J. Gheuens

Monoclonal antibodies with selective specificity for Alzheimer Tau are directed against phosphatase-sensitive epitopes.

SummaryA modified form of the microtubule-associated protein Tau is the major component of the paired helical filaments (PHF) found in Alzheimers disease. The characterization of these posttranslational Tau modifications is hindered by the lack of sufficient PHF-Tau-specific markers. Here we describe several monoclonal antibodies, prepared by immunization with PHF, two of which showed a selective specificity for PHF-Tau without cross-reactivity with normal Tau. Epitope recognition by these two monoclonals was sensitive to alkaline phosphatase treatment. In Western blotting these monoclonal antibodies reacted specifically with the abnormally phosphorylated epitopes on Alzheimers disease-associated PHF-Tau. One of the new antibodies can be used for the construction of a sandwich enzyme-linked immunosorbent assay for the specific detection of PHF-Tau without cross-reactivity to normal Tau proteins.

Early‐onset Alzheimer's disease in 2 large Belgian families

Familial Alzheimers disease (FAD) is a dominantly inherited condition that may present with an early onset, and myoclonus occurs frequently in the course of the disease. We report clinical and neuropathologic data on 2 large Belgian families with FAD in which we obtained 17 autopsies of the CNS. In family A, each of 11 autopsies had the typical neuropathologic features of Alzheimers disease (AD), and there were a few cerebellar plaques in the molecular layer. In family B, in addition to the typical characteristics of AD in 6 autopsies, there were numerous amyloid plaques in the cortical cerebellar layers. In both families, we immunostained the amyloid deposits for the A4 protein, and they were negative for prion-associated protein immunoreactivity.

Affinity Purification of Human τ Proteins and the Construction of a Sensitive Sandwich Enzyme‐Linked Immunosorbent Assay for Human τ Detection

Abstract: Immunoaffinity chromatography with a monoclonal antibody produced against bovine τ protein was used to purify τ proteins from human brain. Fifty grams of brain tissue yielded τ 2 mg of pure τ proteins. The affinity‐purified human τ was used to produce a high‐titered rabbit anti‐human τ serum. The monoclonal anti‐τ antibody and the polyclonal rabbit anti‐τ serum were then used to construct a sandwich enzyme‐linked immunosorbent assay for detection of human τ proteins, with a sensitivity of 1 ng/ml.

A two-site immunoradiometric assay for the determination of α-albumin

Abstract • A two-site immunoradiometric assay for a brain specific protein (α-albumin or glial fibrillary acidic protein) is described which may be applied to other proteins. The assay variables studied are immunoadsorbent dilution, temperature, incubation times, reactivity of the labelled antibodies and effect of the washing. Each of these factors is optimalised, resulting in a sensitive, specific, reliable assay. • The working range is 5–5000 ng/ml, the within-assay variance is 5%. No high dose hook effect is seen in this range. The method is applied for the measurement of α-albumin present in cerebrospinal fluid, nervous tissue extracts and cell cultures.

Identification of Several Forms of the Glial Fibrillary Acidic Protein, or α‐Albumin, by a Specific Monoclonal Antibody

Abstract: A monoclonal antibody (mAb), termed UIA/ NEU/I/G1 (G1), that reacted with the astroglial marker glial fibrillary acidic protein (GFAP), or α‐albumin, is described. It was directed against a structural determinant of GFAP. The G1 mAb could be used for quantitative determination of GFAP in two‐site radiometric assays and for histoimmunological demonstration of GFAP. The G1 mAb reacted with the GFAP from rat as well as from man. The presence of several different molecular weight forms of GFAP in aqueous and detergent extracts from human brain was shown with the G1 mAb. The possible meaning of these forms is discussed.

Human γγ‐Enolase: Two‐Site Immunoradiometric Assay with a Single Monoclonal Antibody

Abstract: A monoclonal antibody (mAb), termed BBS/NC/VI‐H14 (H14), that reacts with the human enzyme γγ‐enolase was prepared. It was directed against the γ‐subunit and did not cross‐react with the α‐ or β‐subunit. The mAb H14 can be used for quantitative determination of γγ‐enolase in a two‐site immunoradiometric assay (two‐site IRMA). It is also suitable for immunostaining formalin‐fixed tissues. The specific identification of γγ‐enolase provided by the two‐site IRMA with H14 is discussed in relation to the cellular distribution of this protein.

