Advances in the development of a reliable assay for the measurement of stool decay-accelerating factor in the detection of colorectal cancer

Naofumi Iwagaki, Motowo Mizuno, Jyunichirou Nasu, Masakatsu Mizuno, Hiroaki Okazaki, Shinichirou Hori, Kazuhide Yamamoto, Hiroyuki Okada, Takao Tsuji, Teizo Fujita, Yasushi Shiratori

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

We have previously shown that stool concentrations of decay-accelerating factor (DAF; CD55), a membrane-bound complement-regulatory protein, are significantly elevated in patients with colorectal cancer and that the measurement of stool DAF may be a valuable test for the detection of colorectal cancer. Accordingly, we are working to develop a clinically useful immunoassay for fecal DAF. A requirement for such assay is a plentiful and reliable supply of anti-DAF antibodies. We developed a sandwich enzyme-linked immunosorbent assay (ELISA) for DAF in stool specimens, using two monoclonal anti-DAF antibodies recognizing different epitopes on the DAF molecule. When we first used a biotin-labeled antibody and enzyme-linked streptavidin method, we often observed stool interference, probably due to the presence of a substance(s) with biotin activity which non-specifically bound to the Fc portion of IgG of the first anti-DAF antibody on the ELISA wells. By the use of inorganic salts in the sample-dilution buffer and HRP-labeled anti-DAF as second antibody, we circumvented the stool interference and established that the new ELISA system could reliably measure DAF at low concentrations in stool specimens. Because the new assay system uses only monoclonal antibodies, we can now consistently supply ample amounts of antibodies for routine measurement of stool DAF.

Original languageEnglish
Pages (from-to)497-507
Number of pages11
JournalJournal of Immunoassay and Immunochemistry
Volume23
Issue number4
DOIs
Publication statusPublished - 2002

Keywords

  • CD55
  • Colorectal cancer
  • Immunoassay
  • Stool

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology
  • Clinical Biochemistry
  • Medical Laboratory Technology

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