrete vacuolar compartment in macrophages.

Despite the rapidly expanding use of antibody-based therapeutics to treat cancer, knowledge of the cellular processes following phagocytosis of antibody-opsonized tumor cells is limited. Here we report the formation of a phagosome-associated vacuole that is observed in macrophages as these degradative compartments mature following phagocytosis of HER2-positive cancer cells in the presence of the HER2-specific antibody, trastuzumab. We demonstrate that this vacuole is a distinct organelle that is closely apposed to the phagosome. Furthermore, the size of the phagosome-associated vacuole is increased by inhibition of the mTOR pathway. Collectively, the identification of this vacuolar compartment has implications for understanding the subcellular trafficking processes leading to the destruction of phagocytosed, antibody-opsonized cancer cells by macrophages.

Phase 2 study of efgartigimod, a novel FcRn antagonist, in adult patients with primary immune thrombocytopenia.

Primary immune thrombocytopenia (ITP) is an acquired autoimmune bleeding disorder, characterized by a low platelet count (<100 × 109 /L) in the absence of other causes associated with thrombocytopenia. In most patients, IgG autoantibodies directed against platelet receptors can be detected. They accelerate platelet clearance and destruction, inhibit platelet production, and impair platelet function, resulting in increased risk of bleeding and impaired quality of life. Efgartigimod is a human IgG1 antibody Fc-fragment, a natural ligand of the neonatal Fc receptor (FcRn), engineered for increased affinity to FcRn, while preserving its characteristic pH-dependent binding. Efgartigimod blocks FcRn, preventing IgG recycling, and causing targeted IgG degradation. In this Phase 2 study, 38 patients were randomized 1:1:1 to receive four weekly intravenous infusions of either placebo (N = 12) or efgartigimod at a dose of 5 mg/kg (N = 13) or 10 mg/kg (N = 13). This short treatment cycle of efgartigimod in patients with ITP, predominantly refractory to previous lines of therapy, was shown to be well tolerated, and demonstrated a favorable safety profile consistent with Phase 1 data. Efgartigimod induced a rapid reduction of total IgG levels (up to 63.7% mean change from baseline), which was associated with clinically relevant increases in platelet counts (46% patients on efgartigimod vs 25% on placebo achieved a platelet count of ≥50 × 109 /L on at least two occasions, and 38% vs 0% achieved ≥50 × 109 /L for at least 10 cumulative days), and a reduced proportion of patients with bleeding. Taken together, these data warrant further evaluation of FcRn antagonism as a novel therapeutic approach in ITP.

An optimal "Click" formulation strategy for antibody-drug conjugate synthesis.

As a versatile reaction for bioconjugation, Cu(I)-catalyzed alkyne-azide cycloaddition (CuAAC) has enormous potential in the synthesis of antibody-drug conjugates (ADCs). In order to optimize CuAAC-based ADC synthesis, we characterized kinetically different formulation processes by mimicking ADC synthesis using small molecules and subsequently revealed unique kinetic behaviors of different combinations of alkyne and azide conditions. Our results indicate that under ADC synthesis conditions, for an alkyne-containing drug, its concentration has minimal impact on the reaction rate when an antibody has a non-metal-chelating azide but is proportional to concentration when an antibody contains a metal-chelating azide; however, for an alkyne-containing antibody, the ADC synthesis rate is proportional to the concentration of a drug with a non-metal-chelating azide but displays almost no dependence on drug concentration with a metal-chelating azide. Based on our results, we designed and tested an optimal "click" formulation strategy that allowed rapid and cost-effective synthesis of a new ADC.

Influence of Inhalation Injury on Incidence, Clinical Profile and Recovery Pattern of Dysphagia Following Burn Injury.

