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Biomedical subjects

H Thormar

Publications and source records attributed to H Thormar.

At least 73 records · Page 4Linked to original sources
PubMed1979

Myelin lesions in the rabbit eye model as a bystander effect of herpes simplex and visna virus sensitization.

Rabbits were immunized with herpes simplex and visna virus in complete Freund's adjuvant. Uv-inactivated herpes virus and the purified visna virus protein p25 injected intraocularly into these rabbits elicited a moderate inflammatory cell infiltration in the epiretinal myelinated nerve fiber bundles accompanied by signs of demyelination. It is therefore apparent that also viral antigen can induce myelin lesions as a so-called "bystander effect" of a cell-mediated immune response (bystander demyelination).

Animals↗
PubMed1979

Immunological studies of subacute measles encephalitis in ferrets: similarities to human subacute sclerosing panencephalitis.

Ferrets inoculated with subacute sclerosing panencephalitis virus strains D.R. and Biken developed a subacute encephalitis. Brain extracts, at neutral pH, from these ferrets showed high measles antibody titers, increased concentrations of immunoglobulin G (IgG), and higher IgG/albumin ratios than those of controls. Although the brain extracts of subacute encephalitic animals showed significant synthesis of measles-specific IgG (20 to 60% of the total IgG) within the central nervous system, the electrophoretic patterns of these extracts did not show oligoclonal bands in the gamma-globulin region. Brain residues from most ferrets with subacute encephalitis, when eluted at low pH, demonstrated the presence of bound measles-specific antibodies. Excluding the electrophoresis data, other results are identical to those seen in human subacute sclerosing panencephalitis, indicating that the subacute encephalitis in ferrets may serve as a model for human subacute sclerosing panencephalitis.

Animals↗
PubMed1979

Precipitation of visna viral proteins by immune sera of rabbits and sheep.

Eighteen polypeptides equivalent to 1.2 x 10(6) daltons of visna virus were specifically precipitated by immune sera from rabbits and sheep. The hyperimmunized rabbit antisera contained high concentrations of antibodies against p25 and p14, whereas the sera from sheep actively infected with visna virus showed a large quantity of anti-gp115 antibody. The results indicate that almost all the polypeptides reported previously (F. H. Lin, J. Virol. 25:207--214, 1978) are virus-specific components of visna. The presence of anti-gp115 antibody in sera of infected sheep may offer a simple and sensitive diagnostic procedure for visna.

Animals↗
PubMed1978

Comparison of wild-type and subacute sclerosing panencephalitis strains of measles virus. Neurovirulence in ferrets and biological properties in cell cultures.

The neurovirulence of two wild type (wt) and seven Subacute Sclerosing Panencephalitis (SSPE) measles virus strains was tested in young adult ferrets by intracerebral (IC) inoculation of infected Vero cell suspensions. Wt strains Edmonston and Woodfolk and SSPE strains Mantooth, Halle, and LEC-S did not produce a detectable encephalitis in the ferrets, but caused a significant formation of serum antibodies against measles virus. SSPE strains LEC, IP-3, Biken, and D.R., on the other hand, were all neurovirulent in ferrets, particularly strain D.R. which caused an acute encephalitis in all inoculated animals. Strain Biken was of particular interest since it caused a subacute encephalitis in four of seven ferrets. The subacute encephalitis was characterized by a long incubation time, persistence of virus in the brain for at least 8 mo, widespread inflammatory lesions, and production of measles virus specific IgG in the brain. A study of the biological properties of the various measles virus strains showed that wt strains Edmonston and Woodfolk and SSPE strains Mantooth, Halle, and LEC-S produced free virus particles in significant titers both in Vero and ferret brain (FB) cultures. Cytopathic effect (CPE) with cell-fusion was marked in Vero cultures, whereas only minimal CPE and no cell-fusion were observed in the FB cultures. SSPE strains LEC, IP-3, Biken, and D.R., on the other hand, were mostly cell-associated in Vero and FB cultures, although atypical cell-free particles were produced by strains Biken and IP-3. All four strains showed cell-fusing activity in FB cultures, particularly strain D.R., which was the only strain that spread more actively by fusion in FB than in Vero cultures. The results are discussed in relation to the neurovirulence of the various measles virus strains in adult ferrets. Pronounced cell-fusing activity in FB cells and cell-association with minimal or no production of cell-free virus seem to be essential to establish a brain infection in the animals.

