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Background Brainstem cavernous malformations (CMs) represent dangerous clinical entities associated with high rates of rebleeding and morbidity compared with those in other locations. Particularly rare are those located within the fourth ventricle. Although fourth ventricular CMs are favorable from a surgical standpoint, there are no defined guidelines on definitive indications and optimal timing of surgery. In addition, the surgical approaches, anatomic considerations, and general observations regarding these lesions are not well reported in the literature. Case Presentation A 27-year-old man with a known history of a CM on the floor of the fourth ventricle presented with new cranial nerve deficits and signs of increased intracranial pressure. Imaging revealed acute bleeding from a fourth ventricular CM. The patient was urgently taken to surgery for resection. Despite a noneventful surgery which resulted in gross total resection, the patient developed a unique constellation of cranial nerve deficits postoperatively, most notably of which was eight-and-a-half syndrome. Conclusions CMs of the fourth ventricle are rare clinical entities that can be treated successfully with surgery. The indications for surgery may not always be clear-cut; therefore, the neurosurgeon's decision to proceed with surgery must reside on a case-by-case basis using a multifactorial approach. The location of these lesions presents unique challenges given their proximity to vital structures and the technical difficulty required. For these reasons, the resection of these lesions often results in new or persistent neurologic deficits. However, despite the associated risks, the potential benefits of surgery oftentimes outweigh the risks of the alternative.

Background: Glossopharyngeal neuralgia (GPN) is a rare facial pain syndrome with debilitating symptoms. For medication-resistant GPN, stereotactic radiosurgery (SRS) is an emerging treatment option with a promising role; however, recurrence rates after SRS are fairly high. We present a patient who underwent repeat SRS for recurrent GPN and subsequently maintained over 3 years of complete pain relief. For the first time, we present a systematic review of repeat SRS for recurrent GPN. Summary: Twelve cases of repeat SRS for GPN have previously been reported in the literature (13 studies including ours). Among patients with follow-up, initial pain relief was achieved in 83% (n = 10) of cases a median of 5 weeks after repeat SRS; 2 patients failed to obtain any pain relief. A favorable pain response (BNI I–IIIb) was achieved in 67 and 58% of cases at 6 and 12 months, respectively. All 13 were targeted to the glossopharyngeal meatus. Three patients (23%) experienced adverse radiation effects. Five patients (50%) experienced recurrence a median of 14 months after repeat SRS. Two patients (17%) required additional surgical intervention. At the final follow-up, 75% (n = 9) of the patients had a favorable pain outcome. Key Messages: Repeat SRS may be a viable alternative to open surgery for the treatment of recurrent GPN, albeit with an increased risk of adverse radiation effects. Though limited by a small cohort of patients, the best predictors of an effective second treatment may be a response to initial SRS for >5 months, a maximum dose >75 Gy, and a target at the glossopharyngeal meatus. Larger prospective studies are needed to better define its role.

OBJECTIVE Laser interstitial thermal therapy (LITT) provides a minimally invasive alternative to open brain surgery, making it a powerful neurosurgical tool especially in pediatric patients. This systematic review aimed to highlight the indications and complications of LITT in the pediatric population. METHODS In line with the PRISMA guidelines, the authors conducted a systematic review to summarize the current applications and safety profiles of LITT in pediatrics. PubMed and Embase were searched for studies that reported the outcomes of LITT in patients < 21 years of age. Retrospective studies, case series, and case reports were included. Two authors independently screened the articles by title and abstract followed by full text. Relevant variables were extracted from studies that met final eligibility, and results were pooled using descriptive statistics. RESULTS The selection process captured 303 pediatric LITT procedures across 35 studies. Males comprised approximately 60% of the aggregate sample, with a mean age of 10.5 years (range 0.5–21 years). The LITT technologies used included Visualase (89%), NeuroBlate (9%), and Multilase 2100 (2%). The most common indication was treatment of seizures (86%), followed by brain tumors (16%). The mean follow-up duration was 15.6 months (range 1.3–48 months). The overall complication rate was 15.8%, which comprised transient neurological deficits, cognitive and electrolyte disturbances, hemorrhage, edema, and hydrocephalus. No deaths were reported. CONCLUSIONS As of now, LITT’s most common applications in pediatrics are focused on treating medically refractory epilepsy and brain tumors that can be difficult to resect. The safety of LITT can provide an attractive alternative to open brain surgery in the pediatric population.

