Neuronal antibodies in patients with suspected or confirmed sporadic Creutzfeldt-Jakob disease

OBJECTIVES

There have been reports of patients with antibodies to neuronal antigens misdiagnosed as sporadic Creutzfeldt-Jakob disease (sCJD). Conversely, low levels of antibodies to neuronal proteins have been reported in patients with sCJD. However, the frequency of misdiagnoses, or of antibodies in patients with subsequently confirmed sCJD, is not clear.

METHODS

We reviewed 256 consecutive cases of sCJD seen in the National Prion Clinic, of whom 150 had sera previously referred for selected antibody tests. Eighty-two available samples were retested for antibodies to N-methyl-d-aspartate receptor (NMDAR), the glycine receptor (GlyR), voltage-gated potassium channel (VGKC)-complex and the associated proteins, leucine-rich glioma inactivated 1 (LGI1) and contactin-associated protein 2 (CASPR2).

RESULTS

Four of the initial 150 sera referred were positive; two had antibodies to NMDAR, and two to the VGKC-complex, one of which was also positive for GlyR antibodies. Of the 82 sCJD sera retested, one had VGKC-complex antibodies confirming the previous result, two had CASPR2 and GlyR antibodies and one had CASPR2 and NMDAR antibodies; all antibodies were at low levels. Over the same period three patients with autoimmune encephalitis and high VGKC-complex antibodies were initially referred as sCJD.

CONCLUSIONS

This study indicates that <5% patients with sCJD develop serum antibodies to these neuronal antigens and, when positive, only at low titres. By contrast, three patients referred with possible prion disease had a clinical picture in keeping with autoimmune encephalitis and very high VGKC-complex/LGI1 antibodies. Low titres of neuronal antibodies occur only rarely in suspected patients with sCJD and when present should be interpreted with caution.

Autoantibodies in sporadic Creutzfeldt-Jakob disease

IMPORTANCE

The diagnosis of autoimmune and neurodegenerative conditions can be unclear. Treatments such as removing the associated tumor, if present, and immunosuppression can halt or often reverse the progression of autoimmune conditions, but there is no curative treatment for neurodegenerative conditions. The presence of autoantibodies can sometimes be misleading. This report illustrates potential difficulties in differentiating autoimmune encephalopathies from sporadic Creutzfeldt-Jakob disease.

OBSERVATIONS

In a clinical follow-up of an older man with rapidly evolving encephalopathy at a neuroscience center, unsuccessful treatment with immunosuppression based on the incorrect presumptive diagnosis of Morvan syndrome was followed by the correct histological diagnosis of sporadic Creutzfeldt-Jakob disease.

CONCLUSIONS AND RELEVANCE

Autoimmune encephalopathies raise important treatment options and potential for recovery. However, since neuronal antibodies may be positive in prion disease, interpretation can be complex and must be rooted in the clinical picture.

Creutzfeldt-Jakob disease in a patient treated by etanercept for rheumatoid arthritis (RA): just a coincidence?

We describe a patient in whom sporadic Creutzfeldt-Jakob disease (sCJD) occurred one year after the onset of etanercept therapy for rheumatoid arthritis (RA). This association could be a chance occurrence. However, TNF-alpha has been implicated in the pathogenesis of neurodegeneration in sCJD and etanercept might worsen the disease. Such an aggravation has been observed in multiple sclerosis, in which TNF-alpha is the key mediator of demyelination. It may be of interest studying the impact of treatment with TNF-alpha antagonists on prevalence and incidence of those neurodegenerative diseases involving TNF-alpha mediation, such as Alzheimer disease.

A systematic review of prion therapeutics in experimental models

Prion diseases are transmissible, invariably fatal, neurodegenerative diseases which include Creutzfeldt-Jakob disease (CJD) in humans and bovine spongiform encephalopathy and scrapie in animals. A large number of putative treatments have been studied in experimental models over the past 30 years, with at best modest disease-modifying effects. The arrival of variant CJD in the UK in the 1990s has intensified the search for effective therapeutic agents, using an increasing number of animal, cellular and in vitro models with some recent promising proof of principle studies. Here, for the first time, we present a comprehensive systematic, rather than selective, review of published data on experimental approaches to prion therapeutics to provide a scientific resource for informing future therapeutics research, both in laboratory models and in clinical studies.

Immunohistochemistry for the prion protein: comparison of different monoclonal antibodies in human prion disease subtypes

Demonstration of the abnormal form of the prion protein (PrP) in the brain confirms the diagnosis of human prion disease (PrD). Using immunohistochemistry, we have compared ten monoclonal antibodies in PrD subtypes including sporadic and variant Creutzfeldt-Jakob disease (CJD), fatal familial insomnia, Alzheimer's disease (AD), and control brains. CJD subgroups were determined using Western blot analysis for the protease-resistant PrP type in combination with sequencing to determine the genotype at the methionine/valine polymorphism at codon 129 of the prion protein gene. None of the antibodies labeled given subgroups exclusively, but the intensity of immunoreactivity varied among morphologically distinct types of deposit. Fine granular or synaptic PrP deposits stained weakly or not at all with antibodies against the N-terminus of PrP, and were visible in one case only with 12F10 and SAF54. Coarser and plaque type deposits were immunolabeled with all antibodies. The immunostaining patterns appear characteristic for the disease subgroups. Labeling of certain neurons in all cases irrespective of disease, and staining at the periphery and/or throughout the senile plaques of AD patients were also noted. Antibodies such as 6H4 and 12F10 failed to give this type of labeling and are therefore less likely to recognise non-pathological PrP material in immunohistochemistry.

