Expression of the interferon-alpha/beta-inducible MxA protein in brain lesions of subacute sclerosing panencephalitis

Immune-dysregulation in subacute sclerosing panencephalitis: An exploratory case-control study

Subacute sclerosing panencephalitis (SSPE) is a chronic progressive neurological condition caused by a defective measles virus. It is postulated that immune-dysregulation might result in persistent infection (immune evasion) as well as initiation of autoimmune phenomenon (via natural killer cells) leading to panencephalitis. The primary objective of this case-control study was to analyse the pattern of immune dysregulation in cases with SSPE. The secondary objective was to assess the correlation between the measured immunological variables and disability/death at 6 months. This was an exploratory case-control study conducted at a tertiary-care referral-facility from January 2020 to September 2021. Thirty consecutive patients fulfilling the Dyken's criteria for SSPE and 30 age-and-sex-matched healthy controls were enrolled. Immunological profile constituted by lymphocyte subset analysis, immunoglobulin levels and complement levels were done in all cases and controls. Cases were staged as per Jabbour's system; disability was assessed using the modified Rankin Scale (mRS). Patients with SSPE had a mean age of 14.76 years (±6.9 years). There were 25 males and 5 females; 6.7% cases belonged to Jabbour's first stage, 40% to second stage and 53.3% to third stage. At least 1/4th had evidence of measles vaccination. Levels of absolute lymphocyte count, B-cells, T cells, helper T-cells, and cytotoxic T-cells were significantly higher in cases. IgG, IgM, and IgE levels were significantly higher while IgD levels were significantly lower in cases. At baseline, 13.3% of cases had a mRS score of 0-2 and 86.7% had a score of 3-6; at 6 months 10% had a mRS score 0-2 (favorable outcome) while 90% had a mRS score 3-6 (poor outcome). Higher IgE levels were found to correlate significantly with favorable outcome. Immune-dysregulation may play a significant role in shaping one's response to measles infection as well as in determining vaccine-efficacy.

La panencéphalite sclérosante subaiguë de la rougeole

La panencéphalite sclérosante subaiguë (PESS), une complication tardive de la rougeole, est encore présente lors d’épidémies de cette maladie dues aux insuffisances de la vaccination. Après un rappel historique, nous aborderons la physiopathologie de la PESS et l’importance des critères diagnostiques. De nombreux travaux portant sur les paramètres de l’immunité innée et sur ceux des réponses interféron tendent à montrer une baisse de l’activité de l’immunité cellulaire au cours de cette maladie. Nous formulons ici plusieurs hypothèses s’appuyant sur des publications concernant différentes formes de la maladie : congénitales, périnatales, formes à incubation courte, semblables à l’encéphalite aiguë à inclusions (EAI), formes d’évolution rapide, formes retrouvées chez les immunodéprimés ou chez l’adulte. Des formes familiales ont également été identifiées, suggérant une origine génétique. Selon la durée de la période de latence entre rougeole et la PESS, deux groupes de patients ont été individualisés, incitant à des analyses rétrospective et prospective des exomes de ces malades. La connaissance des gènes participant à la maladie devrait être utile pour la compréhension de la physiopathologie de la PESS mais aussi d’autres infections neurologiques tardives dues à des virus à ARN.

Measles Sclerosing Subacute PanEncephalitis (SSPE), an intriguing and ever-present disease: Data, assumptions and new perspectives

BACKGROUND

Subacute sclerosing panencephalitis (SSPE) is a rare, non-treatable and fatal neurological complication of measles, still present due to the return of the epidemic linked to the loosening of vaccination policies. Its mechanism remains unexplained.

OBJECTIVE

The main objective was to investigate explanatory variables relating to the risk of developing SSPE and its pathophysiology.

METHODS

Literature analysis was focused on different varieties of SSPE: perinatal forms, short-incubation forms similar to acute measles inclusion body encephalitis (MIBE), rapidly evolving forms, forms occurring in the immunosuppressed, adult forms, and family forms. In addition, several studies on the parameters of innate immunity and interferon responses of patients were analyzed.

RESULTS

Two main data were highlighted: a relationship between the so-called fulminant forms and the prescription of corticosteroids was established. In familial SSPE, two groups were individualized according to the duration of the latency period, prompting an analysis of patient exomes.

CONCLUSION

Treatment with corticosteroids should be banned. Knowledge of the genes involved and epigenetics should be useful for understanding the pathophysiology of SSPE and other late-onset neurological infections with RNA viruses.