Cognitive problems frequently accompany neurological manifestations of multiple sclerosis (MS). However, during screening of preclinical candidates, assessments of behaviour in mouse models of MS typically focus on locomotor activity. In the present study, we analysed cognitive behaviour of 9 to 10‐week‐old female C57Bl/6J mice orally administered with the toxin cuprizone that induces demyelination, a characteristic feature of MS. Animals received 400 mg/kg cuprizone daily for 2 or 4 weeks, and their performance was compared with that of vehicle‐treated mice. Cuprizone‐treated animals showed multiple deficits in short touchscreen‐based operant tasks: they responded more slowly to visual stimuli, rewards and made more errors in a simple rule‐learning task. In contextual/cued fear conditioning experiments, cuprizone‐treated mice showed significantly lower levels of contextual freezing than vehicle‐treated mice. Diffusion tensor imaging showed treatment‐dependent changes in fractional anisotropy as well as in axial and mean diffusivities in different white matter areas. Lower values of fractional anisotropy and axial diffusivity in cuprizone‐treated mice indicated developing demyelination and/or axonal damage. Several diffusion tensor imaging measurements correlated with learning parameters. Our results show that translational touchscreen operant tests and fear conditioning paradigms can reliably detect cognitive consequences of cuprizone treatment. The suggested experimental approach enables screening novel MS drug candidates in longitudinal experiments for their ability to improve pathological changes in brain structure and reverse cognitive deficits.

Brain metastasis (BM) affects up to one-third of adults with cancer and carries a historically bleak prognosis. Despite advances in stereotactic radiosurgery (SRS), rates of in-field recurrence (IFR) after SRS range from 10 to 25%. High rates of neurologic death have been reported after SRS failure, particularly for recurrences deep in the brain and surgically inaccessible. Laser interstitial thermal therapy (LITT) is an emerging option in this setting, but its ability to prevent a neurologic death is unknown. In this study, we investigate the causes of death among patients with BM who undergo LITT for IFR after SRS. We conducted a single institution retrospective case series of patients with BM who underwent LITT for IFR after SRS. Clinical and demographic data were collected via chart review. The primary endpoint was cause of death. Between 2010 and 2018, 70 patients with BM underwent LITT for IFR after SRS. Median follow-up after LITT was 12.0 months. At analysis, 49 patients died; a cause was determined in 44. Death was neurologic in 20 patients and non-neurologic in 24. The 24-month cumulative incidence of neurologic and non-neurologic death was 35.1% and 38.6%, respectively. Etiologies of neurologic death included local recurrence (n = 7), recovery failure (n = 7), distant progression (n = 5), and other (n = 1). Among our patient population, LITT provided the ability to stabilize neurologic disease in up to 2/3 of patients. For IFR after SRS, LITT may represent a reasonable treatment strategy for select patients. Additional work is necessary to determine the extent to which LITT can prevent neurologic death after recurrence of BM.

Accumulating evidence suggests that a degenerative processes within the brain can trigger the formation of new, focal inflammatory lesions in Multiple Sclerosis (MS). Here, we used a novel pre-clinical MS animal model to test whether the amelioration of degenerative brain events reduces the secondary recruitment of peripheral immune cells and, in consequence, inflammatory lesion development. Neural degeneration was induced by a 3 weeks cuprizone intoxication period. To mitigate the cuprizone-induced pathology, animals were treated with Laquinimod (25 mg/kg) during the cuprizone-intoxication period. At the beginning of week 6, encephalitogenic T cell development in peripheral lymphoid organs was induced by the immunization with myelin oligodendrocyte glycoprotein 35–55 peptide (i.e., Cup/EAE). Demyelination, axonal injury and reactive gliosis were determined by immunohistochemistry. Positron emission tomography (PET) imaging was performed to analyze glia activation in vivo. Vehicle-treated cuprizone mice displayed extensive callosal demyelination, glia activation and enhanced TSPO-ligand binding. This cuprizone-induced pathology was profoundly ameliorated in mice treated with Laquinimod. In vehicle-treated Cup/EAE mice, the cuprizone-induced pathology triggered massive peripheral immune cell recruitment into the forebrain, evidenced by multifocal perivascular inflammation, glia activation and neuro-axonal injury. While anti myelin oligodendrocyte glycoprotein 35–55 peptide immune responses were comparable in vehicle- and Laquinimod-treated Cup/EAE mice, the cuprizone-triggered immune cell recruitment was ameliorated by the Laquinimod treatment. This study clearly illustrates that amelioration of a primary brain-intrinsic degenerative process secondary halts peripheral immune cell recruitment and, in consequence, inflammatory lesion development. These findings have important consequences for the interpretation of the results of clinical studies.

