Development of an ultrasensitive enzyme immunoassay for the determination of matrix metalloproteinase-9 (MMP-9) levels in normal human cerebrospinal fluid.

Determination of matrix metalloproteinase-9 (MMP-9) in human cerebrospinal fluid (CSF) to study blood-brain barrier impairment and immune cell migration in inflammatory neurological diseases recently became a matter of major interest. Regularly, MMP-9 was determined qualitatively or semi-quantitatively by zymography (gelatin gel electrophoresis) or quantitatively by enzyme immunoassay (EIA). As yet, it was not possible by either method to detect MMP-9 in CSF of controls (patients without pathologically increased CSF parameters). We developed an ultrasensitive two-side enzyme-linked immunosorbent assay (ELISA) which allows for the first time to measure reliably MMP-9 concentrations in CSF of controls. This ELISA uses a monoclonal as capture and a polyclonal as detector antibody. The detection limit of the assay is below 10 pg/ml and the assay range is 15-2000 pg/ml. Intra-assay precision is 2.5% for low and 3.7% for high, inter-assay precision is 11% for low and 10.7% for high values, respectively. The determination of the MMP-9 concentration in 50 control CSF gave the following results: range, 22-146 pg/ml; median, 76 pg/ml. The measurement of native and recombinant MMP-9 was carried out with three commercially available ELISAs, most widely employed in MMP-9 research, and compared to the newly developed one. All ELISAs recognize recombinant MMP-9 by factors of 5-20 less sensitively than native MMP-9.

Characterization of the human T cell response against the neuronal protein synapsin in patients with multiple sclerosis.

Although multiple sclerosis (MS) is considered primarily as a demyelinating disease, neuronal damage is abundant and correlates with the neurological deficit. Therefore, we investigated the frequency and characteristics of human T cells specific for synapsin-a neuronal protein highly conserved among species. Synapsin specific T cell responses were detected at a frequency similar to that of MBP specific T cells in MS patients, one patient with acute demyelinating encephalomyelitis (ADEM) and controls. Long-term T cell lines specific for synapsin exhibited a CD3(+), CD4(+), CD8(-) phenotype and produced high amounts of tumor-necrosis-factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) after antigen specific stimulation, whereas lymphotoxin (LT), interleukin-4 (IL-4) and interleukin-10 (IL-10) were detectable in smaller quantities.

Migration of human granulocytes through reconstituted basement membrane is not dependent on matrix metalloproteinase-9 (MMP-9).

Transmigration of human granulocytes across a basal lamina equivalent was studied in vitro. Transwell inserts were coated with Matrigel, a reconstituted basement membrane. Granulocytes (2x10(6)) were applied to the upper chamber. As chemoattractant interleukin-8 (IL-8; 25 ng/ml) was added to the lower chamber. After 1 h of migration, cells were counted in the lower chamber. Specific hydroxamate inhibitors of MMPs (BB-3103, Ro 31-9790) or of serine proteases (Pefabloc, leupeptin) were added at various concentrations to both chambers before the start of migration. Additional experiments were performed with alpha(2)-macroglobulin, a natural inhibitor of MMPs and a monoclonal antibody which specifically blocks the activity of MMP-9. Migration of granulocytes through Matrigel could not be reduced significantly by any of the MMP inhibitors. A dose-dependent impairment of transmigration was only found with Pefabloc, however, this substance also induced severe morphological changes of the cells. The other inhibitor of serine proteases, leupeptin, did not influence migration at all.

Matrix metalloproteinase-9 is elevated in serum of patients with amyotrophic lateral sclerosis.

