Temperature elevation enhances cell surface expression of measles virus fusion protein in infected cells

Cell fusion proceeded gradually in measles virus-infected cells incubated at 35°C. Shift-up of incubation temperature to 39°C induced rapidly increased cell fusion in spite of the cessation of de novo synthesis of the fusion (F) protein. Pulse-chase experiments showed that there was little difference in the acquisition of immunoreactivity by haemagglutinin (H) and F proteins between the two temperatures. H protein was detected on the cell surface 60 min after the chase at either temperature. However, appearance of F protein on the cell surface took less than 3 h at 39°C whereas it took 5 h at 35°C. These data indicate that temperature elevation induces more efficient expression of F protein on the cell surface accompanied by marked syncytium formation in measles virus-infected cells

Glycosylation of measles virus haemagglutinin protein in infected cells

Processing of the measles virus haemagglutinin (H) protein was analysed by the pulse-chase method, immunoprecipitation with an anti-H monoclonal antibody and SDS-polyacrylamide gel electrophoresis, combined with the addition of carbonyl cyanide m-chlorophenylhydrazone (CCCP) or monensin (inhibitors of intracellular processing of secretory proteins) to cultures and digestion of the protein with endoglycosidase H or neuraminidase. The apparent M(r) of the H protein was increased from 74K to 78K during the chase period. Addition of either CCCP or monensin to the chase medium inhibited the appearance of the 78K H protein, but not the immunoreactivity of the H protein or dimer formation, suggesting that these two events occur in the rough endoplasmic reticulum. The 74K H protein processed in the presence of CCCP was fully sensitive to endoglycosidase H digestion, whereas the 74K H protein processed in the presence of monensin was partially resistant to endoglycosidase H. In experiments using 3H-labelled sugars, [3H]galactose was incorporated into the 74K H protein in the presence of monensin. Neuraminidase treatment increased the electrophoretic mobility of the 78K H protein to 74K. Only the 78K H protein was detected on the surface of untreated cells, and it was resistant to endoglycosidase H digestion. These data suggest that after galactose addition sialic acid is added to the H protein in the trans-Golgi complex and then the mature 78K H protein is transported to the cell surface

Thoracic manifestations of adult T-cell leukemia/lymphoma on chest CT: difference between clinical subtypes

PURPOSE:We aimed to evaluate thoracic computed tomography (CT) findings in adult T-cell leukemia/lymphoma (ATL) and their differences among clinical subtypes.METHODS:Thoracic CT scans of 49 ATL patients were retrospectively reviewed. On CT scans, the presence of lung parenchymal abnormalities (10 patterns), enlarged lymph nodes, pleural and pericardial effusions, and subcutaneous nodules was evaluated by two radiologists in cooperation. According to the Shimoyama criteria, the patients were divided into aggressive ATL group (n=28, acute and lymphoma types) and indolent ATL group (n=21, chronic and smoldering types). Differences in the prevalence of the CT findings between the two groups were examined. In the indolent ATL group, CT scans of 10 patients who eventually underwent transformation to aggressive ATL were also evaluated.RESULTS:In aggressive ATL, enlarged lymph nodes (68%) was the most frequently observed finding. Several patterns of lung abnormalities were observed, such as ground-glass attenuation (36%), bronchial wall thickening (32%), nodules (29%), and centrilobular opacities (29%). In indolent ATL, enlarged lymph nodules (24%) and bronchiectasis (24%) were relatively frequently detected. Overall, the incidence of abnormal findings was higher in aggressive than in indolent ATL, except for bronchiectasis. Patients with transformation to aggressive ATL frequently demonstrated enlarged lymph nodes (80%).CONCLUSION:On thoracic CT, enlarged lymph nodes and various lung and airway abnormalities, such as ground-glass attenuation and bronchial wall thickening, were observed in ATL patients, particularly those with aggressive ATL. Bronchiectasis was similarly found in patients with indolent ATL and aggressive ATL

Early detachment of neuromuscular junction proteins in ALS mice with SODG93A mutation

