Development of a fluorescent microsphere immunoassay for cystatin B (CSTB) in serum of patients with hepatocellular carcinoma.
BACKGROUND
Serum cystatin B (CSTB) concentrations have been reported to be increased in patients with hepatocellular carcinoma compared to concentrations seen in normal subjects. In this study, we developed a "fluorescent microsphere immunoassay" (FMI) capable of specifically detecting CSTB in serum.


METHODS
The FMI used a microparticle conjugated polyclonal antibody to CSTB and biotinylated monoclonal antibody as capture protein and probe protein, respectively. The results were obtained using the Bio-Plex(200) system.


RESULTS
The dose-response relationship between CSTB and fluorescent intensity showed linearity in the range 0-1000 pg/mL and 7 pg/mL, sensitivity lower than 11.2 pg/mL. This result revealed that the FMI system was more sensitive than enzyme-linked immunoassay (ELISA). Additionally, the FMI system used smaller sample volumes compared to ELISA.


CONCLUSIONS
We measured CSTB with both the FMI and an ELISA procedure and compared the two methods. The CSTB concentrations in serum specimens as measured with the FMI assay system were similar to those measured with ELISA. Thus, the new FMI using the Bio-Plex system may be useful for detection of CSTB in human serum.
Medical Genomics Research Center, Korea Research Institute of Bioscience and Biotechnology, Dajeon, Korea.
Na Young
NY
Ji
Yun Hee
YH
Kang
Mi-Young
MY
Park
Chung Il
CI
Lee
Mi Kyung
MK
Kim
Dae Ghon
DG
Kim
Jong Wan
JW
Kim
Eun Young
EY
Song
D000911:Antibodies, Monoclonal / Q000737:chemistry; D006528:Carcinoma, Hepatocellular / Q000097:blood*; D055313:Cystatin B / Q000096:biosynthesis / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005455:Fluorescent Antibody Technique / Q000379:methods; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D008113:Liver Neoplasms / Q000097:blood*; D008863:Microspheres; D012680:Sensitivity and Specificity
D000911:Antibodies, Monoclonal; D055313:Cystatin B