Matrix metalloproteinase-9 (MMP-9) and its specific inhibitor, tissue inhibitor of matrix metalloproteinase-1 (TIMP-1), were analysed by enzyme-linked immunosorbent assay (ELISA) and by zymography in serum and cerebrospinal fluid (CSF) of patients with amyotrophic lateral sclerosis (ALS). In contrast to patients with inflammatory diseases, MMP-9 levels were not elevated in CSF of ALS patients. In serum, however, compared to healthy donors, MMP-9 was significantly (p = 0.0003) increased up to levels as high as those of viral meningoencephalitis (VM) or bacterial meningitis (BM) patients. MMP-9 levels remained elevated during long-term observation of ALS patients. In the absence of an inflammatory response, the results indicate that the increase of MMP-9 in serum of ALS patients might be caused by upregulation of MMP-9 in denervated muscles or in degenerating peripheral nerves following motor neurone loss.

Matrix metalloproteinase-9 (MMP-9) in human cerebrospinal fluid (CSF): elevated levels are primarily related to CSF cell count.

Matrix metalloproteinase-9 (MMP-9) was investigated by enzyme-linked immunosorbent assay (ELISA) and zymography in 111 paired CSF and serum samples from patients with various neurological disorders. In 20 patients with blood-brain barrier (BBB) impairment but normal CSF cell count, elevated levels of MMP-9 were not observed by ELISA measurement. Another 11 patients characterized in the same way, exhibited only slightly increased MMP-9 levels. In contrast, in 12 patients with intact BBB but elevated CSF cell count, MMP-9 was increased too. It was shown by the more sensitive zymography that MMP-9 increased if CSF cell count exceeded five cells per microl. Spearman rank statistics revealed that MMP-9 concentration in CSF correlated with CSF cell count (r=0.755; P<0.0001), but not with CSF/serum albumin ratio (Q(Alb)) (r=0.212; P=0.057), a measure for BBB impairment. Moreover, the CSF/serum MMP-9 ratio (Q(MMP-9)) did not correlate with Q(Alb)(r=0.192; P=0.100). By use of a Boyden chamber, in which granulocytes migrated through a reconstituted basement membrane, it was demonstrated that the MMP-9 concentration in the lower chamber correlated very significantly with the number of accumulated cells (r(2)=0.7692; P<0.0001). The meaning of the increase of MMP-9 in CSF is critically discussed.

How to improve the clinical diagnosis of Creutzfeldt-Jakob disease.

This paper describes a prospective follow-up of 364 patients initially notified as suspected Creutzfeldt-Jakob disease to a Surveillance Unit in Göttingen, Germany. Six patients were diagnosed as having genetic prion disease by blood analysis and were excluded from the study. After examination and review of the remaining 358, 193 were classified as probable Creutzfeldt-Jakob disease. However, autopsy revealed that five of the 193 did not have Creutzfeldt-Jakob disease (four cases, Alzheimer's disease; one case, cerebral lymphoma). Of the 54 patients classified as possible Creutzfeldt-Jakob disease, 10 had another diagnosis made at autopsy. Two of the 111 cases originally classified as having other diseases were found to have Creutzfeldt-Jakob disease on autopsy. Autopsy evidence, together with follow-up of the patients still living and those who died without autopsy, revealed a broad range of other diagnoses. In the younger age groups, the commonest were chronic inflammatory diseases including Hashimoto encephalitis, whilst rapidly progressive Alzheimer's disease was most common in the older age groups. The presence of 14-3-3 protein in the CSF discriminated better between Creutzfeldt-Jakob disease and other rapidly progressive dementias than did the EEG pattern or the MRI. The inclusion of this CSF protein in the criteria of Masters and colleagues (Ann Neurol 1979; 5: 177-88) improves the accuracy and confidence in the clinical diagnosis of Creutzfeldt-Jakob disease.

Cisternal S100 protein and neuron-specific enolase are elevated and site-specific markers in intractable temporal lobe epilepsy.

