The complement system in central nervous system diseases

Astrocytes and microglia in multiple sclerosis and neuromyelitis optica

Multiple sclerosis and neuromyelitis optica are autoimmune neurodegenerative diseases primarily targeting myelin sheath and neuroglia. In multiple sclerosis, autoantibodies destroy oligodendrocytes and myelin, which underlies primary neurologic symptoms. Focal damage to myelin triggers reactive astrogliosis and microgliosis, which contribute to and to a large extent define the disease progression. In neuromyelitis optica, autoantibodies against water channel aquaporin 4 (AQP4), which are localized at astrocytic endfeet mediate damage of the glia limitans thus facilitating infiltration of blood-borne molecules and cells that propagate the damage to nerves and neurons. This primary astrocytopathy recruits microglia, which contribute to the neuroinflammatory response. Neuroglial cells therefore are potential targets for cell-specific therapies.

Toxicity and underlying mechanism of the toxic dinoflagellate Gambierdiscus caribaeus to the fish Oryzias melastigma

Gambierdiscus spp. is mainly responsible for the ciguatera fish poisoning (CFP) around the world. The gambiertoxin produced by Gambierdiscus can be passed through the food chain to form ciguatoxins (CTXs) that cause ciguatoxins poisoning. However, the toxic effects of Gambierdiscus on fish through the food chain and related mechanism remains unclear. In this study, the toxicity of Gambierdiscus caribaeus on the marine medaka (Oryzias melastigma) was investigated, where the simulated food chain toxic algae-food organism-fish (G. caribaeus-Artemia metanauplii-O. melastigma) was set. The results showed that direct or indirect exposure through the food chain of G. caribaeus could affect the swimming behaviour of O. melastigma, manifested as decreased swimming performance and spontaneous abnormal swimming behaviours. Histological observation showed that direct or indirect exposure of G. caribaeus caused different degrees of pathological damage to the gills, intestine and liver tissues of O. melastigma. Transcriptome sequencing and RT-qPCR demonstrated that G. caribaeus exposure could trigger a series of physiological and biochemical responses, mainly reflected in energy metabolism, reproductive system, neural activity, immune stress and drug metabolism in marine medaka. Our finding may provide novel insight into the toxicity of Gambierdiscus on fish.

Pathological Features of Enterovirus 71-Associated Brain and Lung Damage in Mice Based on Quantitative Proteomic Analysis

The outbreaks of enterovirus 71 (EV71)-associated hand, foot, and mouth disease (HFMD) have emerged as an emergency of global health due to its association with fatal encephalitis and subsequent neurogenic pulmonary edema; however, the molecular characteristics and pathological features underlying EV71-associated encephalitis and pulmonary edema remain largely unknown. In this study, we performed a proteomic analysis of fresh brain and lung tissues from EV71-infected mice at 7 days post infection. We detected a perturbed expression of 148 proteins in the brain and 78 proteins in the lung after EV71 expression. Further analysis showed that the dysregulated proteins in the brain are involved in a variety of fundamental biological pathways, including complement and coagulation cascades, innate and adaptive immune responses, platelet activation, and nitrogen metabolism, and those proteins in the lung participate in innate and adaptive immune responses, phagosome, arginine biosynthesis, and hypoxia-inducible factor 1 signaling pathway. Our results suggested that immune activation, complement and coagulation dysfunction, platelet activation, imbalance of nitrogen metabolism, and hypoxia could be involved in the pathogenesis of EV71, which explains the major clinical manifestation of hyperinflammatory status of severe HFMD cases. Our study provides further understanding of the molecular basis of EV71 pathogenesis.