Neuronal apoptosis in fatal familial insomnia

The possibility that neuronal loss in prion diseases occurs through an apoptotic process has been postulated and is consistent with the lack of inflammation in these disorders. In order to test this hypothesis in FFI, in which neuronal loss is the predominant neuropathological feature, we examined samples of thalamus, basal ganglia, cerebral cortex, cerebellum and medulla from 10 subjects with FFI. All the patients had the characteristic 178 N mutation of the PrP gene. Eight subjects were homozygous methionine/methionine at codon 129 and 2 were heterozygous methionine/valine. Apoptotic neurons were identified by in situ end labelling in all the FFI cases and in none of the controls. They were mostly found in damaged regions and their presence and abundance seemed to correlate closely with the neuronal loss. They were particularly abundant in the thalamus and medullary olives. In heterozygous cases who had a longer disease duration and more widespread cerebral changes, apoptotic neurons were also found in the neocortex and striatum. The abundance of apoptotic neurons also correlated well with microglial activation as demonstrated by the expression of major histocompatibility complex class II antigens. PrPres immunostaining was almost invariably negative, consistent with previous data showing the lack of obvious correlation between neuronal loss and PrPres deposits in prion diseases.

The brain immune response in human prion diseases. Microglial activation and microglial disease. I. Sporadic Creutzfeldt-Jakob disease

A study of microglial activation and its contribution to the CNS immune response was performed on the brain autopsy material of 40 patients with definite sporadic Creutzfeldt-Jakob disease (sCJD). Spatial patterns of microglial activation and prion protein disease-associated (PrPd) deposition were compared in cerebellar and cerebral cortices using immunohistochemical (IHC) activation markers. Morphological phenotype forms of microglial cells in activation stages were assessed immunohistochemically (IHC). The immune inflammatory response dominated by microglia was found to be a characteristic feature in CJD. Differences in the intensity and patterns of microglial activation corresponded to variable patterns of PrP deposition, whereas the morphological phenotype forms of microglia were specific for activation stages. The presence of activated microglial cells in the various activation stages regardless of illness duration indicates continuous microglial activity and microglial contribution to the spread of infection for the whole symptomatic period of the disease. Remarkable vacuolar degeneration changes of numerous microglial cells in different activation stages including homing stage may suggest dysfunction of microglial immune surveillance in human sCJD that can significantly contribute to transmissible spongiform encephalopathy (TSE) pathogenesis.

PrP glycoforms are associated in a strain-specific ratio in native PrPSc

Prion diseases involve conversion of host-encoded cellular prion protein (PrPC) to a disease-related isoform (PrPSc). Using recombinant human beta-PrP, a panel of monoclonal antibodies was produced that efficiently immunoprecipitated native PrPSc and recognized epitopes between residues 93-105, indicating for the first time that this region is exposed in both human vCJD and mouse RML prions. In contrast, monoclonal antibodies raised to human alpha-PrP were more efficient in immunoprecipitating PrPC than PrPSc, and some of them could also distinguish between different PrP glycoforms. Using these monoclonal antibodies, the physical association of PrP glycoforms was studied in normal brain and in the brains of humans and mice with prion disease. It was shown that while PrPC glycoforms can be selectively immunoprecipitated, the differentially glycosylated molecules of native PrPSc are closely associated and always immunoprecipitate together. Furthermore, the ratio of glycoforms comprising immunoprecipitated native PrPSc from diverse prion strains was similar to those observed on denaturing Western blots. These studies are consistent with the view that the proportion of each glycoform incorporated into PrPSc is probably controlled in a strain-specific manner and that each PrPSc particle contains a mixture of glycoforms.

Human and animal spongiform encephalopathies are the result of chronic autoimmune attack in the CNS: a novel medical theory supported by overwhelming experimental evidence

Spongiform encephalopathies, also called "prion diseases", are fatal degenerative diseases of the central nervous system which can occur in animals (such as the "mad cow disease" in cattle) and also in humans. This paper presents a novel medical theory concerning the pathogenic mechanisms for various human and animal spongiform encephalopathies. It is hypothesized that various forms of prion diseases are essentially autoimmune diseases, resulting from chronic autoimmune attack of the central nervous system. A key step in the pathogenic process leading towards the development of spongiform encephalopathies involves the production of specific autoimmune antibodies against the disease-causing prion protein (PrPsc) and possibly other immunogenic macromolecules present in the brain. As precisely explained in this paper, the autoimmune antibodies produced against PrPsc are responsible for the conversion of the normal cellular prion protein (PrPc) to PrPsc, for the accumulation of PrPsc in the brain and other peripheral tissues, and also for the initiation of an antibody-mediated chronic autoimmune attack of the central nervous system neurons, which would contribute to the development of characteristic pathological changes and clinical symptoms associated with spongiform encephalopathies. The validity and correctness of the proposed theory is supported by an overwhelming body of experimental observations that are scattered in the biomedical literature. In addition, the theory also offers practical new strategies for early diagnosis, treatment, and prevention of various human and animal prion diseases.