Inhalation injury is predictive of dysphagia post burns; however, the nature of dysphagia associated with inhalation burns is not well understood. This study describes the clinical profile and recovery pattern of swallowing following inhalation burn injury. All patients admitted 2008-2017 with confirmed inhalation burns on laryngoscopy and managed by speech-language pathology (SLP) were included. Initial dysphagia presentation and dysphagia recovery pattern were documented using the FOIS. Co-presence of dysphonia was determined clinically and rated present/absent. Persistent laryngeal/pharyngeal injury at 6 months was documented using laryngoscopy. Data were compared to published data from a large adult burn cohort. All patients with confirmed inhalation burns during the study period received SLP input, enabling review of 38 patients (68% male; m = 40.8 years). Percent Total Body Surface Area burn ranged 1-90%, 100% had head and neck burns, 97% required mechanical ventilation (mean 9.4 days), 18% required tracheostomy and 100% had dysphonia. Comparing to non-inhalation burn patients, the inhalation cohort had significantly (p < 0.01) higher dysphagia incidence (89.47% vs 5.6%); more with severe dysphagia at presentation (78.9% vs 1.7%); increased duration to initiate oral intake (m = 24.69 vs 0.089 days); longer duration of enteral feeding (m = 45.03 vs 1.96 days); and longer duration to resolution of dysphagia (m = 29.79 vs 1.67 days). Persistent laryngeal pathology was present in 47.37% at 6 months. This study shows dysphagia incidence in burn patients with inhalation injury is 16 times greater than for those without inhalation injury. Laryngeal pathology due to inhalation injury increases dysphagia severity and duration to dysphagia recovery.

Whiplash-Associated Dysphagia: Considerations of Potential Incidence and Mechanisms.

Non-specific self-reports of dysphagia have been described in people with whiplash-associated disorders (WAD) following motor vehicle collision (MVC); however, incidence and mechanistic drivers remain poorly understood. Alterations in oropharyngeal dimensions on magnetic resonance imaging (MRI), along with heightened levels of stress, pain, and changes in stress-dependent microRNA expression (e.g., miR-320a) have been also associated with WAD, suggesting multi-factorial issues may underpin any potential swallowing changes. In this exploratory paper, we examine key biopsychosocial parameters in three patients with persistent WAD reporting swallowing change and three nominating full recovery after whiplash with no reported swallowing change. Parameters included (1) oropharyngeal volume with 3D MRI, (2) peritraumatic miR-320a expression, and (3) psychological distress. These factors were explored to highlight the complexity of patient presentation and propose future considerations in relation to a potential deglutition disorder following WAD. The three participants reporting changes in swallowing all had smaller oropharyngeal volumes at < 1 week and at 3 months post injury and lower levels of peritraumatic miR-320a. At 3 months post MVC, oropharyngeal volumes between groups indicated a large effect size (Hedge's g = 0.96). Higher levels of distress were reported at both time points for those with persistent symptomatology, including self-reported dysphagia, however, this was not featured in those nominating recovery. This paper considers current evidence for dysphagia as a potentially under-recognized feature of WAD and highlights the need for future, larger-scaled, multidimensional investigation into the incidence and mechanisms of whiplash-associated dysphagia.

Holographic projection for multispot structured illumination microscopy.

This paper describes the design and testing of a multispot structured illumination microscopy system using computer-generated holograms to create the required excitation patterns. Furthermore, it demonstrates the use of an adapted direct search algorithm for calculating the holograms that allows for imaging across an extended field of view. The system was tested on fixed targets and live cells yielding a two times resolution increase over conventional diffraction-limited imaging. LAY DESCRIPTION: We present the design and testing of a multispot structured illumination microscopy system using computer-generated holograms to create the required excitation patterns. It demonstrates the use of an adapted direct search algorithm for calculating the holograms that allows for imaging across an extended field of view. The system was tested on fixed targets and live cells yielding a two times resolution increase over conventional diffraction-limited imaging. The results here demonstrate that holography provides an efficient means of pattern projection for MSIM imaging. It provides a significant improvement in the efficiency of pattern projection and more importantly it allows for the testing of more diverse excitation patterns than possible with amplitude-only projection. For example, PSF engineering using phase modulation can be easily incorporated into the calculated holograms, potentially generating subdiffraction structures in the excitation pattern. The ability to incorporate PSF engineering into SIM opens up holographic MSIM as a potential method for further increasing resolution with little or no change to the imaging system.