Significance of Complement System in Ischemic Stroke: A Comprehensive Review

The complement system is an essential part of innate immunity, typically conferring protection via eliminating pathogens and accumulating debris. However, the defensive function of the complement system can exacerbate immune, inflammatory, and degenerative responses in various pathological conditions. Cumulative evidence indicates that the complement system plays a critical role in the pathogenesis of ischemic brain injury, as the depletion of certain complement components or the inhibition of complement activation could reduce ischemic brain injury. Although multiple candidates modulating or inhibiting complement activation show massive potential for the treatment of ischemic stroke, the clinical availability of complement inhibitors remains limited. The complement system is also involved in neural plasticity and neurogenesis during cerebral ischemia. Thus, unexpected side effects could be induced if the systemic complement system is inhibited. In this review, we highlighted the recent concepts and discoveries of the roles of different kinds of complement components, such as C3a, C5a, and their receptors, in both normal brain physiology and the pathophysiology of brain ischemia. In addition, we comprehensively reviewed the current development of complement-targeted therapy for ischemic stroke and discussed the challenges of bringing these therapies into the clinic. The design of future experiments was also discussed to better characterize the role of complement in both tissue injury and recovery after cerebral ischemia. More studies are needed to elucidate the molecular and cellular mechanisms of how complement components exert their functions in different stages of ischemic stroke to optimize the intervention of targeting the complement system.

Selective accumulation of the complement membrane attack complex in aging choriocapillaris

The complement membrane attack complex (MAC) shows increased abundance in the choriocapillaris during normal aging and is especially prevalent in age-related macular degeneration (AMD). While perivascular MAC accumulation occurs in the choroid, it is not well understood whether similar deposition occurs in other aging tissues. In this study we examined the abundance of MAC across multiple human tissues. For studies on fixed tissues, paraffin sections were obtained from six human donor eyes and a commercially available tissue array containing 19 different tissues. Immunohistochemical labeling was performed using antibodies directed against the MAC and intercellular adhesion molecule-1 (ICAM-1), as well as the lectin Ulex europaeus agglutinin-I (UEA-I). The choriocapillaris was the only tissue with high levels of the MAC, which was not detected in any of the 38 additional samples from 19 tissues. ICAM-1 was abundantly expressed in the majority of tissues evaluated, and UEA-I labeled the vasculature in all tissues. A second experiment was performed using unfixed frozen sections of RPE-choroid and 7 extraocular tissues, which confirmed the relatively limited localization of the MAC to the choriocapillaris. In comparison to other tissues assessed, the restricted accumulation of MAC in the choriocapillaris may, in part, explain the specificity of AMD to the neural retina, RPE and choroid, and the relative absence of systemic pathology in this disease.

2D gel blood serum biomarkers reveal differential clinical proteomics of the neurodegenerative diseases

This review addresses the challenges of neuroproteomics and recent progress in biomarkers and tests for neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis. The review will discuss how the application of quantitative 2D gel electrophoresis, combined with appropriate single-variable and multivariate biostatistics, allows for selection of disease-specific serum biomarkers. It will also address how the use of large cohorts of specifically targeted patient blood serum samples and complimentary age-matched controls, in parallel with the use of selected panels of these biomarkers, are being applied to the development of blood tests to specifically address unmet pressing needs in the differential diagnosis of these diseases, and to provide potential avenues for mechanism-based drug targeting and treatment monitoring. While exploring recent findings in this area, the review discusses differences in critical pathways of immune/inflammation and amyloid formation between Parkinson's disease and amyotrophic lateral sclerosis, as well as discernable synergistic relationships between these pathways that are revealed by this approach. The potential for pathway measurement in blood tests for differential diagnosis, disease burden and therapeutic monitoring is also outlined.

Complement factor C5a and C5a receptor contribute to morphine tolerance and withdrawal-induced hyperalgesia in rats

Morphine is a potent opioid analgesic. However, the repeated use of morphine causes tolerance and hyperalgesia. Neuroinflammation has been reported to be involved in morphine tolerance and withdrawal-induced hyperalgesia. The complement system is a crucial effector mechanism of immune responses. The present study investigated the roles of complement factor C5a and C5a receptor (C5aR) in the development of morphine tolerance and withdrawal-induced hyperalgesia. In the present study, the levels of C5a and C5aR were increased in the L5 lumbar spinal cords of morphine-tolerant rats. The administration of C5a promoted the development of hyperalgesia and the expression of spinal antinociceptive tolerance to intrathecal morphine in both mechanical and thermal test. However, these phenomena caused by morphine were significantly attenuated by the C5aR antagonist PMX53. These results suggest that complement activation within the spinal cord is involved in morphine tolerance and withdrawal-induced hyperalgesia. C5a and C5aR may serve as novel targets for the control of morphine tolerance and withdrawal-induced hyperalgesia.