Growing evidence indicates that B cells play a key role in the pathogenesis of multiple sclerosis (MS). B cells occupy distinct central nervous system (CNS) compartments in MS, including the cerebrospinal fluid and white matter lesions. Also, it is now known that, in addition to entering the CNS, B cells can circulate into the periphery via a functional lymphatic system. Data suggest that the role of B cells in MS mainly involves their in situ activation in demyelinating lesions, leading to altered pro- and anti-inflammatory cytokine secretion, and a highly effective antigen-presenting cell function, resulting in activation of memory or naïve T cells. Clinically, B cell-depleting agents show significant efficacy in MS. In addition, many disease-modifying therapies (DMTs) traditionally understood to target T cells are now known to influence B cell number and function. One of the earliest DMTs to be developed, glatiramer acetate (GA), has been shown to reduce the total frequency of B cells, plasmablasts, and memory B cells. It also appears to promote a shift toward reduced inflammation by increasing anti-inflammatory cytokine release and/or reducing pro-inflammatory cytokine release by B cells. In the authors' opinion, this may be mediated by cross-reactivity of B cell receptors for GA with antigen (possibly myelin basic protein) expressed in the MS lesion. More research is required to further characterize the role of B cells and their bidirectional trafficking in the pathogenesis of MS. This may uncover novel targets for MS treatments and facilitate the development of B cell biomarkers of drug response.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is associated with hypertension in humans and animals, and studies suggest that cytochrome P4501A1 (Cyp1a1) induction and vascular dysfunction may contribute. We investigated the role of perivascular adipose tissue (PVAT) and Cyp1a1 in TCDD-induced vascular dysfunction. Cyp1a1 wild-type (WT) and knockout (KO) male mice were fed a dough pill containing 1,4-p-dioxane (TCDD vehicle control) on days 0 and 7, or 1000 ng/kg TCDD on day 0 and 250 ng/kg TCDD on day 7. mRNA expression of Cyp1a1 was assessed on days 3, 7, and 14, and of Cyp1b1, 1a2, angiotensinogen, and phosphodiesterase 5a on day 14. Dose-dependent vasoconstriction to a thromboxane A2 mimetic (U46619), and vasorelaxation to acetylcholine and a nitric oxide donor (S-nitroso-N-acetyl-DL-penicillamine, SNAP), were investigated in the aorta with and without PVAT. Cyp1a1 and 1a2 mRNA was induced in aorta of WT mice only with PVAT, and Cyp1a1 induction was sustained through day 14. TCDD significantly enhanced constriction to U46619 in WT mice and inhibited relaxation to both acetylcholine and SNAP, but only in the presence of PVAT. The effects of TCDD on U46619 constriction and SNAP relaxation were not observed in Cyp1a1 KO mice. Finally, in aorta + PVAT of WT mice TCDD significantly induced expression of angiotensinogen and phosphodiesterase 5a both of which could contribute to the TCDD-induced vascular dysfunction. These data establish PVAT as a TCDD target which is critically involved in mediating vascular dysfunction. TCDD enhances vasoconstriction via the thromboxane/prostanoid (TP) receptor and inhibits vasorelaxation via nitric oxide (NO) signaling. This TCDD-induced vascular dysfunction requires perivascular adipose (PVAT) and cytochrome P4501a1 (CYP1a1) induction.

ObjectiveMS is an autoimmune demyelinating disease of the CNS, which causes neurologic deficits in young adults and leads to progressive disability. The aryl hydrocarbon receptor (AHR), a ligand-activated transcription factor, can drive anti-inflammatory functions in peripheral immune cells and also in CNS-resident cells. Laquinimod is a drug developed for the treatment of MS known to activate AHR, but the cellular targets of laquinimod are still not completely known. In this work, we analyzed the contribution of AHR activation in astrocytes to its beneficial effects in the experimental autoimmune encephalomyelitis (EAE) preclinical model of MS.MethodsWe used conditional knockout mice, in combination with genome-wide analysis of gene expression by RNA-seq and in vitro culture systems to investigate the effects of laquinimod on astrocytes.ResultsWe found that AHR activation in astrocytes by laquinimod ameliorates EAE, a preclinical model of MS. Genome-wide RNA-seq transcriptional analyses detected anti-inflammatory effects of laquinimod in glial cells during EAE. Moreover, we established that the Delaq metabolite of laquinimod dampens proinflammatory mediator production while activating tissue-protective mechanisms in glia.ConclusionsTaken together, these findings suggest that AHR activation by clinically relevant AHR agonists may represent a novel therapeutic approach for the treatment of MS.