In the brain, S100 protein and neuron-specific enolase (NSE) are mainly found in glial cells and neurons, respectively. We investigated concentrations of S100 protein and NSE in cisternal cerebrospinal fluid obtained during implantation of foramen ovale electrodes in eight patients with temporal lobe epilepsy (TLE). In addition, the meningeal markers cystatin-C and beta-trace as well as total protein were measured. Patients with trigeminal neuralgia (TN) undergoing glycerol rhizotomy served as controls. S100 protein and NSE levels ipsilateral to the site of seizure onset were significantly higher than in TN. Contralateral TLE values were also markedly but not significantly elevated. The meningeal markers cystatin-C and beta-trace protein as well as total protein did not differ in TLE and TN. We conclude that interictal temporal lobe dysfunction corresponds with neuronal and glial marker elevations in the extracellular space and that site-specific elevations may predict the site of seizure origin biochemically.

Hashimoto's encephalitis as a differential diagnosis of Creutzfeldt-Jakob disease.

OBJECTIVES: During an epidemiological study of Creutzfeldt-Jakob disease in Germany, Hashimoto's encephalitis was encountered as a differential diagnosis, which has not yet been described in this context. METHODS: The symptoms and findings of seven patients who fulfilled the criteria for "possible" Creutzfeldt-Jakob disease are presented. RESULTS: A Hashimoto's thyroiditis with antibodies against thyroglobulin or thyroid peroxidase, or both and a hypoechoic thyroid ultrasonogram were found in all cases. Analysis of CSF disclosed an increased leucocyte count in three patients, and a raised CSF:serum concentration ratio of albumin (QA1b) in four patients. The 14-3-3 protein, typical of Creutzfeldt-Jakob disease, could not be detected in any of our patients. No periodic sharp wave complexes, which are typical of Creutzfeldt-Jakob disease, were detected on EEG in any of the cases. By contrast with Creutzfeldt-Jakob disease, which leads to death within a few months, the patients with Hashimoto's encephalitis often recover quickly when treated adequately. All the patients improved after administration of corticosteroids. CONCLUSION: The clinical symptomatology of both diseases may be very similar: dementia, myoclonus, ataxia, and personality change or psychotic phenomena are characteristic symptoms.

Beta-trace protein in cerebrospinal fluid: a blood-CSF barrier-related evaluation in neurological diseases.

Beta-trace protein concentrations in cerebrospinal fluid (CSF) and serum from 113 patients with various neurological diseases and 65 controls were determined with a sensitive and specific immunonephelometric assay. In adult control patients, beta-trace concentrations were 14.6+/-4.6 mg/L in CSF and 0.46+/-0.13 mg/L in serum, that is, 32-fold higher in CSF. beta-trace levels in CSF correlated with age as well as with the albumin CSF/serum ratio (Q(Alb)), which is considered a measure for blood-CSF barrier function. The relationship between CSF beta-trace levels and elevated Q(Alb) values was studied in various neurological diseases with CSF protein increase. In spinal canal stenosis, CSF beta-trace (mean=29.5+/-10.5 mg/L) correlated positively with increasing Q(Alb) values. In bacterial meningitis, CSF beta-trace (mean=8.7+/-3.9 mg/L) remained invariant to changes of Q(Alb) values. In Guillain-Barré syndrome, CSF beta-trace (mean=14.4+/-6.8 mg/L) was below the Q(Alb)-dependent reference range. In multiple sclerosis and viral meningoencephalitis, beta-trace levels were within the reference range. Beta-trace concentration in CSF can be used in conjunction with Q(AlB) to distinguish between different neurological pathologies associated with CSF protein increase.

Correlation of soluble adhesion molecules in blood and cerebrospinal fluid with magnetic resonance imaging activity in patients with multiple sclerosis.