Animals↗
PubMed1978

Further characterization of bound measles-specific IgG eluted from SSPE brains.

Tissue residues from 3 SSPE brains extracted at neutral pH were thoroughly washed with phosphate-buffered saline and further extracted at acidic pH. The low-pH extracts had significant measles antibody titers, and their measles-specific IgG content ranged from 40 to 60% of total IgG. Agarose-gel electrophoretic analysis of the extracts showed oligoclonal IgG bands, most of which disappeared after suitable absorption with measles virus, demonstrating the presence of restricted measles antibody population. Ouchterlony analysis showed a reaction of identity between bound IgG and IgG extracted at neutral pH. Thus IgG extracted at low and neutral pHs is remarkably similar.

Antibody Specificity↗
PubMed1977

Antibody in SSPE serum and brain igG against measles virus smooth nucleocapsids detected by immunoelectron microscopy.

SSPE patients characteristically have high complement-fixing (CF) and neutralizing (N) antibody titers against measles virus in their sera, CSF, and brain. However, using SSPE patients' sera, the immunoperoxidase (IP) labeling of smooth nucleocapsids in SSPE or measles virus infected Vero cells or measles virions has not been achieved using conventional EM fixatives. Using the periodate-lysine-paraformaldehyde (PLP) fixative developed by McLean and Nakane (1974), and the indirect IP technique, antibodies against smooth nucleocapsids in SSPE and measles virus infected Vero cell cultures have been detected in serum from SSPE patients and normal individuals with high measles antibody titers.

Adolescent↗
PubMed1977

Encephalitis in ferrets caused by a nonproductive strain of measles virus (D.R.) isolated from patient with subacute sclerosing panencephalitis.

A nonproductive, syncytiogenic strain (D.R.) of measles virus, isolated from a patient with subacute sclerosing panencephalitis (SSPE), was inoculated intracerebrally into ferrets in an attempt to induce subacute encephalitis. Inoculation of freeze-thawed syncytia before immunization was the least effective procedure, and inoculation of live syncytia after immunization with measles virus vaccine was the most effective procedure, for induction of subacute or persistent subclinical encephalitis in the animals. After the latter procedure three of five ferrets developed subacute or subclinical encephalitis, whereas ferrets inoculated with live syncytia without prior immunization consistently contracted acute fatal encephalitis in one to two weeks. The subacute encephalitis in ferrets was characterized by high titers of antibody to measles virus in serum. At the time of sacrifice 1.25, 4.5, or 8.0 months after inoculation, brains of the ferrets showed histologic lesions similar to those characteristic of SSPE, and nonproductive syncytiogenic measles virus was recovered from the brains of two of the animals. All three ferrets had greatly increased concentrations of gamma-globulin in their brains and high levels of neutralizing and hemagglutination-inhibiting antibodies to measles virus. Only one of these animals developed clinical signs 1.25 months after inoculation.

Animals↗
PubMed1977

Ultrastructural and histological studies of brains of ferrets inoculated with subacute sclerosing panencephalitis: similarities to human disease.

Similarities to human subacute sclerosing panencephalitis (SSPE) were revealed in a study of the brains of ferrets inoculated with a cell associated measles virus originally isolated from an SSPE patient. The similarities were greatest in animals that showed neurological signs 3-4 months after inoculation and had high titers of neutralizing antibodies against measles virus. These included dense core particles, nuclear bodies, alterations of basement membranes of small blood vessels, plasma cells, distorted myelin, and rod-like structures in some nuclei. Other abnormalities seen were Hirano bodies, tubular aggregates in cisternae of endoplasmic reticulum and clusters of cytoplasmic tubules. No cells containing viral inclusion bodies were observed by electron microscopy but cell cultures of the brains of these animals always yielded abundant measles virus nucleocapsids in typical SSPE multinucleated syncytia. These findings suggest that the ferret is a suitable animal model for the study of the pathogenesis of SSPE.