Meningiomas are relatively slow-growing, typically benign tumors that arise from the arachnoid cells which form the meninges. They are the most common primary brain tumor and account for nearly one-third of all primary brain and spine tumors. Meningiomas can arise from any dural site, however they are infrequently found at the cerebellopontine angle (CPA). While WHO grade I meningiomas are benign and the slowest growing, WHO grade II meningiomas grow significantly faster, display cellular atypia, and frequently recur. Compared with WHO grade I meningiomas, these often present a therapeutic challenge. An 87-year-old woman presented to the emergency department with a two-month history of dizziness and dysequilibrium. MRI revealed a large left-sided CPA lesion which was not present on MRI just two years prior. She underwent surgical resection and post-operative imaging confirmed gross-total resection. Surgical histology identified the tumor as an atypical WHO grade II meningioma. WHO grade II meningiomas of the CPA are exceedingly rare entities, but should be considered in patients who present with a rapidly growing CPA mass. The literature supports the notion that complete resection, when possible, is likely the strongest determinant of overall control. Stereotactic radiosurgery (SRS) has established itself as a suitable adjunct for higher grade lesions of the CPA, particularly those that were resected subtotally. These tumors can be successfully managed, even in the elderly population.

INTRODUCTION: Brain metastasis (BM) affects up to one-third of adults with cancer and carries a historically bleak prognosis. Thanks to advances in stereotactic radiosurgery (SRS), patients can live longer, and fewer succumb to their intracranial disease. However, rates of in-field recurrence after SRS range from 10–25%, either as true tumor re-growth or radiation necrosis (RN). In this setting, repeat SRS is not recommended and craniotomy may not be feasible or desired by the patient. Laser interstitial thermal therapy (LITT) is an emerging option with promising outcomes. In this study, we investigated outcomes and determined the mechanisms of death among patients with BM who underwent LITT for in-field recurrence after SRS. METHODS: Single institution retrospective review of patients with BM who underwent LITT for in-field recurrence after SRS. RESULTS: Between 2010–2018, seventy (70) patients with BM underwent LITT for in-field recurrence after SRS. At the time of review, 51/70 (72.9%) patients died, 16/70 (22.9%) were alive, and the status of 3/70 (4.3%) was undetermined. Among those who died, death was neurologic in 17/51 (33.3%), non-neurologic in 21/51 (41.2%), and undetermined in 13/51 (25.5%). Median survival after LITT for patients who died from neurologic and non-neurologic causes were 8.9 and 14.3 months, respectively. Mechanisms of neurologic death included progressive intracranial metastatic disease in eight patients and progressive RN in two. Mechanisms of non-neurologic death were nearly all related to progression of primary or systemic disease. CONCLUSIONS: For patients with BM who develop in-field recurrence after SRS, LITT is a viable alternative to craniotomy and can attenuate the neurological burden of this devastating disease. Among our patient population, very few died as the result of intracranial progression. Future studies that investigate which factors predispose patients to intracranial progression despite LITT will further improve its efficacy and ultimately improve the lives of cancer patients.

SummaryInterleukin-17 (IL-17) is a T-cell-derived cytokine that promotes inflammatory pathology in autoimmune diseases. Blocking IL-17A interactions with its endogenous IL-17 receptor (IL-17RA) can constitute an important target for therapeutic intervention. Here, we utilized a directed evolution approach to generate soluble IL-17RA mutants that exhibit increased IL-17A binding affinity and thermostability, relative to the wild-type. Human fibroblast cell-based assay and in vivo analysis in mice indicated that two improved IL-17RA mutants efficiently inhibit the secretion of IL-17A-induced proinflammatory cytokines. Analysis of one of these mutants in a psoriasis mouse model showed its efficacy in promoting the recovery of psoriasis plaques. This mutant can be used as a promising drug candidate for the treatment of psoriasis and may be a therapeutic agent for various other autoimmune diseases.

Laquinimod is an oral drug currently being evaluated for the treatment of relapsing, remitting, and primary progressive multiple sclerosis and Huntington’s disease. Laquinimod exerts beneficial activities on both the peripheral immune system and the CNS with distinctive changes in CNS resident cell populations, especially astrocytes and microglia. Analysis of genome-wide expression data revealed activation of the aryl hydrocarbon receptor (AhR) pathway in laquinimod-treated mice. The AhR pathway modulates the differentiation and function of several cell populations, many of which play an important role in neuroinflammation. We therefore tested the consequences of AhR activation in myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE) using AhR knockout mice. We demonstrate that the pronounced effect of laquinimod on clinical score, CNS inflammation, and demyelination in EAE was abolished in AhR−/− mice. Furthermore, using bone marrow chimeras we show that deletion of AhR in the immune system fully abrogates, whereas deletion within the CNS partially abrogates the effect of laquinimod in EAE. These data strongly support the idea that AhR is necessary for the efficacy of laquinimod in EAE and that laquinimod may represent a first-in-class drug targeting AhR for the treatment of multiple sclerosis and other neurodegenerative diseases.