Complement activation in the injured central nervous system: another dual-edged sword?

The complement system, a major component of the innate immune system, is becoming increasingly recognised as a key participant in physiology and disease. The awareness that immunological mediators support various aspects of both normal central nervous system (CNS) function and pathology has led to a renaissance of complement research in neuroscience. Various studies have revealed particularly novel findings on the wide-ranging involvement of complement in neural development, synapse elimination and maturation of neural networks, as well as the progression of pathology in a range of chronic neurodegenerative disorders, and more recently, neurotraumatic events, where rapid disruption of neuronal homeostasis potently triggers complement activation. The purpose of this review is to summarise recent findings on complement activation and acquired brain or spinal cord injury, i.e. ischaemic-reperfusion injury or stroke, traumatic brain injury (TBI) and spinal cord injury (SCI), highlighting the potential for complement-targeted therapeutics to alleviate the devastating consequences of these neurological conditions.

Combination of neurofilament heavy chain and complement C3 as CSF biomarkers for ALS

Amyotrophic lateral sclerosis (ALS) is a rapidly progressive and ultimately fatal neurodegenerative disease with an average survival of 3 years from symptom onset. Rapid and conclusive early diagnosis is essential if interventions with disease-modifying therapies are to be successful. Cytoskeletal modification and inflammation are known to occur during the pathogenesis of ALS. We measured levels of cytoskeletal proteins and inflammatory markers in the CSF of ALS, disease controls and healthy subjects. We determined threshold values for each protein that provided the optimal sensitivity and specificity for ALS within a training set, as determined by receiver operating characteristic analysis. Interestingly, the optimal assay was a ratio of the levels for phosphorylated neurofilament heavy chain and complement C3 (pNFH/C3). We next applied this assay to a separate test set of CSF samples to verify our results. Overall, the predictive pNFH/C3 ratio identified ALS with 87.3% sensitivity and 94.6% specificity in a total of 71 ALS subjects, 52 disease control subjects and 40 healthy subjects. In addition, the level of CSF pNFH correlated with survival of ALS patients. We also detected increased pNFH in the plasma of ALS patients and observed a correlation between CSF and plasma pNFH levels within the same subjects. These findings support large-scale prospective biomarker studies to determine the clinical utility of diagnostic and prognostic signatures in ALS.

Complement C5 regulates the expression of insulin-like growth factor binding proteins in chronic experimental allergic encephalomyelitis

Complement activation plays a central role in autoimmune demyelination. To explore the possible effects of C5 on post-inflammatory tissue repair, we investigated the transcriptional profile induced by C5 in chronic experimental allergic encephalomyelitis (EAE) using oligonucleotide arrays. We used C5-deficient (C5-d) and C5-sufficient (C5-s) mice to compare the gene expression profile and we found that 390 genes were differentially regulated in C5-s mice as compared to C5-d mice during chronic EAE. Among them, a group of genes belonging to the family of insulin-like growth factor binding proteins (IGFBP) and transforming growth factor (TGF)-beta3 were found most significantly differentially regulated by C5. The dysregulation of these genes suggests that these proteins might be responsible for the gliosis and lack of remyelination seen in C5-d mice with chronic EAE.

Characterization of early and terminal complement proteins associated with polymorphonuclear leukocytes in vitro and in vivo after spinal cord injury

Background

The complement system has been suggested to affect injury or disease of the central nervous system (CNS) by regulating numerous physiological events and pathways. The activation of complement following traumatic CNS injury can also result in the formation and deposition of C5b-9 membrane attack complex (C5b-9/MAC), causing cell lysis or sublytic effects on vital CNS cells. Although complement proteins derived from serum/blood-brain barrier breakdown can contribute to injury or disease, infiltrating immune cells may represent an important local source of complement after injury. As the first immune cells to infiltrate the CNS within hours post-injury, polymorphonuclear leukocytes (PMNs) may affect injury through mechanisms associated with complement-mediated events. However, the expression/association of both early and terminal complement proteins by PMNs has not been fully characterized in vitro, and has not observed previously in vivo after traumatic spinal cord injury (SCI).

