Human antibodies against the myelin oligodendrocyte glycoprotein can cause complement-dependent demyelination

Background Antibodies to the myelin oligodendrocyte glycoprotein (MOG) are associated with a subset of inflammatory demyelinating diseases of the central nervous system such as acute disseminated encephalomyelitis and neuromyelitis optica spectrum disorders. However, whether human MOG antibodies are pathogenic or an epiphenomenon is still not completely clear. Although MOG is highly conserved within mammals, previous findings showed that not all human MOG antibodies bind to rodent MOG. We therefore hypothesized that human MOG antibody-mediated pathology in animal models may only be evident using species-specific MOG antibodies. Methods We screened 80 human MOG antibody- positive samples for their reactivity to mouse and rat MOG using either a live cell-based assay or immunohistochemistry on murine, rat, and human brain tissue. Selected samples reactive to either human MOG or rodent MOG were subsequently tested for their ability to induce complement-mediated damage in murine organotypic brain slices or enhance demyelination in an experimental autoimmune encephalitis (EAE) model in Lewis rats. The MOG monoclonal antibody 8-18-C5 was used as a positive control. Results Overall, we found that only a subset of human MOG antibodies are reactive to mouse (48/80, 60%) or rat (14/80, 18%) MOG. Purified serum antibodies from 10 human MOG antibody- positive patients (8/10 reactive to mouse MOG, 6/10 reactive to rat MOG), 3 human MOG-negative patients, and 3 healthy controls were tested on murine organotypic brain slices. Purified IgG from one patient with high titers of anti-human, mouse, and rat MOG antibodies and robust binding to myelin tissue produced significant, complement-mediated myelin loss in organotypic brain slices, but not in the EAE model. Monoclonal 8-18-C5 MOG antibody caused complement-mediated demyelination in both the organotypic brain slice model and in EAE. Conclusion This study shows that a subset of human MOG antibodies can induce complement-dependent pathogenic effects in a murine ex vivo animal model. Moreover, a high titer of species-specific MOG antibodies may be critical for demyelinating effects in mouse and rat animal models. Therefore, both the reactivity and titer of human MOG antibodies must be considered for future pathogenicity studies

O brendiranju žigova i pečata

MBP staining of murine organotypic brain slices shows myelin health status of all MOG-positive samples (MOG 1-10) and MOG-negative control (Ctrl 1) as well as healthy control sample (HC 1) in combination with human complement. (DOCX 6029 kb

Über eine Klasse polynomialer Scharen selbstadjungierter Operatoren im Hilbertraum

HEK293A cells expressing either mouse MOG (mMOG) or rat MOG (rMOG) C terminally tagged with EGFP. (DOCX 2792 kb

Highly encephalitogenic AQP4-specific T cells and NMO IgG primarily target spinal cord and retina in experimental neuromyelitis optica