The natural antibody repertoire in humans, apes and Old World primates is distinct from the repertoire of all other placental mammals, and encodes antibodies specific for the carbohydrate epitope Galalpha1-3Galbeta1-4GlcNAc-R (alphaGal). Here, we examined whether conjugating antigens to the alphaGal epitope can augment their immunogenicity in alpha(1,3)galactosyltransferase knockout mice (GT0 mice) which, like humans, produce alphaGal-specific antibodies. Immunization of GT0 mice with BSA conjugated to alphaGal (alphaGal-BSA) led to significant production of anti-BSA IgG antibodies without the need for adjuvant. This response was dependent on the presence of alphaGal-reactive antibodies. Immunization of wild-type mice with alphaGal-BSA failed to induce an anti-BSA response. The presence of alphaGal-reactive antibodies also led to an increase in the T cell response to BSA following immunization with alphaGal-BSA when compared with mice that received BSA alone, resulting in an increased frequency of IFN-gamma- and IL-4-producing BSA-specific T cells. In addition, the ability to produce alphaGal-reactive antibodies enhanced the cytotoxic T lymphocyte anti-viral antigen response following vaccination with murine leukemia virus transformed cell lines that express alphaGal on their cell surface. Natural antibodies that bind alphaGal therefore play a key role in increasing the efficiency of priming to antigens decorated with alphaGal epitopes.

Systemic delivery of therapeutic proteins through gene transfer approaches has been carried out mostly by ex vivo transduction of single cells or by direct in vivo injection of an expression vector. In this work an intact miniature biopsy of human dermis (microdermis) is harvested and transduced ex vivo by a viral vector encoding a gene for the therapeutic protein. The microdermis preserves its three-dimensional structure and viability during the ex vivo manipulations. Furthermore, upon transduction with adenoviral and adeno-associated viral vectors the microdermis secretes recombinant human erythropoietin (hEPO). Biochemical analysis of the secreted hEPO showed similarity to the clinically approved recombinant hEPO. Subcutaneous implantation of microdermal hEPO into SCID mice exhibited hEPO secretion in the blood circulation and preserved elevated hematocrit for several months, demonstrating the technology's potential for sustained delivery of protein therapeutics.

Autoimmune response to the myelin-associated oligodendrocytic basic protein (MOBP), a CNS-specific myelin constituent, was recently suggested to play a role in the pathogenesis of multiple sclerosis (MS). The pathogenic autoimmune response to MOBP and the associated pathology in the CNS have not yet been fully investigated. In this study, we have characterized the clinical manifestations, pathology, T cell epitope-specificity, and TCRs associated with experimental autoimmune encephalomyelitis (EAE) induced in SJL/J mice with recombinant mouse MOBP (long isoform, 170 aa). Analysis of encephalitogenic MOBP-reactive T cells for reactivity to overlapping MOBP peptides defined MOBP15–36 as their major immunodominant epitope. Accordingly, MOBP15–36 was demonstrated to be the major encephalitogenic MOBP epitope for SJL/J mice, inducing severe/chronic clinical EAE associated with intense perivascular and parenchymal infiltrations, widespread demyelination, axonal loss, and remarkable optic neuritis. Molecular modeling of the interaction of I-As with MOBP15–36, together with analysis of the MOBP15–36-specific T cell response to truncated peptides, suggests MOBP20–28 as the core sequence for I-As-restricted recognition of the encephalitogenic region MOBP15–36. Although highly focused in their epitope specificity, the encephalitogenic MOBP-reactive T cells displayed a widespread usage of TCR Vβ genes. These results would therefore favor epitope-directed, rather than TCR-targeted, approaches to therapy of MOBP-associated pathogenic autoimmunity. Localization by molecular modeling of a potential HLA-DRB1*1501-associated MOBP epitope within the encephalitogenic MOBP15–36 sequence suggests the potential relevance of T cell reactivity against MOBP15–36 to MS. The reactivity to MOBP15–36 detected in MS shown here and in another study further emphasizes the potential significance of this epitope for MS.