Characterization of light chain immunoglobulin in urine from animals and humans infected with prion diseases

The necessity of a non-invasive in-vivo test for prion diseases has become more apparent since the transmission of vCJD from the blood of a healthy individual incubating the disease. Here we show that prion urine comprises an array of protease resistant peptides, among them light chain immunoglobulin (LC). This was observed by sequencing gel bands comprising hamster urine samples, as well as by immunoblotting of similar samples with anti mouse IgG reagents for hamster samples, or with anti human IgG reagents for human samples. Our result suggests that urine samples from CJD patients can be identified by the presence of protease resistant proteins such as LC.

A possible link between multiple sclerosis and Creutzfeldt-Jakob disease based on clinical, genetic, pathological and immunological evidence involving Acinetobacter bacteria

Multiple sclerosis (MS) is an immune-mediated demyelinating disease of the nervous system. There is an increasingly likelihood that MS could be triggered/perpetuated by environmental (microbial) agents. Sporadic Creutzfeldt-Jakob disease (sCJD) is a relatively rare but fatal disease, which shows various clinical, genetic, pathological and immunological features through which it resembles a severe form of MS. The disease in some patients with MS may show a rapidly downhill course with death occurring within one to two years and a similar situation occurs in sCJD. The occurrence of these comparative similarities between MS and sCJD could be explained on the basis that both of these conditions might be sharing a common aetiopathogenic factor such as infection by Acinetobacter microbes and this possibility could be investigated further by carrying out immunological studies on a relatively large numbers of patients with MS and CJD.

Bovine Spongiform Encephalopathy, Multiple Sclerosis, and Creutzfeldt-Jakob Disease Are Probably Autoimmune Diseases Evoked byAcinetobacterBacteria

Bovine spongiform encephalopathy (BSE) belongs to a group of conditions named together as transmissible spongiform encephalopathies (TSE). They are fatal neurodegenerative diseases that include "scrapie" in sheep, Creutzfeldt-Jakob disease (CJD) and kuru in humans, and chronic wasting disease in deers. BSE-affected animals suffer from "hindquarters" paralysis, which is also one of the main features of "experimental allergic encephalomyelitis" (EAE). EAE is considered an animal model of multiple sclerosis (MS) and lower limb ataxia is often observed in MS patients. The presence of clinical and histopathological similarities in these diseases suggests a common pathology. Specific brain peptides, which produce EAE, were shown to have "molecular mimicry" with the soil and skin saprophytic microbe, Acinetobacter. BSE-affected animals and patients suffering from MS have been found to have elevated levels of antibodies to both Acinetobacter and Pseudomonas bacteria, as well as autoantibodies to both white and gray matter brain components. The hypothesis is proposed that Acinetobacter/Pseudomonas bacteria may have evoked both BSE and MS through the mechanism of "molecular mimicry" and autoimmunity in a similar way to Streptococcus microbes producing rheumatic fever and Sydenham's chorea. The possibility that CJD patients may show similar features remains to be determined.

Evaluation of urinary PrPSc as a diagnostic test for sporadic, variant, and familial CJD

Previously collected urine specimens from 100 patients referred to the UK National CJD Surveillance Unit as suspected cases of Creutzfeldt-Jakob disease (CJD) were analyzed, testing for abnormal prion protein (PrP(Sc)). In this context, the test had a low sensitivity and was not completely specific for CJD. Additionally, the proteins detected by this assay were not PrP(Sc) but appeared to be immunoglobulins.

Immunoglobulins and virus-specific antibodies in patients with Creutzfeldt-Jakob disease

OBJECTIVES

Cerebrospinal fluid (CSF) pattern in patients with neuropathologically diagnosed Creutzfeldt-Jakob disease was analyzed.

MATERIAL AND METHODS

Routine tests included white blood cells count, protein, albumin, immunoglobulins and the presence of oligoclonal immunoglobulin G (IgG) in the CSF as well as the calculation of intrathecal synthesis of immunoglobulins by standard methods. In addition, antibodies against neurotropic viruses such as measles, rubella, varicella zoster and herpes simplex were measured and the specific antibody index was calculated.

RESULTS

A blood-CSF barrier dysfunction was observed in six of 25 cases. In CSF/serum quotient diagrams, no patient had intrathecally synthesized immunoglobulins, but in two of 25 patients oligoclonal bands were detected. Two patients had intrathecally synthesized antibodies against varicella zoster and three against herpes simplex virus.

CONCLUSION

In conclusion, in the routine diagnosis, the CSF in CJD is normal in most cases. In some patients, abnormalities include the blood-CSF barrier dysfunction, mild pleocytosis, oligoclonal bands and intrathecally synthesized viral antibodies.

Epidemiological evidence of higher susceptibility to vCJD in the young

Background

The strikingly young age of new variant Creutzfeldt-Jacob disease (vCJD) cases remains unexplained. Age dependent susceptibility to infection has been put forward, but differential dietary exposure to contaminated food products in the UK population according to age and sex during the bovine spongiform encephalopathy (BSE) epidemic may provide a simpler explanation.

Methods

Using recently published estimates of dietary exposure in mathematical models of the epidemiology of the new variant Creutzfeldt Jacob disease (vCJD), we examine whether the age characteristics of vCJD cases may be reproduced.

Results

The susceptibility/exposure risk function has likely peaked in adolescents and was followed by a sharp decrease with age, evocative of the profile of exposure to bovine material consumption according to age. However, assuming that the risk of contamination was proportional to exposure, with no age dependent susceptibility, the model failed to reproduce the observed age characteristics of the vCJD cases: The predicted cumulated proportion of cases over 40 years was 48%, in strong disagreement with the observed 10%. Incorporating age dependent susceptibility led to a cumulated proportion of cases over 40 years old of 12%.

