Clarence J. Gibbs

Infectious primate type C viruses: Three isolates belonging to a new subgroup from the brains of normal gibbons

Abstract Three type C viruses (GBr-1, GBr-2, and GBr-3) were isolated by coculativation of normal gibbon brain tissues with cultured mammalian cell lines. The tissues, all frozen since 1968, were obtained from two animals inoculated with brain extracts from human patients with kuru and from one uninoculated cagemate. By viral interference tests and by immunologic studies of the viral polymerases and major internal structural proteins (p30), the new isolates are typical members of a group of mammalian type C viruses infectious for primates. By nucleic acid hybridization, the viruses isolated from the gibbon brains, while highly related to one another, can be readily distinguished from the previously isolated type C viruses of this group. The infectious primate type C viruses isolated to date can be classified into four distinct subgroups.

Alzheimer's Disease and Transmissible Virus Dementia (Creutzfeldt‐Jakob Disease)

Ample justification exists on clinical, pathologic, and biologic grounds for considering a similar pathogenesis for AD and the spongiform virus encephalopathies. However, the crux of the comparison rests squarely on results of attempts to transmit AD to experimental animals, and these results have not as yet validated a common etiology. Investigations of the biologic similarities between AD and the spongiform virus encephalopathies proceed in several laboratories, and our own observation of inoculated animals will be continued in the hope that incubation periods for AD may be even longer than those of CJD.

Scrapie as a model for neuroaxonal dystrophy: Ultrastructural studies☆

Neuritic degeneration is a prominent ultrastructural feature of scrapie in hamsters. To investigate the morphogenesis of neuritic degeneration, we examined brain tissues from hamsters infected with the 263K strain of scrapie virus and from age-matched controls at varying intervals following intracerebral inoculation. Dystrophic neurites--defined as dendrites, axonal preterminals, and myelinated axons containing mitochondria and pleomorphic, electron-dense inclusion bodies--were found as early as 2 weeks postinoculation. Their numbers increased with the incubation period, and their highest density was observed at the terminal stage of disease. Occasionally, small clusters of these structures formed neuritic plaques. Such dystrophic neurites were only rarely seen in brains of uninfected hamsters. Experimental scrapie thus provides an animal model for human neuroaxonal dystrophies. In addition, since this model allows predictable formation of brain amyloid, it may serve as a model for the study of neuronal aging and Alzheimers disease.

Creutzfeldt-Jakob disease in an adolescent

A 16-year-old boy was stricken with a progressive neurologic disorder characterized primarily by dementia progressing to severe neurologic debility in 12 months and death 28 months following the first symptoms. Pathologic examination showed a spongiform encephalopathy, consistent witha clinical diagnosis of Creutzfeldt-Jakob disease (CJD). The noteworthy features of the case are the age of onset, the somewhat prolonged course an the amount of white matter change. These are discussed within the frame of reference of CJD and the spongiform encephalopathies of infancy and childhood. Animal inoculation studies employing post-mortem embalmed brain as inoculum are currently in progress to determine the transmissibility of this patients disease.

Monoclonal antibodies to central nervous system antigens

Thirty monoclonal antibodies produced by mouse hybrid myelomas which react with antigens in hamster or mouse nervous system tissues were derived. Using these antibodies as probes with indirect immunofluorescence and immunoperoxidase techniques, we can selectively identify by morphological criteria many of the structural components of the brain seen at a light-microscopic level, including the neutrophil, neuronal cytoplasm, nuclei, axons, astrocytes and ependyma. Some of the antibodies display cytoskeletal and filamentous structures, including intermediate filaments, microfilaments, neurofilaments, glial and ependymal filaments. The specificity to neural tissue components of these hybridoma antibodies was assessed by their reactivity to mouse and hamster non-neural tissues and selected mouse, hamster, rat and human cultured cell lines. Of the 30 clones analyzed, specificity ranged from 3 clones reacting only with grey matter of mouse and hamster brain, one clone reacting only with axons in animal and human brain, to 19 clones reactive with both neural and non-neural tissue components.