Method

We investigated the expression of complement mRNAs using rt-PCR and the presence of complement proteins associated with PMNs using immunofluroescence and quantitative flow cytometry.

Results

Stimulated or unstimulated PMNs expressed mRNAs encoding for C1q, C3, and C4, but not C5, C6, C7 or C9 in culture. Complement protein C1q or C3 was also detected in less than 30% of cultured PMNs. In contrast, over 70% of PMNs that infiltrated the injured spinal cord were associated with C1q, C3, C7 and C5b-9/MAC 3 days post-SCI. The localization/association of C7 or C5b-9/MAC with infiltrating PMNs in the injured spinal cord suggests the incorporation or internalization of C7 or C5b-9/MAC bound cellular debris by infiltrating PMNs because C7 and C5b-9/MAC were mostly localized to granular vesicles within PMNs at the spinal cord epicenter region. Furthermore, PMN presence in the injured spinal cord was observed for many weeks post-SCI, suggesting that this infiltrating cell population could chronically affect complement-mediated events and SCI pathogenesis after trauma.

Conclusion

Data presented here provide the first characterization of early and terminal complement proteins associated with PMNs in vitro and in vivo after SCI. Data also suggest a role for PMNs in the local internalization or deliverance of complement and complement activation in the post-SCI environment.

Role of spinal microglia in rat models of peripheral nerve injury and inflammation

Mounting evidence supports the hypothesis that spinal microglia modulate the development and maintenance of some chronic pain states. Here we examined the role of spinal microglia following both peripheral inflammatory insult and peripheral nerve injury. We observed significant ipsilateral dorsal horn microglia activation 2 weeks after injury and bilateral activation 50 days following nerve injury as well as 24 h following intraplantar zymosan but not intraplantar complete Freund's adjuvant (CFA). Ipsilateral but not contralateral microglia activation was associated with hind paw mechanical hyperalgesia. Spinal injection of the glial metabolic inactivator fluorocitrate attenuated ipsilateral hyperalgesia and bilateral spinal microglia activation after peripheral nerve injury. Intrathecal fluorocitrate reversed hyperalgesia after intraplantar zymosan and produced no reversal of CFA-induced hyperalgesia. These data suggest a role for spinal glia in the persistence of mechanical hyperalgesia following peripheral nerve injury. However, activation of spinal microglia contralaterally did not correlate to nociception. Furthermore, it would appear that the time course of microglia activation and their contribution to inflammatory pain is dependent on the inflammatory stimulus administered.

Complement activation in diabetic ketoacidosis brains

The metabolic crisis of diabetic ketoacidosis (DKA) and its treatment can result in the life-threatening complication of clinical brain edema. However, there is limited information available regarding either the pathophysiology or histology of this acute complication. It has been reported that DKA and its treatment are associated with a systemic inflammatory response involving the activation of the complement cascade with increases of SC5b-9 serum level. We studied the brains of two patients, both of whom died as the result of DKA-related brain edema, for the presence of C5b-9, C1q and the expression of the CD59. Apoptosis was also evaluated by the TUNEL method. All regions of the brain demonstrated varying degrees of C5b-9 deposits on neurons, oligodendrocytes and blood vessels. C5b-9 was co-localized with C1q, suggesting the activation of classical pathway. No expression of CD59 was found on neurons, oligodendrocytes or blood vessels in DKA brain, but this complement inhibitor was present on these cells in the normal brain. Rarely, C5b-9 was co-localized with apoptotic neurons and OLG. Our data demonstrate that the metabolic crisis of DKA results in a loss of CD59 expression and assembly of C5b-9 on neurons and oligodendrocytes, suggesting that complement activation and C5b-9 may play a role in the pathophysiology of the brain edema of DKA.