Improved correlation of magnetic resonance imaging (MRI) with clinical status in multiple sclerosis (MS) by use of an extensive standardized imaging-protocol.

In a previous study we have shown that the sensitivity of magnetic resonance imaging (MRI) for the detection of multiple sclerosis (MS) lesions was improved significantly, especially in the infratentorial region, by use of an extensive standardized MRI-protocol consisting of sagittal T1, axial protondensity and axial T2, and sagittal protondensity and sagittal moderately T2-weighted images. The goal of the present study was to assess whether the clinical correlation of the visualized lesions had improved accordingly. Using a scoring system based on lesion dimensions, we compared 70 MRI examinations performed in 25 patients with definite MS, with the relevant clinical data as given by the Expanded Disability Status Scale (EDSS) and Functional System scale (FS). We found a significant correlation (r = 0.66, P = 0.0001) between the MRI score and the EDSS. Significant correlations also existed between MRI scores and cerebellar and brainstem FS scores. These correlations were consistently higher than those reported by other authors. We conclude that a standardized MRI examination, including sagittal protondensity and moderately T2-weighted images, should be performed in every MS patient. The improved clinical correlation could be of importance in follow-up studies when assessing the efficacity of therapy.

The Duffy blood group is linked to the α-spectrin locus in a large pedigree with autosomal dominant inheritance of Charcot-marie-Tooth disease type 1

SummaryThe α-spectrin locus (SPTA) on chromsome 1 maps to 1q22–q25 and α-spectrin specific probes detect restriction fragment length polymorphisms (RFLPs) with the endonucleases MspI and PvuII. The Duffy blood group (FY) has been mapped to the 1p21–q23 region. We found positive linkage between the α-spectrin and the Duffy loci with a maximal Lod score of 3.81 at θ=0.0 using the computer program MLINK. This indicates that both loci are very closely linked and probably localized to 1q22–q23.

Demonstration of a novel neurofilament associated antigen with the neurofibrillary pathology of Alzheimer and related diseases

A monoclonal antibody, termed NFT200, was raised after in vitro immunization with sonicated neurofibrillary tangle (NFT)-enriched fractions prepared from Alzheimer brain. The antigen to which NFT200 is directed was expressed in the paired helical filaments of NFT in sporadic and familial Alzheimer disease (AD), in the straight filaments of NFT in AD, progressive supranuclear palsy and of Pick bodies, and the NFT in several other conditions such as Parkinson-dementia complex of Guam and subacute sclerosing panencephalitis. Granulovacuolar degeneration of AD was also labeled with NFT200. Hirano bodies and amyloid deposits in AD, as well as Lewy bodies of idiopathic Parkinson disease lacked in the antigen. The NFT200-antigen was also expressed as a phosphatase-insensitive antigen in normal neurofilaments found in spinal cord and peripheral nerve axons but was absent from the perikaryal accumulation of neurofilaments induced by aluminum intoxication. Nevertheless, immunoblot studies failed to detect the NFT200 in isolated preparations of the neurofilament proteins, MAP-2, tau, ubiquitin or A4-amyloid peptide. The results indicate that the NFT200 monoclonal antibody is directed against a phosphatase-insensitive epitope of an axonal protein associated with neurofilaments but is labile to isolation and expressed as a stable epitope of a 200 kDa component of NFT.

A monoclonal antibody raised against alzheimer cortex that specifically recognizes a subpopulation of microglial cells

A monoclonal antibody (MAb), termed AMC30, was raised after in vitro immunization with sonicated neurofibrillary tangle (NFT)-enriched fractions prepared from Alzheimers brain. The antigen to which AMC30 is directed was expressed by microglial cells in senile plaques of Alzheimers disease (AD). Microglia in the parenchyma surrounding brain tumors or infarctions, multinuclear giant cells, perivascular and parenchymal macrophages throughout the brain of AIDS patients were also labeled. Different non-nervous system lesions in which macrophages participate were also stained. Microglial cells in normal areas of the cortex or white matter were not labeled with MAb AMC30. The antigen to which AMC30 is directed was not detected in normal bone marrow, lymph nodes, lung, or spleen monocytes or macrophages. The epitope recognized by MAb AMC30 was present after formalin fixation and paraffin embedding. Our findings suggest that this MAb is directed against an antigen that is specifically expressed in a subpopulation of microglial cells and macrophages reactive to various pathological conditions.