Improved enzyme immunoassays for the detection of antigens in fecal specimens. Investigation and correction of interfering factors

Raphael Viscidi, Barbara E. Laughon, Mattana Hanvanich, John G. Bartlett, Robert H. Yolken

Research output: Contribution to journalArticlepeer-review

Abstract

Solid phase enzyme immunoassays (EIA) are widely used for the detection of infectious agents in body fluids such as stool specimens. However, we found that stool specimens contained substances which desorb from 50% to 68% of the immunoreactant from solid phase surfaces. This desorbing activity decreased the sensitivity of EIA systems for toxin A of C. difficile, rotavirus and adenovirus. The desorbind activity in stool specimens was partially heat labile at 56°C for 30 min, was present in stool fractions corresponding to an estimated molecular weight of 25,000 and was shown to degrade solid phase protein. In addition, the desorbing activity was partially reversed by specific and nonspecific protease inhibitors. Thus, the desorption may reflect the enzymatic activity of stool proteases. The desorption was markedly reduced by diluting specimens in 50% fetal calf serum or an acid-protein buffer such as 0.25 M citrate buffer, pH 4.7, containing 5% bovine serum albumin. These diluents were shown to improve the recovery of toxin A of C. difficile, rotavirus and adenovirus in EIA systems for these antigens.

Original languageEnglish (US)
Pages (from-to)129-143
Number of pages15
JournalJournal of Immunological Methods
Volume67
Issue number1
DOIs
StatePublished - Feb 24 1984

Keywords

  • C. difficile
  • fecal antigen detection
  • rotavirus
  • solid phase
  • solid phase immunoassay
  • stool proteases

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

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