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The binding specificities of two monoclonal antiglioma antibodies (MAB) derived from hybrids GE2 and BF7 (Schnegg et al. 1981) were tested by indirect immunofluorescence (IF) and two immunoperoxidase (IP) methods. Studies were done on biopsies from 33 human CNS tumors, human derived glioma cells, and N-ethylnitrosourea-induced neurogenic rat cells in culture. The immunohistochemical reactions of MAB were investigated in snap-frozen tumor material, conventionally paraffin-embedded material, and tumors embedded in formol sucrose/gum sucrose/paraffin (FSGSP) by the new tissue processing technique of Bolton and Mesnard (1982), which preserves and enhances the antigenicity of tissues. The FSGSP processing offered a better immunocytochemical staining with MAB as compared to cryostat material, while the conventionally embedded paraffin sections of tumors did not stain at all. The binding of MAB revealed an affinity to both glial tumor cells and normal astrocytes. The techniques described are suitable for the identification of an astrocytic subpopulation within gliomas, and may improve the understaining of antigen expression in various stages of astrocytic dedifferentiation.

To study the permeability of the blood-brain barrier (BBB) and the blood-nerve barrier (BNB) for immunoglobulin G (IgG) we adapted the avidin-biotin system for postembedding demonstration of the tracer IgG in the central and peripheral nervous system (CNS, PNS). Normal mouse and human IgG were biotinylated and injected daily into the intraperitoneal (i.p.) space of adult BDF1 mice. After 24 h, IgG was detected in blood vessels and in the interstitium of various organs, but staining was restricted to the dura mater in the CNS, to the spinal ganglia, and to the perineurium of peripheral nerves. After 4 days, IgG was also present in the endoneurial connective tissue of peripheral nerves, while the brain, spinal cord, and spinal roots remained free of IgG. Our results show a partial permeability of the normal mouse BNB for homologous and heterologous IgG.

A postembedding method is described to localize antigens specific for various paramyxoviruses in sections of cells and tissues that have been fixed and embedded in epoxy resins for conventional electron microscopy. Viral antigens were localized in CV-1 cell cultures infected with simian virus 5 (SV5), brains of suckling hamsters inoculated with either neuroadapted mumps virus or hamster-adapted measles virus, and brains of adult mice infected with Sendai (parainfluenza I) virus. Both 1-micrometer-thick and thin (gold) tissue sections were etched with alcoholic sodium hydroxide-solution and then treated following either the unlabeled antibody peroxidase-antiperoxidase or the biotinylated protein A:avidin peroxidase procedure. Primary reagents included immunoglobulin isolated from hyperimmune rabbit sera with specificity to the major viral components of SV5 or SV5 hemagglutinin-neuraminidase, to whole mumps virus or mumps virus nucleocapsids, and to whole Sendai virus. Crude rabbit anti-Sendai virus antiserum and whole human subacute sclerosing panencephalitis (SSPE) sera were used in parallel. The results indicate that tissues processed for conventional evaluation by electron microscopy may be suitable, within limits, for postembedding immunocytochemical staining of paramyxovirus antigens.

Murine lymphocytic choriomeningitis is a T-cell-mediated pathologic immune phenomenon. The name of this experimental illness was derived from the principal histopathologic alterations of the central nervous system (CNS) of adult mice infected intracerebrally with lymphocytic choriomeningitis virus, i.e., lymphocytic infiltrations of plexus choroidei and meninges. The general assumption that the main event in the pathogenesis is damage to virus-infected target cells by cytotoxic T-lymphocytes is plausible but direct evidence is scarce. We have studied the ultrastructural alterations of both types of cells that are thought to participate in this immunopathologic interaction. Lymphocytes with signs of T-cell transformation were first evident on day 4 after infection. One day later, lymphoblasts, often extending uropods and containing cytoplasmic dense and compound multivesicular bodies, predominated. They were sometimes seen in intimate contact with connective tissue cells of the leptomeninx and epithelial cells of the choroid plexuses which were shown to be infected by immunofluorescence procedure. Lymphoblasts occasionally invaginated the cytoplasm of the putative target cells with cytoplasmic processes, and were even found inside the latter, exhibiting the phenomenon of emperipolesis. Lymphocytic transformation was at its maximum 6 days after infection. At this time, individual leptomeningeal cells and groups of plexus epithelial cells showed signs of cytolysis, and in a few instances these damaged cells were in close spatial association with lymphoblasts. Similar observations have been reported by others who studied the interaction between cytotoxic T-lymphocytes and their appropriate targed cells in vitro. We interpret our findings as providing direct evidence for the assumption that one link in the chain of events leading to the cerebral form of lymphocytic choriomeningitis of the mouse is damage to virus-infected leptomingeal and plexus cells by cytotoxic T-lymphocytes.