Multiple sclerosis (MS) is an inflammatory disease of the central nervous system (CNS) characterized by destruction of myelin. Recent studies have indicated that axonal damage is involved in the pathogenesis of the progressive disability of this disease. To study the role of axonal damage in the pathogenesis of MS-like disease induced by myelin oligodendrocyte glycoprotein (MOG), we compared experimental autoimmune encephalomyelitis (EAE) in wild-type (WT) and transgenic mice expressing the human bcl-2 gene exclusively in neurons under the control of the neuron-specific enolase (NSE) promoter. Our study shows that, following EAE induction with pMOG 35-55, the WT mice developed significant clinical manifestations with complete hind-limb paralysis. In contrast, most of the NSE-bcl-2 mice (16/27) were completely resistant, whereas the others showed only mild clinical signs. Histological examination of CNS tissue sections showed multifocal areas of perivascular lymphohistiocytic inflammation with loss of myelin and axons in the WT mice, whereas only focal inflammation and minimal axonal damage were demonstrated in NSE-bcl-2 mice. No difference could be detected in the immune potency as indicated by delayed-type hypersensitivity (DTH) and T-cell proliferative responses to MOG. We also demonstrated that purified synaptosomes from the NSE-bcl-2 mice produce significantly lower level of reactive oxygen species (ROS) following exposure to H2O2 and nitric oxide (NO) than WT mice. In conclusion, we demonstrated that the expression of the antiapoptotic gene, bcl-2, reduces axonal damage and attenuates the severity of MOG-induced EAE. Our results emphasize the importance of developing neuroprotective therapies, in addition to immune-specific approaches, for treatment of MS.

Natural Abs specific for the carbohydrate Ag Galα1–3Galβ1–4GlcNAc-R (αGal) play an important role in providing protective host immunity to various pathogens; yet little is known about how production of these or other anti-carbohydrate natural Abs is regulated. In this study, we describe the generation of Ig knock-in mice carrying functionally rearranged H chain and L chain variable region genes isolated from a B cell hybridoma producing αGal-specific IgM Ab that make it possible to examine the development of B cells producing anti-carbohydrate natural Abs in the presence or absence of αGal as a self-Ag. Knock-in mice on a αGal-deficient background spontaneously developed αGal-specific IgM Abs of a sufficiently high titer to mediate rejection of αGal expressing cardiac transplants. In the spleen of these mice, B cells expressing αGal-specific IgM are located in the marginal zone. In knock-in mice that express αGal, B cells expressing the knocked in BCR undergo negative selection via receptor editing. Interestingly, production of low affinity αGal-specific Ab was observed in mice that express αGal that carry two copies of the knocked in H chain. We suggest that in these mice, receptor editing functioned to lower the affinity for self-Ag below a threshold that would result in overt pathology, while allowing development of low affinity anti-self Abs.

Myelin oligodendrocyte glycoprotein (MOG) is an important myelin target antigen, and MOG-induced EAE is now a widely used model for multiple sclerosis. Clonal dissection revealed that MOG-induced EAE in H-2(b) mice is associated with activation of an unexpectedly large number of T cell clones reactive against the encephalitogenic epitope MOG35-55. These clones expressed extremely diverse TCR with no obvious CDR3alpha/CDR3beta motif(s). Despite extensive TCR diversity, the cells required MOG40-48 as their common core epitope and shared MOG44F as their major TCR contact. Fine epitope-specificity analysis with progressively truncated peptides suggested that the extensive TCR heterogeneity is mostly related to differential recognition of multiple overlapping epitopes nested within MOG37-52, each comprised of a MOG40-48 core flanked at the N- and/or the C-terminus by a variable number of residues important for interaction with different TCR. Abrogation of both the encephalitogenic potential of MOG and T cell reactivity against MOG by a single mutation (MOG44F/MOG44A), together with effective down-regulation of MOG-induced EAE by MOG37-44A-52, confirmed in vivo the primary role for MOG44F in the selection/activation of MOG-reactive T cells. We suggest that such a highly focused T cell autoreactivity could be a selective force that offsets the extensive TCR diversity to facilitate a more "centralized control" of pathogenic MOG-related T cell autoimmunity.

