12 research outputs found
A cDNA fragment of hepatitis C virus isolated from an implicated donor of post-transfusion non-A, non-B hepatitis in Japan
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Prevalence of antibodies to hepatitis C virus among patients with cryptogenic chronic hepatitis and cirrhosis
Many cases of chronic hepatitis and cirrhosis cannot be attributed to a known cause and are collectively referred to as cryptogenic chronic liver disease. We have evaluated the role of the hepatitis C virus in the pathogenesis of this condition in a retrospective serum analysis for antibody to hepatitis C virus in 129 patients with cryptogenic liver disease. Other causes of chronic hepatitis and cirrhosis were ruled out by clinical, serum biochemical and serological techniques. All 129 patients were HBsAg negative, but 28 (22%) had antibody to HBcAg. Sera were tested by radioimmunoassays using recombinant peptides for antibodies to nonstructural (C 100‐3 and C33c) and structural regions (C22) of HCV. Among the 129 patients, 61 (47%) had antibody to C100‐3, 76 (59%) had antibody to C33c and 74 (57%) had antibody to C22. Seventy‐nine (61%) were reactive with at least one and 76 (59%) were reactive with at least two HCV peptides (this is the criterion used for hepatitis C virus antibody reactivity). A proportion of patients with chronic hepatitis and cirrhosis (55 of 91; 60%) similar to that of patients without cirrhosis (21 of 38; 55%) had hepatitis C virus antibody. No significant clinical, serum biochemical or histological differences were noted between the group of patients with hepatitis C virus antibody and those without this antibody reactivity. Thus more than half the patients with cryptogenic chronic liver disease had hepatitis C virus antibody, suggesting that chronic HCV infection plays a major role in the origin of cryptogenic chronic hepatitis and cirrhosis. (HEPATOLOGY 1992;15: 187–190)
Synthesis and Characterization of a Native, Oligomeric Form of Recombinant Severe Acute Respiratory Syndrome Coronavirus Spike Glycoprotein
We have expressed and characterized the severe acute respiratory syndrome coronavirus (SARS-CoV) spike protein in cDNA-transfected mammalian cells. The full-length spike protein (S) was newly synthesized as an endoglycosidase H (endo H)-sensitive glycoprotein (gp170) that is further modified into an endo H-resistant glycoprotein (gp180) in the Golgi apparatus. No substantial proteolytic cleavage of S was observed, suggesting that S is not processed into head (S1) and stalk (S2) domains as observed for certain other coronaviruses. While the expressed full-length S glycoprotein was exclusively cell associated, a truncation of S by excluding the C-terminal transmembrane and cytoplasmic tail domains resulted in the expression of an endoplasmic reticulum-localized glycoprotein (gp160) as well as a Golgi-specific form (gp170) which was ultimately secreted into the cell culture medium. Chemical cross-linking, thermal denaturation, and size fractionation analyses suggested that the full-length S glycoprotein of SARS-CoV forms a higher order structure of ∼500 kDa, which is consistent with it being an S homotrimer. The latter was also observed in purified virions. The intracellular form of the C-terminally truncated S protein (but not the secreted form) also forms trimers, but with much less efficiency than full-length S. Deglycosylation of the full-length homotrimer with peptide N-glycosidase-F under native conditions abolished recognition of the protein by virus-neutralizing antisera raised against purified virions, suggesting the importance of the carbohydrate in the correct folding of the S protein. These data should aid in the design of recombinant vaccine antigens to prevent the spread of this emerging pathogen