Conclusions

This analysis provides evidence that differential dietary exposure alone fails to explain the pattern of age in vCJD cases. Decreasing age related susceptibility is required to reproduce the characteristics of the age distribution of vCJD cases.

Motif-grafted antibodies containing the replicative interface of cellular PrP are specific for PrPSc

Prion diseases are closely associated with the conversion of the cellular prion protein (PrPC) to an abnormal conformer (PrPSc) [Prusiner, S. B. (1998) Proc. Natl. Acad. Sci. USA 95, 13363-13383]. Monoclonal antibodies that bind epitopes comprising residues 96-104 and 133-158 of PrPC potently inhibit this process, presumably by preventing heterodimeric association of PrPC and PrPSc, and suggest that these regions of PrPC may be critical components of the PrPC-PrPSc replicative interface. We reasoned that transplanting PrP sequence corresponding to these regions into a suitable carrier molecule, such as an antibody, could impart specific recognition of disease-associated forms of PrP. To test this hypothesis, polypeptides containing PrP sequence between residues 89-112 or 136-158 were used to replace the extended heavy chain complementarity-determining region 3 of an IgG antibody specific for the envelope glycoprotein of HIV-1. Herein the resulting engineered PrP-IgGs are shown to bind specifically to infective fractions of PrP in mouse, human, and hamster prion-infected tissues, but not to PrPC, other cellular components, or the HIV-1 envelope. PrPSc reactivity was abolished when the sequence of the PrP 89-112 and 136-158 grafts was mutated, scrambled, or N-terminally truncated. Our findings suggest that residues within the 89-112 and 136-158 segments of PrPC are key components of one face of the PrPC-PrPSc complex. PrPSc-specific antibodies produced by the approach described may find widespread application in the study of prion biology and replication and in the detection of infectious prions in human and animal materials.

Early induction of interferon-responsive mRNAs in Creutzfeldt-Jakob disease

Foreign infectious agents typically evoke a host immune response. In scrapie and Creutzfeldt-Jakob disease (CJD), no immune response has been detectable. However, many latent or persistent viruses evade immune recognition but still activate inflammatory pathways. Unique microglial responses in late CJD infection that could be part of a host defense mechanism were previously delineated, although changes secondary to neurodegeneration could not be excluded. Data here show these microglial transcriptional changes are detectable in CJD brain beginning at 30 days after innoculation. In addition, 10 other interferon-sensitive genes were similarly upregulated at very early stages of infection. These responses occurred well before abnormal prion protein (PrP) and clinical signs of CJD were detectable. Further analyses in very pure microglia from CJD brain suggested the CJD agent activated signaling pathways distinct from those induced by amyloidogenic proteins (including abnormal PrP). Although increases in interferon-alpha or -beta transcript levels were not seen in cultures or in whole brain, CJD microglia exhibited a potentiated interferon response when challenged with double-stranded RNA. The induction of interferon-sensitive genes without appreciable interferon synthesis was strikingly similar to that seen in some viral infections. These data suggest the CJD agent is recognized as a foreign virus-like entity. Moreover, the early reactive gene expression profiles described here may be useful in preclinical diagnosis.

Monoclonal Antibody against a Peptide of Human Prion Protein Discriminates between Creutzfeldt-Jacob's Disease-affected and Normal Brain Tissue

Current methods for diagnosing transmissible spongiform encephalopathies rely on the degradation of the cellular prion protein (PrP(C)) and the subsequent detection of the protease-resistant remnant of the pathological prion isoform PrP(Sc) by antibodies that react with all forms of PrP. We report on a monoclonal antibody, V5B2, raised against a peptide from the C-terminal part of PrP, which recognizes an epitope specific to PrP(Sc). In cryostat sections from Creutzfeldt-Jacob's disease (CJD) patients' brains, V5B2 selectively labels various deposits of PrP(Sc) without any pretreatment for removal of PrP(C). V5B2 does not bind to non-CJD brain samples or to recombinant PrP, either in its native or denatured form. Specificity for PrP is confirmed by a sandwich enzyme-linked immunosorbent assay utilizing V5B2, which discriminates between CJD and normal samples without proteinase K treatment, and by immunoprecipitation from CJD brain homogenate. The PrP(Sc)-specific epitope is disrupted by denaturation. We conclude that the C-terminal part of PrP in disease-associated PrP(Sc) aggregates forms a structural epitope whose conformation is distinct from that of PrP(C).

Creutzfeldt-Jakob disease associated with high titer of antithyroid autoantibodies: case report and literature review

Hashimoto's encephalopathy and Creutzfeldt-Jakob disease (CJD) often have similar clinical features and may be confused, especially at onset. A 61-year-old woman developed rapidly progressive ataxia, myoclonus and dementia, with abnormalities seen on electroencephalography (EEG). Serum analysis disclosed high titers of antithyroid autoantibodies. Both clinical course and autopsy led to a definitive diagnosis of CJD. This case and a literature review of previous cases confirm that CJD may be confused with Hashimoto's encephalopathy. EEG, clinical and laboratory findings (including the positivity of 14.3.3 protein in the cerebrospinal fluid) are not conclusive for a differential diagnosis, especially at early stages. Only the results of genetic exams can allow a definitive diagnosis in a small percentage of cases while patients are still alive. In patients with unclear symptomatology and rapid onset of myoclonus, dementia and ataxia, the presence of antithyroid antibodies should be examined. If their levels are abnormal, corticosteroid therapy remains mandatory.