Evidence for high salinity of Early Cretaceous sea water from the Chesapeake Bay crater.

High-salinity groundwater more than 1,000 metres deep in the Atlantic coastal plain of the USA has been documented in several locations, most recently within the 35-million-year-old Chesapeake Bay impact crater. Suggestions for the origin of increased salinity in the crater have included evaporite dissolution, osmosis and evaporation from heating associated with the bolide impact. Here we present chemical, isotopic and physical evidence that together indicate that groundwater in the Chesapeake crater is remnant Early Cretaceous North Atlantic (ECNA) sea water. We find that the sea water is probably 100-145 million years old and that it has an average salinity of about 70 per mil, which is twice that of modern sea water and consistent with the nearly closed ECNA basin. Previous evidence for temperature and salinity levels of ancient oceans have been estimated indirectly from geochemical, isotopic and palaeontological analyses of solid materials in deep sediment cores. In contrast, our study identifies ancient sea water in situ and provides a direct estimate of its age and salinity. Moreover, we suggest that it is likely that remnants of ECNA sea water persist in deep sediments at many locations along the Atlantic margin.

Myelin oligodendrocyte glycoprotein-specific antibodies from multiple sclerosis patients exacerbate disease in a humanized mouse model.

Myelin oligodendrocyte glycoprotein (MOG) is exposed on the outer surface of the myelin sheath, and as such, represents a possible target antigen for antibodies in multiple sclerosis (MS) and other demyelinating diseases. However, despite extensive analyses, whether MOG-specific antibodies contribute to pathogenesis in human MS remains an area of uncertainty. In the current study we demonstrate that antibodies derived from adult MS patients exacerbate experimental autoimmune encephalomyelitis (EAE) in 'humanized' mice that transgenically express human FcγRs (hFcγRs). Importantly, this exacerbation is dependent on MOG recognition by the human-derived antibodies. The use of mice that express hFcγRs has allowed us to also investigate the contribution of these receptors to disease in the absence of confounding effects of cross-species differences. Specifically, by engineering the Fc region of MOG-specific antibodies to modulate FcγR and complement (C1q) binding, we reveal that FcγRs but not complement activation contribute to EAE pathogenesis. Importantly, selective enhancement of the affinities of these antibodies for specific FcγRs reveals that FcγRIIA is more important than FcγRIIIA in mediating disease exacerbation. These studies not only provide definitive evidence for the contribution of MOG-specific antibodies to MS, but also reveal mechanistic insight that could lead to new therapeutic targets.

Inhibitory receptors bind ANGPTLs and support blood stem cells and leukaemia development.

How environmental cues regulate adult stem cell and cancer cell activity through surface receptors is poorly understood. Angiopoietin-like proteins (ANGPTLs), a family of seven secreted glycoproteins, are known to support the activity of haematopoietic stem cells (HSCs) in vitro and in vivo. ANGPTLs also have important roles in lipid metabolism, angiogenesis and inflammation, but were considered 'orphan ligands' because no receptors were identified. Here we show that the immune-inhibitory receptor human leukocyte immunoglobulin-like receptor B2 (LILRB2) and its mouse orthologue paired immunoglobulin-like receptor (PIRB) are receptors for several ANGPTLs. LILRB2 and PIRB are expressed on human and mouse HSCs, respectively, and the binding of ANGPTLs to these receptors supported ex vivo expansion of HSCs. In mouse transplantation acute myeloid leukaemia models, a deficiency in intracellular signalling of PIRB resulted in increased differentiation of leukaemia cells, revealing that PIRB supports leukaemia development. Our study indicates an unexpected functional significance of classical immune-inhibitory receptors in maintenance of stemness of normal adult stem cells and in support of cancer development.