Experimental Autoimmune Encephalomyelitis (EAE) can be induced in mice of the C57BL/6 strain by subcutaneous immunization with myelin/oligodendrocyte glycoprotein (MOG) peptide p35-55 in CFA, administered twice at an interval of one week and supplemented with Bordetella pertussis toxin given IV. Here, we studied the effect on the induction of EAE of depleting antibodies to CD4, CD8, or CD25 administered before either the first or the second dose of MOG p35-55. We found that anti-CD4 abolished EAE when given before the first immunization; anti-CD4 did not affect the disease when it was given before the second immunization. Anti-CD8 enhanced EAE induction when given before either of the two immunizations. Anti-CD25 enhanced EAE to the same degree as anti-CD8 when given before the first immunization, but anti-CD25 was even more effective in enhancing EAE when given before the second immunization. The anti-CD25 treatment led to significantly enhanced IFNgamma production by T cells responding to MOG p35-55 and persisting anti-MOG antibodies detectable 56 days after the first immunization. Administration of anti-CD8 or anti-CD25 abolished the need for pertussis toxin to induce EAE. These findings are compatible with the idea that CD4 T cells are required for the initial induction of EAE and that the disease is down-regulated by T cells expressing CD8 or CD25. These regulatory T cells exist prior to MOG immunization, but the CD25+ regulators appear to be further amplified by immunization.

Background Host immune responses to foreign gene products have been shown to lead to the elimination of genetically modified cells, and are a major barrier to successful therapeutic gene therapy. We have shown that immunological tolerance to retrovirally transduced cell surface proteins can be induced by expressing the gene encoding these products in bone marrow derived cells. Here, we investigate if expression of foreign gene products in bone marrow derived cells can be used to induce tolerance to cytoplasmic proteins. Methods Balb/c mice were reconstituted with syngeneic bone marrow cells transduced with retrovirus carrying the gene encoding enhanced green fluorescent protein (eGFP), or mock-transduced bone marrow cells. After reconstitution, mice were immunized with cells expressing eGFP, and T cells were tested for the ability to kill eGFP-expressing targets in in vitro cytotoxic T lymphocyte (CTL) assays. Results T cells from Balb/c mice reconstituted with mock-transduced bone marrow were able to kill target cells expressing eGFP. In contrast, T cells from mice reconstituted with eGFP-transduced bone marrow were unable to kill targets expressing eGFP. In addition, we observed that T cell responses to eGFP in C57BL/6 mice were minimal even under highly immunogenic conditions. Conclusions These data suggest that expression of foreign gene products in bone marrow derived cells is capable of inducing T cell tolerance to proteins expressed exclusively in the cytoplasm. Copyright © 2003 John Wiley & Sons, Ltd.

RX-3117 (fluorocyclopentenylcytosine) is a novel small-molecule chemotherapeutic agent that belongs to the class of cytotoxic antimetabolite cytidine analogs. Cytidine analogs, including gemcitabine, have been widely used for the treatment of various types of cancer, both hematologic as well as solid. However, despite the success of gemcitabine, there is no oral formulation of gemcitabine and drug resistance is common. Thus, RX-3117 was synthesized as a oral formulation to overcome gemcitabine resistance with a better pharmacologic profile. In this study, the efficacy of RX-3117 was examined in 12 different human tumor (colon, non-small cell lung, small cell lung, pancreatic, renal, ovarian and cervical) xenograft models, grown subcutaneously in athymic nude mice. Not only has RX-3117 demonstrated potent efficacy in several cancer xenograft models but also oral treatment with RX-3117 results in dose-dependent tumor growth inhibition (TGI), even in tumors that are only moderately sensitive or resistant to gemcitabine. In the Colo-205, H460, H69 and CaSki models, gemcitabine treatment resulted in 28%, 14%, 25%, and 0% TGI, respectively, whereas oral treatment with RX-3117 induced 93%, 91%, 62%, and 66% TGI, respectively. This indicates that RX-3117 may have the potential to be used for the treatment of tumors that do not respond to gemcitabine. In order to extend the results established in cell line xenograft models, and to test efficacy in a potentially more clinically relevant system, RX-3117 was evaluated in a single primary low passage human pancreatic Tumorgraft™CTG-0298, which is resistant to gemcitabine and has a favorable RX-3117 activating enzyme profile. Treatment with RX-3117 resulted in dose dependent TGI and was superior to the standard of care agent gemcitabine. This study successfully demonstrated preliminary efficacy and therapeutic potential of RX-3117. Citation Format: Mi Young Yang, Young Bok Lee, Deog Joong Kim, Chang-Ho Ahn, Joel Kaye, Tania Fine, Rina Kashi, Osnat Ohne. A novel small molecule cytidine analog, RX-3117, shows potent efficacy in xenograft models, even in tumors that are resistant to treatment with gemcitabine. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 819. doi:10.1158/1538-7445.AM2014-819