Different binding pattern of antibodies to prion protein on lymphocytes from patients with sporadic Creutzfeldt-Jakob disease

In Creutzfeldt-Jakob disease (CJD), progressive neuronal cell death probably occurs as a result of a change in conformation of the physiological prion protein (PrP(C)). There is evidence of participation of the lymphatic system and in particular of lymphocytes in the intracorporeal transportation of the pathological prion protein (PrP(Sc)) in new variant CJD and scrapie. Using fluorescence cytometry, we investigated a possible alteration of PrP(C) on lymphocytes of patients with sporadic CJD. We demonstrated a significantly lower binding pattern of antibodies (3F4) against physiological prion protein to lymphocytes of patients with sporadic CJD (n=16) compared with control patients. In contrast this difference was not found on platelets (n=23). For the first time we were able to present a measurable difference of antibody binding on lymphocytes of patients with CJD. One interpretation of this finding is that lymphocytes patrolling the brain bind and transport PrP(Sc) which has a lower binding affinity for the antibodies directed against physiological PrP.

T cells infiltrate the brain in murine and human transmissible spongiform encephalopathies

CD4 and CD8 T lymphocytes infiltrate the parenchyma of mouse brains several weeks after intracerebral, intraperitoneal, or oral inoculation with the Chandler strain of mouse scrapie, a pattern not seen with inoculation of prion protein knockout (PrP(-/-)) mice. Associated with this cellular infiltration are expression of MHC class I and II molecules and elevation in levels of the T-cell chemokines, especially macrophage inflammatory protein 1beta, IFN-gamma-inducible protein 10, and RANTES. T cells were also found in the central nervous system (CNS) in five of six patients with Creutzfeldt-Jakob disease. T cells harvested from brains and spleens of scrapie-infected mice were analyzed using a newly identified mouse PrP (mPrP) peptide bearing the canonical binding motifs to major histocompatibility complex (MHC) class I H-2(b) or H-2(d) molecules, appropriate MHC class I tetramers made to include these peptides, and CD4 and CD8 T cells stimulated with 15-mer overlapping peptides covering the whole mPrP. Minimal to modest K(b) tetramer binding of mPrP amino acids (aa) 2 to 9, aa 152 to 160, and aa 232 to 241 was observed, but such tetramer-binding lymphocytes as well as CD4 and CD8 lymphocytes incubated with the full repertoire of mPrP peptides failed to synthesize intracellular gamma interferon (IFN-gamma) or tumor necrosis factor alpha (TNF-alpha) cytokines and were unable to lyse PrP(-/-) embryo fibroblasts or macrophages coated with (51)Cr-labeled mPrP peptide. These results suggest that the expression of PrP(sc) in the CNS is associated with release of chemokines and, as shown previously, cytokines that attract and retain PrP-activated T cells and, quite likely, bystander activated T cells that have migrated from the periphery into the CNS. However, these CD4 and CD8 T cells are defective in such an effector function(s) as IFN-gamma and TNF-alpha expression or release or lytic activity.

Cyclooxygenase-1 and -2 in brains of patients who died with sporadic Creutzfeldt-Jakob disease

Cyclooxygenases (COXs) mediate inflammation, immunomodulation, blood flow, apoptosis, and fever in various diseases of the brain. Whereas COX-2 is cytokine inducible, COX-1 is expressed by macrophages/microglial cells that accumulate in pathological foci. We analyzed the localization of COX-1 and COX-2 in postmortem cortex slices of eight patients who died with sporadic Creutzfeldt-Jakob disease (CJD) and four neuropathologically unaltered controls by immunohistochemical double-labeling, reverse transcriptase polymerase chain reaction (RT-PCR), and Western blotting experiments. In healthy brains, COX-1 was expressed by single macrophages/microglial cells and COX-2 by disseminated neurons. In patients with CJD, significantly (p = 0.0195) more COX-1-expressing macrophages/microglial cells were detected adjacent to neurons. COX-2 expression was predominantly observed in neurons, and their number was significantly higher (p < 0.0001) compared to controls. RT-PCR and Western blotting revealed more COX-1 and COX-2 mRNA and protein in one CJD patient than in one control patient. These data show that accumulation of COX-1-expressing macrophages/microglial cells and COX-2-expressing neurons might represent important regulatory mechanisms in the complex process of neuronal degeneration in CJD patients.

Anti-prion antibodies for prophylaxis following prion exposure in mice

Prion disease is characterized by a conformational change of the normal form of the prion protein (PrP(C)) to the scrapie-associated form (PrP(Sc)). Since the emergence of new variant Creutzfeldt-Jakob disease a potentially large human population is at risk for developing prion disease. Currently, no effective treatment or form of post-exposure prophylaxis is available for prion disease. We recently showed that active immunization with recombinant PrP prolongs the incubation period of scrapie. Here we show that anti-PrP antibodies following prion exposure are effective at increasing the incubation period of the infection. Stimulation of the immune system is an important therapeutic target for the prion diseases, as well as for other neurodegenerative illnesses characterized by abnormal protein conformation.