C5b-9 Terminal Complex Protects Oligodendrocytes from Apoptotic Cell Death by Inhibiting Caspase-8 Processing and Up-Regulating FLIP

Activation of the terminal complement cascade involving C5 to C9 proteins has a beneficial role for oligodendrocytes (OLG) in experimental allergic encephalomyelitis, an animal model of multiple sclerosis, by protecting them from apoptotic cell death. We have previously shown that sublytic C5b-9 complexes, through posttranslational regulation of Bad, inhibit the mitochondrial pathway of apoptosis induced by serum deprivation. In the present study, we examined the possible involvement of the caspase-8 and Fas pathway in OLG apoptosis and the role of C5b-9 in this process. In a serum-free defined medium, OLG undergo apoptosis and differentiation concomitantly. Under this condition, we found that caspase-8 processing was increased in association with Bid cleavage and markedly reduced expression of cellular FLIP long isoform protein. The caspase-8 inhibitor Z-IETD-FMK inhibited cell death associated with differentiation in a dose-dependent manner. Exposure to C5b-9 induced an inhibition of caspase-8 activation, Bid cleavage, and a significant increase in expression of cellular FLIP long isoform. These C5b-9 effects were reversed by PI3K inhibitor LY294002. C5b-9 also down-regulated the expression of FasL and the Fas-induced apoptosis. These data suggest that C5b-9 through PI3K signaling can rescue OLG from Fas-mediated apoptosis by regulating caspase-8 processing.

Complement C3c and related protein biomarkers in amyotrophic lateral sclerosis and Parkinson's disease

We have used quantitative 2D gel electrophoresis to analyze serum proteins from 422 patients with neurodegenerative diseases and normal individuals in an unbiased approach to identify biomarkers. Differences in abnormal serum levels were found between amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD), and related disorders for 34 protein biomarker spots, nine of which were related to the complement system. Of these nine, four spots originated from the Complement C3b-alpha-chain (C3c(1), C3c(2a), C3c(2b), and C3dg). The C3c spots (C3c(1), C3c(2a), and C3c(2b)) had the same amino acid sequence and glycosylation, though only C3c(1) was phosphorylated. In addition, Complement Factors H, Bb, and Pre-Serum amyloid protein displayed different serum concentrations in ALS, PD, and normal sera, whereas Complement C4b gamma-chain and Complement Factor I did not. The differential expression of the complement proteins provides potentially useful biomarkers as well as evidence for the involvement of inflammatory processes in the pathogenesis of ALS and PD.

Activation of early components of complement targets myelin and oligodendrocytes in the aged rhesus monkey brain

The disruption and loss of myelin in the white matter are some of the major changes that occur in the brain with age. In vitro studies suggest a role of the complement system in the catabolic breakdown of myelin membranes. This study presents findings on activation of the early components of complement cascade in the brains of both young and aged rhesus monkeys with evidence of increased complement activation in aged animals. Complement containing oligodendrocytes (CAOs) containing C3d and C4d complement activation products bound to oligodendrocytes and myelinated fibers were found in the brain of normal young and old animals. The CAOs, which also contained activated microglia, were distributed throughout the whole brain and in significantly greater numbers in the aged monkeys. These findings, together with the demonstration of covalent binding of the C3 fragments to myelin, suggest the initiation of the complement cascade by myelin and oligodendrocytes, which are known classical complement activators. Activation of terminal complement components was not demonstrable in the CAOs. Taken together the findings support the concept that activation of early components of complement in the brain may be a normal biological process that involves the metabolism of myelin and oligodendrocytes and up-regulates with age.

Intrinsic Resistance of Hepatocytes to Complement-Mediated Injury

When activated on or in the vicinity of cells, complement usually causes loss of function and sometimes cell death. Yet the liver, which produces large amounts of complement proteins, clears activators of complement and activated complexes from portal blood without obvious injury or impaired function. We asked whether and to what extent hepatocytes resist injury and loss of function mediated by exposure to complement. Using cells isolated from porcine livers as a model system, we found that, in contrast to endothelial cells, hepatocytes profoundly resist complement-mediated lysis and exhibit normal synthetic and conjugative functions when complement is activated on their surface. The resistance of hepatocytes to complement-mediated injury was not a function of cell surface control of the complement cascade but rather an intrinsic resistance of the cells dependent on the PI3K/Akt pathway. The resistance of hepatocytes to complement might be exploited in developing approaches to the treatment of hepatic failure or more broadly to the treatment of complement-mediated disease.