The transgenic animals with mutant copper/zinc superoxide dismutase (SOD1) DNA develop paralytic motor neuron disease resembling human amyotrophic lateral sclerosis (ALS) patients and are commonly used as models for ALS. In the transgenic (Tg) mice with the G93A mutation of the human SOD1 gene SOD1G93A mice), the loss of ventral root axons and the synapses between the muscles and the motor neurons suggested that the motor neuron degeneration might proceed in a dying-back degeneration pattern. To reveal the relationship between axonal degeneration and the progression of the muscle atrophy in the SOD1G93A mice, we investigated the status of the neuromuscular junction along the disease progression. As a presynaptic or postsynaptic marker of neuromuscular junction (NMJ), anti-synaptic vesicle protein 2 (anti-SV2) antibody and α-bungarotoxin (α-BuTX) were chosen in this study and, as a marker of synaptic cleft, anti-agrin antibody was chosen in this study. In the immunohistochemistry of α-BuTX and anti-SV2 antibody, the percentages of double positive NMJs among α-BuTX single positive were decreased in Tg mice through time from ten weeks. The number of postsynaptic acethylcholine receptor (AChR) clusters did not decrease in Tg mice even at the end stage. Immunohistochemistry of α-BuTX and anti-agrin antibody revealed that the increase of immunopositive area of anti-agrin antibody around the muscle fiber in Tg mice from ten weeks of age. In this study, we revealed that the detachment of nerve terminals started at ten weeks in Tg mice. The levels of AChR did not change throughout 5–20 weeks of age in both groups of mice, and AChR remains clustering at NMJs, suggesting that the muscle abnormality is the result of detachment of nerve terminals

Human cytomegalovirus persistent infection in a human central nervous system cell line: Production of a variant virus with different growth characteristics

The susceptibility of human central nervous system cell lines to human cytomegalovirus (HCMV) and the fate of infected cultures were studied. Significant amounts of infectious progeny virus were produced in 118MGC glioma and IMR-32 neuroblastoma, but not in KGC oligodendroglioma cells when the cultures were infected with wild-type virus (HCMVwt) at an m.o.i. of 10 p.f.u. per cell. Further passage of infected 118MGC cells resulted in the establishment of a long-term persistent infection. This infection, designated 118MGC/Towne, continuously produced infectious virus (HCMVpi) with titres ranging from 102 to 105 p.f.u./106 cells up to 360 days post-infection (corresponding to 50 subcultures). Since no temperature-sensitive mutants, defective interfering particles or interferon-like activity were found in the 118MGC/Towne cultures, maintenance of the persistent infection seemed to be due to a balance between the release of infectious virus and the growth of uninfected cells. The HCMVpi produced in long-term persistently infected cultures was shown to be different from the HCMVwt originally used to infect by the following characteristics: (i) HCMVpi replicated slowly and yielded lower amounts of progeny virus than HCMVwt; (ii) HCMVpi induced a 73000 mol. wt. immediate early protein that was not synthesized in HCMVwt-infected cells; (iii) HCMVpi had a different DNA structure from that of HCMVwt. These results suggest that HCMVpi is a slower growing variant of HCMVwt and probably plays an important role in the maintenance of the persistent infection

Synthesis of M protein of HVJ (Sendai virus) in rat glial cells is selectively restricted at a non-permissive temperature

Production of HVJ (Sendai virus) wild-type in rat glial cells was characteristically restricted at high temperature. The synthesis of the M protein was selectively decreased in infected cells at 39° C. This temperature-sensitive (ts) character of HVJ was not observed in infection of LLCMK2 cells or chick embryo fibroblast cells. Newcastle disease virus, mumps virus and vesicular stomatitis virus did not show ts growth in glial cells

Enhanced replication of human cytomegalovirus in human fibroblasts treated with dexamethasone

The effect of glucocorticoid hormones on the replication of human cytomegalovirus (HCMV) was studied in human embryonic lung (HEL) cells. Treatment of cells with pharmacological concentrations of adrenal glucocorticoids such as dexamethasone enhanced HCMV replication; treatment with oestrogenic or androgenic hormones did not do so. In dexamethasone-treated HEL cells there was an approximately tenfold increase in virus yield, with the virus eclipse period shortened by 1 day compared to control cultures. Treatment of cells with the hormone also enhanced plaquing efficiency of the virus by approximately tenfold. As the synthesis of virus-specific immediate early proteins and antigens was notably enhanced together with an increase of HCMV DNA synthesis, it appeared that the early stages of the HCMV replication cycle might be under hormonal control. Moreover, the data presented suggest that the hormonal enhancement of HCMV replication involves specific receptor proteins and requires the synthesis of a specific cellular mRNA(s)