Animals↗
PubMed1976

Immunoperoxidase staining of simple nuclear bodies in sclerosing panencephalitis (SSPE) by antiserum to Measles nucleocapsids.

Nuclear bodies have been found with great consistency in brain tissue from patients with subacute sclerosing panencephalitis (SSPE). There has been controversy as to the significance of these structures and their relationship, if any, to the disease. In this study, a non-productive, cell-associated strain of SSPE measles virus grown in tissue culture on Vero cells showed the continued presence of nuclear bodies, frequently in close association with the continued presence of nuclear bodies, frequently in close association with the SSPE measles virus nucleocapsids. Immunoperoxidase (I-P) staining with specific antiserum against measles virus nucleocapsids was done. The resultant positive labeling of the nuclear bodies demonstrates that they contain measles virus antigen and suggests that the nuclear bodies play a role in the development of the measles virus nucleocapsids of SSPE.

Antigens, Viral↗
PubMed1976

A non-productive subacute sclerosing panencephalitis (SSPE) virus of human and ferret: an ultrastructural study.

A non-productive syncytiogenic measles virus isolated from the brain of an SSPE patient was grown on Vero cells. The ultrastructure of the infected syncytia was studied by electron microscopic and immunoperoxidase techniques. It was compared with the isolate of the virus after passage in ferrets, the Edmonston strain of wild measles virus and the Halle productive strain of SSPE, all on Vero cells. The immunoperoxidase labeling of the cell membranes of the Edmonston measles virus infected cells was very heavy and uniform. In contrast, the labeling of the non-productive SSPE infected cells was clearly discontinuous. In the latter, there was a preponderance of intranuclear over cytoplasmic nucleocapsid formation, whereas cytoplasmic nucleocapsids were prevalent in the virion-producing strains. Many similarities between Vero cells infected with the wild measles virus and the Halle strain of SSPE were observed, although differences between this SSPE strain and strains reported by others were noted.

Adolescent↗
PubMed1976

Antigenic analysis of isolated polypeptides from Visna virus.

The antigenic activity of 10 Visna polypeptides separated by gel filtration in the presence of 6 M guanidine hydrochloride (GuHCl) was examined with rabbit antisera made specific for Visna virus. The results showed that the first (GuHCl 1) and the ninth (GuHCl 9) polypeptide peak reacted with the antisera when examined in immunodiffusion, passive hemagglutination, and complement fixation tests. Whole virus, GuHCl 1, and GuHCl 9, when tested with the antisera, appeared to be immunologically identical in the immunodiffusion test. However, GuHCl 1 reacted weakly with the antisera by all three techniques as compared with GuHCl 9 and whole virus. GuHCl 9, when subjected to polyacrylamide gel electrophoresis containing 0.1% sodium lauryl sulfate, revealed the presence of one polypeptide with a molecular weight of 25,000. By the same method, GuHCl 1 was found to contain an aggregate of four different polypeptides, the major one having a molecular weight of 25,000. The results indicate that the antigenic activity of both GuHCl 1 and GuHCl 9 was associated with a single polypeptide having a molecular weight of 25,000.

Antigens, Viral↗
PubMed1976

Relationship between homogeneous IgG fractions and measles virus antibody activities in subacute sclerosing panencephalitis brain.