Sleep abnormalities with REM disorder in experimental Creutzfeldt-Jakob disease in cats: a new pathological feature

Alterations in sleep organization were studied during the clinical phase of experimental Creutzfeldt-Jakob disease (CJD) in cats. Twenty months after intracerebral inoculation of a CJD agent, cats developed clinical signs including behavioral changes, diminished grooming activity, dysmetria, startle reflex, myoclonus, and unusual sleep abnormalities. Rapid eye movement (REM) sleep displayed a new and irreversible organization, with a continuous and constant pseudoperiodic pattern of rapid eye movements, synchronous with diffuse bursts of cortical abnormalities and with ponto-geniculo-occipital (PGO) wave activity. Computer analysis revealed a constant morphology of cortical bursts and their temporal relationship with ocular episodes. Induction of PGO wave activity with benzoquinolizine derivative Ro 4-1284 demonstrated the PGO-dependent nature of the cortical alterations. Abnormal unresponsive states were observed during REM sleep phases and arousal thresholds were increased in CJD cats during REM sleep. The percentages of wakefulness and slow-wave sleep were reversed in these animals. Preliminary neuropathological observations included discrete to minimal spongiosis of cerebral gray matter and a remarkably focalized intracytoplasmic vacuolation in neurons of the raphé system. Our findings suggest that particular neuronal systems involved in sleep regulation are impaired in CJD cats.

Longitudinal spinal cord sections as substratum for anti-neurofilament antibody detection

A rapid and technically simple method for demonstrating anti-neurofilament antibodies using longitudinal sections of rat spinal cord as substratum and indirect immunofluorescent technique is reported. The results compare well with those obtained by the technically more difficult and time-consuming methods using as substratum central neurons cultivated in vitro. A total of 195 serum specimens from different neurological disorders and healthy subjects were studied. Immunofluorescent autoantibodies to neurofilaments were found in specimens of serum from patients with Creutzfeldt-Jakob disease (CJD), kuru, amyotrophic lateral sclerosis, parkinsonism dementia (Guam), Alzheimers disease, and multiple sclerosis but in higher frequency in CJD and kuru than in the other disease or in healthy control subjects.

Choline acetyltransferase activity and [3H]quinuclidinylbenzilate binding in brains of scrapie-infected hamsters

Choline acetyltransferase (ChAT) activity and [3H]quinuclidinylbenzilate binding were studied in the brain of scrapie-infected hamsters and sham inoculated controls. Although scrapie-infected hamsters showed no reduction of ChAT activity compared to the controls, they showed a decrease in the affinity and maximum number of post-synaptic muscarinic receptors. Scrapie virus thus alters the cholinergic system at the post-synaptic rather than at the pre-synaptic level.

Isonicotinic hydrazide causes seizures in scrapie-infected hamstesr with shorter latency than in control animals: A possible GABAergic defect

Isonicotinic hydrazide, a drug that decreases the level of GABA, when injected subcutaneously in control and scrapie-infected hamsters induced tonic-clonic seizures in scrapie hamsters significantly earlier (P less than 0.0001) than in control animals. This suggests depression of the GABAergic system in scrapie-infected hamsters. To determine whether this lesion is pre or postsynaptic we measured the level of GABA, glutamate, cGMP and cAMP and the GABA-benzodiazepine receptor complex.

HLA-DR expression in macaque neuroendothelial cells in vitro and during SIV encephalitis

HLA-DR expression in neuroendothelial cells (NEC) was studied during the course of SIV encephalitis in rhesus monkeys. HLA-DR determinants were detected on NEC in monkeys with SIV encephalitis, but not in control animals. In situ hybridization with an SIV probe indicated that HLA-DR expression was not a consequence of SIV replication within NEC. Cultured rhesus NEC stimulated with gamma interferon expressed HLA-DR to a higher degree than cultured brain fibroblasts or astrocytes. These data support the contention that NEC participate in retrovirus-induced inflammation and autoimmunity within the central nervous system.