Activation of the spinal cord complement cascade might contribute to mechanical allodynia induced by three animal models of spinal sensitization

The present series of experiments examined whether the complement cascade might play a key role in the expression of mechanical allodynia. Soluble complement receptor 1 (sCR1) was used to block the activation of the membrane attack pathway of the complement cascade. In doing so, sCR1 prevents the formation of the biologically active end products C3a, C5a, and membrane attack complexes (MACs). Intrathecal sCR1 had no effect on the behavioral responses of control groups. In contrast, blockade of this pathway abolished the expression of mechanical allodynia induced by peripheral nerve inflammation (sciatic inflammatory neuropathy model), partial sciatic nerve injury (chronic constriction injury model), and intrathecal injection of human immunodeficiency virus type 1 gp120, a viral envelope protein that activates glia. The fact that enhanced nociception was prevented or reversed in all 3 paradigms suggests that complement might be broadly involved in spinally mediated pain enhancement. The mechanisms whereby complement activation might potentially affect the functioning of microglia, astrocytes, and neurons are discussed. The complement cascade has not been previously implicated in spinal sensitization. These data suggest that complement activation within the spinal cord might contribute to enhanced pain states and provide additional evidence for immune regulation of pain transmission.

C5b-9 complement complex in autoimmune demyelination and multiple sclerosis: dual role in neuroinflammation and neuroprotection

Complement system activation plays an important role in innate and acquired immunity. Activation of complement leads to the formation of C5b-9 terminal complex. While C5b-9 can promote cell lysis, sublytic assembly of C5b-9 on plasma membranes induces cell cycle activation and survival. Multiple sclerosis (MS) and its animal model experimental allergic encephalomyelitis (EAE) are inflammatory demyelinating diseases of the central nervous system (CNS) mediated by activated lymphocytes, macrophages/microglia and the complement system. Complement activation may contribute to the pathogenesis of these diseases through its dual role: the ability of activated terminal complex C5b-9 to promote demyelination and the capacity of sublytic C5b-9 to protect oligodendrocytes (OLG) from apoptosis. By inducing EAE in C5-deficient mice, we showed that complement C5 promotes remyelination and protects oligodendrocytes from apoptotic cell death. These findings indicate that activation of complement C5b-9 plays a pro-inflammatory role in the acute phase of the disease, but may also be neuroprotective during the chronic phase of the disease.

Complement Activation following Optic Nerve Crush in the Adult Rat

Activation of the complement cascade following peripheral nerve axotomy and following traumatic brain injury has been demonstrated in previous studies. This study investigates the temporal pattern of microglia/macrophages and complement activation following axotomy of sensory CNS neurons, using a standardized experimental crush injury of the optic nerve in adult rats. Numerous ED1-labeled macrophages were found at the lesion site and distal to the injury at 7 days post injury (dpi). Complement C3-mRNA was upregulated 2-28 days post lesion, indicating local synthesis of complement in the optic nerve. Furthermore, increased immunoreactivity (IR) for the end product of the complement cascade, the membrane attack complex (MAC), was detected along disintegrating axons co-labeled with anti-neurofilament distal to the injury. Double-labeling for microglia show MAC-immunoreactivity expressed in their immediate vicinity, indicating a key role of microglia/macrophages in complement activation. The complement regulator Clusterin was upregulated in astrocytes at the lesion site as well as in the distal portion of the injured optic nerve, suggesting activation of a defense response to endogenous complement attack. A crush injury of the optic nerve leads to complement activation at the site of lesion and along the distal portion of the nerve, as well as upregulation of the complement inhibitor Clusterin at least in astrocytes. Reactive microglial cells seem to have a key role in complement activation as a local source of C3. We suggest that the balance between complement activation and their regulators may have impact on axonal degeneration following optic nerve injury.

