Determination of UDP-N-acetylglucosamine: beta-D-mannoside-1,4-N-acetylglucosaminyltransferase-III in patients sera with chronic hepatitis and liver cirrhosis using a monoclonal antibody.
The glycoprotein UDP-N-acetylglucosamine: beta-D-mannoside-1,4-N-acetylglucosaminyltransferase-III (GnT-III) catalyzes the addition of N-acetylglucosamine via a beta-1, 4-linkage to the beta-linked mannose of the trimannosyl core of N-linked glycans. It has been reported that the expression of GnT-III increases in many oncogenically transformed cells and human hepatocellular carcinoma (HCC) tissues, and GnT-III enzyme activity in serum can be used for the detection and monitoring of primary hepatomas and hepatocellular carcinomas. A solid-phase enzyme-linked immunosorbent sandwich assay in which a polyclonal antibody (PAb) to aglycosylrecombinant GnT-III (AGR-GnT-III) and a monoclonal antibody (mAb) are employed as a capture protein and probe protein, respectively, is described. The sensitivity of the PAb-mAb sandwich assay, as determined by the dose-response effect for AGR-GnT-III, was 10 ng/ml. This assay was specific for GnT-III and did not detect beta-1, 6-N-acetylglucosaminyltrasferase-V (GnT-V). AGR-GnT-III concentrations in 377 serum specimens were determined by the PAb-mAb sandwich assay and the results were analyzed based on the disease category, using 1.99 microg/mL (AGR-GnT-III) as a cut-off value. The AGR-GnT-III level of 61 normal serum samples was 0.57 +/- 0.71 microg/ml (mean +/- SD). The results revealed an elevation in serum AGR-GnT-III levels in 60 of 86 patients (3.03 +/- 2.04 microg/ml) with liver cirrhosis (LC) and 86 of 91 patients (2.73 +/- 0.59 microg/ml) with chronic hepatitis (CH). By contrast, 3 of 61 normal subjects, 9 of 34 patients (1.02 +/- 1.03 microg/ml) with acute hepatitis and 8 of 38 patients (1.79 +/- 0.56 microg/ml) with a variety of non-hepatic diseases exhibited a slight increase above the cut-off value. These results indicate that serum AGR-GnT-III levels are elevated predominantly in LC or CH cases. Serum AGR-GnT-III concentration, as measured by the developed PAb-mAb sandwich assay, may be a useful differential marker as a diagnostic aid for CH and/or LC and warrants further investigations with expanded serum panels.
Song
Eun-Young
EY
Cell Biology Laboratory, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-600, Korea.
Kim
Kyung-Sook
KS
Kim
Kyoung-A
KA
Kim
Yung-Dai
YD
Kwon
Dur-Han
DH
Byun
Si-Myung
SM
Kim
Hee-Jung
HJ
Chung
Tae-Wook
TW
Choe
Yong-Kyung
YK
Chung
Tai-Wha
TW
Kim
Cheorl-Ho
CH
D000911:Antibodies, Monoclonal / Q000276:immunology*; D015153:Blotting, Western; D004305:Dose-Response Relationship, Drug; D006521:Hepatitis, Chronic / Q000097:blood* / Q000201:enzymology; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D008103:Liver Cirrhosis / Q000097:blood* / Q000201:enzymology; D008362:Mannosides / Q000378:metabolism*; D017351:N-Acetylglucosaminyltransferases / Q000097:blood* / Q000276:immunology; D014537:Uridine Diphosphate N-Acetylglucosamine / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D008362:Mannosides; D014537:Uridine Diphosphate N-Acetylglucosamine; D017351:N-Acetylglucosaminyltransferases; C054599:beta-1,4-mannosyl-glycoprotein beta-1,4-N-acetylglucosaminyltransferase