Neuromyelitis optica (NMO) ist eine entzündliche Autoimmunerkrankung des Zentralnervensystems (ZNS). 60-90% der NMO Patienten produzieren Antikörper, die gegen den Wasserkanal Aquaporin-4 (AQP4) gerichtet sind. Diese Antikörper werden NMO IgG genannt. Wenn NMO IgG vom Blutstrom in das ZNS gelangt, bindet es AQP4, das sich auf den Endfortsätzen der Astrozyten befindet. Als Folge wird Komplement fixiert und Effektorzellen werden rekrutiert und Astrozyten werden zerstört. NMO IgG gehört zum IgG Subtyp 1 und wird daher erst nach Aktivierung von AQP4-spezifischen T-Zellen produziert. AQP4-spezifische T-Zellen wurden im peripheren Blut von NMO Patienten nachgewiesen, allerdings ist die Frage, ob diese T-Zellen an der Entstehung der Läsionen beteiligt sind, noch nicht geklärt. In der Regel bilden sich diese entzündliche Läsionen im Rückenmark, optischen Nerven und speziellen Regionen im Gehirn. Bei NMO Patienten werden auch Veränderungen in der Retina beobachtet beispielsweise Verdünnungen der Nervenfaserschicht. Astrozyten und Müller Zellen in der Retina exprimieren auch AQP4, jedoch war es noch ungeklärt, ob die Retina auch ein primäres Ziel der Autoimmunantwort gegen AQP4 sein kann. Wir untersuchten die Pathogenität von AQP4-spezifischen T-Zellen in der Lewis Ratte und konnten nachweisen, dass T-Zellen, die spezifisch für AQP4 p268-285 sind, hochpathogen sind. Transfer dieser Zellen in naive Ratten führte zur Entzündung im ZNS und zusätzlicher peripherer Transfer von NMO IgG zu NMO-ähnlichen Läsionen, gekennzeichnet durch AQP4- und Astrozytenverlust, sowie Komplementanlagerung und Präsenz von Effektorzellen. Darüberhinaus zeigten wir, dass AQP4 p268-285-spezifische T-Zellen auch die Retina infiltrieren und dass dort durch die Entzündung transienter oder permanenten Schader hervorgerufen wird. Wenn zusätzlich NMO IgG injiziert wurde, beobachteten wir Verlust von AQP4 Reaktivität an Müller Zellen, jedoch nicht an Astrozyten. Dieser Verlust war nicht verbunden mit Anlagerung von Komplement auf diesen Zellen. Zusammenfassend zeigt unsere Studie, dass AQP4-spezifische T-Zellen pathogen sein können und dass die Retina Ziel der ani-AQP4 Immunantwort sein kann.Since the identification of a disease-specific pathogenic auto-antibody in Neuromyelitis optica (NMO), our knowledge about NMO has advanced greatly. This auto-antibody, termed NMO IgG, was found to bind the water channel aquaporin-4 (AQP4), which is mainly located on astrocyte end feet in the CNS. Upon binding of NMO IgG complement- and antigen-dependent cytotoxicity causes the death of the astrocyte and inflammatory lesions in the spinal cord, optic nerve and in certain brain areas. Additionally, pathology (e.g. thinning) of retinal layers has been described, which was considered to be a secondary event of the inflammation in the optic nerves. Because NMO IgG is of the IgG subclass type 1, the generation of NMO IgG is dependent on the activation of AQP4-specific T cells. These T cells have been described in the peripheral blood of NMO patients. However, the role of AQP4-specific T cells in NMO lesion formation was still unclear. We investigated the pathogenicity of AQP4-specific T cells in Lewis rats. Lewis rats mounted T cell responses for different epitopes of AQP4, but only T cells specific for AQP4 p268-285 were highly pathogenic. Peripheral injection of NMO IgG during AQP4 p268-285-specific T cell mediated CNS inflammation resulted in the formation of NMO-like complement-dependent astrocyte-destructive lesions. AQP4 p268-285-specific T cells also infiltrated the retina which is a tissue of the CNS that expresses AQP4 in two specific cell types, astrocytes and Müller cells. The inflammation in the retina resulted in dysfunction/damage of the retinal axons. When AQP4 268-285-specific T cells were co-injected with NMO IgG, we observed loss of AQP4 on Müller cells, but not on retinal astrocytes. Interestingly, in contrast to classical NMO lesions this damage was independent of complement. In conclusion, we could show that there are highly pathogenic AQP4-specific T cells in the immune repertoire in the Lewis rats. These T cells can induce primary dysfunction/damage in the retina and can induce NMO-like lesions when co-injected with NMO IgG.submitted by Bleranda Zeka, BSc MScZusammenfassung in deutscher SpracheMedizinische Universität, Dissertation, 2017OeB

Müller cells and retinal axons can be primary targets in experimental neuromyelitis optica spectrum disorder

Recent work from our laboratory, using different models of experimental neuromyelitis optica spectrum disorder (NMOSD), has led to a number of observations that might be highly relevant for NMOSD patients. For example: (i) in the presence of neuromyelitis optica immunoglobulin G, astrocytedestructive lesions can be initiated by CD4+ T cells when these cells recognize aquaporin 4 (AQP4), but also when they recognize other antigens of the central nervous system. The only important prerequisite is that the T cells have to be activated within the central nervous system by “their” specific antigen. Recently activated CD4+ T cells with yet unknown antigen specificity are also found in human NMOSD lesions. (ii) The normal immune repertoire might contain AQP4specific T cells, which are highly encephalitogenic on activation. (iii) The retina might be a primary target of AQP4specific T cells and neuromyelitis optica immunoglobulin G: AQP4specific T cells alone are sufficient to cause retinitis with lowgrade axonal pathology in the retinal nerve fiber/ganglionic cell layer. A thinning of these layers is also observed in NMOSD patients, where it is thought to be a consequence of optic neuritis. Neuromyelitis optica immunoglobulin G might target cellular processes of Müller cells and cause their loss of AQP4 reactivity, when AQP4specific T cells open the bloodretina barrier in the outer plexiform layer. Patchy loss of AQP4 reactivity on Müller cells of NMOSD patients has been recently described. Cumulatively, our findings in experimental NMOSD suggest that both CD4+ T cell and antibody responses directed against AQP4 might play an important role in the pathogenesis of tissue destruction seen in NMOSD.(VLID)484027

Aquaporin 4-specific T cells and NMO-IgG cause primary retinal damage in experimental NMO/SD.

Neuromyelitis optica/spectrum disorder (NMO/SD) is a severe, inflammatory disease of the central nervous system (CNS). In the majority of patients, it is associated with the presence of pathogenic serum autoantibodies (the so-called NMO-IgGs) directed against the water channel aquaporin 4 (AQP4), and with the formation of large, astrocyte-destructive lesions in spinal cord and optic nerves. A large number of recent studies using optical coherence tomography (OCT) demonstrated that damage to optic nerves in NMO/SD is also associated with retinal injury, as evidenced by retinal nerve fiber layer (RNFL) thinning and microcystic inner nuclear layer abnormalities. These studies concluded that retinal injury in NMO/SD patients results from secondary neurodegeneration triggered by optic neuritis.However, the eye also contains cells expressing AQP4, i.e., Müller cells and astrocytes in the retina, epithelial cells of the ciliary body, and epithelial cells of the iris, which raised the question whether the eye can also be a primary target in NMO/SD. Here, we addressed this point in experimental NMO/SD (ENMO) induced in Lewis rat by transfer of AQP4268-285-specific T cells and NMO-IgG.We show that these animals show retinitis and subsequent dysfunction/damage of retinal axons and neurons, and that this pathology occurs independently of the action of NMO-IgG. We further show that in the retinae of ENMO animals Müller cell side branches lose AQP4 reactivity, while retinal astrocytes and Müller cell processes in the RNFL/ganglionic cell layers are spared. These changes only occur in the presence of both AQP4268-285-specific T cells and NMO-IgG.Cumulatively, our data show that damage to retinal cells can be a primary event in NMO/SD