Innate immunity in viral encephalitis: role of C5

The complement system is a critical component of both the innate and acquired immune systems. It is important in host defense against viruses, bacteria, and fungi for opsonization and for lysis of pathogens. However, activated complement can also cause tissue damage. There is compelling evidence that complement factors are presented in the central nervous system (CNS). Complement activation (by any of the three pathways: classical, alternate, and lectin) can lead to inflammation and tissue damage, while at the same time may also restrict certain pathogens in the CNS. C5a is formed by proteolytic cleavage C5. C5a is considered the most potent proinflammatory mediator, often called an anaphylotoxin. In this communication, we examine the roles of C5 (C5a) in vesicular stomatitis virus (VSV)-induced encephalitis. We found that C5a is produced during VSV infection, but C5-deficient mice had similar pathology as their controls. We concluded that C5 is not a critical factor in mediating the host response during VSV encephalitis.

A Comparative Pathological Study on Canine Necrotizing Meningoencephalitis and Granulomatous Meningoencephalomyelitis

Canine necrotizing meningoencephalitis (NME) and granulomatous meningoencephalomyelitis (GME) were compared pathologically. Gross observation exhibited lateral ventricular dilation and discoloration, malacia and/or cavitation of the cerebrum in NME. On the contrary, gross changes were milder in GME, except for occasional visible granulomatous mass formation. Histopathologically, the lesions of NME were distributed predominantly in the cerebral cortex and various degrees of inflammatory and necrotic changes were observed according to clinical stages. Besides, microscopic lesions of GME were mainly distributed in the white matter of the cerebrum, cerebellum and brainstem, which are characterized by perivascular cuffing, multiple granulomas and leptomeningeal infiltrates. Although macrophages and lymphocytes were predominant in the inflammatory lesions of both disorders, macrophages in GME transformed into epithelioid cells and exhibited more massive infiltration. Although lectin RCA-1-reactive cells were numerous in both disorders, lysozyme immunoreactive cells in NME were fewer than that in GME. Parenchymal infiltration of MAC387-positive cells was common in GME and limited in NME. The number of CD3-positive lymphocytes in the GME lesions tended to be greater than in NME, though the difference was not statistically significant. Morphological and immunohistochemical differences of the lesions, in particular, the characteristics of infiltrative macrophages may reflect these different pathogeneses of the two disorders.

Xenoantigen, an alphaGal epitope-expression construct driven by the hTERT-promoter, specifically kills human pancreatic cancer cell line

BACKGROUND: We previously reported the usefulness of the alphaGal epitope as a target molecule for gene therapy against cancer. To induce cancer cell specific transcription of the alphaGal epitope, an expression vector which synthesizes the alphaGal epitope under the control of a promoter region of the human telomerase reverse transcriptase (hTERT), NK7, was constructed. METHODS: NK7 was transfected into a human pancreatic carcinoma cell line, MIA cells, and telomerase-negative SUSM-1 cells served controls. Expression of the alphaGal epitope was confirmed by flow cytometry using IB4 lectin. The susceptibility of transfected MIA cells to human natural antibodies, was examined using a complement-dependent cytotoxic cross-match test (CDC) and a flow cytometry using annexin V. RESULTS: The alphaGal epitope expression was detected only on the cell surfaces of NK7-transfected MIA cells, i.e., not on naive MIA cells or telomerase negative SUSM-1 cells. The CDC results indicated that MIA cells transfected with NK7 are susceptible to human natural antibody-mediated cell killing, and the differences, as compared to NK-7 transfected telomerase negative SUSM-1 cells or telomerase positive naïve MIA cells, were statistically significant. The flow cytometry using annexin V showed a higher number of the apoptotic cells in NK-7 transfected MIA cells than in naïve MIA cells. CONCLUSIONS: The results suggest that alphaGal epitope-expression, under the control of the hTERT-promoter, may be useful in cancer specific gene therapy.