Cellulose acetate and agarose gel electrophoresis of pH 7.4 brain extracts from three patients with subacute sclerosing panencephalitis (SSPE) revealed two to three homogeneous bands in the gamma-globulin region. The IgG concentration in the brain extracts ranged from 6 to 8.5% of the total protein. The IgG was isolated by passing each brain extract twice through gel filtration on Sephadex G-200 column. The Sephadex-isolated IgG preparations, at a concentration of 1 mg/ml, had hemagglutination inhibition (HI) titers ranging from 512 to 800, complement fixation (CF) titers of 64 to 100, and neutralizing titers of 400 to 1024 when tested against envelope, nucleocapsids, and while measles virus, respectively. These IgG preparations were further separated into several fractions by isoelectric focusing (IEF) technique and the reactivities of these eluted fractions were examined against differnt specific measles virus components and against whole virus. The results showed that both slow and fast moving homogeneous IgG had high HI and neutralizing titers. However, CF antibodies were present only in specific IEF-eluted fractions and their profiles differed somewhat from one brain to another. The IgG fractions reacted with both kappa-and gamma-chain antisera, but the reactivity varied from one brain to another. When the polyacrylamide gel electrophoretic (PAGE) patterns of heavy (H) and light (L) chains of SSPE IgG were compared to those of IgG from controls, the H chain patterns of both groups were identical whereas the SSPE brain IgG demonstrated two distinct bands in L chain as compared to a single diffuse band observed in controls. These latter results, in addition to homogeneous bands and selective CF antibody activity in IEF eluted IgG fractions from SSPE brain, fulfill some of the criteria of monoclonality.

Antibodies, Viral↗
PubMed1975

Measles antibodies and immunoglobulins in sera from patients with subacute sclerosing panencephalitis (SSPE) and from an infected ferret.

Cellulose acetate electrophoresis of sera from 2 patients with SSPE revealed a slow-moving and a fast-moving gamma-globulin band. The IgG fractions from sera were isolated by the combination of starch block electrophoresis, Sephadex gel filtration and isoelectric focusing techniques. The purity of each protein was tested by immunoelectrophoresis using a potent goat anti-whole human serum. The isolated IgG preparations were tested in HI, CF and N tests against measles virus envelope, measles virus nucleocapsid and whole measles virus, respectively. The results showed that isolated IgG fractions, having different electrophoretic mobilities, contained high titers of HI, CF and N antibodies, and these titers were proportional to the protein concentration of IgG. Although both IgG fractions appeared to show an increase of K-type chain, neither fraction was devoid of L-type chain. These results indicate that the homogeneous IgG bands observed in the SSPE serum were not monoclonal as they failed to show selective increase of one type of light chain and uneven distribution of measles antibody activity. These findings were compared with the results from a ferret, which developed encephalitis 2 months after intracerebral inoculation with cell-associated measles virus derived from the brain of an SSPE patient. The electrophoretic pattern of the ferret serum was similar to that of the human. High titers of measles HI and N antibodies were seen in the isolated slow- and fast-moving IgG's. The similarities observed in the human and ferret IgG's, with respect to homogeneous bands in electrophoresis and measles HI and H antibody activities, suggest that the ferret may be a useful animal model for studying the immune mechanism of SSPE.

Animals↗
PubMed1975

Comparative studies of Visna and Maedi viruses as antigens.

Rabbits were immunized with purified visna and maedi viruses, using complete Freund adjuvant, in footpad and intramuscular sites. The resulting antisera and their isolated immunoglobulin G (IgG) and M (IgM) classes were evaluated by tanned-cell passive hemagglutination (PHA), complement fixation, gel diffusion, and virus neutralization tests. Early, intermediate, and late bleedings showed increasingly high antibody activities by the PHA, complement fixation, and gel diffusion tests. The activities were associated mainly with the IgG class, although low, but significant activities were also found in the IgM class, as detected by PHA and complement fixation tests. Both antibody classes appeared at the same time during the course of immunization. The viruses, when tested against specific rabbit anti-visna and anti-maedi sera in gel diffusion tests, showed the presence of one to two precipitin lines depending upon the antibody concentration of the sera. A low amount of neutralizing activity was demonstrated in late bleedings but was not seen in earlier bleedings. The neutralizing activity against visna virus in immunized rabbit sera was found to be associated only with the IgG class. Visna and maedi viruses appeared to be immunologically identical when examined in gel diffusion tests and showed the same degree of inhibition when compared in passive hemagglutination inhibition test using antisera made specific for each virus.

Animals↗