Microglia from Creutzfeldt-Jakob disease-infected brains are infectious and show specific mRNA activation profiles

Neurons are often assumed to be the principal sites for replication of the infectious agents causing Creutzfeldt-Jakob disease (CJD), scrapie, and bovine spongiform encephalopathy because they express high levels of normal and pathological prion protein (PrP). However, isolated brain cell types have not been evaluated for either infection or gene expression. Microglia purified from CJD-infected mice showed infectivity comparable to that of starting brain homogenate but expressed approximately 50-fold less PrP. CJD-infected microglia also displayed morphological changes indicative of cellular activation. To determine the molecular pathways of activation, we evaluated pertinent transcripts, including those linked to inflammation. Semiquantitative reverse transcription-PCR showed a >4-fold increase in cathepsin S, an enzyme important in antigen presentation, the cytokine interleukin-1beta, and the chemokine B-lymphocyte chemoattractant. The profile of microglial changes induced by the CJD agent differed substantially from activation induced by bacterial lipopolysaccharide or by beta-amyloid, a structure comparable to pathological PrP. These microglial studies emphasize migratory hematopoietic cells in the dispersion, and possibly replication, of the CJD agent. The low PrP levels in these highly infectious and activated cells further support the concept that pathological PrP is the result of infection rather than the infectious agent itself. Because microglia develop a specific pattern of responses to the CJD agent, microglial markers may be exploited in the diagnosis of these spongiform encephalopathies.

Epidemiological studies on Creutzfeldt-Jakob disease in Poland

The epidemiological, clinical and neuropathological study of Creutzfeldt-Jakob disease (CJD) in Poland was established in 1996. It was preceded by wide, repeated informative action among neurologists and psychiatrists in the whole country. The investigations were partially sponsored by the European Commission (E.C.) as part of the programme Biomed 1. The results obtained by us during the first three years of the study are presented in this paper. In 1996-1998 over 60 probable or possible cases of CJD (or information about them) were referred to our Institute. Neuropathologically typical changes for spongiform encephalopathy were found in 28 cases (among them four cases in laboratories of Medical Schools in Szczecin and Poznań). Neuropathological evaluation was based on paraffin slices stained by H-E, PAS, Bielschowsky, Kanzler-Arendt and Klüver-Barrera methods. In certain cases antibody 3F4 was used. In three patients only clinically probable CJD were diagnosed, since neuropathology was not done. In twenty-five persons, a detailed inquiry form was filled in after the model indicated by the E.C. As the result of processing the whole material, we diagnosed in twenty-four patients a sporadic form of CJD. The remaining case belonged to a family with Gerstmann-Sträussler-Scheinker syndrome. In sporadic CJD cases examined and observed by us no exogenic risk factors for the disease could be detected.

Follicular dendritic cells and dissemination of Creutzfeldt-Jakob disease

The contribution of immune system cells to the propagation of transmissible encephalopathies is not well understood. To determine how follicular dendritic cells (FDC) may act, we challenged lymphotoxin beta null and wild-type (wt) controls with a Creutzfeldt-Jakob disease (CJD) agent. There was only a small difference in incubation time to clinical disease even after peripheral challenge with low infectious doses (31 in a total of 410 days). Brain pathology with extensive microglial infiltration, identified by keratan sulfate, as well as astrocytic hypertrophy, was also equivalent in all groups despite the fact that null mice had neither FDC nor splenic metallophilic macrophages that filter particulate antigen. Because FDC accumulate pathologic prion protein (PrP) in infected but not wt mice, we studied the cellular distribution of PrP by confocal microscopy. The majority of pathologic PrP collected on the plasma membrane of FDC, as identified by the Ca(+2)-binding protein S100A. This surface distribution suggested that agent aggregated with pathologic PrP might spread by cell-to-cell contacts. While several types of leukocytes may be involved in agent dissemination, cells of myeloid lineage were found to be infectious. Moreover, perivascular tracks of microglia and abnormal PrP after intraperitoneal inoculation were consistent with hematogenous spread. In summary, FDC are not required for CJD agent spread from the periphery, although FDC may enhance spread through surface accumulation of pathologic PrP. While it is still not clear where the infectious agent replicates, macrophages can sequester appreciable levels of infectivity and hence act as reservoirs for prolonged latent infection.

Immunoreactivity of the monoclonal antibody F89/160.1.5 for the human prion protein

Monoclonal antibodies (Mab) to the prion protein (PrP) have been critical to the neuropathological characterisation of PrP-related diseases in human and animals. Although PrP is highly evolutionary conserved, there is some sequence divergence among species. We have analysed the F89/160.1.5 Mab raised against the bovine prion protein for immunoreactivity with the human prion protein. The antibody recognised the IHFG epitope of the prion protein. An analysis of the Swiss Prot database confirmed conservation of the epitope in humans. Further immunohistochemical (IHC) analysis showed a highly sensitive (final concentration 55 ng/ml) and specific antibody for prion detection in humans. The observed immunoreactivity of the prion protein did not differ from that observed after staining with the well-known 3F4 (Senetek) monoclonal antibody.