Several studies have reported a positive correlation between levels of soluble adhesion molecules in serum or cerebrospinal fluid and cranial MRI activity. We performed a cross-sectional study in 46 patients with newly diagnosed MS and determined levels of soluble intercellular adhesion molecule-I (sICAM-I) as well as vascular cell adhesion molecule-I (sVCAM-I) in correlation to the number and area of gadolinium enhancing lesions on cranial magnetic resonance images (MRI). The data revealed a significant positive correlation between sVCAM-I serum levels and gadolinium enhancing lesions. In addition, CSF to serum ratios for sICAM-I and sVCAM-I correlated to MRI activity. In patients with a single enhancing lesion (SEL) there was a negative correlation between the QsCAM and the distance of the SEL to the ventricles. As these adhesion molecules are stable and markers of disease activity in MS, we further investigated sVCAM-I serum levels during treatment with interferon beta-Ib (Betaferon). Significant increases in serum levels for sVCAM-I in patients receiving Betaferon were associated with a favourable treatment response after 1 year in 17 out of 19 patients and correlated to decreased MRI activity, whereas stable or reduced sVCAM-I levels occurred more often in non-responders (five out of six patients). Therefore it can be hypothesized that soluble adhesion molecules are released from cerebral endothelial cells as an early immunoregulatory activity of the immune system to reduce cellular traffic across the blood brain barrier and this is further enhanced by IFN-beta treatment.

Determination of synapsin I and synaptophysin in body fluids by two-site enzyme-linked immunosorbent assays.

Two-site enzyme-linked immunosorbent assays (ELISA) have been established for the specific and sensitive determination of two membrane proteins of the small synaptic vesicles (SSV), namely: peripheral synapsin I and integral synaptophysin. The ELISA used highly specific capture monoclonal antibodies (mAB) and polyclonal antibodies (pAB) as detectors. For synapsin I, the mAB were newly generated, whereas for synaptophysin, the commercially available mAB SY38 was applied. In order to calibrate the ELISA and to raise pAB, both proteins were purified in the mg-range. Synapsin I was purified by conventional means from human and porcine brain and synaptophysin was purified by immunoaffinity chromatography from porcine brain. Using the ELISA, neither synapsin I nor synaptophysin could be determined in serum or cerebrospinal fluid (CSF) from healthy donors or patients suffering various neurological disorders or pheochromocytomas. For this reason, the degradation of both proteins in serum and CSF was investigated. With the exception of synaptophysin measured in serum, both proteins exhibited fast rates of degradation. Despite the negative results in human body fluids, the two ELISA are appropriate for the quantification of these membrane proteins in neuronal or neuroendocrine cell extracts or preparations of SSV.

Serum levels of macrophage-derived protein MRP-8/14 are elevated in active multiple sclerosis.

Serum concentrations of two macrophage-derived calcium-binding proteins, MRP-8 and MRP-8/14, were studied in 28 patients with relapsing multiple sclerosis (MS). Serum levels were determined with a commercially available sandwich ELISA and the one-tailed Mann-Whitney U test was used for statistical analysis. Median serum levels of MRP-8/14 were significantly higher in MS patients (5150 ng/ml) compared to 26 healthy controls (1482 ng/ml) and significantly higher in MS patients within an acute relapse (6690 ng/ml) compared to MS patients with stable disease (3050 ng/ml). MRP-8 levels were not elevated in MS patients. These results may indicate an early activation of macrophages in the formation of demyelinating MS plaques. In addition, increased serum levels of MRP-8/14 may prove to be a useful paraclinical disease activity parameter in MS patients.

Acute optic neuritis: combined immunological markers and magnetic resonance imaging predict subsequent development of multiple sclerosis. The Optic Neuritis Study Group.

The diagnostic significance of intrathecally synthesized IgG and virus-specific antibodies to measles, rubella and varicella-zoster (MRZ) in cerebrospinal fluid (CSF) remains controversial in cases of acute optic neuritis (AON). This study evaluates the prognostic value of baseline CSF and serum markers in AON, and correlates them with magnetic resonance imaging (MRI) and progression to multiple sclerosis (MS). Paired CSF and serum samples from 36 AON patients, 26 MS patients and 22 controls were analyzed for albumin, IgG, oligoclonal IgG (OI), MRZ antibodies, and blood-CSF barrier function; baseline MRI scanning of the head was also performed. The most sensitive parameter for detection of intrathecal inflammation in AON was OI (75%). Baseline MRI scans revealed abnormalities in 46% of the 28 patients with AON. Fifty percent of AON patients developed MS over the following 4 years. Ninety four percent of patients progressing to MS were positive for either OI, MRI or both. Of the AON patients initially positive for MRI and intrathecally-produced MRZ antibodies, 86% developed MS after 4 years. Only 17% of AON patients with negative results for OI and MRI developed MS. Six patients with abnormal OI but normal MRI progressed to MS. CSF and serum analyses, together with MRI, are the methods of choice for prognostic evaluation of patients with AON.