Intensity-based axial localization approaches for multifocal plane microscopy.

Multifocal plane microscopy (MUM) can be used to visualize biological samples in three dimensions over large axial depths and provides for the high axial localization accuracy that is needed in applications such as the three-dimensional tracking of single particles and super-resolution microscopy. This report analyzes the performance of intensity-based axial localization approaches as applied to MUM data using Fisher information calculations. In addition, a new non-parametric intensity-based axial location estimation method, Multi-Intensity Lookup Algorithm (MILA), is introduced that, unlike typical intensity-based methods that make use of a single intensity value per data image, utilizes multiple intensity values per data image in determining the axial location of a point source. MILA is shown to be robust against potential bias induced by differences in the sub-pixel location of the imaged point source. The method's effectiveness on experimental data is also evaluated.

Image scanning microscopy: an overview.

For almost a century, the resolution of optical microscopy was thought to be limited by Abbé's law describing the diffraction limit of light. At the turn of the millennium, aided by new technologies and fluorophores, the field of optical microscopy finally surpassed the diffraction barrier: a milestone achievement that has been recognized by the 2014 Nobel Prize in Chemistry. Many super-resolution methods rely on the unique photophysical properties of the fluorophores to improve resolution, posing significant limitations on biological imaging, such as multicoloured staining, live-cell imaging and imaging thick specimens. Structured Illumination Microscopy (SIM) is one branch of super-resolution microscopy that requires no such special properties of the applied fluorophores, making it more versatile than other techniques. Since its introduction in biological imaging, SIM has proven to be a popular tool in the biologist's arsenal for following biological interaction and probing structures of nanometre scale. SIM continues to see much advancement in design and implementation, including the development of Image Scanning Microscopy (ISM), which uses patterned excitation via either predefined arrays or raster-scanned single point-spread functions (PSF). This review aims to give a brief overview of the SIM and ISM processes and subsequent developments in the image reconstruction process. Drawing from this, and incorporating more recent achievements in light shaping (i.e. pattern scanning and super-resolution beam shaping), this study also intends to suggest potential future directions for this ever-expanding field.

Ultrahigh accuracy imaging modality for super-localization microscopy.

Super-localization microscopy encompasses techniques that depend on the accurate localization of individual molecules from generally low-light images. The obtainable localization accuracies, however, are ultimately limited by the image detector's pixelation and noise. We present the ultrahigh accuracy imaging modality (UAIM), which allows users to obtain accuracies approaching the accuracy that is achievable only in the absence of detector pixelation and noise, and which we found can experimentally provide a >200% accuracy improvement over conventional low-light imaging.

Antigen dynamics govern the induction of CD4(+) T cell tolerance during autoimmunity.

Antigen-specific T cell tolerance holds great promise for the treatment of autoimmune diseases. However, strategies to induce durable tolerance using high doses of soluble antigen have to date been unsuccessful, due to lack of efficacy and the risk of hypersensitivity. In the current study we have overcome these limitations by developing a platform for tolerance induction based on engineering the immunoglobulin Fc region to modulate the dynamic properties of low doses (1 µg/mouse; ∼50 µg/kg) of Fc-antigen fusions. Using this approach, we demonstrate that antigen persistence is a dominant factor governing the elicitation of tolerance in the model of multiple sclerosis (MS), experimental autoimmune encephalomyelitis (EAE), induced by immunizing B10.PL mice with the N-terminal epitope of myelin basic protein. Unexpectedly, our analyses reveal a stringent threshold of antigen persistence for both prophylactic and therapeutic treatments, although distinct mechanisms lead to tolerance in these two settings. Importantly, the delivery of tolerogenic Fc-antigen fusions during ongoing disease results in the downregulation of T-bet and CD40L combined with amplification of Foxp3(+) T cell numbers. The generation of effective, low dose tolerogens using Fc engineering has potential for the regulation of autoreactive T cells.