Semax, an analog of ACTH(4-7), regulates expression of immune response genes during ischemic brain injury in rats

Brain stroke continues to claim the lives of million people every year. To build the effective strategies for stroke treatment it is necessary to understand the neuroprotective mechanisms that are able to prevent the ischemic injury. Consisting of the ACTH_(4-7) fragment and the tripeptide Pro-Gly-Pro (PGP), the synthetic peptide Semax effectively protects brain against ischemic stroke. However, the molecular mechanisms underlying its neuroprotection and participation of PGP in them are still needed to be clarified. To reveal biological processes and signaling pathways, which are affected by Semax and PGP, we performed the transcriptome analysis of cerebral cortex of rats with focal cerebral ischemia treated by these peptides. The genome-wide biochip data analysis detected the differentially expressed genes (DEGs) and bioinformatic web-tool Ingenuity iReport found DEGs associations with several biological processes and signaling pathways. The immune response is the process most markedly affected by the peptide: Semax enhances antigen presentation signaling pathway, intensifies the effect of ischemia on the interferon signaling pathways and affects the processes for synthesizing immunoglobulins. Semax significantly increased expression of the gene encoding the immunoglobulin heavy chain, highly affects on cytokine, stress response and ribosomal protein-encoding genes after occlusion. PGP treatment of rats with ischemia attenuates the immune activity and suppresses neurotransmission in the CNS. We suppose that neuroprotective mechanism of Semax is realized via the neuroimmune crosstalk, and the new properties of PGP were found under ischemia. Our results provided the basis for further proteomic investigations in the field of searching Semax neuroprotection mechanism.

Immunohistochemical Evaluation of Mx Protein Expression in Canine Encephalitides

Mx proteins are a group of interferon-induced GTPases whose expression has been demonstrated in a number of human viral infections and in some idiopathic inflammatory diseases. In this study, the expression of Mx protein was evaluated in known viral, nonviral, and idiopathic encephalitides in the dog via immunohistochemistry using an antibody against human MxA. All 12 cases of confirmed viral encephalitis, including 7 cases of canine distemper, 4 cases of canine herpesvirus, and 1 case of rabies, were Mx positive. In canine distemper cases, staining was particularly strong and a variety of cell types were positive, including astrocytes, macrophages/microglia, and neurons. Immunoreactivity for Mx protein was evident in a few cases of nonviral infectious encephalitis, including neosporosis (1/1), Chagas disease (2/3), aspergillosis (1/2), and encephalitozoonosis (1/1). Consistent staining was observed in most cases of idiopathic encephalitis, including granulomatous meningoencephalomyelitis (7/7), necrotizing meningoencephalitis of pug dogs (6/7), and necrotizing encephalitis of the Yorkshire Terrier (3/3) and Maltese (1/1) breeds. Mx staining was negative in 5 normal dog brains; 3 cases of cryptococcosis; and single cases of blastomycosis, protothecosis, and bacterial meningitis.

Measles virus infection of the CNS: human disease, animal models, and approaches to therapy

Viral infections of the central nervous system(CNS) mostly represent clinically important, often life-threatening complications of systemic viral infections. After acute measles, CNS complications may occur early (acute postinfectious measles encephalitis, APME) or after years of viral persistence (subacute sclerosing panencephalitis, SSPE). In spite of a presumably functional cell-mediated immunity and high antiviral antibody titers, an immunological control of the CNS infection is not achieved in patients suffering from SSPE. There is still no specific therapy for acute complications and persistent MV infections of the CNS. Hamsters, rats, and (genetically unmodified and modified) mice have been used as model systems to study mechanisms of MV-induced CNS infections. Functional CD4+ and CD8+ T cells together with IFN-gamma are required to overcome the infection. With the help of recombinant measles viruses and mice expressing endogenous or transgenic receptors, interesting aspects such as receptor-dependent viral spread and viral determinants of virulence have been investigated. However, many questions concerning the lack of efficient immune control in the CNS are still open. Recent research opened new perspectives using specific antivirals such as short interfering RNA (siRNA) or small molecule inhibitors. Inspite of obvious hurdles, these treatments are the most promising approaches to future therapies.

Preparation of polyclonal antibody against human MxA protein and its specificity to diversified myxovirus resistant protein A

OBJECTIVE

To study the human myxovirus resistant protein A (MxA), a specifically induced peptide by interferon I, and to use its level as a diagnostic criterion for viral infections.

METHODS

Anti-MxA antisera from immunized mice were prepared with the expressed MxA protein of pET32a-MxA in E. coli BL-21(DE3). To confirm the antiserum activity and specificity, the expression product of BL21, wild type MxA pEGFP-C1-wMxA and site-directed mutant MxA pEGFP-C1-mMxA(N589S) stably transfected 3T3 cells and induced A549 cells were detected by Western blot with the antisera using non-MxA transfected or non-IFN-beta induced cells, intact A549, NIH 3T3 cells transfected with pEGFP-C1 and pET32a (+)-transformed BL-21 as controls.

RESULTS

The antisera had specific positive immunoreactivity to the NIH3T3 cells transformed with pEGFP-C1-wMxA and pEGFP-C1-mMxA, INF-beta induced A549 cells and BL21 proteins expressed with pET32a (+)-MxA. The hybridization signals from IFN-beta induced A549 cells depended on the IFN-beta inducing concentrations. Meanwhile, immunohistochemical assay showed that NIH 3T3 cells with pEGFP-C1-wMxA and pEGFP-C1-mMxA had > 98% of positive cells at 1:50 dilution of the serum and A549 cells induced by 20 ng/mL IFN-beta for 48 h showed 95% positive cells. pEGFP-C1-transfected NIH 3T3 cells were all negative.