Beta-trace protein concentration in cerebrospinal fluid is decreased in patients with bacterial meningitis.

Although meninges represent a major site of biosynthesis, beta-trace protein (beta-trace) has not been studied in the cerebrospinal fluid (CSF) of meningitis patients. We measured beta-trace in lumbar CSF of normal controls (n = 27) and in patients with various neurological diseases (n = 92) by an immunonephelometric assay. The mean concentration of beta-trace in CSF of control patients was 16.6+/-3.6 mg/l. In bacterial meningitis (n = 41), CSF beta-trace was significantly decreased (8.7+/-3.9 mg/l; P< 0.001), whereas in spinal canal stenosis it was elevated (29.2+/-10.3 mg/l; P= 0.002). In viral meningoencephalitis (n = 12), beta-trace CSF concentrations were normal. Beta-trace concentrations remained below the normal range even after curing of bacterial meningitis, and normalisation of CSF leucocytes and blood-CSF barrier function. Beta-trace may be a useful tool for studying the pathophysiology of bacterial meningitis.

A method for preventing artifactual binding of cRNA probes to neurons caused by in situ hybridization.

When in situ hybridization was used for the detection of mRNA for the beta-trace protein (beta-trace; prostaglandin-D-synthase) in sections of rat and porcine brains, unspecific binding reactions of sense and antisense probes to neurons were observed. The beta-trace fragment which served as a template for the synthesis of cRNA probes was blunt end-cloned in the vector pCR-Script SK (+). It was demonstrated that the unspecific signals were caused by artifactual binding of two portions of the cRNA which correspond to sequences of the multicloning site of this vector. These sequences are localized between the SrfI restriction site (or the insert) and the promoter for the T7 RNA polymerase. Thus, artifactual binding could be prevented using riboprobes synthesized by T3 RNA polymerase instead of T7 RNA polymerase. Because of the relatively weak transcription efficiency of T3 RNA polymerase, as compared with T7 RNA polymerase, a blocking procedure was established which allowed successful in situ hybridization with T7 RNA polymerase-synthesized probes. Blocking was performed using synthetic oligonucleotides deduced from the two sequences of the multicloning site which were found to be responsible for artifactual binding.

Characterization of monoclonal and polyclonal antibodies to human choline acetyltransferase and epitope analysis.

Choline acetyltransferase (ChAT) was partially purified from human placenta and brain. In order to raise monoclonal antibodies, Balb/c mice were immunized with a preparation from placenta or with a mixture of eight synthetic peptides that were deduced from the primary structures of porcine and human ChAT. Polyclonal antibodies were raised in rabbits against five synthetic peptides deduced from the amino acid sequence of human ChAT. The monoclonal and polyclonal antibodies were characterized by their ability to recognize ChAT in various immunoassays: immunoblot, enzyme-linked immunosorbent assay (ELISA), two-side ELISA and immunohistochemistry. With one exception all monoclonal antibodies recognized ChAT on immunoblots, some were particularly sensitive; one bound active ChAT in ELISA when used as capture reagent; most antibodies recognized immobilized ChAT in ELISA. Two monoclonal antibodies out of nine gave particularly excellent results in staining cholinergic neurons and fibers on sections from rat and primate brain. With the help of nine synthetic peptides it was possible to evaluate two major binding sites for the monoclonal antibodies on the ChAT molecule, comprising amino acids 167-189 and 57-76, respectively.

[The Creutzfeld-Jakob disease. A sphinx of current neurobiology]. / Die Creutzfeldt-Jakob-Krankheit. Eine Sphinx der heutingen Neurobiologie.