Microglial activation varies in different models of Creutzfeldt-Jakob disease

Progressive changes in host mRNA expression can illuminate crucial pathogenetic pathways in infectious disease. We examined general and specific approaches to mRNA expression in three rodent models of Creutzfeldt-Jakob disease (CJD). Each of these models displays distinctive neuropathology. Although mRNAs for the chemokine receptor CCR5, the lysosomal protease cathepsin S, and the pleiotropic cytokine transforming growth factor beta1 (TGF-beta1) were progressively upregulated in rodent CJD, the temporal patterns and peak magnitudes of each of these transcripts varied substantially among models. Cathepsin S and TGF-beta1 were elevated more than 15-fold in mice and rats infected with two different CJD strains, but not in CJD-infected hamsters. In rats, an early activation of microglial transcripts preceded obvious deposits of prion protein (PrP) amyloid. However, in each of the three CJD models, the upregulation of CCR5, cathepsin S, and TGF-beta1 was variable with respect to the onset of PrP pathology. These results show glial cell involvement varies as a consequence of the agent strain and species infected. Although neurons are generally assumed to be the primary sites for agent replication and abnormal PrP formation, microglia may be targeted by some agent strains. In such instances, microglia can both process PrP to become amyloid and can enhance neuronal destruction. Because microglia can participate in agent clearance, they may also act as chronic reservoirs of infectivity. Finally, the results here strongly suggest that TGF-beta1 can be an essential signal for amyloid deposition.

Heightened intrathecal release of proinflammatory cytokines in Creutzfeldt-Jakob disease

The authors report high intrathecal release of tumor necrosis factor alpha (TNF-alpha) and interleukin (IL)-1beta in five patients with sporadic or new-variant Creutzfeldt-Jakob disease (CJD) without activation of the humoral or lymphocytic immune responses. Increased release of TNF-alpha and IL-1beta was also detected in some patients with progressive dementias. CJD is associated with a local cerebral host response that involves the release of proinflammatory cytokines.

An antibody raised against a conserved sequence of the prion protein recognizes pathological isoforms in human and animal prion diseases, including Creutzfeldt-Jakob disease and bovine spongiform encephalopathy

Antibodies to the prion protein (PrP) have been critical to the neuropathological and biochemical characterization of PrP-related degenerative diseases in humans and animals. Although PrP is highly conserved evolutionarily, there is some sequence divergence among species; as a consequence, anti-PrP antibodies have a wide spectrum of reactivity (from strong immunopositivity to lack of reactivity) when challenged with PrP from diverse species. We have produced an antibody (anti-PrP95-108) raised against a synthetic peptide corresponding to residues 95 to 108 of human PrP and have characterized it by epitope mapping, Western immunoblot analysis, and immunohistochemistry. The antibody recognizes not only human PrP isoforms but also pathological PrP from all species tested (ie, cattle, sheep, hamsters, and mice). This is probably due to the fact that the epitope recognized by this antibody includes residues 100 to 108 of human PrP, a sequence that is also present in PrP of several other species. Thus, this reagent is valuable not only for the study of human prion diseases but also for analysis of the possible relationship between human and animal disorders.

Vaccination with an attenuated Creutzfeldt-Jakob disease strain prevents expression of a virulent agent

Although slow and persistent viruses often escape host defenses infection may be prevented by live vaccines. To determine whether an attenuated "slow" strain of the Creutzfeldt-Jakob disease agent (SY) could block expression of a virulent "fast" strain (FU), outbred CD-1 mice were inoculated intracerebrally with low infectious doses of SY and challenged 80 days later with higher doses of FU. For comparison, the same SY and FU samples were inoculated in two parallel control groups. All 18 superinfected mice showed incubation times identical to those inoculated with only the SY strain, yielding clinical disease >110 days later than predicted for the FU strain. Neurological signs, such as scratching and an extended clinical phase, were also characteristic for SY but not FU infection. Moreover, the widespread cortical pathology of FU was not detectable in superinfected mice. Western blot analyses further showed no strain-specific differences in prion protein (PrP) band profiles for all experimental groups, although there was approximately 10-fold more protease-resistant PrP (PrP-res) in FU brains during terminal disease. In contrast, infectivity assays revealed an approximately 10,000-fold difference between SY and FU at terminal stages, indicating that PrP-res content does not correlate with infectivity. In summary, an attenuated strain of the Creutzfeldt-Jakob disease agent evokes substantial interference against a virulent agent. Because superinfected mice had little PrP-res just before the onset of clinical disease and retained abundant cellular PrP, cellular PrP was not the factor limiting FU replication. The mechanisms underlying SY interference are not understood but could be based on host recognition of foreign molecular features shared by this class of invasive agents involving antibody production, and possibly involve defective viral particles produced by attenuated variants.

Polymorphism at codon 129 of the prion protein gene determines cerebellar pathology in Creutzfeldt-Jakob disease

Creutzfeldt-Jakob disease (CJD) is a transmissible neurodegenerative disorder characterized by the accumulation of proteinase-resistant prion protein (PrP) in the brain. Pathological changes in the cerebellum are common and include atrophy of the granular layer, spongiform change in the molecular layer, and astrocytic gliosis of the cerebellar cortex and white matter. In most cases of sporadic CJD immunohistochemistry for PrP shows widespread granular deposits of the scrapie isoform of the prion protein (PrPSc) in the cerebellar cortex. In a minority of cases plaque-like deposits of PrPSc are detectable. The genetic background of this phenomenon was investigated in 47 cases of sporadic CJD. Immunohistochemistry using antibodies against PrP was performed in brain autopsy specimens. A genetic analysis of the prion protein gene (PRNP) showed overrepresentation of homozygosity for either methionine (M/M) or valine (V/V) at the polymorphic codon 129 in CJD patients as compared to 74 controls. No significant difference in allele frequency between the 2 groups was found. Plaques or plaque-like PrPSc deposits were found in 9 cases of CJD and were associated with the presence of valine at codon 129 on at least 1 allele of PRNP. CJD patients homozygous for valine (V/V) were on an average more than 5 years younger than patients with M/M or M/V at codon 129.