T-cell autoimmunity to myelin basic protein was recently shown to be neuroprotective in injured rat optic nerves. In the present study, using the mouse optic nerve, we examined whether active immunization rather than passive transfer of T-cells can be beneficial in protecting retinal ganglion cells (RGCs) from post-traumatic death. Before severe crush injury of the optic nerve, SJL/J and C3H.SW mice were actively immunized with encephalitogenic or nonencephalitogenic peptides of proteolipid protein (PLP) or myelin oligodendrocyte glycoprotein (MOG), respectively. At different times after the injury, the numbers of surviving RGCs in both strains immunized with the nonencephalitogenic peptides pPLP 190–209 or pMOG 1–22 were significantly higher than in injured controls treated with the non-self-antigen ovalbumin or with a peptide derived from β-amyloid, a non-myelin-associated protein. Immunization with the encephalitogenic myelin peptide pPLP 139–151 was beneficial only when the disease it induced, experimental autoimmune encephalomyelitis, was mild. The results of this study show that survival of RGCs after axonal injury can be enhanced by vaccination with an appropriate self-antigen. Furthermore, the use of nonencephalitogenic myelin peptides for immunization apparently allows neuroprotection without incurring the risk of an autoimmune disease. Application of these findings might lead to a promising new approach for treating optic neuropathies such as glaucoma.

Eight rhesus monkeys with different MHC backgrounds were immunized with myelin oligodendrocyte glycoprotein (MOG). All developed severe experimental autoimmune encephalomyelitis associated with large inflammatory foci and extensive demyelination. T-cell autoreactivity to MOG was directed against three main epitopes encompassed within amino acids 4–20, 35–50 and 94–116, of which two are also immunodominant epitopes for the autoimmune T cell response to MOG in patients with MS. A strong B cell response to MOG was observed in all monkeys and major epitopes recognized were located within amino acids 4–26, 24–46 and 44–66/54–76.

Uncovering primary target antigens in multiple sclerosis (MS) is of major significance for understanding the etiology and pathophysiology of the disease, and for designing immunospecific therapy. In this study, a synthetic peptide representing a predicted T cell epitope on myelin oligodendrocytic basic protein (MOBP) was found to be encephalitogenic in C3H.SW mice, inducing experimental autoimmune encephalomyelitis with an abrupt onset. Two separate preliminary studies with MOBP peptides indicated that autoreactivity to MOBP occurs in MS. These data strongly suggest that MOBP is a highly relevant target in MS and further point to the complexity of antigen specificities in MS.

Objective: Studying whether laquinimod treatment added on top of either GA (glatiramer acetate) or IFNb would result in an additive effect on disease severity in MOG-induced EAE. Background Laquinimod is an orally administered CNS-active immunomodulator. Phase III data in RRMS patients indicate clear effects of laquinimod 0.6mg on disease progression and on the accumulation of brain-tissue loss, as measured by MRI, coupled with a favorable safety and tolerability profile. Laquinimod has shown a significant effect in Experimental Autoimmune Encephalomyelitis (EAE), an animal model of MS. In the EAE model, laquinimod has been shown to significantly abrogate disease severity. It was suggested that Laquinimod exhibits its effect via NFkB signaling inhibition. It was shown to affect CNS residential cells as astrocytes and microglia resulting in reduction of proinflammatory cytokines. Glatiramer acetate (GA), a well-known disease modifying treatment for relapsing RRMS, is an immunomodulator that significantly inhibits disease activity in EAE. GA was shown to bind to various class II major histocompatibility complex (MHC) molecules and to create GA specific Th2 cells. These cells are migrating into the CNS and secreting anti inflammatory cytokines. INFb-which is also in use for RRMS treatment is effective in reducing inflammatory activity in EAE. Laquinimod has shown efficacy, using IFNb knock out mouse model, suggesting that laquinimod efficacy is IFNb independent. Design/Methods: MOG induced EAE C57BL/6 mice were treated with Laquinimod (5 and 25mg/kg) alone or together with suboptimal dose of GA (12.5mg/kg) or IFNb (500,000 and 50,000 IU/mouse). All treatments were started 1 day after immunization. Scoring of EAE clinical signs were carried out daily. Results: Both GA/laquinimod and IFNb/laquinimod adjunct treatment resulted in improved efficacy when compared to each treatment alone. Conclusions: These results suggesting the use of both treatment regimens together as a potential treatment for RRMS patients. Supported by: Teva Pharmaceutical industries. Disclosure: Dr. Hayardeny Nisimov has nothing to disclose. Dr. Birnberg has nothing to disclose. Dr. Raymond has received research support from TEVA Pharmaceutical. Dr. Fine has received research support from Teva Pharmaceutical. Dr. Kaye has received personal compensation for activities with Teva Neuroscience as an employee. Dr. Kaye has received research support from Teva Neuroscience.