BACKGROUND: Prospective epidemiological studies are being employed to determine the incidence and possible risk factors of Creutzfeldt-Jakob disease (CJD) in five European countries in which bovine spongiform encephalopathy (BSE) occurs at different rates of incidence. PATIENTS AND METHODS: Using a voluntary reporting system throughout the Federal Republic of Germany, suspected cases of CJD were investigated and the incidence calculated. Possible risk factors in patients and control groups were obtained by questionnaire. Serum and cerebrospinal fluid samples served to delineate genetic forms and distinguish the disease from other major dementias. RESULTS: A total of 544 patients with suspected CJD, reported in Germany between 1993 and 1997, were examined. 232 (plus 27 investigated only neuropathologically) were confirmed as definite or probable, an annual incidence per million population of between 0.76 (for 1994) and 0.98 (for 1995), similar to figures from other European countries. In Great Britain, the cases of "new variant" CJD, not yet observed in Germany, were excluded from the calculation of incidence. So far, dementia in the family and handling of horn shavings have been identified as risk factors. A rise in the concentrations of neurone-specific enolase and of S100 protein as well as the demonstration of certain proteins in cerebrospinal fluid (p130/ 131 and 14-3-3, respectively) have been shown as being diagnostically superior to EEG changes. INTERPRETATION: There has so far been no increase in the incidence of CJD within Europe. However, the occurrence of the new variant in Great Britain requires long-term monitoring. The diagnostic criteria used for this can be improved by biochemical methods.

Establishment of an efficient enzyme-linked immunosorbent assay for the determination of human choline acetyltransferase.

A specific and sensitive two-side enzyme-linked immunosorbent assay (sandwich-ELISA) was established for the reliable quantification of human brain and placental choline acetyltransferase (ChAT). In contrast to the radiometric assay developed by Fonnum, which is widely used for the measurement of enzyme activity, the sandwich-ELISA particularly recognized inactivated forms of the antigen. In the assay, affinity-purified polyclonal synthetic peptide antibodies adsorbed to the polystyrene surface of the microtiter plate were employed as capture reagent. Based on standard peroxidase protocols, immobilized ChAT was detected using monoclonal antibodies raised against human placental ChAT. By use of this ELISA, ChAT was determined at various purification stages of the enzyme, in body fluids, during recovery experiments and in sera of patients with severe brain damage.

Detection of T cells reactive to intestinal alkaline phosphatase, an autoantigen in acute bacterial infections, and discrimination between autoantigen-specific CD5+ and CD5- B cells.

Autoantibodies of the IgG isotype, specifically directed against intestinal alkaline phosphatase (IAP), occur transiently in the majority of sera from patients with acute bacterial infections. Sometimes they are observed in autoimmune diseases. Using a T cell proliferation assay, it was found that isolated peripheral blood mononuclear cells (PBMC) from IAP autoantibody (IAPA)-positive patients (n = 18) responded significantly to IAP, whereas proliferation could not be induced in PBMC from healthy donors (n = 11). Significant stimulation of PBMC from patients (n = 11) was not obtained by use of transferrin, a common autoantigen in humans, indicating the specificity of stimulation of IAP-reactive T cells. Furthermore, T cell proliferation was observed when a highly purified IAP fragment (CNBr 21) spanning amino acids 334-462 of the primary structure of IAP was used as antigen. Thus, it was shown that an immunodominant T cell epitope resides within the CNBr 21 fragment which also contains a discontinuous B cell epitope as evaluated previously. Double immunocytochemical staining of T cell-depleted PBMC with IAP and an anti-human CD5 antibody allowed the detection of CD5+ B lymphocytes, which probably produce natural IAPA (nIAPA). These nIAPA-specific CD5+ B cells occurred with approximately the same frequency among T cell-depleted PBMC from healthy donors and those from patients. In contrast, IAPA-producing CD5- B cells were found in B cell-enriched preparations from patients, but not in those from healthy individuals.