The effects of intracerebral inoculation of Sendai virus into young adult mice were investigated by immunofluorescence, light, and electron microscopy. Immunofluorescence of virus-specific antigens was maximal on the third day after inoculation, revealing infection of leptomeninges, ependyma, and choroid plexus. Histologically, meningitis, ependymitis, and choroiditis occurred between the second and third days. The choroiditis was associated with formation of vacuoles within the cytoplasm of epithelial cells. The vacuoles reached diameters up to 50 µm. The ubiquitous vacuolization of plexus epithelia resulted in a honeycomb-like pattern. Opaque viral inclusions were visible within the cytoplasm of choroidal and ependymal epithelium as well as in mononuclear inflammatory cells. On electron microscopy, they were composed of intracytoplasmic nucleocapsid accumulations. Viria lay free between microvilli of plexus epithelial cells, and budding virus structures were observed at cellular surfaces. Occasionally, complete viria occurred in the cytoplasm of plexus epithelial cells and were surrounded by a unit membrane from which they appeared to arise by budding. The formation of this small cavity can be interpreted as the first stage of vacuole formation.

A man, aged 63, had an illness which lasted 11 months from onset with pain under the left costal margin which radiated to the epigastrium, until his death from cardiac failure. His symptoms consisted principally of parasthesias and proximal weakness of both upper and lower extremities with atrophy of the shoulder and pelvic girdles. He developed pyramidal tract signs, became euphoric, emotionally unstable and mentally retarded. There was no clinical evidence of cerebellar dysfunction. Bronchogenic carcinoma was suspected from a tomograph of the thorax, but, in spite of extensive clinical and laboratory studies, the diagnosis was verified only postmortem. The CSF cell count was high at first but diminished as the disease progressed. Muscle biopsies revealed chronic generalized denervation without signs of myopathy.

Factors which determine the pathogenesis and course of Toxoplasma encephalitis are poorly understood. In the present study, the influence of genetic factors in congenic B10 and BALB mice of H-2q, H-2k, and H-2b haplotypes was examined following oral infection with a low-virulence strain of Toxoplasma gondii (DX). There were striking differences among these strains. Whereas B10 mice were highly susceptible, BALB mice had a less severe and more protracted disease. In all animals with a fatal outcome, Toxoplasma encephalitis was the cause of death. Within the two congenic groups, the major histocompatibility complex haplotype had a strong impact on the disease. The H-2k haplotype was associated with early death in B10 mice but with a favorable outcome in BALB mice, whereas the reverse was observed for the H-2q haplotype. These findings indicate that genetically determined factors are critically involved in determining the intracerebral immune response and the course of murine toxoplasmosis. Some of these factors appear to be associated with the major histocompatibility complex haplotype, but significant differences between B10 and BALB mice point to a modulating role of additional genetic loci. Immunohistochemical studies and cytokine analyses of cerebrospinal fluid and serum revealed significant differences in the intracerebral immune response between susceptible and resistant strains. A poor outcome was associated with a large number of intracerebral parasites, significant tissue necrosis, a reduced number of intracerebral CD4+ T cells, low intrathecal tumor necrosis factor levels, and, to a lesser extent, a reduced number of intracerebral CD8+ T cells.