A multicentre, international, observational study on transarterial chemoembolisation in colorectal cancer liver metastases : design and rationale of CIREL

Background: About 70–80% of patients with colorectal liver metastases appear as ineligible for a curative treatment approach. Transarterial chemoembolisation (TACE) using irinotecan-eluting beads has emerged as a promising treatment option in cases with irresectable liver metastases. Despite being in clinical practice for years, little is known about the treatment characteristics and outcomes when used as per routine hospital practice. Methods: Patients with hepatic metastases from colorectal cancer origin, admitted to contributing centres to receive TACE with drug-eluting LifePearl® Microspheres loaded with irinotecan, as part of their standard care, will be consecutively added to the registry. Data will be collected until the end of study, loss to follow-up or death. Primary endpoint is the characterisation of the treatment usage at the selected sites in Europe. Secondary endpoints include outcome parameters, safety and toxicity, as well as quality of life. Conclusion and AIMS: This multicentre, international, prospective observational study conducted in European centres plans to collect real-life data. This data will form an evidence-base from which conclusions can be drawn on how to improve patient selection and optimise treatment protocols when treating with TACE using irinotecan-eluting microspheres

Footprints of the action/production of type I interferons in ENMO and EAE, as revealed by microarray analysis.

<p>In the first column of pairwise comparison of log₂-fold changes in gene expression, mean values were compared between rats receiving T cells and NMO-IgG (ENMO, n = 5) and their counterparts receiving T cells and subcuvia as control IgG (EAE_coI, n = 5) or T cells and PBS (EAE_coP, n = 5). In the second column of pairwise comparison of log₂-fold changes in gene expression, mean values were compared between a group containing all ENMO plus EAE_coI plus EAE_coP animals (n = 15, “all T”) and a group containing animals injected with antibodies only (“abs only” (5 animals with NMO-IgG plus 5 animals with subcuvia as control IgG) or containing healthy control animals only (“hc”, n = 3). The differentially expressed genes shown here belong to 7 different, large groups, i.e. to ischemic damage, ubiquitination, antigen presentation/antigen processing/inflammation, activity against pathogens, anti-inflammatory action, protection from tissue damage, and unknown function (“others”). In experimental autoimmune neuromyelitis optica (ENMO), 31 differentially expressed genes are found. 19/32 differentially expressed genes were already upregulated in all T cell-induced CNS inflammations compared to all other non-inflammatory controls.</p

Highly encephalitogenic aquaporin 4-specific T cells and NMO-IgG jointly orchestrate lesion location and tissue damage in the CNS

In neuromyelitis optica (NMO), astrocytes become targets for pathogenic aquaporin 4 (AQP4)-specific antibodies which gain access to the central nervous system (CNS) in the course of inflammatory processes. Since these antibodies belong to a T cell-dependent subgroup of immunoglobulins, and since NMO lesions contain activated CD4+ T cells, the question arose whether AQP4-specific T cells might not only provide T cell help for antibody production, but also play an important role in the induction of NMO lesions. We show here that highly pathogenic, AQP4-peptide-specific T cells exist in Lewis rats, which recognize AQP4268285 as their specific antigen and cause severe panencephalitis. These T cells are re-activated behind the bloodbrain barrier and deeply infiltrate the CNS parenchyma of the optic nerves, the brain, and the spinal cord, while T cells with other AQP4-peptide specificities are essentially confined to the meninges. Although AQP4268285-specific T cells are found throughout the entire neuraxis, they have NMO-typical “hotspots” for infiltration, i.e. periventricular and periaqueductal regions, hypothalamus, medulla, the dorsal horns of spinal cord, and the optic nerves. Most remarkably, together with NMO-IgG, they initiate large astrocyte-destructive lesions which are located predominantly in spinal cord gray matter. We conclude that the processing of AQP4 by antigen presenting cells in Lewis rats produces a highly encephalitogenic AQP4 epitope (AQP4268285), that T cells specific for this epitope are found in the immune repertoire of normal Lewis rats and can be readily expanded, and that AQP4268285-specific T cells produce NMO-like lesions in the presence of NMO-IgG.(VLID)484311

Comparison of immunohistochemical findings in ENMO animals treated for 24 hours with interferon-alpha (IFN-α) or phosphate-buffered saline (PBS; vehicle control).

<p>Comparison of immunohistochemical findings in ENMO animals treated for 24 hours with interferon-alpha (IFN-α) or phosphate-buffered saline (PBS; vehicle control).</p