Michael Landon

Anti-ubiquitin immunocytochemistry is more sensitive than conventional techniques in the detection of diffuse Lewy body disease.

Brainstem and cortical Lewy bodies in diffuse Lewy body disease show intense immunoreactivity to antibodies against ubiquitin. Quantitative studies show that the novel neuropathological technique of anti-ubiquitin immunocytochemistry is more than twice as sensitive as conventional haematoxylin and eosin stains in detecting cortical Lewy bodies. Anti-ubiquitin immunocytochemistry should be regarded as the method of choice for the diagnosis and quantification of diffuse Lewy body disease.

Diffuse Lewy body disease: correlative neuropathology using anti-ubiquitin immunocytochemistry.

Diffuse Lewy body disease is an important pathological substrate of the common syndrome of parkinsonian dementia. The new technique of anti-ubiquitin immunocytochemistry has been used in a correlative quantitative neuropathological study of fifteen cases of diffuse Lewy body disease, showing that the severity of dementia is related to cortical Lewy body density, whilst subcortical abnormalities make a much less significant contribution. Cortical senile plaques also appear to be part of the pathology of diffuse Lewy body disease and should not therefore be used as an isolated diagnostic criterion for Alzheimers disease. Diagnostic criteria for diffuse Lewy body disease are discussed.

Monoclonal antibodies raised against a subsequence of senile plaque core protein react with plaque cores, plaque periphery and cerebrovascular amyloid in Alzheimer's disease

Four monoclonal antibodies (1D2/1/2, 1G10/2/3, 3B6/1/1, 4D12/2/6) were raised against a synthetic peptide consisting of residues 8-17 of a protein reported to be common to senile plaque cores, cerebrovascular amyloid and neurofibrillary tangles in Alzheimers disease. In an immunoperoxidase study of Alzheimer brain tissue, these antibodies stained plaque and vascular amyloid but not tangles, suggesting that the polypeptide chain in the region of residues 8-17 is exposed in the former two but, if present, inaccessible in the latter. In addition, staining of granular material in the plaque periphery was observed. These antibodies will be useful tools for future work on the origin of this protein.

CNS amyloid proteins in neurodegenerative diseases

The amyloid plaques found in neurodegenerative diseases show considerable morphologic diversity. Two amyloidogenic proteins have been isolated from the brains of humans and animals with neurodegenerative diseases-β-protein from Alzheimers disease (AD) and Downs syndrome, and prion protein (PrP) from scrapie and Creutzfeldt-Jakob disease (CJD). Using monoclonal antibodies to a synthetic peptide corresponding to a portion of β-protein and rabbit antiserum to hamster scrapie PrP 27–30, we examined in situ amyloid plaques on sections from cases of neurodegenerative diseases, including cases with a spectrum of plaque types. Anti-β-peptide stained cerebrovascular and plaque core amyloid in all AD cases as well as cerebrovascular amyloid and senile plaque core amyloid in five elderly CJD cases. Anti-PrP stained plaques in CJD, kuru, and Gerstmann-Sträussler syndrome cases but not cerebrovascular amyloid or plaques in AD. Dual localization experiments showed that in cases with a mixture of plaque types, the antibodies identified different populations of plaques that showed anatomic heterogeneity. Colocalization of the two proteins was not observed in any plaque type. The data suggest that in neurodegenerative diseases two major plaque types exist, which have different etiologic origins. Our results emphasize the need for classification of CNS amyloids based not on their morphology but on the macromolecular components comprising these pathologic polymers.

EXTRACTION AND PROTEIN SEQUENCING OF IMMUNOGLOBULIN LIGHT CHAIN FROM FORMALIN-FIXED CEREBROVASCULAR AMYLOID DEPOSITS

Substantial amounts of a single protein have been extracted into electrophoresis sample buffer from archived formalin‐fixed brain blood vessels, taken from a case of cerebral amyloidosis. Cyanogen bromide cleavage and tryptic digestion of the protein on Western blots allowed amino acid sequences from three resultant peptides to be determined. Comparison of these peptides with database sequences identified the extracted protein as being derived from an immunoglobulin light chain. This is the first demonstration of amino acid sequencing of a polypeptide extracted from formalin‐fixed tissue. This case also appears to be unique, since primary cerebrovascular amyloidosis involving immunoglobulin light chains has not been previously described. The amyloid protein had clearly resisted formalin fixation; it is possible that this resistance occurred because the protein was deposited in large amounts as insoluble densely packed aggregates, which may exclude infiltration of the formalin. This technique may therefore have applications in the post‐mortem diagnosis of amyloidoses and in the purification of other amyloids.