CONCLUSION

Anti-sera are highly specific to diversified MxAs. The antibody is detectable by Western blot, immunocytochemistry and immunofluorescence assay.

Making it to the synapse: measles virus spread in and among neurons

Measles virus (MV) is one of the most transmissible microorganisms known, continuing to result in extensive morbidity and mortality worldwide. While rare, MV can infect the human central nervous system, triggering fatal CNS diseases weeks to years after exposure. The advent of crucial laboratory tools to dissect MV neuropathogenesis, including permissive transgenic mouse models, the capacity to manipulate the viral genome using reverse genetics, and cell biology advances in understanding the processes that govern intracellular trafficking of viral components, have substantially clarified how MV infects, spreads, and persists in this unique cell population. This review highlights some of these technical advances, followed by a discussion of our present understanding of MV neuronal infection and transport. Because some of these processes may be shared among diverse viruses, comparisons are made to parallel studies with other neurotropic viruses. While a crystallized view of how the unique environment of the neuron affects MV replication, spread, and, ultimately, neuropathogenesis is not fully realized, the tools and ideas are in place for exciting advances in the coming years.

The type I interferon system protects mice from Semliki Forest virus by preventing widespread virus dissemination in extraneural tissues, but does not mediate the restricted replication of avirulent virus in central nervous system neurons

Semliki Forest virus (SFV) infection of the mouse provides a powerful model to study the pathogenesis of virus encephalitis. SFV and other alphavirus-based vector systems are increasingly used in biotechnology and medicine. This study analysed the strong susceptibility of this virus to type I interferon (IFN) responses. Following intraperitoneal infection of adult mice, SFV strain A7(74) was efficiently (100 %) neuroinvasive. In contrast, SFV4 was poorly (21 %) neuroinvasive. Upon entry into the brain, both viruses activated type I IFN responses. As determined by quantitative RT-PCR, activation of the IFN-alpha gene was proportional to virus RNA load. An intact type I IFN system was required for protection against both strains of SFV. IFN strongly curtailed virus spread in many cell types and in many tissues. In mice with an intact type I IFN system, infected cells were rarely observed and tissue tropism was difficult to determine. In the absence of a functional type I IFN system, the tropism and the potential for rapid and widespread infection of this virus was revealed. Virus infection was readily observed in the myocardium, endocardium, exocrine pancreas, adipose tissue, smooth muscle cells and in the brain in meningeal cells, ependymal cells and oligodendrocytes. In the brains of mice with and without type I IFN responses, virus infection of neurons remained rare and focal, indicating that the previously described restricted replication of SFV A7(74) in neurons is not mediated by type I IFN responses.

Recombinant Measles Virus Induces Cytolysis of Cutaneous T-Cell Lymphoma In Vitro and In Vivo

Measles virus (MV) has shown promise as an oncolytic virus in the treatment of different tumor models for human B-cell lymphoma, multiple myeloma, ovarian cancer, and glioma. We have shown that, in a phase I clinical trial, MV vaccine induces tumor regression in cutaneous T-cell lymphoma (CTCL) patients. Here, we investigated in detail, the effect of recombinant MV (rMV) vaccine strain in CTCL cell cultures, and in vivo in established CTCL xenografts in nude mice. The susceptibility of three CTCL cell lines, originating from patients, to rMV was tested by determination of cell surface expression of MV receptors. All cell lines expressed the receptors CD150 and CD46 and were easily infected by rMV and induced complete cell lysis. The cytoreductive activity was apparent in cells forming aggregates, indicating a cell-to-cell spread of MV and cytolysis owing to virus infection. Intratumoral (i.t.) injection of rMV, expressing enhanced green fluorescent protein induced complete regression of large established human CTCL tumors in nude mice, whereas tumors with control treatment progressed exponentially. Immunohistochemical analysis of tumor biopsies, after i.t. treatment, for MV-NP protein complex demonstrated replication of MV within the tumors. The data demonstrate the potential of MV as a therapeutic agent against CTCL.

Oncolytic measles virus in cutaneous T-cell lymphomas mounts antitumor immune responses in vivo and targets interferon-resistant tumor cells

Some cutaneous T-cell lymphomas, (CTCLs) clonal T cells are deficient in interferon signaling, making them promising targets for viral oncolysis. We evaluated cytopathic effects of measles virus (MV) in CTCL. CTCL cell lines and infiltrating lymphocytes in CTCL expressed MV receptors CD150 and CD46. In a phase 1 dose escalation trial a total of 16 injections of live MV, Edmonston-Zagreb vaccine strain, were given intratumorally to 5 patients with CTCL. Patients had antimeasles-serum antibodies and were pretreated with interferon-alpha to prevent uncontrolled virus spread. The well-tolerated treatment with MV resulted in clinical responses. Evaluation of biopsies, before and at 11 days after injection, by immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR) demonstrated local viral activity with positive staining for MV nucleoprotein (NP), an increase of the interferon gamma (IFN-gamma)/CD4 and IFN-gamma/CD8 mRNA ratios and a reduced CD4/CD8 ratio. All patients demonstrated an increased antimeasles antibody titer after therapy. The data demonstrate that CTCLs are promising targets for an MV-based oncolytic therapy.