Jerry S. Wolinsky

Cerebrospinal-fluid lymphocyte populations and immune complexes in active multiple sclerosis.

A specific subpopulation of mononuclear cells bearing a surface receptor for the Fc portion of IgG was considerably reduced in the cerebrospinal fluid (CSF) of multiple sclerosis (MS) patients during exacerbation, but returned toward normal levels as the patient entered remission. Low concentrations of immune complexes were found in the CSF in nearly 50% of MS patients during exacerbations but immune complexes were not found in patients with stable MS.

Biochemical features of mumps virus neuraminidases and their relationship with pathogenicity

Abstract The neuraminidases (NANases) of six strains of mumps virus were characterized biochemically. Though the hemagglutinin-neuraminidase (HN) glycoproteins were similar in apparent size and immunological properties, the NANase activities exhibited different behavior. Each NANase had a characteristic pH optimum and thermal stability. Kinetic analyses demonstrated unique Km catalytic constants, and Ki (Cl−) values for the different NANases. Three strains, Enders, RW, and OTake, had active NANases (V′max = 179–680 nmol/min/mg virus protein) that hydrolyzed 37–50% of the total neuraminic acid (NANA) of fetuin; the other strains, Kilham, MJ, and Jeryl Lynn B, had less active NANases (V′max = 48–95 nmol/min/mg) capable of hydrolyzing only 10–27% NANA of fetuin. The virus hemagglutination activities (HA) and the elution rates for adsorbed virions were consistent with the NANase properties. Enders, RW, and OTake strains agglutinated erythrocytes most efficiently at physiological NaCl concentration; HA activities for Kilham, MJ, and Jeryl Lynn B strains were not affected by NaCl concentration. Adsorbed Enders, RW, and OTake virus eluted more rapidly from erythrocytes than did adsorbed Kilham, MJ, and Jeryl Lynn B strains. These properties, associated with the HN glycoprotein, are correlated with the cytopathogenicity of the strains. The OTake and RW strains cause no cell fusion and little cytopathology; Kilham, MJ, and Jeryl Lynn B strains produce extensive cell fusion after infection of CV-1 cells. These results suggest that, in concert with the paramyxovirus fusion (F) glycoprotein, the viral NANase contributes to the cytopathology of an infection, an active NANase promoting rapid release of progeny virions, so that no cell fusion occurs, and the action of a less active NANase prolonging the association of progeny virus with the infected cell surface, increasing the likelihood of cell fusion.

The production of a membrane by purified oligodendroglia maintained in culture

Abstract Purified oligodendroglia maintained in culture produce whorls of membrane lamellae, adjacent to the cell soma. When subcellular fractions are prepared from the cells in culture, three membrane fractions are obtained: a glial light fraction which electron micrographs show to be predominantly large vesicles; an intermediate fraction that on electron micrographs consists of whorls of membrane lamellae; and a plasma membrane fraction consisting primarily of small vesicles. In a study on the production of the membrane lamellae, the results show that there is a rapid incorporation of radiolabel into cerebrosides and phosphatidylcholine, with lower incorporation into other phospholipids. There is a delay in incorporation into sulfatides. Incorporation into proteins show a complex heterogeneous pattern of proteins, ranging from high to low molecular weight (MW) bands. The incorporation data may reflect the composition of the subfractions after different times in culture.

Conversion of nonfusing mumps virus infections to fusing infections by selective proteolysis of the HN glycoprotein

Mumps virus strains differ in their ability to induce cell fusion following an infection: strains with active neuraminidase (NANase) fail to cause cell fusion, while strains with less active NANase cause cell fusion. When chymotrypsin is added to infected cells, cell fusion is amplified in a concentration-dependent manner for all mumps virus strains. Virions produced in such infections do not express HN glycoprotein-associated activities. Chymotrypsin treatment of purified mumps virus in vitro results in sequential cleavage of the HN glycoprotein without affecting F glycoprotein structure. Initially, HN is cleaved into two glycopolypeptides, HNc1 (32K) and HNc2 (41K), with concomitant loss of hemagglutinating and NANase activities, and infectivity. Further incubation with chymotrypsin causes complete degradation of HNc1 and digestion of HNc2 to HNc2 (13K-19K). Both HNc2 and HNc2 contain the [3H]palmitic acid label found in the HN polypeptide, which suggests that these fragments are associated with the viral membrane. Analyses of infected cells and released virions indicate that chymotrypsin acts similarly on HN exposed at the cell surface. Exogenous NANase does not abolish the protease-augmented cell fusion, though it does reduce cell fusion of untreated fusing strain infections. These results confirm that mumps virus HN glycoprotein is critically linked to cell fusion cytopathology and show that cryptic cell fusion activity in nonfusing strain infections can be unmasked by the proteolytic removal of the HN glycoprotein.