Summary: In addition to ependymal epithelial cells, numerous tanycytes are found along the entire central canal of the mouse. These tanycytes are arranged in clusters in the cervical, thoracic and lumbar segments of the spinal cord. In the conus medullaris, tanycytes separate and ensheath bundles of myelinated and unmyelinated axons; their processes take part in the formation of the stratum marginale gliae. In the caudal part of the spinal cord, the ventral wall of the central canal is thin and some areas are reduced to a single-cell thickness. In this region, ependymal cells participate directly in the formation of the stratum marginale gliae.The meninges consist of the intima piae, the pia mater, the arachnoid, a subdural neurothelium and the dura mater. The subarachnoid space appears occluded and opens only around the spinal roots. In the vicinity of the spinal ganglia, the dura mater, the subdural neurothelium and the arachnoid form a cellular reticulum.

Abstract: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is characterized clinically by recurrent cerebral infarcts, subcortical dementia and pseudobulbar palsy, and morphologically by a granular degeneration of cerebral and, to a lesser degree, extracerebral blood vessels. We present morphological findings in a further German family affected by CADASIL. The index case showed the typical periodic acid-Schiff-positive granular degeneration of vascular smooth muscle cells (VSMC) in cerebral vessels, which did not react with antibodies against various immunoglobulins or complement factors. Ultrastructurally, granular osmiophilic material (GOM) covered the VSMC in different cerebral regions as well as in extracerebral organs (muscle, nerve, skin, small and large intestine, liver, kidney and heart). Skin biopsy samples from other family members of the last two generations also revealed GOM irrespective of the clinical symptomatology (CADASIL, migraine only or asymptomatic). Patients in the third generation had higher amounts of GOM in skin vessels than did asymptomatic or migraine patients in the fourth generation. We conclude that skin biopsy is a useful and less-invasive screening method for the differential diagnosis of CADASIL.

Plasma viscosity, erythrocyte aggregation and platelet aggregation were determined in 4 patients suffering from pseudotumor cerebri. The results revealed hemorheological abnormalities in all patients. Plasma viscosity was elevated in 4, erythrocyte aggregation in 3 and platelet aggregation in one case. An involvement of hyperviscosity in the pathophysiology of PC is discussed.

A 57-year-old male was repeatedly admitted to hospital because of complex neurological symptoms, including radicular pain, disturbance of micturition, seizures, and severely impaired mental state. The diagnosis was encephalomyeloradiculitis possibly of viral origin, and treatment with immunosuppressants was initiated. An alternating course with a tendency towards improvement ensued. Two and a half years after the occurrence of the initial symptoms, identification of specific antibodies in the blood and CSF led to the diagnosis of borreliosis with CNS involvement. High-dose therapy with penicillin rapidly reduced the symptoms, beginning with those of radicular pain and followed by an improvement of the mental state. Attention is directed to the wide spectrum of clinical symptoms of chronic borreliosis with CNS involvement. Previous reports that immunosuppression may result in some improvement but with a tendency towards relapse are confirmed. Our encouraging treatment results support those of other reports that penicillin therapy may lead to improvement even at late chronic stages in patients with severe CNS deficits.

The capacity of the avidin-biotin system for post-embedding cytochemical detection of a biotin-labeled proteinaceous tracer was investigated. By testing modifications of the fixatives, the epoxy embedding medium, and various etching solutions, a procedure was developed to localize specifically the biotinylated tracer on 1-micron thick and thin sections. By use of this technique, a systemically administered IgG tracer was demonstrated after 24 hr throughout the endomysium of mouse skeletal muscle. In the adjoining sciatic nerve, the tracer IgG occurred at the perineurium and within endoneurial blood vessels, although the endoneurium itself was spared because of the presence of the blood-nerve barrier. Because of the small size of the biotin ligand and the non-denaturing method of labeling proteins, our mode of application of the avidin-biotin system appears suitable for tracer studies.