Immunhistological evaluation of Creutzfeldt-Jakob disease with reference to the type PrPres deposition

German patients suspected of having Creutzfeldt-Jakob disease (CJD) and related diseases were studied pathologically. The immunohistochemical findings after hydrolytic autoclaving pretreatment sensitively detected the synaptic-type deposition of the protease-resistant isoform of the prion protein (PrPres which thus served to establish the consensus diagnosis of CJD.

Proliferating cell nuclear antigen immunohistochemistry in astrocytes in experimental Creutzfeldt-Jakob disease and in human kuru, Creutzfeldt-Jakob disease and Gerstmann-Sträussler-Scheinker syndrome

We have used immunohistochemical techniques and a monoclonal antibody against proliferating cell nuclear antigen (PCNA) to investigate the proliferative activity of glial cells in mice with experimental Creutzfeldt-Jakob disease (CJD), and in human cases of CJD, kuru and Gerstmann-Sträussler-Scheinker syndrome (GSS). Only a small proportion of hypertrophic astrocytes showed PCNA immunoreactivity (labelling index, LI: 0-4.5%). PCNA-specific immunostaining was confined entirely to cell nuclei. During the early stages of illness, with minimal CJD pathology, PCNA-immunopositive nuclei were occasionally observed in the subependymal zone of experimentally infected mice. From 18 weeks postinoculation, PCNA-immunopositive astrocytes were most frequently found in the corpus callosum and cerebellar white matter; regions which characteristically exhibit robust vacuolation. No other cells, particularly no cells of microglial morphology, showed PCNA immunoreactivity. In human cases of kuru, CJD and GSS, no PCNA-immunopositive cells were detected despite the presence of numerous microglial cells and reactive hypertrophic astrocytes. These results indicate that only a limited proportion of astrocytes proliferate in the experimental models of subacute spongiform encephalopathies and that microglia are probably postmitotic cells.

Immunohistochemical study of microglia in the Creutzfeldt-Jakob diseased brain

Immunohistochemical techniques have been used to investigate microglial reaction in Creutzfeldt-Jakob diseased (CJD) brains. Autopsy cases of six patients with CJD and age-matched controls were studied. Formalin-fixed, paraffin-embedded brain tissue samples were stained with antibodies against major histocompatibility complex (MHC) class II antigen (Ag), leukocyte common antigen (LCA), CDw75, CD68 and glial fibrillary acidic protein. Of the patients with CJD, two with a subacute spongiform encephalopathic type and short-survival periods after onset of the disease showed an increased number of reactive microglia labeled with anti-MHC class II Ag or LCA in the affected cerebral cortex. In advanced cases of the panencephalopathic type of CJD, in which both cerebral atrophy and astrocytosis were marked, the increase of reactive microglia was small. Some vacuoles developing in the neuropil of the CJD patients were surrounded by MHC class II Ag- or LCA-immunoreactive microglial cells. The number of ramified microglia in the affected lesions was decreased, although their number in the hippocampus was not affected. These results indicate that microglia can frequently be involved in the process of CJD and may be activated at the early stage of the disease.

Ultrastructural and immunohistochemical studies on ballooned cortical neurons in Creutzfeldt-Jakob disease: expression of alpha B-crystallin, ubiquitin and stress-response protein 27

This report concerns ultrastructural and immunohistochemical studies on ballooned neurons of ten patients with Creutzfeldt-Jakob disease (CJD). While abundant ballooned neurons and severe white matter degeneration was seen in six Japanese cases, only occasional ballooned neurons and no white matter degeneration was observed in four cases from the files of Montefiore Medical Center. Ultrastructurally, the ballooned neurons contained granule-coated fibrils of 25 to 40 nm in width and 10-nm neurofilaments. The immunohistochemical studies revealed that most ballooned neurons expressed alpha B-crystallin, with deposits of reaction products observed in the cytoplasm. A similar intracellular staining pattern was also seen with the antibody to phosphorylated neurofilament proteins (pNFP). Although the proportion of stained ballooned neurons was less, a positive reaction was also observed with antibodies against ubiquitin, stress-response protein 27 (srp 27) and synaptophysin, but not with an antibody to srp 72. Our findings suggest that expression of pNFP and synaptophysin by ballooned neurons may reflect axonal impairment and that the presence of alpha B-crystallin, srp 27 and ubiquitin may be related to the degenerative processes that neurons undergo in CJD.

Immunohistochemical study of kuru plaques using antibodies against synthetic prion protein peptides

Prion protein (PrP) is a protein closely associated with the transmission of scrapie and Creutzfeldt-Jakob disease (CJD). Kuru plaques are composed of this protein. PrP33-35 is converted to protease-resistant PrP27-30 by proteinase K digestion. It has not yet been determined which of these PrPs is present in kuru plaques in vivo. Accordingly we synthesized two peptides (peptide-N and peptide-M) that, respectively, corresponded to the protease-sensitive and protease-resistant portions of PrP33-35, based on the amino acid sequence deduced from human PrP cDNA. These two synthetic peptides were used to immunize rabbits and produce antisera (anti-N and anti-M). Both antisera stained kuru plaques in a patient with Gerstmann-Sträussler syndrome and one with CJD. Peptide-N has an amino acid sequence which does not exist in PrP27-30. Staining of kuru plaques by the antiserum against peptide-N indicated that the entire molecule, including the N-terminal portion of PrP33-35, was deposited in the kuru plaques.