Role of Viruses in Chronic Neurological Diseases

Viruses play unique roles in a variety of chronic neurological diseases. The prototype slow infections of sheep (scrapie and visna) and the five established slow infections of man [kuru, Creutzfeldt-Jakob disease, subacute sclerosing panencephalitis (SSPE), progressive multifocal leukoencephalopathy, and progressive rubella panencephalitis] all are manifest primarily as neurological diseases. In those due to the spongiform encephalopathy agents, scrapie, kuru, and Creutzfeldt-Jakob disease, infectivity is found in many organs, but clinical and pathological abnormalities are confined to the CNS. In the slow infections associated with conventional viruses, infection may be generalized or limited to brain and spinal cord.

Experimental panencephalitis induced in suckling mice by parainfluenza I (6/94) virus. III. Ultrastructural studies.

Intracerebral inoculation of newborn mice with Parainfluenza I (6/94) virus produces a chronic panencephalitis. Electron microscopic studies were carried out over 125 days of the infection. Productive infection of choroidal and ependymal epithelial cells was seen from postinoculation days 2nd to the 8th. Fusion of adjacent choroid and ependymal cells resulted in giant cell forma-tion. Completed virions were seen adsorbed to circulating macrophages and these cells replicated intracytoplasmic nucleocapsids. Neuronal infection was evident on the 3rd postinoculation day, was widespread by the 6th day postinoculation and persisted to the 35th day postinoculation. Nucleocapsid alignment and budding from neuronal plasma membranes was never seen. An initially intense mononuclear cell infiltrate subsided by the 35th day but residual inflammation persisted throughout the study. Late in the course of the infection, vacuolation of the neuropil and a periventricular and deep cerebral spongiform change was seen which could not be directly associated with local viral replication. These ultrastructural findings are correlated with prior light microscopic, virological and immunofluorescent studies of the infection and compared to other experimental models of myxovirus central nervous system infections.

EXPERIMENTAL PANENCEPHALITIS INDUCED IN SUCKLING MICE BY PARAINFLUENZA TYPE 1 (6/94) VIRUS: II. VIROLOGIC STUDIES

6/94 virus, a parainfluenza type 1 isolate from multiple sclerosis brain tissue, produced a chronic panencephalitis when inoculated intracerebrally into suckling ICR mice. Immunofluorescent staining revealed 6/94 viral antigen in ependyma, meninges, choroid plexus, and perivascular parenchy-mal sites from day 3 to 128 days after infection. Hemadsorption-neutralizing antibody was first detected between 20–25 days after infection and remained at high titers for 7 months. Using embryonated chicken eggs, virus was recovered from mouse brains for only 8 days, but could be recovered from brains grown in vitro as explants for 37 days after infection. In cell lines established from explanted brain tissue, immunofluorescence was the most sensitive indicator of virus presence, although infectious virus was not produced. Fusion of these mouse brain cells with human (WI38) indicator cells was the most effective means of rescuing 6/94 virus.

Experimental panencephalitis induced in suckling mice by parainfluenza type 1 (6/94) virus. I. Clinical and pathological features.

Intracerebral inoculation of two strains of suckling mice with 6/94 virus, a parainfluenza type 1 virus originally isolated from two patients with multiple sclerosis, produced clinical disease 1–2 weeks after inoculation. Of 528 ani-mals inoculated, 33% died (26% of the ICR strain and 76% of the BALB/c strain) usually between two or three weeks after injection. Animals that recovered appeared to develop normally. Pathological changes were of two types. Initially, there was a necrotizing panencephalitis with virus-specific intracytoplasmic inclusions in choroid and ependymal epithelial cells and neurons. The second major lesion appeared about 6 weeks post inoculation and consisted of a noninflammatory spongiform degeneration of white matter that primarily involved the cerebral hemispheres; a diffuse vacuolar encepha-lopathy primarily affecting the brain stem; and a persistent minimal inflammation.